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Vieu S, Le Poul N, Tur L, Aupée C, Kerbrat-Copy R, Bouhsina N, Cojean O, Fusellier M. Ultrasound description of the coelomic cavity of the axolotl (Ambystoma mexicanum) in a clinically healthy population: a pilot study. Sci Rep 2024; 14:11787. [PMID: 38782987 PMCID: PMC11116527 DOI: 10.1038/s41598-024-62264-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2023] [Accepted: 05/15/2024] [Indexed: 05/25/2024] Open
Abstract
Axolotls (Ambystoma mexicanum) are extensively studied for their relevance in human medical research. Despite being critically endangered in the wild, they have gained popularity as household pets. Although they have been kept in captivity for over a century, detailed descriptions of their coelomic organ anatomy remain limited. Also, this species exhibits significant variations compared to other amphibians. Ultrasound is a non-invasive and painless medical imaging technique, ideally suited for investigating internal organs or structures. This study focused on describing the ultrasound appearance of the axolotl coelomic cavity. It details the identification, localization and parenchymal description of major organs in 28 neotenic axolotls using ultrasound frequencies ranging from 7 to 15 MHz. The accuracy of the results was validated by comparing ultrasound findings with necropsy results from one male and one female axolotl. The heart, lung surface, liver and reproductive tracts were visualized. Measurements, along with confidence intervals, were calculated for the spleen, kidneys, testicles, gastric wall, gallbladder, and pylorus. Occasional detection of hyperechoic millimetric particles in the gallbladder or ascites was noted. However, visualization of the pancreas and bladder was not possible. This research outcomes involve the development of a comprehensive atlas comprising images obtained throughout the study. Additionally, the experiment established a reproducible and readily accessible protocol for conducting anatomy-morphological assessments in axolotl medicine. This protocol stands as a crucial preliminary stage before advancing to lesion identification.
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Affiliation(s)
- Sabrina Vieu
- Oniris, CHUV, Service des Nouveaux Animaux de Compagnie, 44300, Nantes, France.
- BIOEPAR, Oniris, INRAE, 44300, Nantes, France.
| | - Ninon Le Poul
- Oniris, CHUV, Service des Nouveaux Animaux de Compagnie, 44300, Nantes, France
| | - Léa Tur
- Oniris, CHUV, Service Transversal d'Imagerie Médicale, 44300, Nantes, France
| | - Cécile Aupée
- Oniris, CHUV, Service Transversal d'Imagerie Médicale, 44300, Nantes, France
| | - Réjane Kerbrat-Copy
- Oniris, CHUV, Service Transversal d'Imagerie Médicale, 44300, Nantes, France
| | - Nora Bouhsina
- Oniris, CHUV, Service Transversal d'Imagerie Médicale, 44300, Nantes, France
- CHU Nantes, INSERM, Regenerative Medicine and Skeleton, RMeS, UMR 1229, Nantes Université, Oniris, 44000, Nantes, France
| | | | - Marion Fusellier
- Oniris, CHUV, Service Transversal d'Imagerie Médicale, 44300, Nantes, France
- CHU Nantes, INSERM, Regenerative Medicine and Skeleton, RMeS, UMR 1229, Nantes Université, Oniris, 44000, Nantes, France
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2
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Hogan MP, Holding ML, Nystrom GS, Colston TJ, Bartlett DA, Mason AJ, Ellsworth SA, Rautsaw RM, Lawrence KC, Strickland JL, He B, Fraser P, Margres MJ, Gilbert DM, Gibbs HL, Parkinson CL, Rokyta DR. The genetic regulatory architecture and epigenomic basis for age-related changes in rattlesnake venom. Proc Natl Acad Sci U S A 2024; 121:e2313440121. [PMID: 38578985 PMCID: PMC11032440 DOI: 10.1073/pnas.2313440121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2023] [Accepted: 03/13/2024] [Indexed: 04/07/2024] Open
Abstract
Developmental phenotypic changes can evolve under selection imposed by age- and size-related ecological differences. Many of these changes occur through programmed alterations to gene expression patterns, but the molecular mechanisms and gene-regulatory networks underlying these adaptive changes remain poorly understood. Many venomous snakes, including the eastern diamondback rattlesnake (Crotalus adamanteus), undergo correlated changes in diet and venom expression as snakes grow larger with age, providing models for identifying mechanisms of timed expression changes that underlie adaptive life history traits. By combining a highly contiguous, chromosome-level genome assembly with measures of expression, chromatin accessibility, and histone modifications, we identified cis-regulatory elements and trans-regulatory factors controlling venom ontogeny in the venom glands of C. adamanteus. Ontogenetic expression changes were significantly correlated with epigenomic changes within genes, immediately adjacent to genes (e.g., promoters), and more distant from genes (e.g., enhancers). We identified 37 candidate transcription factors (TFs), with the vast majority being up-regulated in adults. The ontogenetic change is largely driven by an increase in the expression of TFs associated with growth signaling, transcriptional activation, and circadian rhythm/biological timing systems in adults with corresponding epigenomic changes near the differentially expressed venom genes. However, both expression activation and repression contributed to the composition of both adult and juvenile venoms, demonstrating the complexity and potential evolvability of gene regulation for this trait. Overall, given that age-based trait variation is common across the tree of life, we provide a framework for understanding gene-regulatory-network-driven life-history evolution more broadly.
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Affiliation(s)
- Michael P. Hogan
- Department of Biological Science, Florida State University, Tallahassee, FL32306
| | - Matthew L. Holding
- Department of Biological Science, Florida State University, Tallahassee, FL32306
- Life Sciences Institute, University of Michigan, Ann Arbor, MI48109
| | - Gunnar S. Nystrom
- Department of Biological Science, Florida State University, Tallahassee, FL32306
| | - Timothy J. Colston
- Department of Biological Science, Florida State University, Tallahassee, FL32306
- Department of Biology, University of Puerto Rico at Mayagüez, Mayagüez, PR00681
| | - Daniel A. Bartlett
- Department of Biological Science, Florida State University, Tallahassee, FL32306
| | - Andrew J. Mason
- Department of Biological Sciences, Clemson University, Clemson, SC29634
- Department of Evolution, Ecology and Organismal Biology, The Ohio State University, Columbus, OH43210
| | - Schyler A. Ellsworth
- Department of Biological Science, Florida State University, Tallahassee, FL32306
| | - Rhett M. Rautsaw
- Department of Biological Sciences, Clemson University, Clemson, SC29634
- Department of Integrative Biology, University of South Florida, Tampa, FL33620
- School of Biological Sciences, Washington State University, Pullman, WA99164
| | - Kylie C. Lawrence
- Department of Biological Science, Florida State University, Tallahassee, FL32306
| | - Jason L. Strickland
- Department of Biological Sciences, Clemson University, Clemson, SC29634
- Department of Biology, University of South Alabama, Mobile, AL36688
| | - Bing He
- Department of Biological Science, Florida State University, Tallahassee, FL32306
| | - Peter Fraser
- Department of Biological Science, Florida State University, Tallahassee, FL32306
| | - Mark J. Margres
- Department of Integrative Biology, University of South Florida, Tampa, FL33620
| | - David M. Gilbert
- Laboratory of Chromosome Replication and Epigenome Regulation, San Diego Biomedical Research Institute, San Diego, CA92121
| | - H. Lisle Gibbs
- Department of Evolution, Ecology and Organismal Biology, The Ohio State University, Columbus, OH43210
| | - Christopher L. Parkinson
- Department of Biological Sciences, Clemson University, Clemson, SC29634
- Department of Forestry and Environmental Conservation, Clemson University, Clemson, SC29634
| | - Darin R. Rokyta
- Department of Biological Science, Florida State University, Tallahassee, FL32306
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3
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Brocklehurst N, Field DJ. Tip dating and Bayes factors provide insight into the divergences of crown bird clades across the end-Cretaceous mass extinction. Proc Biol Sci 2024; 291:20232618. [PMID: 38351798 PMCID: PMC10865003 DOI: 10.1098/rspb.2023.2618] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2023] [Accepted: 01/05/2024] [Indexed: 02/16/2024] Open
Abstract
The origin of crown birds (Neornithes) remains contentious owing to conflicting divergence time hypotheses obtained from alternative sources of data. The fossil record suggests limited diversification of Neornithes in the Late Mesozoic and a substantial radiation in the aftermath of the Cretaceous-Palaeogene (K-Pg) mass extinction, approximately 66 Ma. Molecular clock studies, however, have yielded estimates for neornithine origins ranging from the Early Cretaceous (130 Ma) to less than 10 Myr before the K-Pg. We use Bayes factors to compare the fit of node ages from different molecular clock studies to an independent morphological dataset. Our results allow us to reject scenarios of crown bird origins deep in the Early Cretaceous, as well as an origin of crown birds within the last 10 Myr of the Cretaceous. The scenario best supported by our analyses is one where Neornithes originated between the Early and Late Cretaceous (ca 100 Ma), while numerous divergences within major neoavian clades either span or postdate the K-Pg. This study affirms the importance of the K-Pg on the diversification of modern birds, and the potential of combined-evidence tip-dating analyses to illuminate recalcitrant 'rocks versus clocks' debates.
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Affiliation(s)
- Neil Brocklehurst
- Department of Earth Sciences, University of Cambridge, Cambridge, UK
| | - Daniel J. Field
- Department of Earth Sciences, University of Cambridge, Cambridge, UK
- Museum of Zoology, University of Cambridge, Cambridge, UK
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Witzmann F, Fröbisch N. Morphology and ontogeny of carpus and tarsus in stereospondylomorph temnospondyls. PeerJ 2023; 11:e16182. [PMID: 37904842 PMCID: PMC10613440 DOI: 10.7717/peerj.16182] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Accepted: 09/05/2023] [Indexed: 11/01/2023] Open
Abstract
Skeletal development is well known in temnospondyls, the most diverse group of Paleozoic and Mesozoic amphibians. However, the elements of carpus and tarsus (i.e., the mesopodium) were always the last bones to ossify relative to the other limb bones and with regard to the rest of the skeleton, and are preserved only in rare cases. Thus, in contrast to the other parts of the limb skeleton, little is known about the ontogeny and sequence of ossification of the temnospondyl carpus and tarsus. We intended to close this gap by studying the ontogenies of a number of Permo/Carboniferous stereospondylomorphs, the only temnospondyls with preserved growth series in which the successive ossification of carpals and tarsals can be traced. Studying the degree of mesopodial ossification within the same species show that it is not necessarily correlated with body size. This indicates that individual age rather than size determined the degree of mesopodial ossification in stereospondylomorphs and that the largest individuals are not necessarily the oldest ones. In the stereospondylomorph tarsus, the distal tarsals show preaxial development in accordance with most early tetrapods and salamanders. However, the more proximal mesopodials exhibit postaxial dominance, i.e., the preaxial column (tibiale, centrale 1) consistently started to ossify after the central column (centralia 2-4, intermedium) and the postaxial column (fibulare). Likewise, we observed preaxial development of the distal carpals in the stereospondylomorph carpus, as in most early tetrapods for which a statement can be made. However, in contrast to the tarsus, the more proximal carpals were formed by preaxial development, i.e., the preaxial column (radiale, centrale 1) ossified after the central column (centralia 2-4, intermedium) and before the postaxial column (ulnare). This pattern is unique among known early tetrapods and occurs only in certain extant salamanders. Furthermore, ossification proceeded from distal to proximal in the central column of the stereospondylomorph carpus, whereas the ossification advanced from proximal to distal in the central column of the tarsus. Despite these differences, a general ossification pattern that started from proximolateral (intermedium or centrale 4) to mediodistal (distal tarsal and carpal 1) roughly in a diagonal line is common to all stereospondylomorph mesopodials investigated. This pattern might basically reflect the alignment of stress within the mesopodium during locomotion. Our observations might point to a greater variability in the development of the mesopodium in stereospondylomorphs and probably other early tetrapods than in most extant tetrapods, possibly mirroring a similar variation as seen in the early phases of skeletogenesis in salamander carpus and tarsus.
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Affiliation(s)
- Florian Witzmann
- Museum für Naturkunde Berlin, Leibniz Institute for Evolution and Biodiversity Science, Berlin, Germany
| | - Nadia Fröbisch
- Museum für Naturkunde Berlin, Leibniz Institute for Evolution and Biodiversity Science, Berlin, Germany
- Department of Biology, Humboldt Universität Berlin, Berlin, Germany
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5
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Hartmann AM, McGrath-Blaser SE, Colón-Piñeiro Z, Longo AV. Ontogeny drives shifts in skin bacterial communities in facultatively paedomorphic salamanders. MICROBIOLOGY (READING, ENGLAND) 2023; 169:001399. [PMID: 37815535 PMCID: PMC10634365 DOI: 10.1099/mic.0.001399] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Accepted: 10/02/2023] [Indexed: 10/11/2023]
Abstract
Microbiomes are major determinants of host growth, development and survival. In amphibians, host-associated bacteria in the skin can inhibit pathogen infection, but many processes can influence the structure and composition of the community. Here we quantified the shifts in skin-associated bacteria across developmental stages in the striped newt (Notophthalmus perstriatus), a threatened salamander species with a complex life history and vulnerable to infection by the amphibian chytrid fungus Batrachochytrium dendrobatidis and ranavirus. Our analyses show that pre-metamorphic larval and paedomorphic stages share similar bacterial compositions, and that the changes in the microbiome coincided with physiological restructuring during metamorphosis. Newts undergoing metamorphosis exhibited microbiome compositions that were intermediate between paedomorphic and post-metamorphic stages, further supporting the idea that metamorphosis is a major driver of host-associated microbes in amphibians. We did not find support for infection-related disruption of the microbiome, though infection replicates were small for each respective life stage.
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Affiliation(s)
- Arik M. Hartmann
- Department of Biology, University of Florida, Gainesville, Florida, USA
| | | | | | - Ana V. Longo
- Department of Biology, University of Florida, Gainesville, Florida, USA
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6
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Mueller RL, Cressler CE, Schwartz RS, Chong RA, Butler M. Metamorphosis Imposes Variable Constraints on Genome Expansion through Effects on Development. Integr Org Biol 2023; 5:obad015. [PMID: 37143961 PMCID: PMC10153748 DOI: 10.1093/iob/obad015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Revised: 02/25/2023] [Accepted: 04/14/2023] [Indexed: 05/06/2023] Open
Abstract
Genome size varies ∼100,000-fold across eukaryotes and has long been hypothesized to be influenced by metamorphosis in animals. Transposable element accumulation has been identified as a major driver of increase, but the nature of constraints limiting the size of genomes has remained unclear, even as traits such as cell size and rate of development co-vary strongly with genome size. Salamanders, which possess diverse metamorphic and non-metamorphic life histories, join the lungfish in having the largest vertebrate genomes-3 to 40 times that of humans-as well as the largest range of variation in genome size. We tested 13 biologically-inspired hypotheses exploring how the form of metamorphosis imposes varying constraints on genome expansion in a broadly representative phylogeny containing 118 species of salamanders. We show that metamorphosis during which animals undergo the most extensive and synchronous remodeling imposes the most severe constraint against genome expansion, with the severity of constraint decreasing with reduced extent and synchronicity of remodeling. More generally, our work demonstrates the potential for broader interpretation of phylogenetic comparative analysis in exploring the balance of multiple evolutionary pressures shaping phenotypic evolution.
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Affiliation(s)
| | - C E Cressler
- School of Biological Sciences, University of Nebraska Lincoln, Lincoln, NE 68588, USA
| | - R S Schwartz
- Department of Biological Sciences, University of Rhode Island, Kingston, RI 02881, USA
| | - R A Chong
- School of Life Sciences, University of Hawai'i, Honolulu, HI 96822, USA
| | - M Butler
- School of Life Sciences, University of Hawai'i, Honolulu, HI 96822, USA
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7
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Placing juvenile specimens in phylogenies: An ontogenetically sensitive phylogenetic assessment of a new genus of iguanodontian dinosaur from the Early Cretaceous Kirkwood Formation, South Africa. Anat Rec (Hoboken) 2022. [DOI: 10.1002/ar.25095] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 09/29/2022] [Accepted: 09/30/2022] [Indexed: 11/05/2022]
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8
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Gee BM, Kufner AM. Revision of the Late Triassic metoposaurid “ Metoposaurus” bakeri (Amphibia: Temnospondyli) from Texas, USA and a phylogenetic analysis of the Metoposauridae. PeerJ 2022. [DOI: 10.7717/peerj.14065] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Metoposaurids are a clade of large-bodied temnospondyls commonly found in non-marine Late Triassic deposits across northern Pangea. Three taxa are known from North America: Anaschisma browni, Apachesaurus gregorii, and “Metoposaurus” bakeri. While the osteology of most metoposaurids has been recently revised, that of a few taxa, including “Metoposaurus” bakeri remains poorly characterized. This taxon was formally described in 1931 as “Buettneria bakeri,” and its taxonomy has remained in flux ever since then. “Metoposaurus” bakeri is the earliest appearing metoposaurid in North America (Carnian of Texas), and Metoposaurus has frequently been utilized as an index taxon of the Otischalkian estimated holochron (‘land vertebrate faunachron’) and for biostratigraphic correlations with other geographic regions. The taxonomy of this species is therefore relevant for both taxonomic experts and biostratigraphers. Here we redescribe all material from the type locality of “M.” bakeri, the Elkins Place bone bed, and perform a phylogenetic analysis using a revised matrix assembled from several previous studies. Anatomical comparisons and phylogenetic analyses do not support placement in either Metoposaurus, a taxon otherwise only found in Europe, or Anaschisma, the only other large-bodied taxon from North America. Therefore, we erect a new genus, Buettnererpeton gen. nov., to accommodate this species. Metoposaurus is consequently absent from North America, and this genus cannot be used in global biostratigraphy. Phylogenetic analyses provide evidence that the phylogeny of the Metoposauridae remains extremely labile, with drastic differences in topological resolution and structure being linked to just a handful of characters and scores. Metoposaurids’ morphological conservatism and the increased recognition of intraspecific variation thus continue to be major confounds to elucidating the evolutionary history of this clade.
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Affiliation(s)
- Bryan M. Gee
- Burke Museum and Department of Biology, University of Washington, Seattle, Washington, United States
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario, Canada
| | - Aaron M. Kufner
- Department of Geoscience, University of Wisconsin, Madison, Wisconsin, United States
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9
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Abstract
Salamanders are an important group of living amphibians and model organisms for understanding locomotion, development, regeneration, feeding, and toxicity in tetrapods. However, their origin and early radiation remain poorly understood, with early fossil stem-salamanders so far represented by larval or incompletely known taxa. This poor record also limits understanding of the origin of Lissamphibia (i.e., frogs, salamanders, and caecilians). We report fossils from the Middle Jurassic of Scotland representing almost the entire skeleton of the enigmatic stem-salamander Marmorerpeton. We use computed tomography to visualize high-resolution three-dimensional anatomy, describing morphologies that were poorly characterized in early salamanders, including the braincase, scapulocoracoid, and lower jaw. We use these data in the context of a phylogenetic analysis intended to resolve the relationships of early and stem-salamanders, including representation of important outgroups alongside data from high-resolution imaging of extant species. Marmorerpeton is united with Karaurus, Kokartus, and others from the Middle Jurassic-Lower Cretaceous of Asia, providing evidence for an early radiation of robustly built neotenous stem-salamanders. These taxa display morphological specializations similar to the extant cryptobranchid "giant" salamanders. Our analysis also demonstrates stem-group affinities for a larger sample of Jurassic species than previously recognized, highlighting an unappreciated diversity of stem-salamanders and cautioning against the use of single species (e.g., Karaurus) as exemplars for stem-salamander anatomy. These phylogenetic findings, combined with knowledge of the near-complete skeletal anatomy of Mamorerpeton, advance our understanding of evolutionary changes on the salamander stem-lineage and provide important data on early salamanders and the origins of Batrachia and Lissamphibia.
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10
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Insufficient Evidence for Multiple Species of Tyrannosaurus in the Latest Cretaceous of North America: A Comment on “The Tyrant Lizard King, Queen and Emperor: Multiple Lines of Morphological and Stratigraphic Evidence Support Subtle Evolution and Probable Speciation Within the North American Genus Tyrannosaurus”. Evol Biol 2022. [DOI: 10.1007/s11692-022-09573-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
AbstractThe Late Cretaceous dinosaur Tyrannosaurus rex was recently split into three species based on the premise that variation in the T. rex hypodigm is exceptional, indicating cryptic species and “robust” and “gracile” morphs. The morphs are based on proportional ratios throughout the skeleton. The species are claimed to be stratigraphically separate, with an early robust species followed by robust and gracile descendants. There are problems with the hypothesis: the taxon diagnoses are based on two features that overlap between the species; several skulls cannot be identified based on the diagnoses; proportional comparisons between Tyrannosaurus and other theropods are based on incomparable samples; the tooth data are problematic; the stratigraphic framework divides the Hell Creek Formation into thirds, without the stratigraphic position of each specimen, or independent age control showing the subdivisions are coeval over the entire geographic area; previous work found variation in T. rex, but it cannot be parsed into discrete categories. We tested for “gracile” and “robust” morphs by analyzing the femoral and tooth ratios that were published in the multiple species study using agglomerative hierarchical clustering. The results found that each set of ratios are explained by one cluster, showing that dimorphism is not supported. We tested for exceptional variation of the femoral ratio of Tyrannosaurus; we calculated the mean intraspecific robusticity for 112 species of living birds and 4 nonavian theropods. The results showed that the absolute variation in Tyrannosaurus is unexceptional and it does not indicate cryptic diversity. We conclude that “T. regina” and “T. imperator” are subjective junior synonyms of T. rex.
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Jia J, Li G, Gao KQ. Palatal morphology predicts the paleobiology of early salamanders. eLife 2022; 11:e76864. [PMID: 35575462 PMCID: PMC9170251 DOI: 10.7554/elife.76864] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2022] [Accepted: 05/15/2022] [Indexed: 11/13/2022] Open
Abstract
Ecological preferences and life history strategies have enormous impacts on the evolution and phenotypic diversity of salamanders, but the yet established reliable ecological indicators from bony skeletons hinder investigations into the paleobiology of early salamanders. Here, we statistically demonstrate by using time-calibrated cladograms and geometric morphometric analysis on 71 specimens in 36 species, that both the shape of the palate and many non-shape covariates particularly associated with vomerine teeth are ecologically informative in early stem- and basal crown-group salamanders. Disparity patterns within the morphospace of the palate in ecological preferences, life history strategies, and taxonomic affiliations were analyzed in detail, and evolutionary rates and ancestral states of the palate were reconstructed. Our results show that the palate is heavily impacted by convergence constrained by feeding mechanisms and also exhibits clear stepwise evolutionary patterns with alternative phenotypic configurations to cope with similar functional demand. Salamanders are diversified ecologically before the Middle Jurassic and achieved all their present ecological preferences in the Early Cretaceous. Our results reveal that the last common ancestor of all salamanders share with other modern amphibians a unified biphasic ecological preference, and metamorphosis is significant in the expansion of ecomorphospace of the palate in early salamanders.
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Affiliation(s)
- Jia Jia
- School of Earth and Space Sciences, Peking UniversityBeijingChina
- State Key Laboratory of Palaeobiology and Stratigraphy (Nanjing Institute of Geology and Palaeontology, CAS)NanjingChina
- Department of Comparative Biology and Experimental Medicine, University of CalgaryCalgaryCanada
| | - Guangzhao Li
- Department of Microbiology, Immunology, and Tropical Medicine, The George Washington UniversityWashington D.C.United States
| | - Ke-Qin Gao
- School of Earth and Space Sciences, Peking UniversityBeijingChina
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Martynov A, Lundin K, Korshunova T. Ontogeny, Phylotypic Periods, Paedomorphosis, and Ontogenetic Systematics. Front Ecol Evol 2022. [DOI: 10.3389/fevo.2022.806414] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The key terms linking ontogeny and evolution are briefly reviewed. It is shown that their application and usage in the modern biology are often inconsistent and incorrectly understood even within the “evo-devo” field. For instance, the core modern reformulation that ontogeny not merely recapitulates, but produces phylogeny implies that ontogeny and phylogeny are closely interconnected. However, the vast modern phylogenetic and taxonomic fields largely omit ontogeny as a central concept. Instead, the common “clade-” and “tree-thinking” prevail, despite on the all achievements of the evo-devo. This is because the main conceptual basis of the modern biology is fundamentally ontogeny-free. In another words, in the Haeckel’s pair of “ontogeny and phylogeny,” ontogeny is still just a subsidiary for the evolutionary process (and hence, phylogeny), instead as in reality, its main driving force. The phylotypic periods is another important term of the evo-devo and represent a modern reformulation of Haeckel’s recapitulations and biogenetic law. However, surprisingly, this one of the most important biological evidence, based on the natural ontogenetic grounds, in the phylogenetic field that can be alleged as a “non-evolutionary concept.” All these observations clearly imply that a major revision of the main terms which are associated with the “ontogeny and phylogeny/evolution” field is urgently necessarily. Thus, “ontogenetic” is not just an endless addition to the term “systematics,” but instead a crucial term, without it neither systematics, nor biology have sense. To consistently employ the modern ontogenetic and epigenetic achievements, the concept of ontogenetic systematics is hereby refined. Ontogenetic systematics is not merely a “research program” but a key biological discipline which consistently links the enormous biological diversity with underlying fundamental process of ontogeny at both molecular and morphological levels. The paedomorphosis is another widespread ontogenetic-and-evolutionary process that is significantly underestimated or misinterpreted by the current phylogenetics and taxonomy. The term paedomorphosis is refined, as initially proposed to link ontogeny with evolution, whereas “neoteny” and “progenesis” are originally specific, narrow terms without evolutionary context, and should not be used as synonyms of paedomorphosis. Examples of application of the principles of ontogenetic systematics represented by such disparate animal groups as nudibranch molluscs and ophiuroid echinoderms clearly demonstrate that perseverance of the phylotypic periods is based not only on the classic examples in vertebrates, but it is a universal phenomenon in all organisms, including disparate animal phyla.
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13
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Salamander braincase morphology as revealed by micro‐computed tomography. J Morphol 2022; 283:462-501. [DOI: 10.1002/jmor.21454] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Revised: 01/13/2022] [Accepted: 01/20/2022] [Indexed: 11/07/2022]
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14
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Feduccia A. Contextualizing avian origins and evolution How Birds Evolve: What Science Reveals About Their Origin, Lives, and Diversity Douglas J. Futuyma Princeton University Press, 2021. 320 pp. Science 2021; 374:411-412. [PMID: 34672759 DOI: 10.1126/science.abk1689] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
[Figure: see text].
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Affiliation(s)
- Alan Feduccia
- The reviewer is S. K. Heninger Distinguished Professor Emeritus and former chair, Department of Biology, University of North Carolina, Chapel Hill, NC 27599, USA
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15
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Olejnickova V, Kolesova H, Bartos M, Sedmera D, Gregorovicova M. The Tale-Tell Heart: Evolutionary tetrapod shift from aquatic to terrestrial life-style reflected in heart changes in axolotl (Ambystoma mexicanum). Dev Dyn 2021; 251:1004-1014. [PMID: 34423892 DOI: 10.1002/dvdy.413] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Revised: 08/02/2021] [Accepted: 08/18/2021] [Indexed: 11/05/2022] Open
Abstract
BACKGROUND During amphibian metamorphosis, the crucial moment lies in the rearrangement of the heart, reflecting the changes in circulatory demands. However, little is known about the exact shifts linked with this rearrangement. Here, we demonstrate such myocardial changes in axolotl (Ambystoma mexicanum) from the morphological and physiological point of view. RESULTS Micro-CT and histological analysis showed changes in ventricular trabeculae organization, completion of the atrial septum and its connection to the atrioventricular valve. Based on Myosin Heavy Chain and Smooth Muscle Actin expression we distinguished metamorphosis-induced changes in myocardial differentiation at the ventricular trabeculae and atrioventricular canal. Using optical mapping, faster speed of conduction through the atrioventricular canal was demonstrated in metamorphic animals. No differences between the groups were observed in the heart rates, ventricular activation times, and activation patterns. CONCLUSIONS Transition from aquatic to terrestrial life-style is reflected in the heart morphology and function. Rebuilding of the axolotl heart during metamorphosis was connected with reorganization of ventricular trabeculae, completion of the atrial septum and its connection to the atrioventricular valve, and acceleration of AV conduction.
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Affiliation(s)
- Veronika Olejnickova
- First Faculty of Medicine, Institute of Anatomy, Charles University, Prague, Czech Republic.,Department of Developmental Cardiology, Czech Academy of Sciences, Institute of Physiology, Prague, Czech Republic
| | - Hana Kolesova
- First Faculty of Medicine, Institute of Anatomy, Charles University, Prague, Czech Republic.,Department of Developmental Cardiology, Czech Academy of Sciences, Institute of Physiology, Prague, Czech Republic
| | - Martin Bartos
- First Faculty of Medicine, Institute of Anatomy, Charles University, Prague, Czech Republic.,First Faculty of Medicine, Institute of Dental Medicine, Charles University, Prague, Czech Republic
| | - David Sedmera
- First Faculty of Medicine, Institute of Anatomy, Charles University, Prague, Czech Republic.,Department of Developmental Cardiology, Czech Academy of Sciences, Institute of Physiology, Prague, Czech Republic
| | - Martina Gregorovicova
- First Faculty of Medicine, Institute of Anatomy, Charles University, Prague, Czech Republic.,Department of Developmental Cardiology, Czech Academy of Sciences, Institute of Physiology, Prague, Czech Republic
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16
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Jia J, Anderson JS, Gao KQ. Middle Jurassic stem hynobiids from China shed light on the evolution of basal salamanders. iScience 2021; 24:102744. [PMID: 34278256 PMCID: PMC8264161 DOI: 10.1016/j.isci.2021.102744] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Revised: 03/28/2021] [Accepted: 06/15/2021] [Indexed: 12/02/2022] Open
Abstract
The Hynobiidae are an early-diverging clade of crown-group salamanders (urodeles) with an important bearing on the evolution of urodeles. Paleobiology and early-branching patterns of the Hynobiidae remain unclear owing to a poorly documented fossil record. We reported a newly referred specimen to the stem hynobiid, originally named as "Liaoxitriton daohugouensis," but here as Neimengtriton daohugouensis comb. nov., and predates the previously estimated origination time of Hynobiidae for at least 8 Myr. We interpret N. daohugouensis as semiaquatic at the adult stage, a previously unknown paleoecological preference among Mesozoic salamanders. Phenotypic variations of N. daohugouensis enlighten an unrecognized association between caudosacral vertebrae and fertilization modes in the early evolution of urodeles. Our cladistic analyses based on morphological characters not only recognize several stem hynobiids and establish Panhynobia nomen cladinovum for the total-group hynobiids but also shed light on the sequential evolution of morphological features in this primitive urodele clade.
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Affiliation(s)
- Jia Jia
- School of Earth and Space Sciences, Peking University, 5 Yiheyuan Road, Beijing 100871, China
- State Key Laboratory of Palaeobiology and Stratigraphy (Nanjing Institute of Geology and Palaeontology, CAS), 39 East Beijing Road, Nanjing, Jiangsu Province 210008, China
- Department of Comparative Biology and Experimental Medicine, University of Calgary, 3330 Hospital Drive, Calgary, AB T2N 4N1, Canada
| | - Jason S. Anderson
- Department of Comparative Biology and Experimental Medicine, University of Calgary, 3330 Hospital Drive, Calgary, AB T2N 4N1, Canada
| | - Ke-Qin Gao
- School of Earth and Space Sciences, Peking University, 5 Yiheyuan Road, Beijing 100871, China
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17
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Bonett RM, Ledbetter NM, Hess AJ, Herrboldt MA, Denoël M. Repeated ecological and life cycle transitions make salamanders an ideal model for evolution and development. Dev Dyn 2021; 251:957-972. [PMID: 33991029 DOI: 10.1002/dvdy.373] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Revised: 04/16/2021] [Accepted: 05/10/2021] [Indexed: 11/11/2022] Open
Abstract
Observations on the ontogeny and diversity of salamanders provided some of the earliest evidence that shifts in developmental trajectories have made a substantial contribution to the evolution of animal forms. Since the dawn of evo-devo there have been major advances in understanding developmental mechanisms, phylogenetic relationships, evolutionary models, and an appreciation for the impact of ecology on patterns of development (eco-evo-devo). Molecular phylogenetic analyses have converged on strong support for the majority of branches in the Salamander Tree of Life, which includes 764 described species. Ancestral reconstructions reveal repeated transitions between life cycle modes and ecologies. The salamander fossil record is scant, but key Mesozoic species support the antiquity of life cycle transitions in some families. Colonization of diverse habitats has promoted phenotypic diversification and sometimes convergence when similar environments have been independently invaded. However, unrelated lineages may follow different developmental pathways to arrive at convergent phenotypes. This article summarizes ecological and endocrine-based causes of life cycle transitions in salamanders, as well as consequences to body size, genome size, and skeletal structure. Salamanders offer a rich source of comparisons for understanding how the evolution of developmental patterns has led to phenotypic diversification following shifts to new adaptive zones.
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Affiliation(s)
- Ronald M Bonett
- Department of Biological Science, The University of Tulsa, Tulsa, Oklahoma, USA
| | | | - Alexander J Hess
- Department of Biological Science, The University of Tulsa, Tulsa, Oklahoma, USA
| | - Madison A Herrboldt
- Department of Biological Science, The University of Tulsa, Tulsa, Oklahoma, USA
| | - Mathieu Denoël
- Laboratory of Ecology and Conservation of Amphibians (LECA), Freshwater and Oceanic science Unit of reSearch (FOCUS), University of Liège, Liège, Belgium
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18
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Marjanović D. The Making of Calibration Sausage Exemplified by Recalibrating the Transcriptomic Timetree of Jawed Vertebrates. Front Genet 2021; 12:521693. [PMID: 34054911 PMCID: PMC8149952 DOI: 10.3389/fgene.2021.521693] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Accepted: 03/22/2021] [Indexed: 01/20/2023] Open
Abstract
Molecular divergence dating has the potential to overcome the incompleteness of the fossil record in inferring when cladogenetic events (splits, divergences) happened, but needs to be calibrated by the fossil record. Ideally but unrealistically, this would require practitioners to be specialists in molecular evolution, in the phylogeny and the fossil record of all sampled taxa, and in the chronostratigraphy of the sites the fossils were found in. Paleontologists have therefore tried to help by publishing compendia of recommended calibrations, and molecular biologists unfamiliar with the fossil record have made heavy use of such works (in addition to using scattered primary sources and copying from each other). Using a recent example of a large node-dated timetree inferred from molecular data, I reevaluate all 30 calibrations in detail, present the current state of knowledge on them with its various uncertainties, rerun the dating analysis, and conclude that calibration dates cannot be taken from published compendia or other secondary or tertiary sources without risking strong distortions to the results, because all such sources become outdated faster than they are published: 50 of the (primary) sources I cite to constrain calibrations were published in 2019, half of the total of 280 after mid-2016, and 90% after mid-2005. It follows that the present work cannot serve as such a compendium either; in the slightly longer term, it can only highlight known and overlooked problems. Future authors will need to solve each of these problems anew through a thorough search of the primary paleobiological and chronostratigraphic literature on each calibration date every time they infer a new timetree, and that literature is not optimized for that task, but largely has other objectives.
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Affiliation(s)
- David Marjanović
- Department of Evolutionary Morphology, Science Programme “Evolution and Geoprocesses”, Museum für Naturkunde – Leibniz Institute for Evolutionary and Biodiversity Research, Berlin, Germany
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19
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Strong CRC, Scherz MD, Caldwell MW. Deconstructing the Gestalt: New concepts and tests of homology, as exemplified by a re‐conceptualization of “microstomy” in squamates. Anat Rec (Hoboken) 2021; 304:2303-2351. [DOI: 10.1002/ar.24630] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Revised: 02/22/2021] [Accepted: 03/22/2021] [Indexed: 12/19/2022]
Affiliation(s)
| | - Mark D. Scherz
- Institute for Biochemistry and Biology University of Potsdam Potsdam Germany
| | - Michael W. Caldwell
- Department of Biological Sciences University of Alberta Edmonton Alberta Canada
- Department of Earth and Atmospheric Sciences University of Alberta Edmonton Alberta Canada
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20
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Strong CRC, Palci A, Caldwell MW. Insights into skull evolution in fossorial snakes, as revealed by the cranial morphology of Atractaspis irregularis (Serpentes: Colubroidea). J Anat 2021; 238:146-172. [PMID: 32815172 PMCID: PMC7755084 DOI: 10.1111/joa.13295] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Revised: 07/20/2020] [Accepted: 07/21/2020] [Indexed: 01/03/2023] Open
Abstract
Comparative osteological analyses of extant organisms provide key insight into major evolutionary transitions and phylogenetic hypotheses. This is especially true for snakes, given their unique morphology relative to other squamates and the persistent controversy regarding their evolutionary origins. However, the osteology of several major snake groups remains undescribed, thus hindering efforts to accurately reconstruct the phylogeny of snakes. One such group is the Atractaspididae, a family of fossorial colubroids. We herein present the first detailed description of the atractaspidid skull, based on fully segmented micro-computed tomography (micro-CT) scans of Atractaspis irregularis. The skull of Atractaspis presents a highly unique morphology influenced by both fossoriality and paedomorphosis. This paedomorphosis is especially evident in the jaws, palate, and suspensorium, the major elements associated with macrostomy (large-gaped feeding in snakes). Comparison to scolecophidians-a group of blind, fossorial, miniaturized snakes-in turn sheds light on current hypotheses of snake phylogeny. Features of both the naso-frontal joint and the morphofunctional system related to macrostomy refute the traditional notion that scolecophidians are fundamentally different from alethinophidians (all other extant snakes). Instead, these features support the controversial hypothesis of scolecophidians as "regressed alethinophidians," in contrast to their traditional placement as the earliest-diverging snake lineage. We propose that Atractaspis and scolecophidians fall along a morphological continuum, characterized by differing degrees of paedomorphosis. Altogether, a combination of heterochrony and miniaturization provides a mechanism for the derivation of the scolecophidian skull from an ancestral fossorial alethinophidian morphotype, exemplified by the nonminiaturized and less extreme paedomorph Atractaspis.
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Affiliation(s)
| | - Alessandro Palci
- Earth Sciences SectionSouth Australian MuseumAdelaideSAAustralia,College of Science and EngineeringFlinders UniversityBedford ParkSAAustralia
| | - Michael W. Caldwell
- Department of Biological SciencesUniversity of AlbertaEdmontonABCanada,Department of Earth and Atmospheric SciencesUniversity of AlbertaEdmontonABCanada
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21
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Griffin CT, Stocker MR, Colleary C, Stefanic CM, Lessner EJ, Riegler M, Formoso K, Koeller K, Nesbitt SJ. Assessing ontogenetic maturity in extinct saurian reptiles. Biol Rev Camb Philos Soc 2020; 96:470-525. [PMID: 33289322 DOI: 10.1111/brv.12666] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Revised: 10/09/2020] [Accepted: 10/28/2020] [Indexed: 01/06/2023]
Abstract
Morphology forms the most fundamental level of data in vertebrate palaeontology because it is through interpretations of morphology that taxa are identified, creating the basis for broad evolutionary and palaeobiological hypotheses. Assessing maturity is one of the most basic aspects of morphological interpretation and provides the means to study the evolution of ontogenetic changes, population structure and palaeoecology, life-history strategies, and heterochrony along evolutionary lineages that would otherwise be lost to time. Saurian reptiles (the least-inclusive clade containing Lepidosauria and Archosauria) have remained an incredibly diverse, numerous, and disparate clade through their ~260-million-year history. Because of the great disparity in this group, assessing maturity of saurian reptiles is difficult, fraught with methodological and terminological ambiguity. We compiled a novel database of literature, assembling >900 individual instances of saurian maturity assessment, to examine critically how saurian maturity has been diagnosed. We review the often inexact and inconsistent terminology used in saurian maturity assessment (e.g. 'juvenile', 'mature') and provide routes for better clarity and cross-study coherence. We describe the various methods that have been used to assess maturity in every major saurian group, integrating data from both extant and extinct taxa to give a full account of the current state of the field and providing method-specific pitfalls, best practices, and fruitful directions for future research. We recommend that a new standard subsection, 'Ontogenetic Assessment', be added to the Systematic Palaeontology portions of descriptive studies to provide explicit ontogenetic diagnoses with clear criteria. Because the utility of different ontogenetic criteria is highly subclade dependent among saurians, even for widely used methods (e.g. neurocentral suture fusion), we recommend that phylogenetic context, preferably in the form of a phylogenetic bracket, be used to justify the use of a maturity assessment method. Different methods should be used in conjunction as independent lines of evidence when assessing maturity, instead of an ontogenetic diagnosis resting entirely on a single criterion, which is common in the literature. Critically, there is a need for data from extant taxa with well-represented growth series to be integrated with the fossil record to ground maturity assessments of extinct taxa in well-constrained, empirically tested methods.
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Affiliation(s)
- Christopher T Griffin
- Department of Geosciences, Virginia Tech, 926 West Campus Drive, Blacksburg, VA, 24061, U.S.A
| | - Michelle R Stocker
- Department of Geosciences, Virginia Tech, 926 West Campus Drive, Blacksburg, VA, 24061, U.S.A
| | - Caitlin Colleary
- Department of Geosciences, Virginia Tech, 926 West Campus Drive, Blacksburg, VA, 24061, U.S.A
- Department of Vertebrate Paleontology, Cleveland Museum of Natural History, 1 Wade Oval Drive, Cleveland, OH, 44106, U.S.A
| | - Candice M Stefanic
- Department of Geosciences, Virginia Tech, 926 West Campus Drive, Blacksburg, VA, 24061, U.S.A
- Department of Anatomical Sciences, Stony Brook University, 100 Nicolls Road, Stony Brook, NY, 11794, U.S.A
| | - Emily J Lessner
- Department of Geosciences, Virginia Tech, 926 West Campus Drive, Blacksburg, VA, 24061, U.S.A
- Department of Pathology and Anatomical Sciences, University of Missouri, 1 Hospital Drive, Columbia, MO, 65212, U.S.A
| | - Mitchell Riegler
- Department of Geosciences, Virginia Tech, 926 West Campus Drive, Blacksburg, VA, 24061, U.S.A
- Department of Geological Sciences, University of Florida, 241 Williamson Hall, Gainesville, FL, 32611, U.S.A
| | - Kiersten Formoso
- Department of Geosciences, Virginia Tech, 926 West Campus Drive, Blacksburg, VA, 24061, U.S.A
- Department of Earth Sciences, University of Southern California, 3651 Trousdale Pkwy, Los Angeles, CA, 90089, U.S.A
- Dinosaur Institute, Natural History Museum of Los Angeles County, 900 W Exposition Boulevard, Los Angeles, CA, 90007, U.S.A
| | - Krista Koeller
- Department of Geosciences, Virginia Tech, 926 West Campus Drive, Blacksburg, VA, 24061, U.S.A
- Department of Biology, University of Florida, 220 Bartram Hall, Gainesville, FL, 32611, U.S.A
| | - Sterling J Nesbitt
- Department of Geosciences, Virginia Tech, 926 West Campus Drive, Blacksburg, VA, 24061, U.S.A
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22
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Schwarz D, Konow N, Porro LB, Heiss E. Ontogenetic plasticity in cranial morphology is associated with a change in the food processing behavior in Alpine newts. Front Zool 2020; 17:34. [PMID: 33292303 PMCID: PMC7667761 DOI: 10.1186/s12983-020-00373-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Accepted: 08/28/2020] [Indexed: 12/16/2022] Open
Abstract
Background The feeding apparatus of salamanders consists mainly of the cranium, mandible, teeth, hyobranchial apparatus and the muscles of the cranial region. The morphology of the feeding apparatus in turn determines the boundary conditions for possible food processing (i.e., intraoral mechanical reduction) mechanisms. However, the morphology of the feeding apparatus changes substantially during metamorphosis, prompting the hypothesis that larvae might use a different food processing mechanism than post-metamorphic adults. Salamandrid newts with facultative metamorphosis are suitable for testing this hypothesis as adults with divergent feeding apparatus morphologies often coexist in the same population, share similar body sizes, and feed on overlapping prey spectra. Methods We use high-speed videography to quantify the in vivo movements of key anatomical elements during food processing in paedomorphic and metamorphic Alpine newts (Ichthyosaura alpestris). Additionally, we use micro-computed tomography (μCT) to analyze morphological differences in the feeding apparatus of paedomorphic and metamorphic Alpine newts and sort them into late-larval, mid-metamorphic and post-metamorphic morphotypes. Results Late-larval, mid-metamorphic and post-metamorphic individuals exhibited clear morphological differences in their feeding apparatus. Regardless of the paedomorphic state being externally evident, paedomorphic specimens can conceal different morphotypes (i.e., late-larval and mid-metamorphic morphotypes). Though feeding on the same prey under the same (aquatic) condition, food processing kinematics differed between late-larval, mid-metamorphic and post-metamorphic morphotypes. Conclusions The food processing mechanism in the Alpine newt changes along with morphology of the feeding apparatus during ontogeny, from a mandible-based to a tongue-based processing mechanism as the changing morphology of the mandible prevents chewing and the tongue allows enhanced protraction. These results could indicate that early tetrapods, in analogy to salamanders, may have developed new feeding mechanisms in their aquatic environment and that these functional innovations may have later paved the way for terrestrial feeding mechanisms.
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Affiliation(s)
- Daniel Schwarz
- Institute of Zoology and Evolutionary Research, Friedrich Schiller University Jena, Erbertstraße 1, D-07743, Jena, Germany.
| | - Nicolai Konow
- Department of Biological Sciences, University of Massachusetts Lowell, 198 Riverside St, Lowell, MA, 01854, USA
| | - Laura B Porro
- Centre for Integrative Anatomy, Department of Cell and Developmental Biology, University College London, London, WC1E 6BT, UK
| | - Egon Heiss
- Institute of Zoology and Evolutionary Research, Friedrich Schiller University Jena, Erbertstraße 1, D-07743, Jena, Germany
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23
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Brocklehurst N. Olson's Gap or Olson's Extinction? A Bayesian tip-dating approach to resolving stratigraphic uncertainty. Proc Biol Sci 2020; 287:20200154. [PMID: 32517621 DOI: 10.1098/rspb.2020.0154] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Adaptive radiations and mass extinctions are of critical importance in structuring terrestrial ecosystems. However, the causes and progress of these transitions often remain controversial, in part because of debates surrounding the completeness of the fossil record and biostratigraphy of the relevant fossil-bearing formations. The early-middle Permian, when a substantial faunal turnover in tetrapods coincided with a restructuring of the trophic structure of ecosystems, is such a time. Some have suggested the transition is obscured by a gap in the tetrapod fossil record (Olson's Gap), while others suggest a correlation between North American and Russian tetrapod-bearing formations allows the interval to be documented in detail. The latter biostratigraphic scheme has been used to support a mass extinction at this time (Olson's Extinction). Bayesian tip-dating methods used frequently in phylogenetics are employed to resolve this debate. Bayes factors are used to compare the results of analyses incorporating tip age priors based on different stratigraphic hypotheses, to show which stratigraphic scheme best fits the morphological data and phylogeny. Olson's Gap is rejected, and the veracity of Olson's Extinction is given further support. Tip-dating approaches have great potential to resolve debates surrounding the stratigraphic ages of critical formations where appropriate morphological data is available.
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Affiliation(s)
- Neil Brocklehurst
- Department of Earth Sciences, University of Oxford, South Parks Road, Oxford OX1 3AN, UK
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24
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Holland BR, Ketelaar-Jones S, O'Mara AR, Woodhams MD, Jordan GJ. Accuracy of ancestral state reconstruction for non-neutral traits. Sci Rep 2020; 10:7644. [PMID: 32376845 PMCID: PMC7203120 DOI: 10.1038/s41598-020-64647-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Accepted: 04/09/2020] [Indexed: 12/05/2022] Open
Abstract
The assumptions underpinning ancestral state reconstruction are violated in many evolutionary systems, especially for traits under directional selection. However, the accuracy of ancestral state reconstruction for non-neutral traits is poorly understood. To investigate the accuracy of ancestral state reconstruction methods, trees and binary characters were simulated under the BiSSE (Binary State Speciation and Extinction) model using a wide range of character-state-dependent rates of speciation, extinction and character-state transition. We used maximum parsimony (MP), BiSSE and two-state Markov (Mk2) models to reconstruct ancestral states. Under each method, error rates increased with node depth, true number of state transitions, and rates of state transition and extinction; exceeding 30% for the deepest 10% of nodes and highest rates of extinction and character-state transition. Where rates of character-state transition were asymmetrical, error rates were greater when the rate away from the ancestral state was largest. Preferential extinction of species with the ancestral character state also led to higher error rates. BiSSE outperformed Mk2 in all scenarios where either speciation or extinction was state dependent and outperformed MP under most conditions. MP outperformed Mk2 in most scenarios except when the rates of character-state transition and/or extinction were highly asymmetrical and the ancestral state was unfavoured.
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Affiliation(s)
- Barbara R Holland
- School of Natural Sciences, University of Tasmania, Private Bag 55, Hobart, Tas, 7001, Australia.
| | - Saan Ketelaar-Jones
- School of Natural Sciences, University of Tasmania, Private Bag 55, Hobart, Tas, 7001, Australia
| | - Aidan R O'Mara
- School of Health Sciences, University of Tasmania, Private Bag 121, Hobart, Tas, 7001, Australia
| | - Michael D Woodhams
- School of Natural Sciences, University of Tasmania, Private Bag 55, Hobart, Tas, 7001, Australia
| | - Gregory J Jordan
- School of Natural Sciences, University of Tasmania, Private Bag 55, Hobart, Tas, 7001, Australia
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25
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Gee BM. Size matters: the effects of ontogenetic disparity on the phylogeny of Trematopidae (Amphibia: Temnospondyli). Zool J Linn Soc 2020. [DOI: 10.1093/zoolinnean/zlz170] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Abstract
Trematopids are a clade of terrestrial Permo-Carboniferous temnospondyl amphibians. The intrarelationships of this clade are poorly known. This is largely attributable to a substantial disparity in size between type specimens, which range from the small-bodied lectotype of Mattauschia laticeps (< 4 cm skull length) to the large-bodied holotype of Acheloma cumminsi (> 15 cm skull length). Inferred correlation of size disparity with ontogenetic disparity has led previous workers either to omit taxa in phylogenetic analyses or to forgo an analysis altogether. Here, I take a specimen-level approach and multiple subsampling permutations to explore the phylogeny of the Trematopidae as a case study for assessing the effects of ontogenetic disparity on phylogenetic reconstruction in temnospondyls. The various analyses provide evidence that ontogenetic disparity confounds the phylogenetic inference of trematopids but without a directional bias. Tree topologies of most permutations are poorly resolved and weakly supported, reflecting character conflict that results from the inability of the analyses to differentiate retained plesiomorphies from juvenile features. These findings urge caution in the interpretation of phylogenetic analyses for which ontogenetic disparity exists, but is unaccounted for, and provide a strong impetus for more directed exploration of the interplay of ontogeny and phylogeny across Temnospondyli.
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Affiliation(s)
- Bryan M Gee
- Department of Biology, University of Toronto Mississauga, Mississauga, Ontario, Canada
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26
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Heiss E, Grell J. Same but different: aquatic prey capture in paedomorphic and metamorphic Alpine newts. ZOOLOGICAL LETTERS 2019; 5:24. [PMID: 31372238 PMCID: PMC6660708 DOI: 10.1186/s40851-019-0140-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/05/2019] [Accepted: 07/08/2019] [Indexed: 06/10/2023]
Abstract
Paedomorphosis describes the retention of larval characters in adult stages and is widespread amongst salamanders. Salamandrid newts exhibit facultative paedomorphosis, where paedomorphic and metamorphic adult forms coexist in the same population. Previous studies have shown that prey capture kinematics do not differ between paedomorphic and metamorphosed ambystomatid salamanders, despite diverging morphology and prey capture performance. It remained unclear, however, whether the stereotypy of prey capture kinematics across morphotypes is restricted to ambystomatids, or can be found in other salamander groups too. Here, we performed biplanar high-speed-recordings of the prey capture behavior in paedomorphic and metamorphic salamandrid newts and only found minor kinematic differences across morphotypes, suggesting that stereotypy across morphotypes is a more general feature within salamanders. We then compared anatomy of skull and hyobranchial skeleton, along with the physiological cross sectional area (PCSA) of the rectus cervicis muscle, the main muscle empowering suction feeding. Besides the overall morphological differences of the feeding apparatus, the PCSA of the rectus cervicis also differs significantly between morphotypes, being twice as large in paedomorphs. Accordingly, paedomorphs can exert more powerful suction strikes, which in turn may be one of the key factors why paedomorphs are more efficient in capturing elusive prey compared to metamorphs.
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Affiliation(s)
- Egon Heiss
- Institute of Zoology and Evolutionary Research, Friedrich-Schiller-University of Jena, Erbertstr. 1, 07743 Jena, Germany
| | - Julia Grell
- Institute of Zoology and Evolutionary Research, Friedrich-Schiller-University of Jena, Erbertstr. 1, 07743 Jena, Germany
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27
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Cryptic diversity in Brazilian endemic monkey frogs (Hylidae, Phyllomedusinae, Pithecopus) revealed by multispecies coalescent and integrative approaches. Mol Phylogenet Evol 2019; 132:105-116. [DOI: 10.1016/j.ympev.2018.11.022] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2018] [Revised: 11/29/2018] [Accepted: 11/30/2018] [Indexed: 11/22/2022]
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Marjanović D, Laurin M. Phylogeny of Paleozoic limbed vertebrates reassessed through revision and expansion of the largest published relevant data matrix. PeerJ 2019; 6:e5565. [PMID: 30631641 PMCID: PMC6322490 DOI: 10.7717/peerj.5565] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2016] [Accepted: 08/12/2018] [Indexed: 01/23/2023] Open
Abstract
The largest published phylogenetic analysis of early limbed vertebrates (Ruta M, Coates MI. 2007. Journal of Systematic Palaeontology 5:69-122) recovered, for example, Seymouriamorpha, Diadectomorpha and (in some trees) Caudata as paraphyletic and found the "temnospondyl hypothesis" on the origin of Lissamphibia (TH) to be more parsimonious than the "lepospondyl hypothesis" (LH)-though only, as we show, by one step. We report 4,200 misscored cells, over half of them due to typographic and similar accidental errors. Further, some characters were duplicated; some had only one described state; for one, most taxa were scored after presumed relatives. Even potentially continuous characters were unordered, the effects of ontogeny were not sufficiently taken into account, and data published after 2001 were mostly excluded. After these issues are improved-we document and justify all changes to the matrix-but no characters are added, we find (Analysis R1) much longer trees with, for example, monophyletic Caudata, Diadectomorpha and (in some trees) Seymouriamorpha; Ichthyostega either crownward or rootward of Acanthostega; and Anthracosauria either crownward or rootward of Temnospondyli. The LH is nine steps shorter than the TH (R2; constrained) and 12 steps shorter than the "polyphyly hypothesis" (PH-R3; constrained). Brachydectes (Lysorophia) is not found next to Lissamphibia; instead, a large clade that includes the adelogyrinids, urocordylid "nectrideans" and aïstopods occupies that position. As expected from the taxon/character ratio, most bootstrap values are low. Adding 56 terminal taxa to the original 102 increases the resolution (and decreases most bootstrap values). The added taxa range in completeness from complete articulated skeletons to an incomplete lower jaw. Even though the lissamphibian-like temnospondyls Gerobatrachus, Micropholis and Tungussogyrinus and the extremely peramorphic salamander Chelotriton are added, the difference between LH (R4; unconstrained) and TH (R5) rises to 10 steps, that between LH and PH (R6) to 15; the TH also requires several more regains of lost bones than the LH. Casineria, in which we tentatively identify a postbranchial lamina, emerges rather far from amniote origins in a gephyrostegid-chroniosuchian grade. Bayesian inference (Analysis EB, settings as in R4) mostly agrees with R4. High posterior probabilities are found for Lissamphibia (1.00) and the LH (0.92); however, many branches remain weakly supported, and most are short, as expected from the small character sample. We discuss phylogeny, approaches to coding, methods of phylogenetics (Bayesian inference vs. equally weighted vs. reweighted parsimony), some character complexes (e.g. preaxial/postaxial polarity in limb development), and prospects for further improvement of this matrix. Even in its revised state, the matrix cannot provide a robust assessment of the phylogeny of early limbed vertebrates. Sufficient improvement will be laborious-but not difficult.
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Affiliation(s)
- David Marjanović
- Science Programme “Evolution and Geoprocesses”, Museum für Naturkunde—Leibniz Institute for Evolutionary and Biodiversity Research, Berlin, Germany
| | - Michel Laurin
- Centre de Recherches sur la Paléobiologie et les Paléoenvironnements (CR2P), Centre national de la Recherche scientifique (CNRS)/Muséum national d’Histoire naturelle (MNHN)/Sorbonne Université, Paris, France
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Pritchard AC, Gauthier JA, Hanson M, Bever GS, Bhullar BAS. A tiny Triassic saurian from Connecticut and the early evolution of the diapsid feeding apparatus. Nat Commun 2018; 9:1213. [PMID: 29572441 PMCID: PMC5865133 DOI: 10.1038/s41467-018-03508-1] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2017] [Accepted: 02/20/2018] [Indexed: 11/25/2022] Open
Abstract
Following the Permo–Triassic Extinction, large-bodied diapsid reptiles—with a body length >1 m—rapidly expanded their ecological roles. This diversification is reflected in enormous disparity in the development of the rostrum and adductor chamber. However, it is unclear how marked the diversity of the feeding apparatus was in contemporary small-bodied diapsids. Here we describe the remarkably small skull (2.5 cm long) of a saurian reptile, Colobops noviportensis, gen. et sp. nov., from the Triassic New Haven Arkose of Connecticut, USA. The taxon possesses an exceptionally reinforced snout and strikingly expanded supratemporal fossae for adductor musculature relative to any known Mesozoic or Recent diapsid of similar size. Our phylogenetic analyses support C. noviportensis as an early diverging pan-archosaur. Colobops noviportensis reveals extraordinary disparity of the feeding apparatus in small-bodied early Mesozoic diapsids, and a suite of morphologies, functionally related to a powerful bite, unknown in any small-bodied diapsid. The Triassic fossil record is biased towards large species, obscuring the anatomical diversity of small species. Here, the authors describe a new species, Colobops noviportensis, based on a 2.5 cm-long skull with proportionally large attachments for jaw muscles, expanding the known diversity of early diapsids.
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Affiliation(s)
- Adam C Pritchard
- Department of Geology and Geophysics, Yale University, 210 Whitney Avenue, New Haven, CT, 06511, USA.
| | - Jacques A Gauthier
- Department of Geology and Geophysics, Yale University, 210 Whitney Avenue, New Haven, CT, 06511, USA.,Yale Peabody Museum of Natural History, Yale University, 170 Whitney Avenue, New Haven, CT, 06511, USA
| | - Michael Hanson
- Department of Geology and Geophysics, Yale University, 210 Whitney Avenue, New Haven, CT, 06511, USA
| | - Gabriel S Bever
- Center for Functional Anatomy and Evolution, School of Medicine, Johns Hopkins University, 1830 E. Monument Street, Baltimore, MD, 21205, USA
| | - Bhart-Anjan S Bhullar
- Department of Geology and Geophysics, Yale University, 210 Whitney Avenue, New Haven, CT, 06511, USA. .,Yale Peabody Museum of Natural History, Yale University, 170 Whitney Avenue, New Haven, CT, 06511, USA.
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30
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Pyron RA. Novel Approaches for Phylogenetic Inference from Morphological Data and Total-Evidence Dating in Squamate Reptiles (Lizards, Snakes, and Amphisbaenians). Syst Biol 2018; 66:38-56. [PMID: 28173602 DOI: 10.1093/sysbio/syw068] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2015] [Revised: 07/12/2016] [Accepted: 07/20/2016] [Indexed: 02/04/2023] Open
Abstract
Here, I combine previously underutilized models and priors to perform more biologically realistic phylogenetic inference from morphological data, with an example from squamate reptiles. When coding morphological characters, it is often possible to denote ordered states with explicit reference to observed or hypothetical ancestral conditions. Using this logic, we can integrate across character-state labels and estimate meaningful rates of forward and backward transitions from plesiomorphy to apomorphy. I refer to this approach as MkA, for “asymmetric.” The MkA model incorporates the biological reality of limited reversal for many phylogenetically informative characters, and significantly increases likelihoods in the empirical data sets. Despite this, the phylogeny of Squamata remains contentious. Total-evidence analyses using combined morphological and molecular data and the MkA approach tend toward recent consensus estimates supporting a nested Iguania. However, support for this topology is not unambiguous across data sets or analyses, and no mechanism has been proposed to explain the widespread incongruence between partitions, or the hidden support for various topologies in those partitions. Furthermore, different morphological data sets produced by different authors contain both different characters and different states for the same or similar characters, resulting in drastically different placements for many important fossil lineages. Effort is needed to standardize ontology for morphology, resolve incongruence, and estimate a robust phylogeny. The MkA approach provides a preliminary avenue for investigating morphological evolution while accounting for temporal evidence and asymmetry in character-state changes.
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Affiliation(s)
- R Alexander Pyron
- Department of Biological Sciences, The George Washington University, 2023 G St. NW, Washington, DC, USA
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31
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Vučić T, Vukov TD, Tomašević Kolarov N, Cvijanović M, Ivanović A. The study of larval tail morphology reveals differentiation between two Triturus species and their hybrids. AMPHIBIA-REPTILIA 2018. [DOI: 10.1163/15685381-17000190] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
In amphibians, morphological differentiation and disparity at the larval and post-metamorphic ontogenetic stages can diverge, owing to various contrasting environments and different selective pressures. In the monophyletic clade of nineTriturusnewt species, five different morphotypes can be recognized, but information on larval morphology is limited. Here we explore divergence of larval morphology inTriturus ivanbureschi,T. macedonicus, and their F1 hybrids. These two genetically and morphologically distinct crested newt species hybridize in nature and form a relatively wide hybrid zone in the central part of the Balkan Peninsula. Using a geometric morphometric approach and multivariate statistics, we evaluated differences of tail size and shape, colouration pattern, and the presence of a tail filament at the mid-larval stage in larvae reared under controlled laboratory conditions. We chose the tail as the main propulsive organ crucial for locomotion, feeding, and escaping predators. We found thatTriturus ivanbureschiandT. macedonicuslarvae differ in tail shape, but not in tail size. Two groups of F1 hybrid larvae (obtained from reciprocal crossing) were similar to each other, but differed from the parental species in size and shape of the tail, colouration pattern, and the presence of a tail filament. Our results indicate that, like adults, larvae diverge morphologically and hybrid larvae do not exhibit intermediate morphology of the parental species.
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Affiliation(s)
- Tijana Vučić
- Department of Evolutionary Biology, Institute for Biological Research “Siniša Stanković”, University of Belgrade, Bulevar Despota Stefana 142, 11060 Belgrade, Serbia
- Institute of Zoology, Faculty of Biology, University of Belgrade, Studentski trg 16, 11000 Belgrade, Serbia
| | - Tanja D. Vukov
- Department of Evolutionary Biology, Institute for Biological Research “Siniša Stanković”, University of Belgrade, Bulevar Despota Stefana 142, 11060 Belgrade, Serbia
| | - Nataša Tomašević Kolarov
- Department of Evolutionary Biology, Institute for Biological Research “Siniša Stanković”, University of Belgrade, Bulevar Despota Stefana 142, 11060 Belgrade, Serbia
| | - Milena Cvijanović
- Department of Evolutionary Biology, Institute for Biological Research “Siniša Stanković”, University of Belgrade, Bulevar Despota Stefana 142, 11060 Belgrade, Serbia
| | - Ana Ivanović
- Institute of Zoology, Faculty of Biology, University of Belgrade, Studentski trg 16, 11000 Belgrade, Serbia
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32
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Chong RA, Mueller RL. Polymorphic duplicate genes and persistent non-coding sequences reveal heterogeneous patterns of mitochondrial DNA loss in salamanders. BMC Genomics 2017; 18:992. [PMID: 29281973 PMCID: PMC5745709 DOI: 10.1186/s12864-017-4358-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2016] [Accepted: 11/29/2017] [Indexed: 12/03/2022] Open
Abstract
Background Mitochondria are the site of the citric acid cycle and oxidative phosphorylation (OXPHOS). In metazoans, the mitochondrial genome is a small, circular molecule averaging 16.5 kb in length. Despite evolutionarily conserved gene content, metazoan mitochondrial genomes show a diversity of gene orders most commonly explained by the duplication-random loss (DRL) model. In the DRL model, (1) a sequence of genes is duplicated in tandem, (2) one paralog sustains a loss-of-function mutation, resulting in selection to retain the other copy, and (3) the non-functional paralog is eventually deleted from the genome. Despite its apparent role in generating mitochondrial gene order diversity, little is known about the tempo and mode of random gene loss after duplication events. Here, we determine mitochondrial gene order across the salamander genus Aneides, which was previously shown to include at least two DRL-mediated rearrangement events. We then analyze these gene orders in a phylogenetic context to reveal patterns of DNA loss after mitochondrial gene duplication. Results We identified two separate duplication events that resulted in mitochondrial gene rearrangements in Aneides; one occurred at the base of the clade tens of millions of years ago, while the other occurred much more recently (i.e. within a single species), resulting in gene order polymorphism and paralogs that are readily identifiable. We demonstrate that near-complete removal of duplicate rRNA genes has occurred since the recent duplication event, whereas duplicate protein-coding genes persist as pseudogenes and duplicate tRNAs persist as functionally intact paralogs. In addition, we show that non-coding DNA duplicated at the base of the clade has persisted across species for tens of millions of years. Conclusions The evolutionary history of the mitochondrial genome, from its inception as a bacterial endosymbiont, includes massive genomic reduction. Consistent with this overall trend, selection for efficiency of mitochondrial replication and transcription has been hypothesized to favor elimination of extra sequence. Our results, however, suggest that there may be no strong disadvantage to extraneous sequences in salamander mitochondrial genomes, although duplicate rRNA genes may be deleterious. Electronic supplementary material The online version of this article (10.1186/s12864-017-4358-2) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Rebecca A Chong
- Department of Biology, Colorado State University, Fort Collins, CO, 80523-1878, USA. .,Present address: Department of Biology, University of Hawai'i at Mānoa, Honolulu, HI, 96822, USA.
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33
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Ivanović A, Arntzen JW. Evolution of skull shape in the family Salamandridae (Amphibia: Caudata). J Anat 2017; 232:359-370. [PMID: 29239487 DOI: 10.1111/joa.12759] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/09/2017] [Indexed: 11/30/2022] Open
Abstract
We carried out a comparative morphometric analysis of 56 species of salamandrid salamanders, representing 19 out of 21 extant genera, with the aim of uncovering the major patterns of skull shape diversification, and revealing possible trends and directions of evolutionary change. To do this we used micro-computed tomography scanning and three-dimensional geometric morphometrics, along with a well-resolved molecular phylogeny. We found that allometry explains a relatively small amount of shape variation across taxa. Congeneric species of salamandrid salamanders are more similar to each other and cluster together producing distinct groups in morphospace. We detected a strong phylogenetic signal and little homoplasy. The most pronounced changes in the skull shape are related to the changes of the frontosquamosal arch, a unique feature of the cranial skeleton for the family Salamandridae, which is formed by processes arising from the frontal and squamosal bones that arch over the orbits. By mapping character states over the phylogeny, we found that a reduction of the frontosquamosal arch occurs independently in three lineages of the subfamily Pleurodelinae. This reduction can probably be attributed to changes in the development and ossification rates of the frontosquamosal arch. In general, our results are similar to those obtained for caecilian amphibians, with an early expansion into the available morphospace and a complex history characterizing evolution of skull shape in both groups. To evaluate the specificity of the inferred evolutionary trajectories and Caudata-wide trends in the diversity of skull morphology, information from additional groups of tailed amphibians is needed.
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Affiliation(s)
- Ana Ivanović
- Faculty of Biology, University of Belgrade, Belgrade, Serbia.,Naturalis Biodiversity Center, Leiden, The Netherlands
| | - Jan W Arntzen
- Naturalis Biodiversity Center, Leiden, The Netherlands
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34
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Trauth SE, Siegel DS, Godley JS, Adcock ZC, McDiarmid RW. Testicular Histology Reveals a Novel Type of Spermatogenesis in Pseudobranchus axanthus (Caudata: Sirenidae). COPEIA 2017. [DOI: 10.1643/cg-17-621] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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35
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Evidence for complex life cycle constraints on salamander body form diversification. Proc Natl Acad Sci U S A 2017; 114:9936-9941. [PMID: 28851828 DOI: 10.1073/pnas.1703877114] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Metazoans display a tremendous diversity of developmental patterns, including complex life cycles composed of morphologically disparate stages. In this regard, the evolution of life cycle complexity promotes phenotypic diversity. However, correlations between life cycle stages can constrain the evolution of some structures and functions. Despite the potential macroevolutionary consequences, few studies have tested the impacts of life cycle evolution on broad-scale patterns of trait diversification. Here we show that larval and adult salamanders with a simple, aquatic-only (paedomorphic) life cycle had an increased rate of vertebral column and body form diversification compared to lineages with a complex, aquatic-terrestrial (biphasic) life cycle. These differences in life cycle complexity explain the variations in vertebral number and adult body form better than larval ecology. In addition, we found that lineages with a simple terrestrial-only (direct developing) life cycle also had a higher rate of adult body form evolution than biphasic lineages, but still 10-fold lower than aquatic-only lineages. Our analyses demonstrate that prominent shifts in phenotypic evolution can follow long-term transitions in life cycle complexity, which may reflect underlying stage-dependent constraints.
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36
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Simões TR, Vernygora O, Paparella I, Jimenez-Huidobro P, Caldwell MW. Mosasauroid phylogeny under multiple phylogenetic methods provides new insights on the evolution of aquatic adaptations in the group. PLoS One 2017; 12:e0176773. [PMID: 28467456 PMCID: PMC5415187 DOI: 10.1371/journal.pone.0176773] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2017] [Accepted: 04/17/2017] [Indexed: 11/28/2022] Open
Abstract
Mosasauroids were a successful lineage of squamate reptiles (lizards and snakes) that radiated during the Late Cretaceous (95-66 million years ago). They can be considered one of the few lineages in the evolutionary history of tetrapods to have acquired a fully aquatic lifestyle, similarly to whales, ichthyosaurs and plesiosaurs. Despite a long history of research on this group, their phylogenetic relationships have only been tested so far using traditional (unweighted) maximum parsimony. However, hypotheses of mosasauroid relationships and the recently proposed multiple origins of aquatically adapted pelvic and pedal features in this group can be more thoroughly tested by methods that take into account variation in branch lengths and evolutionary rates. In this study, we present the first mosasauroid phylogenetic analysis performed under different analytical methods, including maximum likelihood, Bayesian inference, and implied weighting maximum parsimony. The results indicate a lack of congruence in the topological position of halisaurines and Dallasaurus. Additionally, the genus Prognathodon is paraphyletic under all hypotheses. Interestingly, a number of traditional mosasauroid clades become weakly supported, or unresolved, under Bayesian analyses. The reduced resolutions in some consensus trees create ambiguities concerning the evolution of fully aquatic pelvic/pedal conditions under many analyses. However, when enough resolution was obtained, reversals of the pelvic/pedal conditions were favoured by parsimony and likelihood ancestral state reconstructions instead of independent origins of aquatic features in mosasauroids. It is concluded that most of the observed discrepancies among the results can be associated with different analytical procedures, but also due to limited postcranial data on halisaurines, yaguarasaurines and Dallasaurus.
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Affiliation(s)
- Tiago R. Simões
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada
| | - Oksana Vernygora
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada
| | - Ilaria Paparella
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada
| | | | - Michael W. Caldwell
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada
- Department of Earth and Atmospheric Sciences, University of Alberta, Edmonton, Alberta, Canada
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37
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Powers AK. Digest: Old world climates give rise to "young" lizard skulls. Evolution 2017; 71:1116-1117. [PMID: 28272735 DOI: 10.1111/evo.13224] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Accepted: 02/22/2017] [Indexed: 11/28/2022]
Affiliation(s)
- Amanda K Powers
- Department of Biological Sciences, University of Cincinnati, Cincinnati, Ohio, 45221
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38
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Stöhr S, Martynov A. Paedomorphosis as an Evolutionary Driving Force: Insights from Deep-Sea Brittle Stars. PLoS One 2016; 11:e0164562. [PMID: 27806039 PMCID: PMC5091845 DOI: 10.1371/journal.pone.0164562] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2016] [Accepted: 09/05/2016] [Indexed: 11/29/2022] Open
Abstract
Heterochronic development has been proposed to have played an important role in the evolution of echinoderms. In the class Ophiuroidea, paedomorphosis (retention of juvenile characters into adulthood) has been documented in the families Ophiuridae and Ophiolepididae but not been investigated on a broader taxonomic scale. Historical errors, confusing juvenile stages with paedomorphic species, show the difficulties in correctly identifying the effects of heterochrony on development and evolution. This study presents a detailed analysis of 40 species with morphologies showing various degrees of juvenile appearance in late ontogeny. They are compared to a range of early ontogenetic stages from paedomorphic and non-paedomorphic species. Both quantitative and qualitative measurements are taken and analysed. The results suggest that strongly paedomorphic species are usually larger than other species at comparable developmental stage. The findings support recent notions of polyphyletic origin of the families Ophiuridae and Ophiolepididae. The importance of paedomorphosis and its correct recognition for the practice of taxonomy and phylogeny are emphasized.
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Affiliation(s)
- Sabine Stöhr
- Swedish Museum of Natural History, Department of Zoology, Stockholm, Sweden
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Jia J, Gao KQ. A new hynobiid-like salamander (Amphibia, Urodela) from Inner Mongolia, China, provides a rare case study of developmental features in an Early Cretaceous fossil urodele. PeerJ 2016; 4:e2499. [PMID: 27761316 PMCID: PMC5068444 DOI: 10.7717/peerj.2499] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2016] [Accepted: 08/29/2016] [Indexed: 01/23/2023] Open
Abstract
A new fossil salamander, Nuominerpeton aquilonaris (gen. et sp. nov.), is named and described based on specimens from the Lower Cretaceous Guanghua Formation of Inner Mongolia, China. The new discovery documents a far northern occurrence of Early Cretaceous salamanders in China, extending the geographic distribution for the Mesozoic fossil record of the group from the Jehol area (40th-45th parallel north) to near the 49th parallel north. The new salamander is characterized by having the orbitosphenoid semicircular in shape; coracoid plate of the scapulocoracoid greatly expanded with a convex ventral and posterior border; ossification of two centralia in carpus and tarsus; and first digit being about half the length of the second digit in both manus and pes. The new salamander appears to be closely related to hynobiids, although this inferred relationship awaits confirmation by research in progress by us on a morphological and molecular combined analysis of cryptobranchoid relationships. Comparison of adult with larval and postmetamorphic juvenile specimens provides insights into developmental patterns of cranial and postcranial skeletons in this fossil species, especially resorption of the palatine and anterior portions of the palatopterygoid in the palate and the coronoid in the mandible during metamorphosis, and postmetamorphic ossification of the mesopodium in both manus and pes. Thus, this study provides a rare case study of developmental features in a Mesozoic salamander.
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Affiliation(s)
- Jia Jia
- School of Earth and Space Sciences, Peking University, Beijing, China
| | - Ke-Qin Gao
- School of Earth and Space Sciences, Peking University, Beijing, China
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40
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Abstract
SUMMARYComplex life cycles are common in free-living and parasitic organisms alike. The adaptive decoupling hypothesis postulates that separate life cycle stages have a degree of developmental and genetic autonomy, allowing them to be independently optimized for dissimilar, competing tasks. That is, complex life cycles evolved to facilitate functional specialization. Here, I review the connections between the different stages in parasite life cycles. I first examine evolutionary connections between life stages, such as the genetic coupling of parasite performance in consecutive hosts, the interspecific correlations between traits expressed in different hosts, and the developmental and functional obstacles to stage loss. Then, I evaluate how environmental factors link life stages through carryover effects, where stressful larval conditions impact parasites even after transmission to a new host. There is evidence for both autonomy and integration across stages, so the relevant question becomes how integrated are parasite life cycles and through what mechanisms? By highlighting how genetics, development, selection and the environment can lead to interdependencies among successive life stages, I wish to promote a holistic approach to studying complex life cycle parasites and emphasize that what happens in one stage is potentially highly relevant for later stages.
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41
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Gregory AL, Sears BR, Wooten JA, Camp CD, Falk A, O'Quin K, Pauley TK. Evolution of dentition in salamanders: relative roles of phylogeny and diet. Biol J Linn Soc Lond 2016. [DOI: 10.1111/bij.12831] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Anna L. Gregory
- Department of Biology; Centre College; 600 West Walnut Street Danville KY 40422 USA
| | - Brittany R. Sears
- Department of Biology; Centre College; 600 West Walnut Street Danville KY 40422 USA
| | - Jessica A. Wooten
- Department of Biology; Centre College; 600 West Walnut Street Danville KY 40422 USA
| | - Carlos D. Camp
- Department of Biology; Piedmont College; 1021 Central Avenue Demorest GA 30535 USA
| | - Amanda Falk
- Department of Biology; Centre College; 600 West Walnut Street Danville KY 40422 USA
| | - Kelly O'Quin
- Department of Biology; Centre College; 600 West Walnut Street Danville KY 40422 USA
| | - Thomas K. Pauley
- Department of Biological Sciences; Marshall University; 1 John Marshall Way Huntington WV 25755 USA
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Jia J, Gao KQ. A New Basal Salamandroid (Amphibia, Urodela) from the Late Jurassic of Qinglong, Hebei Province, China. PLoS One 2016; 11:e0153834. [PMID: 27144770 PMCID: PMC4856324 DOI: 10.1371/journal.pone.0153834] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2015] [Accepted: 04/02/2016] [Indexed: 12/12/2022] Open
Abstract
A new salamandroid salamander, Qinglongtriton gangouensis (gen. et sp. nov.), is named and described based on 46 fossil specimens of juveniles and adults collected from the Upper Jurassic (Oxfordian) Tiaojishan Formation cropping out in Hebei Province, China. The new salamander displays several ontogenetically and taxonomically significant features, most prominently the presence of a toothed palatine, toothed coronoid, and a unique pattern of the hyobranchium in adults. Comparative study of the new salamander with previously known fossil and extant salamandroids sheds new light on the early evolution of the Salamandroidea, the most species-diverse clade in the Urodela. Cladistic analysis places the new salamander as the sister taxon to Beiyanerpeton, and the two taxa together form the basalmost clade within the Salamandroidea. Along with recently reported Beiyanerpeton from the same geological formation in the neighboring Liaoning Province, the discovery of Qinglongtriton indicates that morphological disparity had been underway for the salamandroid clade by early Late Jurassic (Oxfordian) time.
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Affiliation(s)
- Jia Jia
- School of Earth and Space Sciences, Peking University, 5 Yiheyuan Road, Beijing, 100871, China
| | - Ke-Qin Gao
- School of Earth and Space Sciences, Peking University, 5 Yiheyuan Road, Beijing, 100871, China
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Sharma PP, Clouse RM, Wheeler WC. Hennig's semaphoront concept and the use of ontogenetic stages in phylogenetic reconstruction. Cladistics 2016; 33:93-108. [DOI: 10.1111/cla.12156] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/27/2016] [Indexed: 11/30/2022] Open
Affiliation(s)
- Prashant P. Sharma
- Department of Zoology; University of Wisconsin-Madison; 430 Lincoln Drive Madison WI USA
| | - Ronald M. Clouse
- Division of Invertebrate Zoology; American Museum of Natural History; Central Park West at 79th Street New York NY USA
| | - Ward C. Wheeler
- Department of Zoology; University of Wisconsin-Madison; 430 Lincoln Drive Madison WI USA
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44
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The phylogeny and evolutionary history of tyrannosauroid dinosaurs. Sci Rep 2016; 6:20252. [PMID: 26830019 PMCID: PMC4735739 DOI: 10.1038/srep20252] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2015] [Accepted: 12/31/2015] [Indexed: 11/09/2022] Open
Abstract
Tyrannosauroids--the group of carnivores including Tyrannosaurs rex--are some of the most familiar dinosaurs of all. A surge of recent discoveries has helped clarify some aspects of their evolution, but competing phylogenetic hypotheses raise questions about their relationships, biogeography, and fossil record quality. We present a new phylogenetic dataset, which merges published datasets and incorporates recently discovered taxa. We analyze it with parsimony and, for the first time for a tyrannosauroid dataset, Bayesian techniques. The parsimony and Bayesian results are highly congruent, and provide a framework for interpreting the biogeography and evolutionary history of tyrannosauroids. Our phylogenies illustrate that the body plan of the colossal species evolved piecemeal, imply no clear division between northern and southern species in western North America as had been argued, and suggest that T. rex may have been an Asian migrant to North America. Over-reliance on cranial shape characters may explain why published parsimony studies have diverged and filling three major gaps in the fossil record holds the most promise for future work.
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Martynov A, Ishida Y, Irimura S, Tajiri R, O’Hara T, Fujita T. When Ontogeny Matters: A New Japanese Species of Brittle Star Illustrates the Importance of Considering both Adult and Juvenile Characters in Taxonomic Practice. PLoS One 2015; 10:e0139463. [PMID: 26509273 PMCID: PMC4625035 DOI: 10.1371/journal.pone.0139463] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2015] [Accepted: 09/11/2015] [Indexed: 11/19/2022] Open
Abstract
Current taxonomy offers numerous approaches and methods for species delimitation and description. However, most of them are based on the adult characters and rarely suggest a dynamic representation of developmental transformations of taxonomically important features. Here we show how the underestimation of ontogenetic changes may result in long term lack of recognition of a new species of one of the most common ophiacanthid brittle stars (Echinodermata: Ophiuroidea) from the North Pacific. Based on vast material collected predominantly by various Japanese expeditions in the course of more than 50 years, and thorough study of appropriate type material, we revise the complex of three common species of the ophiuroid genus Ophiacantha which have been persistently confused with each other. The present study thus reveals the previously unrecognized new species Ophiacantha kokusai sp.nov. which is commonly distributed off the Pacific coast of Japan. The new species shows developmental differentiation from the closely related species Ophiacantha rhachophora H. L. Clark, 1911 and retains clearly expressed early juvenile features in the adult morphology. Another species, Ophiacantha clypeata Kyte, 1977, which had been separated from O. rhachophora, is in turn shown to be just a juvenile stage of another North Pacific species, Ophiacantha trachybactra H.L. Clark, 1911. For every species, detailed morphological data from both adult and juvenile specimens based on scanning electron microscopy are presented. A special grinding method showing complex internal features has been utilized for the first time. For all three species in this complex, a clear bathymetric differentiation is revealed: O. rhachophora predominantly inhabits shallow waters, 0-250 m, the new species O. kokusai lives deeper, at 250-600 m, and the third species, O. trachybactra, is found at 500-2,000 m. The present case clearly highlights the importance of considering developmental transformations, not only for a limited number of model organisms, but as part of the taxonomic process.
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Affiliation(s)
| | | | | | - Rie Tajiri
- Department of Earth Science, Waseda University, Tokyo, Japan
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Tissier J, Rage JC, Boistel R, Fernandez V, Pollet N, Garcia G, Laurin M. Synchrotron analysis of a ‘mummified’ salamander (Vertebrata: Caudata) from the Eocene of Quercy, France. Zool J Linn Soc 2015. [DOI: 10.1111/zoj.12341] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Jérémy Tissier
- Centre de Recherches sur la Paléobiodiversité et les Paléoenvironnements CR2P; UMR CNRS 7207; Sorbonne Universités; MNHN/CNRS/UPMC; Muséum national d'histoire naturelle; 57 rue Cuvier, CP 38 and 48 75005 Paris France
| | - Jean-Claude Rage
- Centre de Recherches sur la Paléobiodiversité et les Paléoenvironnements CR2P; UMR CNRS 7207; Sorbonne Universités; MNHN/CNRS/UPMC; Muséum national d'histoire naturelle; 57 rue Cuvier, CP 38 and 48 75005 Paris France
| | - Renaud Boistel
- IPHEP; Université de Poitiers UMR CNRS 7262; 6 rue Michel Brunet 86073 Poitiers France
| | - Vincent Fernandez
- ESRF (European Synchrotron Radiation Facility); 71 avenue des Martyrs 38000 Grenoble France
| | - Nicolas Pollet
- Evolution; Génomes; Comportement et Ecologie, CNRS, Université Paris-Sud, IRD, Université Paris-Saclay; 1 avenue de la Terrasse F-91198 Gif-sur-Yvette France
| | - Géraldine Garcia
- IPHEP; Université de Poitiers UMR CNRS 7262; 6 rue Michel Brunet 86073 Poitiers France
| | - Michel Laurin
- Centre de Recherches sur la Paléobiodiversité et les Paléoenvironnements CR2P; UMR CNRS 7207; Sorbonne Universités; MNHN/CNRS/UPMC; Muséum national d'histoire naturelle; 57 rue Cuvier, CP 38 and 48 75005 Paris France
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Marjanović D, Witzmann F. An Extremely Peramorphic Newt (Urodela: Salamandridae: Pleurodelini) from the Latest Oligocene of Germany, and a New Phylogenetic Analysis of Extant and Extinct Salamandrids. PLoS One 2015; 10:e0137068. [PMID: 26421432 PMCID: PMC4589347 DOI: 10.1371/journal.pone.0137068] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2015] [Accepted: 08/12/2015] [Indexed: 11/29/2022] Open
Abstract
We describe an Oligocene newt specimen from western Germany that has gone practically unnoticed in the literature despite having been housed in the Museum für Naturkunde (Berlin) for a century. It is referable to the coeval Chelotriton, but is unusually peramorphic; for many characters it is more peramorphic than all other caudates or even all other lissamphibians. Most noticeable are the position of the jaw joints far caudal to the occiput, the honeycombed sculpture on the maxilla, and the possible presence of a septomaxilla (which would be unique among salamandrids). Referral to a species would require a revision of the genus, but the specimen likely does not belong to the type species. A phylogenetic analysis of nonmolecular characters of Salamandridae, far larger than all predecessors, confirms the referral to Chelotriton. It further loosely associates the Oligocene Archaeotriton and the Miocene Carpathotriton with the extant Lissotriton, though the former may alternatively lie outside Pleurodelinae altogether. The Miocene? I. randeckensis may not belong to the extant Ichthyosaura. The Miocene “Triturus” roehrsi is found neither with the extant Ommatotriton nor with Lissotriton, but inside an Asian/aquatic clade or, when geographic distribution is included as a character, as the sister-group to all other European molgins. The main cause for discrepancies between the results and the molecular consensus is not heterochrony, but adaptations to a life in mountain streams; this is the most likely reason why the Paleocene Koalliella from western Europe forms the sister-group to some or all of the most aquatic extant newts in different analyses. We would like to urge neontologists working on salamandrids to pay renewed attention to the skeleton, not limited to the skull, as a source of diagnostic and phylogenetically informative characters.
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Affiliation(s)
- David Marjanović
- Museum für Naturkunde, Leibniz Institute for Evolutionary and Biodiversity Research, Humboldt University, Berlin, Germany
- * E-mail:
| | - Florian Witzmann
- Museum für Naturkunde, Leibniz Institute for Evolutionary and Biodiversity Research, Humboldt University, Berlin, Germany
- Department of Ecology and Evolutionary Biology, Brown University, Providence, Rhode Island, United States of America
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Struck T, Golombek A, Weigert A, Franke F, Westheide W, Purschke G, Bleidorn C, Halanych K. The Evolution of Annelids Reveals Two Adaptive Routes to the Interstitial Realm. Curr Biol 2015. [DOI: 10.1016/j.cub.2015.06.007] [Citation(s) in RCA: 90] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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49
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Fortuny J, Marcé-Nogué J, Heiss E, Sanchez M, Gil L, Galobart À. 3D bite modeling and feeding mechanics of the largest living amphibian, the Chinese giant salamander Andrias davidianus (Amphibia:Urodela). PLoS One 2015; 10:e0121885. [PMID: 25853557 PMCID: PMC4390218 DOI: 10.1371/journal.pone.0121885] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2014] [Accepted: 02/04/2015] [Indexed: 11/19/2022] Open
Abstract
Biting is an integral feature of the feeding mechanism for aquatic and terrestrial salamanders to capture, fix or immobilize elusive or struggling prey. However, little information is available on how it works and the functional implications of this biting system in amphibians although such approaches might be essential to understand feeding systems performed by early tetrapods. Herein, the skull biomechanics of the Chinese giant salamander, Andrias davidianus is investigated using 3D finite element analysis. The results reveal that the prey contact position is crucial for the structural performance of the skull, which is probably related to the lack of a bony bridge between the posterior end of the maxilla and the anterior quadrato-squamosal region. Giant salamanders perform asymmetrical strikes. These strikes are unusual and specialized behavior but might indeed be beneficial in such sit-and-wait or ambush-predators to capture laterally approaching prey. However, once captured by an asymmetrical strike, large, elusive and struggling prey have to be brought to the anterior jaw region to be subdued by a strong bite. Given their basal position within extant salamanders and their "conservative" morphology, cryptobranchids may be useful models to reconstruct the feeding ecology and biomechanics of different members of early tetrapods and amphibians, with similar osteological and myological constraints.
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Affiliation(s)
- Josep Fortuny
- Institut Català de Paleontologia Miquel Crusafont, Sabadell, Spain
- Universitat Politècnica de Catalunya—BarcelonaTech, Terrassa, Spain
| | - Jordi Marcé-Nogué
- Institut Català de Paleontologia Miquel Crusafont, Sabadell, Spain
- Universitat Politècnica de Catalunya—BarcelonaTech, Terrassa, Spain
| | - Egon Heiss
- Department of Integrative Zoology, University of Vienna, Vienna, Austria
- Institute of Systematic Zoology and Evolutionary Biology, Friedrich-Schiller-University Jena, Jena, Germany
| | | | - Lluis Gil
- Universitat Politècnica de Catalunya—BarcelonaTech, Terrassa, Spain
| | - Àngel Galobart
- Institut Català de Paleontologia Miquel Crusafont, Sabadell, Spain
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50
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Harrison LB, Larsson HCE. Among-Character Rate Variation Distributions in Phylogenetic Analysis of Discrete Morphological Characters. Syst Biol 2014; 64:307-24. [DOI: 10.1093/sysbio/syu098] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Luke B. Harrison
- Redpath Museum, McGill University, 859 Sherbrooke Street West Montreal, Quebec, Canada H3A 0C4 and 2Redpath Museum, McGill University, 859 Sherbrooke ST W, Montreal, Quebec, Canada H3A 0C4
| | - Hans C. E. Larsson
- Redpath Museum, McGill University, 859 Sherbrooke Street West Montreal, Quebec, Canada H3A 0C4 and 2Redpath Museum, McGill University, 859 Sherbrooke ST W, Montreal, Quebec, Canada H3A 0C4
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