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Cornman RS. A genomic hotspot of diversifying selection and structural change in the hoary bat ( Lasiurus cinereus). PeerJ 2024; 12:e17482. [PMID: 38832043 PMCID: PMC11146322 DOI: 10.7717/peerj.17482] [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: 11/29/2023] [Accepted: 05/07/2024] [Indexed: 06/05/2024] Open
Abstract
Background Previous work found that numerous genes positively selected within the hoary bat (Lasiurus cinereus) lineage are physically clustered in regions of conserved synteny. Here I further validate and expand on those finding utilizing an updated L. cinereus genome assembly and additional bat species as well as other tetrapod outgroups. Methods A chromosome-level assembly was generated by chromatin-contact mapping and made available by DNAZoo (www.dnazoo.org). The genomic organization of orthologous genes was extracted from annotation data for multiple additional bat species as well as other tetrapod clades for which chromosome-level assemblies were available from the National Center for Biotechnology Information (NCBI). Tests of branch-specific positive selection were performed for L. cinereus using PAML as well as with the HyPhy package for comparison. Results Twelve genes exhibiting significant diversifying selection in the L. cinereus lineage were clustered within a 12-Mb genomic window; one of these (Trpc4) also exhibited diversifying selection in bats generally. Ten of the 12 genes are landmarks of two distinct blocks of ancient synteny that are not linked in other tetrapod clades. Bats are further distinguished by frequent structural rearrangements within these synteny blocks, which are rarely observed in other Tetrapoda. Patterns of gene order and orientation among bat taxa are incompatible with phylogeny as presently understood, implying parallel evolution or subsequent reversals. Inferences of positive selection were found to be robust to alternative phylogenetic topologies as well as a strong shift in background nucleotide composition in some taxa. Discussion This study confirms and further localizes a genomic hotspot of protein-coding divergence in the hoary bat, one that also exhibits an increased tempo of structural change in bats compared with other mammals. Most genes in the two synteny blocks have elevated expression in brain tissue in humans and model organisms, and genetic studies implicate the selected genes in cranial and neurological development, among other functions.
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Affiliation(s)
- Robert S. Cornman
- U.S. Geological Survey, Fort Collins Science Center, Fort Collins, Colorado, United States
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2
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Schuh A, Heuzé Y, Gunz P, Berthaume MA, Shaw CN, Hublin JJ, Freidline S. A shared pattern of midfacial bone modelling in hominids suggests deep evolutionary roots for human facial morphogenesis. Proc Biol Sci 2024; 291:20232738. [PMID: 38628118 PMCID: PMC11022013 DOI: 10.1098/rspb.2023.2738] [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: 12/05/2023] [Accepted: 03/19/2024] [Indexed: 04/19/2024] Open
Abstract
Midfacial morphology varies between hominoids, in particular between great apes and humans for which the face is small and retracted. The underlying developmental processes for these morphological differences are still largely unknown. Here, we investigate the cellular mechanism of maxillary development (bone modelling, BM), and how potential changes in this process may have shaped facial evolution. We analysed cross-sectional developmental series of gibbons, orangutans, gorillas, chimpanzees and present-day humans (n = 183). Individuals were organized into five age groups according to their dental development. To visualize each species's BM pattern and corresponding morphology during ontogeny, maps based on microscopic data were mapped onto species-specific age group average shapes obtained using geometric morphometrics. The amount of bone resorption was quantified and compared between species. Great apes share a highly similar BM pattern, whereas gibbons have a distinctive resorption pattern. This suggests a change in cellular activity on the hominid branch. Humans possess most of the great ape pattern, but bone resorption is high in the canine area from birth on, suggesting a key role of canine reduction in facial evolution. We also observed that humans have high levels of bone resorption during childhood, a feature not shared with other apes.
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Affiliation(s)
- Alexandra Schuh
- CNRS, Ministère de la Culture, PACEA, UMR 5199, Université de Bordeaux, Bât. B2, Allée Geoffroy Saint-Hilaire, Pessac 33615, France
- Department of Human Origins, Max Planck Institute for Evolutionary Anthropology, Deutscher Platz 6, Leipzig 04103, Germany
| | - Yann Heuzé
- CNRS, Ministère de la Culture, PACEA, UMR 5199, Université de Bordeaux, Bât. B2, Allée Geoffroy Saint-Hilaire, Pessac 33615, France
| | - Philipp Gunz
- Department of Human Origins, Max Planck Institute for Evolutionary Anthropology, Deutscher Platz 6, Leipzig 04103, Germany
| | - Michael A. Berthaume
- Department of Engineering, Faculty of Natural, Mathematical and Engineering Sciences, King's College London, London, UK
| | - Colin N. Shaw
- Department of Evolutionary Anthropology, University of Zurich, Zurich, Switzerland
| | - Jean-Jacques Hublin
- Department of Human Origins, Max Planck Institute for Evolutionary Anthropology, Deutscher Platz 6, Leipzig 04103, Germany
- Chaire de Paléoanthropologie, Collège de France, Paris, France
| | - Sarah Freidline
- Department of Human Origins, Max Planck Institute for Evolutionary Anthropology, Deutscher Platz 6, Leipzig 04103, Germany
- Department of Anthropology, University of Central Florida, Orlando, FL, USA
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3
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Anthwal N, Hall RP, de la Rosa Hernandez FA, Koger M, Yohe LR, Hedrick BP, Davies KTJ, Mutumi GL, Roseman CC, Dumont ER, Dávalos LM, Rossiter SJ, Sadier A, Sears KE. Cochlea development shapes bat sensory system evolution. Anat Rec (Hoboken) 2023. [PMID: 37994725 DOI: 10.1002/ar.25353] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2023] [Revised: 11/01/2023] [Accepted: 11/08/2023] [Indexed: 11/24/2023]
Abstract
Sensory organs must develop alongside the skull within which they are largely encased, and this relationship can manifest as the skull constraining the organs, organs constraining the skull, or organs constraining one another in relative size. How this interplay between sensory organs and the developing skull plays out during the evolution of sensory diversity; however, remains unknown. Here, we examine the developmental sequence of the cochlea, the organ responsible for hearing and echolocation, in species with distinct diet and echolocation types within the ecologically diverse bat super-family Noctilionoidea. We found the size and shape of the cochlea largely correlates with skull size, with exceptions of Pteronotus parnellii, whose high duty cycle echolocation (nearly constant emission of sound pulses during their echolocation process allowing for detailed information gathering, also called constant frequency echolocation) corresponds to a larger cochlear and basal turn, and Monophyllus redmani, a small-bodied nectarivorous bat, for which interactions with other sensory organs restrict cochlea size. Our findings support the existence of developmental constraints, suggesting that both developmental and anatomical factors may act synergistically during the development of sensory systems in noctilionoid bats.
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Affiliation(s)
- Neal Anthwal
- King's College London, Centre for Craniofacial and Regenerative Biology, London, UK
- Department of Ecology and Evolutionary Biology, University of California Los Angeles, Los Angeles, California, USA
| | - Ronald P Hall
- Department of Life and Environment Sciences, University of California Merced, Merced, California, USA
| | | | - Michael Koger
- Department of Ecology and Evolutionary Biology, University of California Los Angeles, Los Angeles, California, USA
| | - Laurel R Yohe
- Department of Bioinformatics and Genomics, University of North Carolina Charlotte, Charlotte, North Carolina, USA
| | - Brandon P Hedrick
- Department of Biomedical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, New York, USA
| | - Kalina T J Davies
- School of Biological and Behavioural Sciences, Queen Mary University of London, London, UK
| | - Gregory L Mutumi
- Department of Life and Environment Sciences, University of California Merced, Merced, California, USA
| | - Charles C Roseman
- Department of Evolution, Ecology, and Behavior, University of Illinois at Urbana-Champaign, Urbana-Champaign, Illinois, USA
| | - Elizabeth R Dumont
- Department of Life and Environment Sciences, University of California Merced, Merced, California, USA
| | - Liliana M Dávalos
- Department of Ecology and Evolution and Consortium for Inter-Disciplinary Environmental Research, Stony Brook University, Stony Brook, New York, USA
| | - Stephen J Rossiter
- School of Biological and Behavioural Sciences, Queen Mary University of London, London, UK
| | - Alexa Sadier
- Department of Ecology and Evolutionary Biology, University of California Los Angeles, Los Angeles, California, USA
| | - Karen E Sears
- Department of Ecology and Evolutionary Biology, University of California Los Angeles, Los Angeles, California, USA
- Department of Molecular, Cellular, and Developmental Biology, University of California Los Angeles, Los Angeles, California, USA
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Verma N. Digest: Trilobites to vertebrates: how development influences the evolution of segmental patterning. Evolution 2023; 77:2109-2110. [PMID: 37407222 DOI: 10.1093/evolut/qpad123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Accepted: 07/03/2023] [Indexed: 07/07/2023]
Abstract
How has the evolution of segment size patterning been developmentally regulated and what does the trilobite fossil record tell us about these ancestral control mechanisms? Nikolic et al. relate the evolutionary and developmental mechanisms of segmentation in extinct trilobites to those seen in extant arthropods and vertebrates to examine how ontogenic renovations are echoed in the phylogeny of segmental patterning.
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Affiliation(s)
- Neeharika Verma
- Department of Organismal Biology and Anatomy, University of Chicago, Chicago, IL, United States
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5
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Sadier A, Anthwal N, Krause AL, Dessalles R, Lake M, Bentolila LA, Haase R, Nieves NA, Santana SE, Sears KE. Bat teeth illuminate the diversification of mammalian tooth classes. Nat Commun 2023; 14:4687. [PMID: 37607943 PMCID: PMC10444822 DOI: 10.1038/s41467-023-40158-4] [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: 11/16/2022] [Accepted: 07/11/2023] [Indexed: 08/24/2023] Open
Abstract
Tooth classes are an innovation that has contributed to the evolutionary success of mammals. However, our understanding of the mechanisms by which tooth classes diversified remain limited. We use the evolutionary radiation of noctilionoid bats to show how the tooth developmental program evolved during the adaptation to new diet types. Combining morphological, developmental and mathematical modeling approaches, we demonstrate that tooth classes develop through independent developmental cascades that deviate from classical models. We show that the diversification of tooth number and size is driven by jaw growth rate modulation, explaining the rapid gain/loss of teeth in this clade. Finally, we mathematically model the successive appearance of tooth buds, supporting the hypothesis that growth acts as a key driver of the evolution of tooth number and size. Our work reveal how growth, by tinkering with reaction/diffusion processes, drives the diversification of tooth classes and other repeated structure during adaptive radiations.
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Affiliation(s)
- Alexa Sadier
- Department of Ecology and Evolutionary Biology, University of California Los Angeles, Los Angeles, CA, USA.
| | - Neal Anthwal
- Department of Ecology and Evolutionary Biology, University of California Los Angeles, Los Angeles, CA, USA
- Centre for Craniofacial and Regenerative Biology, King's College London, London, UK
| | | | - Renaud Dessalles
- Department of Ecology and Evolutionary Biology, University of California Los Angeles, Los Angeles, CA, USA
- Greenshield, 46 rue Saint-Antoine, 75004, Paris, France
| | - Michael Lake
- Advanced Light Microscopy and Spectroscopy Laboratory, California NanoSystems Institute, UCLA, Los Angeles, CA, 90095, USA
| | - Laurent A Bentolila
- Advanced Light Microscopy and Spectroscopy Laboratory, California NanoSystems Institute, UCLA, Los Angeles, CA, 90095, USA
| | - Robert Haase
- DFG Cluster of Excellence "Physics of Life", TU Dresden, Dresden, Germany
| | - Natalie A Nieves
- Department of Ecology and Evolutionary Biology, University of California Los Angeles, Los Angeles, CA, USA
| | - Sharlene E Santana
- Department of Biology and Burke Museum of Natural History and Culture, University of Washington, Seattle, WA, USA
| | - Karen E Sears
- Department of Ecology and Evolutionary Biology, University of California Los Angeles, Los Angeles, CA, USA.
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Kyomen S, Murillo-Rincón AP, Kaucká M. Evolutionary mechanisms modulating the mammalian skull development. Philos Trans R Soc Lond B Biol Sci 2023; 378:20220080. [PMID: 37183900 PMCID: PMC10184257 DOI: 10.1098/rstb.2022.0080] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/16/2023] Open
Abstract
Mammals possess impressive craniofacial variation that mirrors their adaptation to diverse ecological niches, feeding behaviour, physiology and overall lifestyle. The spectrum of craniofacial geometries is established mainly during embryonic development. The formation of the head represents a sequence of events regulated on genomic, molecular, cellular and tissue level, with each step taking place under tight spatio-temporal control. Even minor variations in timing, position or concentration of the molecular drivers and the resulting events can affect the final shape, size and position of the skeletal elements and the geometry of the head. Our knowledge of craniofacial development increased substantially in the last decades, mainly due to research using conventional vertebrate model organisms. However, how developmental differences in head formation arise specifically within mammals remains largely unexplored. This review highlights three evolutionary mechanisms acknowledged to modify ontogenesis: heterochrony, heterotopy and heterometry. We present recent research that links changes in developmental timing, spatial organization or gene expression levels to the acquisition of species-specific skull morphologies. We highlight how these evolutionary modifications occur on the level of the genes, molecules and cellular processes, and alter conserved developmental programmes to generate a broad spectrum of skull shapes characteristic of the class Mammalia. This article is part of the theme issue 'The mammalian skull: development, structure and function'.
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Affiliation(s)
- Stella Kyomen
- Max Planck Institute for Evolutionary Biology, August-Thienemann-Strasse 2, Plön 24306, Germany
| | - Andrea P Murillo-Rincón
- Max Planck Institute for Evolutionary Biology, August-Thienemann-Strasse 2, Plön 24306, Germany
| | - Markéta Kaucká
- Max Planck Institute for Evolutionary Biology, August-Thienemann-Strasse 2, Plön 24306, Germany
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Rhoda DP, Haber A, Angielczyk KD. Diversification of the ruminant skull along an evolutionary line of least resistance. SCIENCE ADVANCES 2023; 9:eade8929. [PMID: 36857459 PMCID: PMC9977183 DOI: 10.1126/sciadv.ade8929] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Accepted: 01/30/2023] [Indexed: 05/28/2023]
Abstract
Clarifying how microevolutionary processes scale to macroevolutionary patterns is a fundamental goal in evolutionary biology, but these analyses, requiring comparative datasets of population-level variation, are limited. By analyzing a previously published dataset of 2859 ruminant crania, we find that variation within and between ruminant species is biased by a highly conserved mammalian-wide allometric pattern, CREA (craniofacial evolutionary allometry), where larger species have proportionally longer faces. Species with higher morphological integration and species more biased toward CREA have diverged farther from their ancestors, and Ruminantia as a clade diversified farther than expected in the direction of CREA. Our analyses indicate that CREA acts as an evolutionary "line of least resistance" and facilitates morphological diversification due to its alignment with the browser-grazer continuum. Together, our results demonstrate that constraints at the population level can produce highly directional patterns of phenotypic evolution at the macroevolutionary scale. Further research is needed to explore how CREA has been exploited in other mammalian clades.
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Affiliation(s)
- Daniel P. Rhoda
- Committee on Evolutionary Biology, University of Chicago, 1025 E. 57th St., Chicago, IL 60637, USA
- Negaunee Integrative Research Center, Field Museum of Natural History, 1400 S. DuSable Lake Shore Dr., Chicago, IL 60605, USA
| | - Annat Haber
- The Jackson Laboratory, Farmington, CT 06032, USA
| | - Kenneth D. Angielczyk
- Committee on Evolutionary Biology, University of Chicago, 1025 E. 57th St., Chicago, IL 60637, USA
- Negaunee Integrative Research Center, Field Museum of Natural History, 1400 S. DuSable Lake Shore Dr., Chicago, IL 60605, USA
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8
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Ferreira-Cardoso S, Claude J, Goswami A, Delsuc F, Hautier L. Flexible conservatism in the skull modularity of convergently evolved myrmecophagous placental mammals. BMC Ecol Evol 2022; 22:87. [PMID: 35773630 PMCID: PMC9248141 DOI: 10.1186/s12862-022-02030-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Accepted: 06/06/2022] [Indexed: 12/05/2022] Open
Abstract
Background The skull of placental mammals constitutes one of the best studied systems for phenotypic modularity. Several studies have found strong evidence for the conserved presence of two- and six-module architectures, while the strength of trait correlations (integration) has been associated with major developmental processes such as somatic growth, muscle-bone interactions, and tooth eruption. Among placentals, ant- and termite-eating (myrmecophagy) represents an exemplar case of dietary convergence, accompanied by the selection of several cranial morphofunctional traits such as rostrum elongation, tooth loss, and mastication loss. Despite such drastic functional modifications, the covariance patterns of the skull of convergently evolved myrmecophagous placentals are yet to be studied in order to assess the potential consequences of this dietary shift on cranial modularity. Results Here, we performed a landmark-based morphometric analysis of cranial covariance patterns in 13 species of myrmecophagous placentals. Our analyses reveal that most myrmecophagous species present skulls divided into six to seven modules (depending on the confirmatory method used), with architectures similar to those of non-myrmecophagous placentals (therian six modules). Within-module integration is also similar to what was previously described for other placentals, suggesting that most covariance-generating processes are conserved across the clade. Nevertheless, we show that extreme rostrum elongation and tooth loss in myrmecophagid anteaters have resulted in a shift in intermodule correlations in the proximal region of the rostrum. Namely, the naso-frontal and maxillo-palatine regions are strongly correlated with the oro-nasal module, suggesting an integrated rostrum conserved from pre-natal developmental processes. In contrast, the similarly toothless pangolins show a weaker correlation between the anterior rostral modules, resembling the pattern of toothed placentals. Conclusions These results reveal that despite some integration shifts related to extreme functional and morphological features of myrmecophagous skulls, cranial modular architectures have conserved the typical mammalian scheme. Supplementary Information The online version contains supplementary material available at 10.1186/s12862-022-02030-9.
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10
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Dobreva MP, Camacho J, Abzhanov A. Time to synchronize our clocks: Connecting developmental mechanisms and evolutionary consequences of heterochrony. JOURNAL OF EXPERIMENTAL ZOOLOGY. PART B, MOLECULAR AND DEVELOPMENTAL EVOLUTION 2022; 338:87-106. [PMID: 34826199 DOI: 10.1002/jez.b.23103] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Revised: 09/27/2021] [Accepted: 10/12/2021] [Indexed: 06/13/2023]
Abstract
Heterochrony, defined as a change in the timing of developmental events altering the course of evolution, was first recognized by Ernst Haeckel in 1866. Haeckel's original definition was meant to explain the observed parallels between ontogeny and phylogeny, but the interpretation of his work became a source of controversy over time. Heterochrony took its modern meaning following the now classical work in the 1970-80s by Steven J. Gould, Pere Alberch, and co-workers. Predicted and described heterochronic scenarios emphasize the many ways in which developmental changes can influence evolution. However, while important examples of heterochrony detected with comparative morphological methods have multiplied, the more mechanistic understanding of this phenomenon lagged conspicuously behind. Considering the rapid progress in imaging and molecular tools available now for developmental biologists, this review aims to stress the need to take heterochrony research to the next level. It is time to synchronize the different levels of heterochrony research into a single analysis flow: from studies on organismal-level morphology to cells to molecules and genes, using complementary techniques. To illustrate how to achieve a more comprehensive understanding of phyletic morphological diversification associated with heterochrony, we discuss several recent case studies at various phylogenetic scales that combine morphological, cellular, and molecular analyses. Such a synergistic approach offers to more fully integrate phylogenetic and ontogenetic dimensions of the fascinating evolutionary phenomenon of heterochrony.
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Affiliation(s)
| | - Jasmin Camacho
- Stowers Institute for Medical Research, Kansas City, Missouri, USA
| | - Arkhat Abzhanov
- Department of Life Sciences, Imperial College London, Ascot, UK
- Department of Life Sciences, Natural History Museum, London, UK
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Sadier A, Sears KE, Womack M. Unraveling the heritage of lost traits. JOURNAL OF EXPERIMENTAL ZOOLOGY. PART B, MOLECULAR AND DEVELOPMENTAL EVOLUTION 2022; 338:107-118. [PMID: 33528870 DOI: 10.1002/jez.b.23030] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Revised: 12/22/2020] [Accepted: 01/03/2021] [Indexed: 12/22/2022]
Abstract
We synthesize ontogenetic work spanning the past century that show evolutionarily lost structures are rarely entirely absent from earlier developmental stages. We discuss morphological and genetic insights from developmental studies reveal about the evolution of trait loss and regain.
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Affiliation(s)
- Alexa Sadier
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, California, USA
| | - Karen E Sears
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, California, USA
| | - Molly Womack
- Department of Biology, Utah State University, Logan, Utah, USA
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Morris ZS, Vliet KA, Abzhanov A, Pierce SE. Developmental origins of the crocodylian skull table and platyrostral face. Anat Rec (Hoboken) 2021; 305:2838-2853. [PMID: 34694063 DOI: 10.1002/ar.24802] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Accepted: 09/13/2021] [Indexed: 11/10/2022]
Abstract
The dorsoventrally flattened skull typifies extant Crocodylia perhaps more than any other anatomical feature and is generally considered an adaptation for semi-aquatic feeding. Although the evolutionary origins of caniofacial flattening have been extensively studied, the developmental origins have yet to be explored. To understand how the skull table and platyrostral snout develop, we quantified embryonic development and post-hatching growth (ontogeny) of the crocodylian skull in lateral view using geometric morphometrics. Our dataset (n = 103) includes all but one extant genus and all of the major ecomorphs, including the extremely slender-snouted Gavialis and Tomistoma. Our analysis reveals that the embryonic development of the flattened skull is remarkably similar across ecomorphs, including the presence of a conserved initial embryonic skull shape, similar to prior analysis of dorsal snout shape. Although differences during posthatching ontogeny are recovered among ecomorphs, embryonic patterns are not distinct, revealing an important shift in developmental rate near hatching. In particular, the flattened skull table is achieved by the end of embryonic development with no changes after hatching. Further, the rotation of skull roof and facial bones during development is critical for the stereotypical flatness of the crocodylian skull. Our results suggest selection on hatchling performance and constraints on embryonic skull shape may have been important in this pattern of developmental conservation. The appearance of aspects of cranial flatness among Jurassic stem crocodylians suggests key aspects of these cranial developmental patterns may have been conserved for over 200 million years.
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Affiliation(s)
- Zachary S Morris
- Museum of Comparative Zoology and Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massachusetts, USA
| | - Kent A Vliet
- Department of Biology, University of Florida, Gainesville, Florida, USA
| | - Arhat Abzhanov
- Department of Life Sciences, Imperial College London, Berkshire, UK.,Natural History Museum, Cromwell Road, London, UK
| | - Stephanie E Pierce
- Museum of Comparative Zoology and Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massachusetts, USA
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Heading for higher ground: Developmental origins and evolutionary diversification of the amniote face. Curr Top Dev Biol 2021; 141:241-277. [PMID: 33602490 DOI: 10.1016/bs.ctdb.2020.12.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Amniotes, a clade of terrestrial vertebrates, which includes all of the descendants of the last common ancestor of the reptiles (including dinosaurs and birds) and mammals, is one of the most successful group of animals on our planet. In addition to having an egg equipped with an amnion, an adaptation to lay eggs on land, amniotes possess a number of other major morphological characteristics. Chief among them is the amniote skull, which can be classified into several major types distinguished by the presence and number of temporal fenestrae (windows) in the posterior part. Amniotes evolved from ancestors who possessed a skull composed of a complex mosaic of small bones separated by sutures. Changes in skull composition underlie much of the large-scale evolution of amniotes with many lineages showing a trend in reduction of cranial elements known as the "Williston's Law." The skull of amniotes is also arranged into a set of modules of closely co-evolving bones as revealed by modularity and integration tests. One of the most consistently recovered and at the same time most versatile modules is the "face," anatomically defined as the anterior portion of the head. The faces of amniotes display extraordinary amount of variation, with many adaptive radiations showing parallel tendencies in facial scaling, e.g., changes in length or width. This review explores the natural history of the amniote face and discusses how a better understanding of its anatomy and developmental biology helps to explain the outstanding scale of adaptive facial diversity. We propose a model for facial evolution in the amniotes, based on the differential rate of cranial neural crest cell proliferation and the timing of their skeletal differentiation.
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