1
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Bhat MS, Cullen TM. Growth and life history of freshwater chelydrid turtles (Testudines: Cryptodira): A bone histological approach. J Anat 2024. [PMID: 39169639 DOI: 10.1111/joa.14130] [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: 05/15/2024] [Revised: 07/25/2024] [Accepted: 08/07/2024] [Indexed: 08/23/2024] Open
Abstract
The current study examines the growth pattern and lifestyle habits of the freshwater snapping turtles Chelydra and Macrochelys based on limb bone histology. Femora, humeri, and tibiae of 25 individuals selected from a range of ontogenetic stages were assessed to determine inter-element and intraskeletal histological variation. Osteohistological assessment of multiple elements is consistent with overall moderate growth rates as revealed by the dominance of parallel-fibered bone. However, the growth was cyclical as shown by deposition of multiple lines of arrested growths in the compacta. It appears that the bone tissue of C. serpentina is more variable through ontogeny with intermittent higher growth rates. M. temminckii appears to grow more slowly than C. serpentina possessing compact and thick cortices in accordance with their larger size. Overall, vascularization decreases through ontogeny with humeri and femora being well-vascularized in both species. Contrarily, epipodials are poorly vascularized, though simple longitudinal and radial canals are present, suggesting differences in growth patterns when compared with associated diaphyseal sections. The tibiae were found to be the least remodeled of the limb bones and therefore better suited for skeletochronology for snapping turtles. Intra-elementally, femora and humeri preserved higher cortical vascularity ventrally, suggestive of faster relative growth. We hypothesize that the differential growth pattern in limb bones of snapping turtles may relate to differential functional constraints, where forelimbs are operational in swimming while the hindlimbs provide stability.
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Affiliation(s)
- Mohd Shafi Bhat
- Department of Geosciences, Auburn University, Auburn, Alabama, USA
| | - Thomas M Cullen
- Department of Geosciences, Auburn University, Auburn, Alabama, USA
- Auburn University Museum of Natural History, Auburn, Alabama, USA
- Department of Earth Sciences, Carleton University, Ottawa, Ontario, Canada
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2
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Sato H, Adachi N, Kondo S, Kitayama C, Tokita M. Turtle skull development unveils a molecular basis for amniote cranial diversity. SCIENCE ADVANCES 2023; 9:eadi6765. [PMID: 37967181 PMCID: PMC10651123 DOI: 10.1126/sciadv.adi6765] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2023] [Accepted: 10/16/2023] [Indexed: 11/17/2023]
Abstract
Amniote skulls display diverse architectural patterns including remarkable variations in the number of temporal arches surrounding the upper and lower temporal fenestrae. However, the cellular and molecular basis underlying this diversification remains elusive. Turtles are a useful model to understand skull diversity due to the presence of secondarily closed temporal fenestrae and different extents of temporal emarginations (marginal reduction of dermal bones). Here, we analyzed embryos of three turtle species with varying degrees of temporal emargination and identified shared widespread coexpression of upstream osteogenic genes Msx2 and Runx2 and species-specific expression of more downstream osteogenic genes Sp7 and Sparc in the head. Further analysis of representative amniote embryos revealed differential expression patterns of osteogenic genes in the temporal region, suggesting that the spatiotemporal regulation of Msx2, Runx2, and Sp7 distinguishes the temporal skull morphology among amniotes. Moreover, the presence of Msx2- and/or Runx2-positive temporal mesenchyme with osteogenic potential may have contributed to their extremely diverse cranial morphology in reptiles.
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Affiliation(s)
- Hiromu Sato
- Department of Biology, Faculty of Science, Toho University, 2-2-1 Miyama, Funabashi, Chiba 274-8510, Japan
| | - Noritaka Adachi
- Department of Biology, Faculty of Science, Toho University, 2-2-1 Miyama, Funabashi, Chiba 274-8510, Japan
| | - Satomi Kondo
- Everlasting Nature of Asia (ELNA), Ogasawara Marine Center, Byobudani, Chichi-Jima, Ogasawara, Tokyo 100-2101, Japan
| | - Chiyo Kitayama
- Everlasting Nature of Asia (ELNA), Ogasawara Marine Center, Byobudani, Chichi-Jima, Ogasawara, Tokyo 100-2101, Japan
| | - Masayoshi Tokita
- Department of Biology, Faculty of Science, Toho University, 2-2-1 Miyama, Funabashi, Chiba 274-8510, Japan
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3
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Gene Regulation during Carapacial Ridge Development of Mauremys reevesii: The Development of Carapacial Ridge, Ribs and Scutes. Genes (Basel) 2022; 13:genes13091676. [PMID: 36140843 PMCID: PMC9498798 DOI: 10.3390/genes13091676] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2022] [Revised: 08/26/2022] [Accepted: 09/14/2022] [Indexed: 11/17/2022] Open
Abstract
The unique topological structure of a turtle shell, including the special ribs-scapula relationship, is an evolutionarily novelty of amniotes. The carapacial ridge is a key embryonic tissue for inducing turtle carapace morphologenesis. However, the gene expression profiles and molecular regulatory mechanisms that occur during carapacial ridge development, including the regulation mechanism of rib axis arrest, the development mechanism of the carapacial ridge, and the differentiation between soft-shell turtles and hard-shell turtles, are not fully understood. In this study, we obtained genome-wide gene expression profiles during the carapacial ridge development of Mauremys reevesii using RNA-sequencing by using carapacial ridge tissues from stage 14, 15 and 16 turtle embryos. In addition, a differentially expressed genes (DEGs) analysis and a gene set enrichment analysis (GSEA) of three comparison groups were performed. Furthermore, a Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis was used to analyze the pathway enrichment of the differentially expressed genes of the three comparative groups. The result displayed that the Wnt signaling pathway was substantially enriched in the CrTK14 vs. the CrTK15 comparison group, while the Hedgehog signaling pathway was significantly enriched in the CrTK15 vs. the CrTK16 group. Moreover, the regulatory network of the Wnt signaling pathway showed that Wnt signaling pathways might interact with Fgfs, Bmps, and Shh to form a regulatory network to regulate the carapacial ridge development. Next, WGCNA was used to cluster and analyze the expression genes during the carapacial ridge development of M. reevesii and P. sinensis. Further, a KEGG functional enrichment analysis of the carapacial ridge correlation gene modules was performed. Interesting, these results indicated that the Wnt signaling pathway and the MAPK signaling pathway were significantly enriched in the gene modules that were highly correlated with the stage 14 and stage 15 carapacial ridge samples of the two species. The Hedgehog signaling pathway was significantly enriched in the modules that were strongly correlated with the stage 16 carapacial ridge samples of M. reevesii, however, the PI3K-Akt signaling and the TGF-β signaling pathways were significantly enriched in the modules that were strongly correlated with the stage 16 carapacial ridge samples of P. sinensis. Furthermore, we found that those modules that were strongly correlated with the stage 14 carapacial ridge samples of M. reevesii and P. sinensis contained Wnts and Lef1. While the navajo white 3 module which was strongly correlated with the stage 16 carapacial ridge samples of M. reevesii contained Shh and Ptchs. The dark green module strongly correlated with the stage 16 carapacial ridge samples of P. sinensis which contained Col1a1, Col1a2, and Itga8. Consequently, this study systematically revealed the signaling pathways and genes that regulate the carapacial ridge development of M. reevesii and P. sinensis, which provides new insights for revealing the molecular mechanism that is underlying the turtle's body structure.
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Tekko T, Lozovska A, Nóvoa A, Mallo M. Assessing Myf5 and Lbx1 contribution to carapace development by reproducing their turtle-specific signatures in mouse embryos. Dev Dyn 2022; 251:1698-1710. [PMID: 35618666 DOI: 10.1002/dvdy.502] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Revised: 05/16/2022] [Accepted: 05/19/2022] [Indexed: 11/05/2022] Open
Abstract
BACKGROUND The turtle carapace is an evolutionary novelty resulting from changes in the processes that build ribs and their associated muscles in most tetrapod species. Turtle embryos have several unique features that might play a role in this process, including the carapacial ridge, a Myf5 gene with shorter coding region that generates an alternative splice variant lacking exon 2, and unusual expression patterns of Lbx1 and HGF. RESULTS We investigated these turtle-specific expression differences using genetic approaches in mouse embryos. At mid gestation, mouse embryos producing Myf5 transcripts lacking exon 2 replicated some early properties of turtle somites, but still developed into viable and fertile mice. Extending Lbx1 expression into the hypaxial dermomyotomal lip of trunk somites to mimic the turtle Lbx1 expression pattern, produced fusions in the distal part of the ribs. CONCLUSIONS Turtle-like Myf5 activity might generate a plastic state in developing trunk somites under which they can either enter carapace morphogenetic routes, possibly triggered by signals from the carapacial ridge, or still engage in the development of a standard tetrapod ribcage in the absence of those signals. In addition, trunk Lbx1 expression might play a later role in the formation of the lateral border of the carapace. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Triin Tekko
- Instituto Gulbenkian de Ciência, Rua da Quinta Grande 6, 2780-156 Oeiras, Portugal
| | - Anastasiia Lozovska
- Instituto Gulbenkian de Ciência, Rua da Quinta Grande 6, 2780-156 Oeiras, Portugal
| | - Ana Nóvoa
- Instituto Gulbenkian de Ciência, Rua da Quinta Grande 6, 2780-156 Oeiras, Portugal
| | - Moisés Mallo
- Instituto Gulbenkian de Ciência, Rua da Quinta Grande 6, 2780-156 Oeiras, Portugal
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Ascarrunz E, Sánchez-Villagra MR. The macroevolutionary and developmental evolution of the turtle carapacial scutes. VERTEBRATE ZOOLOGY 2022. [DOI: 10.3897/vz.72.e76256] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The scutes of the carapace of extant turtles exhibit common elements in a narrow range of topographical arrangements. The typical arrangement has remained constant since its origin in the clade Mesochelydia (Early Jurassic), after a period of apparent greater diversity in the Triassic. This contribution is a review of the development and evolutionary history of the scute patterns of the carapace, seen through the lens of recent developmental models. This yields insights on pattern variations in the fossil record. We reinterpret the “supracaudal” scute and propose that Proganochelys had five vertebral scutes. We discuss the relationship between supramarginal scutes and Turing processes, and we show how a simple change during embryogenesis could account for origin of the configuration of the caudal region of the carapace in mesochelydians. We also discuss the nature of the decrease in number of scutes over the course of evolution, and whether macroevolutionary trends can be discerned. We argue that turtles with complete loss of scutes (e.g., softshells) follow clade-specific macroevolutionary regimes, which are distinct from the majority of other turtles. Finally, we draw a parallel between the variation of scute patterns on the carapace of turtles and the scale patterns in the pileus region (roof of the head) of squamates. The size and numbers of scales in the pileus region can evolve over a wide range, but we recognized tentative evidence of convergence towards a typical configuration when the scales become larger and fewer. Thus, typical patterns could be a more general property of similar systems of integumentary appendages.
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Global Analysis of Transcriptome and Translatome Revealed That Coordinated WNT and FGF Regulate the Carapacial Ridge Development of Chinese Soft-Shell Turtle. Int J Mol Sci 2021; 22:ijms222212441. [PMID: 34830331 PMCID: PMC8621500 DOI: 10.3390/ijms222212441] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2021] [Revised: 11/14/2021] [Accepted: 11/15/2021] [Indexed: 12/16/2022] Open
Abstract
The turtle carapace is composed of severely deformed fused dorsal vertebrae, ribs, and bone plates. In particular, the lateral growth in the superficial layer of turtle ribs in the dorsal trunk causes an encapsulation of the scapula and pelvis. The recent study suggested that the carapacial ridge (CR) is a new model of epithelial–mesenchymal transition which is essential for the arrangement of the ribs. Therefore, it is necessary to explore the regulatory mechanism of carapacial ridge development to analyze the formation of the turtle shell. However, the current understanding of the regulatory network underlying turtle carapacial ridge development is poor due to the lack of both systematic gene screening at different carapacial ridge development stages and gene function verification studies. In this study, we obtained genome-wide gene transcription and gene translation profiles using RNA sequencing and ribosome nascent-chain complex mRNA sequencing from carapacial ridge tissues of Chinese soft-shell turtle at different development stages. A correlation analysis of the transcriptome and translatome revealed that there were 129, 670, and 135 codifferentially expressed genes, including homodirection and opposite-direction differentially expressed genes, among three comparison groups, respectively. The pathway enrichment analysis of codifferentially expressed genes from the Kyoto Encyclopedia of Genes and Genomes showed dynamic changes in signaling pathways involved in carapacial ridge development. Especially, the results revealed that the Wnt signaling pathway and MAPK signaling pathway may play important roles in turtle carapacial ridge development. In addition, Wnt and Fgf were expressed during the carapacial ridge development. Furthermore, we discovered that Wnt5a regulated carapacial ridge development through the Wnt5a/JNK pathway. Therefore, our studies uncover that the morphogenesis of the turtle carapace might function through the co-operation between conserved WNT and FGF signaling pathways. Consequently, our findings revealed the dynamic signaling pathways acting on the carapacial ridge development of Chinese soft-shell turtle and provided new insights into uncover the molecular mechanism underlying turtle shell morphogenesis.
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Congenital Malformations in Sea Turtles: Puzzling Interplay between Genes and Environment. Animals (Basel) 2021; 11:ani11020444. [PMID: 33567785 PMCID: PMC7915190 DOI: 10.3390/ani11020444] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Revised: 02/02/2021] [Accepted: 02/03/2021] [Indexed: 12/28/2022] Open
Abstract
Simple Summary Congenital malformations can lead to embryonic mortality in many species, and sea turtles are no exception. Genetic and/or environmental alterations occur during early development in the embryo, and may produce aberrant phenotypes, many of which are incompatible with life. Causes of malformations are multifactorial; genetic factors may include mutations, chromosomal aberrations, and inbreeding effects, whereas non-genetic factors may include nutrition, hyperthermia, low moisture, radiation, and contamination. It is possible to monitor and control some of these factors (such as temperature and humidity) in nesting beaches, and toxic compounds in feeding areas, which can be transferred to the embryo through their lipophilic properties. In this review, we describe possible causes of different types of malformations observed in sea turtle embryos, as well as some actions that may help reduce embryonic mortality. Abstract The completion of embryonic development depends, in part, on the interplay between genetic factors and environmental conditions, and any alteration during development may affect embryonic genetic and epigenetic regulatory pathways leading to congenital malformations, which are mostly incompatible with life. Oviparous reptiles, such as sea turtles, that produce numerous eggs in a clutch that is buried on the beach provide an opportunity to study embryonic mortality associated with malformations that occur at different times during development, or that prevent the hatchling from emerging from the nest. In sea turtles, the presence of congenital malformations frequently leads to mortality. A few years ago, a detailed study was performed on external congenital malformations in three species of sea turtles from the Mexican Pacific and Caribbean coasts, the hawksbill turtle, Eretmochelys imbricata (n = 23,559 eggs), the green turtle, Chelonia mydas (n = 17,690 eggs), and the olive ridley, Lepidochelys olivacea (n = 20,257 eggs), finding 63 types of congenital malformations, of which 38 were new reports. Of the three species, the olive ridley showed a higher incidence of severe anomalies in the craniofacial region (49%), indicating alterations of early developmental pathways; however, several malformations were also observed in the body, including defects in the carapace (45%) and limbs (33%), as well as pigmentation disorders (20%), indicating that deviations occurred during the middle and later stages of development. Although intrinsic factors (i.e., genetic mutations or epigenetic modifications) are difficult to monitor in the field, some environmental factors (such as the incubation temperature, humidity, and probably the status of feeding areas) are, to some extent, less difficult to monitor and/or control. In this review, we describe the aetiology of different malformations observed in sea turtle embryos, and provide some actions that can reduce embryonic mortality.
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Lyson TR, Bever GS. Origin and Evolution of the Turtle Body Plan. ANNUAL REVIEW OF ECOLOGY, EVOLUTION, AND SYSTEMATICS 2020. [DOI: 10.1146/annurev-ecolsys-110218-024746] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The origin of turtles and their uniquely shelled body plan is one of the longest standing problems in vertebrate biology. The unfulfilled need for a hypothesis that both explains the derived nature of turtle anatomy and resolves their unclear phylogenetic position among reptiles largely reflects the absence of a transitional fossil record. Recent discoveries have dramatically improved this situation, providing an integrated, time-calibrated model of the morphological, developmental, and ecological transformations responsible for the modern turtle body plan. This evolutionary trajectory was initiated in the Permian (>260 million years ago) when a turtle ancestor with a diapsid skull evolved a novel mechanism for lung ventilation. This key innovation permitted the torso to become apomorphically stiff, most likely as an adaption for digging and a fossorial ecology. The construction of the modern turtle body plan then proceeded over the next 100 million years following a largely stepwise model of osteological innovation.
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Affiliation(s)
- Tyler R. Lyson
- Department of Earth Sciences, Denver Museum of Nature & Science, Denver, Colorado 80205, USA
| | - Gabriel S. Bever
- Department of Earth Sciences, Denver Museum of Nature & Science, Denver, Colorado 80205, USA
- Center for Functional Anatomy and Evolution, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA
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Cordero GA. Transcriptomic similarities and differences between the limb bud AER and unique carapacial ridge of turtle embryos. Evol Dev 2020; 22:370-383. [PMID: 32862496 DOI: 10.1111/ede.12351] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2020] [Revised: 07/10/2020] [Accepted: 08/02/2020] [Indexed: 01/04/2023]
Abstract
Evolutionary innovation may arise via major departures from an ancestral condition. Turtle shell morphogenesis depends on a unique structure known as the carapacial ridge (CR). This lateral tissue protrusion in turtle embryos exhibits similar properties as the apical ectodermal ridge (AER)-a well-known molecular signaling center involved in limb development. Still, how the CR influences shell morphogenesis is not entirely clear. The present study aimed to describe the CR transcriptome shortly before ribs were halted within its mesenchyme, as required for shell development. Analyses exposed that the mesenchymal marker VIM was one of the most highly co-expressed genes and numerous appendage formation genes were situated within the core of CR and AER co-expression networks. However, there were tissue-specific differences in the activity of these genes. For instance, WNT5A was most frequently assigned to appendage-related annotations of the CR network core, but not in the AER. Several homeobox transcription factors known to regulate limb bud patterning exhibited their highest expression levels in the AER, but were underexpressed in the CR. The results of this study corroborate that novel body plans often originate via alterations of pre-existing genetic networks. Altogether, this exploratory study enhances the groundwork for future experiments on the molecular underpinnings of turtle shell development and evolution.
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Affiliation(s)
- Gerardo A Cordero
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, Iowa, USA
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Smith Paredes D, Lord A, Meyer D, Bhullar BS. A developmental staging system and musculoskeletal development sequence of the common musk turtle (
Sternotherus odoratus
). Dev Dyn 2020; 250:111-127. [DOI: 10.1002/dvdy.210] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Accepted: 05/24/2020] [Indexed: 01/02/2023] Open
Affiliation(s)
- Daniel Smith Paredes
- Department of Earth and Planetary Science, Peabody Museum of Natural History Yale University New Haven Connecticut USA
| | - Arianna Lord
- Department of Earth and Planetary Science, Peabody Museum of Natural History Yale University New Haven Connecticut USA
| | - Dalton Meyer
- Department of Earth and Planetary Science, Peabody Museum of Natural History Yale University New Haven Connecticut USA
| | - Bhart‐Anjan S. Bhullar
- Department of Earth and Planetary Science, Peabody Museum of Natural History Yale University New Haven Connecticut USA
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11
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Scaal M. Development of the amniote ventrolateral body wall. Dev Dyn 2020; 250:39-59. [PMID: 32406962 DOI: 10.1002/dvdy.193] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Revised: 04/30/2020] [Accepted: 04/30/2020] [Indexed: 12/16/2022] Open
Abstract
In vertebrates, the trunk consists of the musculoskeletal structures of the back and the ventrolateral body wall, which together enclose the internal organs of the circulatory, digestive, respiratory and urogenital systems. This review gives an overview on the development of the thoracic and abdominal wall during amniote embryogenesis. Specifically, I briefly summarize relevant historical concepts and the present knowledge on the early embryonic development of ribs, sternum, intercostal muscles and abdominal muscles with respect to anatomical bauplan, origin and specification of precursor cells, initial steps of pattern formation, and cellular and molecular regulation of morphogenesis.
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Affiliation(s)
- Martin Scaal
- Faculty of Medicine, Institute of Anatomy II, University of Cologne, Cologne, Germany
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12
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Mayerl CJ, Capano JG, Moreno AA, Wyneken J, Blob RW, Brainerd EL. Pectoral and pelvic girdle rotations during walking and swimming in a semi-aquatic turtle: testing functional role and constraint. ACTA ACUST UNITED AC 2019; 222:jeb.212688. [PMID: 31767737 DOI: 10.1242/jeb.212688] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Accepted: 11/20/2019] [Indexed: 01/29/2023]
Abstract
Pectoral and pelvic girdle rotations play a substantial role in enhancing stride length across diverse tetrapod lineages. However, the pectoral and pelvic girdle attach the limbs to the body in different ways and may exhibit dissimilar functions, especially during locomotion in disparate environments. Here, we tested for functional differences between the forelimb and hindlimb of the freshwater turtle Pseudemys concinna during walking and swimming using X-ray reconstruction of moving morphology (XROMM). In doing so, we also tested the commonly held notion that the shell constrains girdle motion in turtles. We found that the pectoral girdle exhibited greater rotations than the pelvic girdle on land and in water. Additionally, pelvic girdle rotations were greater on land than in water, whereas pectoral girdle rotations were similar in the two environments. These results indicate that although the magnitude of pelvic girdle rotations depends primarily on whether the weight of the body must be supported against gravity, the magnitude of pectoral girdle rotations likely depends primarily on muscular activity associated with locomotion. Furthermore, the pectoral girdle of turtles rotated more than has been observed in other taxa with sprawling postures, showing an excursion similar to that of mammals (∼38 deg). These results suggest that a rigid axial skeleton and internally positioned pectoral girdle have not constrained turtle girdle function, but rather the lack of lateral undulations in turtles and mammals may contribute to a functional convergence whereby the girdle acts as an additional limb segment to increase stride length.
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Affiliation(s)
- Christopher J Mayerl
- Department of Anatomy and Neurobiology, Northeast Ohio Medical University (NEOMED), Rootstown, OH 44272, USA
| | - John G Capano
- Department of Ecology and Evolutionary Biology, Brown University, Providence, RI 02912, USA
| | - Adam A Moreno
- Department of Ecology and Evolutionary Biology, Brown University, Providence, RI 02912, USA
| | - Jeanette Wyneken
- Department of Biology, Florida Atlantic University, Boca Raton, FL 33431, USA
| | - Richard W Blob
- Department of Biological Sciences, Clemson University, Clemson, SC 29634, USA
| | - Elizabeth L Brainerd
- Department of Ecology and Evolutionary Biology, Brown University, Providence, RI 02912, USA
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Crotty SM, Minh BQ, Bean NG, Holland BR, Tuke J, Jermiin LS, Haeseler AV. GHOST: Recovering Historical Signal from Heterotachously Evolved Sequence Alignments. Syst Biol 2019; 69:249-264. [DOI: 10.1093/sysbio/syz051] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2017] [Revised: 07/18/2019] [Accepted: 07/22/2019] [Indexed: 01/01/2023] Open
Abstract
Abstract
Molecular sequence data that have evolved under the influence of heterotachous evolutionary processes are known to mislead phylogenetic inference. We introduce the General Heterogeneous evolution On a Single Topology (GHOST) model of sequence evolution, implemented under a maximum-likelihood framework in the phylogenetic program IQ-TREE (http://www.iqtree.org). Simulations show that using the GHOST model, IQ-TREE can accurately recover the tree topology, branch lengths, and substitution model parameters from heterotachously evolved sequences. We investigate the performance of the GHOST model on empirical data by sampling phylogenomic alignments of varying lengths from a plastome alignment. We then carry out inference under the GHOST model on a phylogenomic data set composed of 248 genes from 16 taxa, where we find the GHOST model concurs with the currently accepted view, placing turtles as a sister lineage of archosaurs, in contrast to results obtained using traditional variable rates-across-sites models. Finally, we apply the model to a data set composed of a sodium channel gene of 11 fish taxa, finding that the GHOST model is able to elucidate a subtle component of the historical signal, linked to the previously established convergent evolution of the electric organ in two geographically distinct lineages of electric fish. We compare inference under the GHOST model to partitioning by codon position and show that, owing to the minimization of model constraints, the GHOST model offers unique biological insights when applied to empirical data.
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Affiliation(s)
- Stephen M Crotty
- Center for Integrative Bioinformatics Vienna, Max F. Perutz Laboratories, University of Vienna and Medical University of Vienna, Vienna, Austria
- School of Mathematical Sciences, University of Adelaide, Adelaide, SA 5005, Australia
| | - Bui Quang Minh
- Center for Integrative Bioinformatics Vienna, Max F. Perutz Laboratories, University of Vienna and Medical University of Vienna, Vienna, Austria
- Research School of Biology, Australian National University, Canberra, ACT 2601, Australia
| | - Nigel G Bean
- School of Mathematical Sciences, University of Adelaide, Adelaide, SA 5005, Australia
- ARC Centre of Excellence for Mathematical and Statistical Frontiers, The University of Adelaide, Adelaide, SA, Australia
| | - Barbara R Holland
- School of Natural Sciences, University of Tasmania, Hobart, TAS 7001, Australia
| | - Jonathan Tuke
- School of Mathematical Sciences, University of Adelaide, Adelaide, SA 5005, Australia
- ARC Centre of Excellence for Mathematical and Statistical Frontiers, The University of Adelaide, Adelaide, SA, Australia
| | - Lars S Jermiin
- Research School of Biology, Australian National University, Canberra, ACT 2601, Australia
- CSIRO Land & Water, Black Mountain Laboratories, Canberra, ACT 2601, Australia
- School of Biology and Environmental Science, University College Dublin, Belfield, Dublin 4, Ireland
- Earth Institute, University College Dublin, Belfield, Dublin 4, Ireland
| | - Arndt Von Haeseler
- Center for Integrative Bioinformatics Vienna, Max F. Perutz Laboratories, University of Vienna and Medical University of Vienna, Vienna, Austria
- Bioinformatics & Computational Biology, Faculty of Computer Science, University of Vienna, Vienna, Austria
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14
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Chinese lantern in Physalis is an advantageous morphological novelty and improves plant fitness. Sci Rep 2019; 9:596. [PMID: 30679462 PMCID: PMC6345875 DOI: 10.1038/s41598-018-36436-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2018] [Accepted: 11/22/2018] [Indexed: 01/04/2023] Open
Abstract
The origin of morphological novelties is an important but neglected issue of evolutionary biology. The fruit of the genus Physalis, a berry, is encapsulated by a novel morphological feature of the post-floral, accrescent calyx that is referred to as a Chinese lantern. The evolutionary developmental genetics of the Chinese lantern have been investigated in the last decade; however, the selective values of the morphological novelty remain elusive. Here, we measured the photosynthetic parameters of the fruiting calyces, monitored microclimatic variation within the Chinese lanterns during fruit development, performed floral-calyx-removal experiments, and recorded the fitness-related traits in Physalis floridana. Ultimately, we show that the green-fruiting calyx of Physalis has photosynthetic capabilities, thus serving as an energy source for fruit development. Moreover, the developing Chinese lantern provides a microclimate that benefits the development and maturation of berry and seed, and it improves plant fitness in terms of fruit/seed weight and number, and fruit maturation under low-temperature environments. Furthermore, the lantern structure facilitates the dispersal of fruits and seeds by water and wind. Our results suggest that the Chinese lantern morphology of Physalis is an evolutionary adaptive trait and improves plant fitness, thus providing new insight into the origin of morphological novelties.
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Szczygielski T, Słowiak J, Dróżdż D. Shell variability in the stem turtles Proterochersis spp. PeerJ 2019; 6:e6134. [PMID: 30595986 PMCID: PMC6305121 DOI: 10.7717/peerj.6134] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Accepted: 11/19/2018] [Indexed: 12/11/2022] Open
Abstract
Background Turtle shells tend to exhibit frequent and substantial variability, both in bone and scute layout. Aside from secondary changes, caused by diseases, parasites, and trauma, this variability appears to be inherent and result from stochastic or externally induced flaws of developmental programs. It is, thus, expected to be present in fossil turtle species at least as prominently, as in modern populations. Descriptions of variability and ontogeny are, however, rare for fossil turtles, mainly due to rarity, incompleteness, damage, and post-mortem deformation of their remains. This paper is an attempt at description and interpretation of external shell variability in representatives of the oldest true turtles, Proterochersis robusta and Proterochersis porebensis (Proterochersidae, the sister group to all other known testudinatans) from the Late Triassic (Norian) of Germany and Poland. Methods All the available shell remains of Proterochersis robusta (13 specimens) and Proterochersis porebensis (275 specimens) were studied morphologically in order to identify any ontogenetic changes, intraspecific variability, sexual dimorphism, and shell abnormalities. To test the inferred sexual dimorphism, shape analyses were performed for two regions (gular and anal) of the plastron. Results Proterochersis spp. exhibits large shell variability, and at least some of the observed changes seem to be correlated with ontogeny (growth of gulars, extragulars, caudals, and marginals, disappearance of middorsal keel on the carapace). Several specimens show abnormal layout of scute sulci, several others unusual morphologies of vertebral scute areas, one has an additional pair of plastral scutes, and one extraordinarily pronounced, likely pathological, growth rings on the carapace. Both species are represented in a wide spectrum of sizes, from hatchlings to old, mature individuals. The largest fragmentary specimens of Proterochersis porebensis allow estimation of its maximal carapace length at approximately 80 cm, while Proterochersis robusta appears to have reached lower maximal sizes. Discussion This is the second contribution describing variability among numerous specimens of Triassic turtles, and the first to show evidence of unambiguous shell abnormalities. Presented data supplement the sparse knowledge of shell scute development in the earliest turtles and suggest that at least some aspects of the developmental programs governing scute development were already similar in the Late Triassic to these of modern forms.
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Affiliation(s)
- Tomasz Szczygielski
- Department of Evolutionary Paleobiology, Institute of Paleobiology, Polish Academy of Sciences, Warsaw, Poland.,Department of Paleobiology and Evolution, Faculty of Biology, Biological and Chemical Research Centre, University of Warsaw, Warsaw, Poland
| | - Justyna Słowiak
- Department of Evolutionary Paleobiology, Institute of Paleobiology, Polish Academy of Sciences, Warsaw, Poland
| | - Dawid Dróżdż
- Department of Evolutionary Paleobiology, Institute of Paleobiology, Polish Academy of Sciences, Warsaw, Poland
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Evolution, Diversity, and Development of the Craniocervical System in Turtles with Special Reference to Jaw Musculature. HEADS, JAWS, AND MUSCLES 2019. [DOI: 10.1007/978-3-319-93560-7_8] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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17
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Vieira LG, Lima FC, Mendonôa SHST, Menezes LT, Hirano LQL, Santos ALQ. Ontogeny of the Postcranial Axial Skeleton of Melanosuchus niger (Crocodylia, Alligatoridae). Anat Rec (Hoboken) 2017; 301:607-623. [PMID: 29150983 DOI: 10.1002/ar.23722] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2017] [Revised: 07/11/2017] [Accepted: 07/24/2017] [Indexed: 11/07/2022]
Abstract
This study proposes the description of the development of the postcranial axial skeleton, including vertebrae, gastralium, ribs, sternum, and interclavicle, in Melanosuchus niger. Six nests were marked and two eggs removed from each nest at 24-hr intervals until hatching. For posthatching evaluation, 30 hatchlings were kept in captivity and one exemplar was euthanized at three-day intervals. Samples were diaphanized using potassium hydroxide (KOH), alizarin red S, and Alcian blue. A routinely generally used method was applied for histological evaluation. It was difficult to define in which vertebrae the development of cartilaginous centers began, but it was possible to observe that this condensation advanced in the craniocaudal direction. The condensation started in the vertebral arches and was visibly stronger in the cervical and dorsal regions, advancing to the lumbar, sacral and, last, to the caudal region. The atlas showed a highly different morphology compared with the other cervical vertebrae, with a short intercenter, two neural arches, and a proatlas. The ossification process began in the body of cervical vertebrae III to VIII and alizarin retention decreased in the last vertebrae, indicating a craniocaudal direction in bone development, similar to cartilage formation. In the histological sections of gastralium and interclavicles of M. niger at several development stages, it was possible to observe that these elements showed intramembranous development. Anat Rec, 301:607-623, 2018. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- LucéLia Gonçalves Vieira
- Institute of Biomedical Sciences, Federal University of Uberlândia, Av. Pará 1720, Bloco 2B, Uberlândia, Minas Gerais CEP 38400-902 - CP 592, Brazil
| | - Fabiano Campos Lima
- Federal University of Goiás, Rodovia BR 364, Km 192. Setor Industrial, Jataí, Goiás CEP 75801615, Brazil
| | | | - Lorena Tannús Menezes
- Institute of Biomedical Sciences, Federal University of Uberlândia, Av. Pará 1720, Bloco 2B, Uberlândia, Minas Gerais CEP 38400-902 - CP 592, Brazil
| | - Líria Queiroz Luz Hirano
- University Center of Triângulo, Av. Raulino Cotta Pacheco, 70, apto 201, Osvaldo Resende, Uberlândia, Minas Gerais CEP 38400-370, Brazil
| | - André Luiz Quagliatto Santos
- Laboratory for Teaching and Research on Wild Animals, Federal University of Uberlândia, Rua Piauí, s/n, 4S, Uberlândia, MG, 38400-902, Brazil
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Böhmer C, Werneburg I. Deep time perspective on turtle neck evolution: chasing the Hox code by vertebral morphology. Sci Rep 2017; 7:8939. [PMID: 28827543 PMCID: PMC5566328 DOI: 10.1038/s41598-017-09133-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2017] [Accepted: 07/21/2017] [Indexed: 12/24/2022] Open
Abstract
The unparalleled ability of turtle neck retraction is possible in three different modes, which characterize stem turtles, living side-necked (Pleurodira), and hidden-necked (Cryptodira) turtles, respectively. Despite the conservatism in vertebral count among turtles, there is significant functional and morphological regionalization in the cervical vertebral column. Since Hox genes play a fundamental role in determining the differentiation in vertebra morphology and based on our reconstruction of evolutionary genetics in deep time, we hypothesize genetic differences among the turtle groups and between turtles and other land vertebrates. We correlated anterior Hox gene expression and the quantifiable shape of the vertebrae to investigate the morphological modularity in the neck across living and extinct turtles. This permitted the reconstruction of the hypothetical ancestral Hox code pattern of the whole turtle clade. The scenario of the evolution of axial patterning in turtles indicates shifts in the spatial expression of HoxA-5 in relation to the reduction of cervical ribs in modern turtles and of HoxB-5 linked with a lower morphological differentiation between the anterior cervical vertebrae observed in cryptodirans. By comparison with the mammalian pattern, we illustrate how the fixed count of eight cervical vertebrae in turtles resulted from the emergence of the unique turtle shell.
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Affiliation(s)
- Christine Böhmer
- UMR 7179 CNRS/MNHN, Muséum National d'Histoire Naturelle, 57 rue Cuvier CP-55, 75005, Paris, France.
| | - Ingmar Werneburg
- Senckenberg Center for Human Evolution and Palaeoenvironment at Eberhard Karls Universität, Sigwartstr, 10, 72076, Tübingen, Germany.
- Fachbereich Geowissenschaften, Eberhard Karls Universität, Hölderlinstraße 12, D-72074, Tübingen, Germany.
- Museum für Naturkunde, Leibniz-Institut für Evolutions- und Biodiversitätsforschung an der Humboldt-Universität zu Berlin, Invalidenstraße 43, 10115, Berlin, Germany.
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Moustakas-Verho JE, Cebra-Thomas J, Gilbert SF. Patterning of the turtle shell. Curr Opin Genet Dev 2017; 45:124-131. [DOI: 10.1016/j.gde.2017.03.016] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Revised: 03/06/2017] [Accepted: 03/21/2017] [Indexed: 12/30/2022]
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Zimm R, Bentley BP, Wyneken J, Moustakas-Verho JE. Environmental Causation of Turtle Scute Anomalies in ovo and in silico. Integr Comp Biol 2017; 57:1303-1311. [DOI: 10.1093/icb/icx066] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
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Joyce WG. A Review of the Fossil Record of Basal Mesozoic Turtles. BULLETIN OF THE PEABODY MUSEUM OF NATURAL HISTORY 2017. [DOI: 10.3374/014.058.0105] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Walter G. Joyce
- Department of Geosciences, University of Fribourg, 1700 Fribourg, Switzerland—
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22
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Foth C, Rabi M, Joyce WG. Skull shape variation in extant and extinct Testudinata and its relation to habitat and feeding ecology. ACTA ZOOL-STOCKHOLM 2016. [DOI: 10.1111/azo.12181] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Affiliation(s)
- Christian Foth
- Departement für Geowissenschaften; Universität Freiburg; 1700 Freiburg Switzerland
| | - Márton Rabi
- Department of Earth Sciences; University of Turin; 10125 Turin Italy
- Institut für Geowissenschaften; Universität Tübingen; 72074 Tübingen Germany
| | - Walter G. Joyce
- Departement für Geowissenschaften; Universität Freiburg; 1700 Freiburg Switzerland
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Vieira LG, Santos AL, Lima FC, Mendonça SH, Menezes LT, Sebben A. Osteologia de Melanosuchus niger (Crocodylia: Alligatoridae) e a evidência evolutiva. PESQUISA VETERINARIA BRASILEIRA 2016. [DOI: 10.1590/s0100-736x2016001000018] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
RESUMO: O objetivo foi realizar a descrição anatômica do esqueleto de Melanosuchus niger, com o intuito de contribuir com informações evolutivas sobre a espécie. Utilizaram-se três espécimes adultos de M. niger, com comprimento médio de 2,40m, provenientes da coleção biológica do Lapas-UFU. Na cintura peitoral, a escápula é maior do que o coracóide. Já nos elementos da cintura pelvina, o púbis não participa da formação do acetábulo, o contato com o ilío, ocorre por ligamentos, e sua articulação com o ísquio, permite movimentos dorso-ventrais. Nos membros torácicos, o úmero figura como elemento do estilopódio, a ulna e rádio como elementos do zeugopódio. No carpo há o ulnar do carpo, fusão do radial+intermédio, fusão dos distais do carpo 3+4+5 e o pisiforme; possui cinco metacarpos, numerados lateromedialmente e a fórmula falângica 2:3:4:3:2. Nos membros pelvinos, o estilopódio é formado pelo fêmur e o zeugopódio pela tíbia e fíbula. No tarso há a fusão do intermédio+central, fibular do tarso, distal do tarso 3, distal do tarso 4; possui quatro metatarsos longos I, II, III e IV, sendo os metatarsos II e III maiores que os demais. O metatarso V é um osso bastante reduzido e o pé possui a fórmula falângica 2:3:4:4. No crânio, a abertura nasal é única, o palatino, vômer, pterigóide, pré-maxila e maxila formam a estrutura óssea do palato secundário; o osso parietal é o único elemento no teto craniano. No esqueleto pós- axial em pares de costelas distintas que se articulam com as vértebras cervicais, dorsais, lombares, sacrais e caudais. A gastrália é formada por sete fileiras de ossos finos localizados entre o púbis e a região caudal do esterno.
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Lyson T, Rubidge B, Scheyer T, de Queiroz K, Schachner E, Smith R, Botha-Brink J, Bever G. Fossorial Origin of the Turtle Shell. Curr Biol 2016; 26:1887-94. [DOI: 10.1016/j.cub.2016.05.020] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2016] [Revised: 05/03/2016] [Accepted: 05/05/2016] [Indexed: 10/21/2022]
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Schmidt M, Mehlhorn M, Fischer MS. Shoulder girdle rotation, forelimb movement and the influence of carapace shape on locomotion in Testudo hermanni (Testudinidae). ACTA ACUST UNITED AC 2016; 219:2693-703. [PMID: 27340203 DOI: 10.1242/jeb.137059] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2016] [Accepted: 06/20/2016] [Indexed: 11/20/2022]
Abstract
Studies into the function of structures are crucial for making connections between morphology and behaviour of organisms, but are still rare for the terrestrial Testudinidae. We investigated the kinematics of shoulder girdle and forelimb motion in Hermann's tortoise Testudo hermanni using biplanar X-ray fluoroscopy with a twofold aim: firstly, to understand how the derived shapes of shoulder girdle and carapace together influence rotation of the girdle; and, secondly, to understand how girdle rotation affects forelimb excursion. The total degree of shoulder rotation in the horizontal plane is similar to a species with a less domed shell, but because of the long and nearly vertically oriented scapular prong, shoulder girdle rotation contributes more than 30% to the horizontal arc of the humerus and nearly 40% to the rotational component of step length. The antebrachium and manus, which act as a functional unit, contribute roughly 50% to this component of the step length because of their large excursion almost parallel to the mid-sagittal plane. This large excursion is the result of the complex interplay between humerus long-axis rotation, counter-rotation of the antebrachium, and elbow flexion and extension. A significant proportion of forelimb step length results from body translation that is due to the propulsive effect of the other limbs during their stance phases. Traits that are similar to other tortoises and terrestrial or semi-aquatic turtles are the overall slow walk because of a low stride frequency, and the lateral-sequence, diagonally coupled footfall pattern with high duty factors. Intraspecific variation of carapace shape and shoulder girdle dimensions has a corresponding effect on forelimb kinematics.
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Affiliation(s)
- Manuela Schmidt
- Institute of Systematic Zoology and Evolutionary Biology, Friedrich-Schiller-University Jena, Erbertstraße 1, Jena 07743, Germany
| | - Martin Mehlhorn
- Institute of Systematic Zoology and Evolutionary Biology, Friedrich-Schiller-University Jena, Erbertstraße 1, Jena 07743, Germany
| | - Martin S Fischer
- Institute of Systematic Zoology and Evolutionary Biology, Friedrich-Schiller-University Jena, Erbertstraße 1, Jena 07743, Germany
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Peterson T, Müller GB. Phenotypic Novelty in EvoDevo: The Distinction Between Continuous and Discontinuous Variation and Its Importance in Evolutionary Theory. Evol Biol 2016; 43:314-335. [PMID: 27512237 PMCID: PMC4960286 DOI: 10.1007/s11692-016-9372-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2015] [Accepted: 01/29/2016] [Indexed: 10/25/2022]
Abstract
The introduction of novel phenotypic structures is one of the most significant aspects of organismal evolution. Yet the concept of evolutionary novelty is used with drastically different connotations in various fields of research, and debate exists about whether novelties represent features that are distinct from standard forms of phenotypic variation. This article contrasts four separate uses for novelty in genetics, population genetics, morphology, and behavioral science, before establishing how novelties are used in evolutionary developmental biology (EvoDevo). In particular, it is detailed how an EvoDevo-specific research approach to novelty produces insight distinct from other fields, gives the concept explanatory power with predictive capacities, and brings new consequences to evolutionary theory. This includes the outlining of research strategies that draw attention to productive areas of inquiry, such as threshold dynamics in development. It is argued that an EvoDevo-based approach to novelty is inherently mechanistic, treats the phenotype as an agent with generative potential, and prompts a distinction between continuous and discontinuous variation in evolutionary theory.
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Affiliation(s)
- Tim Peterson
- Department of Theoretical Biology, University of Vienna, Althanstrasse 14, 1090 Vienna, Austria
| | - Gerd B. Müller
- Department of Theoretical Biology, University of Vienna, Althanstrasse 14, 1090 Vienna, Austria
- The KLI Institute, Martinstrasse 12, 3400 Klosterneuburg, Austria
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Development of the turtle plastron, the order-defining skeletal structure. Proc Natl Acad Sci U S A 2016; 113:5317-22. [PMID: 27114549 DOI: 10.1073/pnas.1600958113] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
The dorsal and ventral aspects of the turtle shell, the carapace and the plastron, are developmentally different entities. The carapace contains axial endochondral skeletal elements and exoskeletal dermal bones. The exoskeletal plastron is found in all extant and extinct species of crown turtles found to date and is synaptomorphic of the order Testudines. However, paleontological reconstructed transition forms lack a fully developed carapace and show a progression of bony elements ancestral to the plastron. To understand the evolutionary development of the plastron, it is essential to know how it has formed. Here we studied the molecular development and patterning of plastron bones in a cryptodire turtle Trachemys scripta We show that plastron development begins at developmental stage 15 when osteochondrogenic mesenchyme forms condensates for each plastron bone at the lateral edges of the ventral mesenchyme. These condensations commit to an osteogenic identity and suppress chondrogenesis. Their development overlaps with that of sternal cartilage development in chicks and mice. Thus, we suggest that in turtles, the sternal morphogenesis is prevented in the ventral mesenchyme by the concomitant induction of osteogenesis and the suppression of chondrogenesis. The osteogenic subroutines later direct the growth and patterning of plastron bones in an autonomous manner. The initiation of plastron bone development coincides with that of carapacial ridge formation, suggesting that the development of dorsal and ventral shells are coordinated from the start and that adopting an osteogenesis-inducing and chondrogenesis-suppressing cell fate in the ventral mesenchyme has permitted turtles to develop their order-specific ventral morphology.
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Moustakas-Verho JE, Cherepanov GO. The integumental appendages of the turtle shell: an evo-devo perspective. JOURNAL OF EXPERIMENTAL ZOOLOGY PART B-MOLECULAR AND DEVELOPMENTAL EVOLUTION 2016; 324:221-9. [PMID: 25877335 DOI: 10.1002/jez.b.22619] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2014] [Accepted: 02/26/2015] [Indexed: 12/24/2022]
Abstract
The turtle shell is composed of dorsal armor (carapace) and ventral armor (plastron) covered by a keratinized epithelium. There are two epithelial appendages of the turtle shell: scutes (large epidermal shields separated by furrows and forming a unique mosaic) and tubercles (numerous small epidermal bumps located on the carapaces of some species). In our perspective, we take a synthetic, comparative approach to consider the homology and evolution of these integumental appendages. Scutes have been more intensively studied, as they are autapomorphic for turtles and can be diagnostic taxonomically. Their pattern of tessellation is stable phylogenetically, but labile in the individual. We discuss the history of developmental investigations of these structures and hypotheses of evolutionary and anomalous variation. In our estimation, the scutes of the turtle shell are an evolutionary novelty, whereas the tubercles found on the shells of some turtles are homologous to reptilian scales.
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Holthaus KB, Strasser B, Sipos W, Schmidt HA, Mlitz V, Sukseree S, Weissenbacher A, Tschachler E, Alibardi L, Eckhart L. Comparative Genomics Identifies Epidermal Proteins Associated with the Evolution of the Turtle Shell. Mol Biol Evol 2015; 33:726-37. [PMID: 26601937 PMCID: PMC4760078 DOI: 10.1093/molbev/msv265] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
The evolution of reptiles, birds, and mammals was associated with the origin of unique integumentary structures. Studies on lizards, chicken, and humans have suggested that the evolution of major structural proteins of the outermost, cornified layers of the epidermis was driven by the diversification of a gene cluster called Epidermal Differentiation Complex (EDC). Turtles have evolved unique defense mechanisms that depend on mechanically resilient modifications of the epidermis. To investigate whether the evolution of the integument in these reptiles was associated with specific adaptations of the sequences and expression patterns of EDC-related genes, we utilized newly available genome sequences to determine the epidermal differentiation gene complement of turtles. The EDC of the western painted turtle (Chrysemys picta bellii) comprises more than 100 genes, including at least 48 genes that encode proteins referred to as beta-keratins or corneous beta-proteins. Several EDC proteins have evolved cysteine/proline contents beyond 50% of total amino acid residues. Comparative genomics suggests that distinct subfamilies of EDC genes have been expanded and partly translocated to loci outside of the EDC in turtles. Gene expression analysis in the European pond turtle (Emys orbicularis) showed that EDC genes are differentially expressed in the skin of the various body sites and that a subset of beta-keratin genes within the EDC as well as those located outside of the EDC are expressed predominantly in the shell. Our findings give strong support to the hypothesis that the evolutionary innovation of the turtle shell involved specific molecular adaptations of epidermal differentiation.
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Affiliation(s)
- Karin Brigit Holthaus
- Research Division of Biology and Pathobiology of the Skin, Department of Dermatology, Medical University of Vienna, Vienna, Austria Dipartimento di Scienze Biologiche, Geologiche ed Ambientali (BiGeA), University of Bologna, Bologna, Italy
| | - Bettina Strasser
- Research Division of Biology and Pathobiology of the Skin, Department of Dermatology, Medical University of Vienna, Vienna, Austria
| | - Wolfgang Sipos
- Clinical Department for Farm Animals and Herd Management, University of Veterinary Medicine Vienna, Vienna, Austria
| | - Heiko A Schmidt
- Center for Integrative Bioinformatics Vienna (CIBIV), Max F. Perutz Laboratories, Medical University of Vienna, University of Vienna, Vienna, Austria
| | - Veronika Mlitz
- Research Division of Biology and Pathobiology of the Skin, Department of Dermatology, Medical University of Vienna, Vienna, Austria
| | - Supawadee Sukseree
- Research Division of Biology and Pathobiology of the Skin, Department of Dermatology, Medical University of Vienna, Vienna, Austria
| | | | - Erwin Tschachler
- Research Division of Biology and Pathobiology of the Skin, Department of Dermatology, Medical University of Vienna, Vienna, Austria
| | - Lorenzo Alibardi
- Dipartimento di Scienze Biologiche, Geologiche ed Ambientali (BiGeA), University of Bologna, Bologna, Italy
| | - Leopold Eckhart
- Research Division of Biology and Pathobiology of the Skin, Department of Dermatology, Medical University of Vienna, Vienna, Austria
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Joyce WG. The origin of turtles: a paleontological perspective. JOURNAL OF EXPERIMENTAL ZOOLOGY PART B-MOLECULAR AND DEVELOPMENTAL EVOLUTION 2015; 324:181-93. [PMID: 25712176 DOI: 10.1002/jez.b.22609] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2014] [Accepted: 10/27/2014] [Indexed: 11/10/2022]
Abstract
The origin of turtles and their unusual body plan has fascinated scientists for the last two centuries. Over the course of the last decades, a broad sample of molecular analyses have favored a sister group relationship of turtles with archosaurs, but recent studies reveal that this signal may be the result of systematic biases affecting molecular approaches, in particular sampling, non-randomly distributed rate heterogeneity among taxa, and the use of concatenated data sets. Morphological studies, by contrast, disfavor archosaurian relationships for turtles, but the proposed alternative topologies are poorly supported as well. The recently revived paleontological hypothesis that the Middle Permian Eunotosaurus africanus is an intermediate stem turtle is now robustly supported by numerous characters that were previously thought to be unique to turtles and that are now shown to have originated over the course of tens of millions of years unrelated to the origin of the turtle shell. Although E. africanus does not solve the placement of turtles within Amniota, it successfully extends the stem lineage of turtles to the Permian and helps resolve some questions associated with the origin of turtles, in particular the non-composite origin of the shell, the slow origin of the shell, and the terrestrial setting for the origin of turtles.
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Affiliation(s)
- Walter G Joyce
- Department of Geoscience, University of Fribourg, Fribourg, Switzerland
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Rice R, Riccio P, Gilbert SF, Cebra-Thomas J. Emerging from the rib: resolving the turtle controversies. JOURNAL OF EXPERIMENTAL ZOOLOGY PART B-MOLECULAR AND DEVELOPMENTAL EVOLUTION 2015; 324:208-20. [PMID: 25675951 DOI: 10.1002/jez.b.22600] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2014] [Accepted: 09/29/2014] [Indexed: 12/15/2022]
Abstract
Two of the major controversies in the present study of turtle shell development involve the mechanism by which the carapacial ridge initiates shell formation and the mechanism by which each rib forms the costal bones adjacent to it. This paper claims that both sides of each debate might be correct-but within the species examined. Mechanism is more properly "mechanisms," and there is more than one single way to initiate carapace formation and to form the costal bones. In the initiation of the shell, the rib precursors may be kept dorsal by either "axial displacement" (in the hard-shell turtles) or "axial arrest" (in the soft-shell turtle Pelodiscus), or by a combination of these. The former process would deflect the rib into the dorsal dermis and allow it to continue its growth there, while the latter process would truncate rib growth. In both instances, though, the result is to keep the ribs from extending into the ventral body wall. Our recent work has shown that the properties of the carapacial ridge, a key evolutionary innovation of turtles, differ greatly between these two groups. Similarly, the mechanism of costal bone formation may differ between soft-shell and hard-shell turtles, in that the hard-shell species may have both periosteal flattening as well as dermal bone induction, while the soft-shelled turtles may have only the first of these processes.
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Affiliation(s)
- Ritva Rice
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland
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Moustakas-Verho JE, Zimm R, Cebra-Thomas J, Lempiäinen NK, Kallonen A, Mitchell KL, Hämäläinen K, Salazar-Ciudad I, Jernvall J, Gilbert SF. The origin and loss of periodic patterning in the turtle shell. Development 2014; 141:3033-9. [DOI: 10.1242/dev.109041] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The origin of the turtle shell over 200 million years ago greatly modified the amniote body plan, and the morphological plasticity of the shell has promoted the adaptive radiation of turtles. The shell, comprising a dorsal carapace and a ventral plastron, is a layered structure formed by basal endochondral axial skeletal elements (ribs, vertebrae) and plates of bone, which are overlain by keratinous ectodermal scutes. Studies of turtle development have mostly focused on the bones of the shell; however, the genetic regulation of the epidermal scutes has not been investigated. Here, we show that scutes develop from an array of patterned placodes and that these placodes are absent from a soft-shelled turtle in which scutes were lost secondarily. Experimentally inhibiting Shh, Bmp or Fgf signaling results in the disruption of the placodal pattern. Finally, a computational model is used to show how two coupled reaction-diffusion systems reproduce both natural and abnormal variation in turtle scutes. Taken together, these placodal signaling centers are likely to represent developmental modules that are responsible for the evolution of scutes in turtles, and the regulation of these centers has allowed for the diversification of the turtle shell.
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Affiliation(s)
- Jacqueline E. Moustakas-Verho
- Developmental Biology Program, Institute of Biotechnology, University of Helsinki, P.O. Box 56, Helsinki FIN-00014, Finland
| | - Roland Zimm
- Developmental Biology Program, Institute of Biotechnology, University of Helsinki, P.O. Box 56, Helsinki FIN-00014, Finland
| | - Judith Cebra-Thomas
- Biology Department, Millersville University, P.O. Box 1002, Millersville, PA 17551, USA
| | - Netta K. Lempiäinen
- Developmental Biology Program, Institute of Biotechnology, University of Helsinki, P.O. Box 56, Helsinki FIN-00014, Finland
| | - Aki Kallonen
- Division of Materials Physics, Department of Physics, University of Helsinki, P.O. Box 64, Helsinki FIN-00014, Finland
| | - Katherine L. Mitchell
- Biology Department, Swarthmore College, 500 College Avenue, Swarthmore, PA 19081, USA
| | - Keijo Hämäläinen
- Division of Materials Physics, Department of Physics, University of Helsinki, P.O. Box 64, Helsinki FIN-00014, Finland
| | - Isaac Salazar-Ciudad
- Developmental Biology Program, Institute of Biotechnology, University of Helsinki, P.O. Box 56, Helsinki FIN-00014, Finland
- Departament de Genètica i Microbiologia, Universitat Autònoma de Barcelona, 08193 Cerdanyola del Vallès, Barcelona, Spain
| | - Jukka Jernvall
- Developmental Biology Program, Institute of Biotechnology, University of Helsinki, P.O. Box 56, Helsinki FIN-00014, Finland
| | - Scott F. Gilbert
- Developmental Biology Program, Institute of Biotechnology, University of Helsinki, P.O. Box 56, Helsinki FIN-00014, Finland
- Biology Department, Swarthmore College, 500 College Avenue, Swarthmore, PA 19081, USA
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MacCord K, Caniglia G, Moustakas-Verho JE, Burke AC. The dawn of chelonian research: Turtles between comparative anatomy and embryology in the 19th century. JOURNAL OF EXPERIMENTAL ZOOLOGY PART B-MOLECULAR AND DEVELOPMENTAL EVOLUTION 2014; 324:169-80. [DOI: 10.1002/jez.b.22587] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2014] [Accepted: 06/18/2014] [Indexed: 11/10/2022]
Affiliation(s)
- Kate MacCord
- Center for Biology and Society; Arizona State University; Tempe Arizona
| | - Guido Caniglia
- Center for Biology and Society; Arizona State University; Tempe Arizona
| | | | - Ann C. Burke
- Department of Biology; Wesleyan University; Middletown Connecticut
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Nagashima H, Shibata M, Taniguchi M, Ueno S, Kamezaki N, Sato N. Comparative study of the shell development of hard- and soft-shelled turtles. J Anat 2014; 225:60-70. [PMID: 24754673 PMCID: PMC4089346 DOI: 10.1111/joa.12189] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/18/2014] [Indexed: 12/23/2022] Open
Abstract
The turtle shell provides a fascinating model for the investigation of the evolutionary modifications of developmental mechanisms. Different conclusions have been put forth for its development, and it is suggested that one of the causes of the disagreement could be the differences in the species of the turtles used - the differences between hard-shelled turtles and soft-shelled turtles. To elucidate the cause of the difference, we compared the turtle shell development in the two groups of turtle. In the dorsal shell development, these two turtle groups shared the gene expression profile that is required for formation, and shared similar spatial organization of the anatomical elements during development. Thus, both turtles formed the dorsal shell through a folding of the lateral body wall, and the Wnt signaling pathway appears to have been involved in the development. The ventral portion of the shell, on the other hand, contains massive dermal bones. Although expression of HNK-1 epitope has suggested that the trunk neural crest contributed to the dermal bones in the hard-shelled turtles, it was not expressed in the initial anlage of the skeletons in either of the types of turtle. Hence, no evidence was found that would support a neural crest origin.
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Affiliation(s)
- Hiroshi Nagashima
- Division of Gross Anatomy and Morphogenesis, Niigata University Graduate School of Medical and Dental SciencesNiigata, Japan
| | - Masahiro Shibata
- Division of Gross Anatomy and Morphogenesis, Niigata University Graduate School of Medical and Dental SciencesNiigata, Japan
| | - Mari Taniguchi
- Suma Aqualife ParkKobe, Japan
- Sea Turtle Association of JapanHirakata, Japan
| | - Shintaro Ueno
- Suma Aqualife ParkKobe, Japan
- Sea Turtle Association of JapanHirakata, Japan
| | - Naoki Kamezaki
- Suma Aqualife ParkKobe, Japan
- Sea Turtle Association of JapanHirakata, Japan
| | - Noboru Sato
- Division of Gross Anatomy and Morphogenesis, Niigata University Graduate School of Medical and Dental SciencesNiigata, Japan
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Hirasawa T, Pascual-Anaya J, Kamezaki N, Taniguchi M, Mine K, Kuratani S. The evolutionary origin of the turtle shell and its dependence on the axial arrest of the embryonic rib cage. JOURNAL OF EXPERIMENTAL ZOOLOGY PART B-MOLECULAR AND DEVELOPMENTAL EVOLUTION 2014; 324:194-207. [PMID: 24898540 DOI: 10.1002/jez.b.22579] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2014] [Revised: 04/25/2014] [Accepted: 05/07/2014] [Indexed: 12/22/2022]
Abstract
Turtles are characterized by their possession of a shell with dorsal and ventral moieties: the carapace and the plastron, respectively. In this review, we try to provide answers to the question of the evolutionary origin of the carapace, by revising morphological, developmental, and paleontological comparative analyses. The turtle carapace is formed through modification of the thoracic ribs and vertebrae, which undergo extensive ossification to form a solid bony structure. Except for peripheral dermal elements, there are no signs of exoskeletal components ontogenetically added to the costal and neural bones, and thus the carapace is predominantly of endoskeletal nature. Due to the axial arrest of turtle rib growth, the axial part of the embryo expands laterally and the shoulder girdle becomes encapsulated in the rib cage, together with the inward folding of the lateral body wall in the late phase of embryogenesis. Along the line of this folding develops a ridge called the carapacial ridge (CR), a turtle-specific embryonic structure. The CR functions in the marginal growth of the carapacial primordium, in which Wnt signaling pathway might play a crucial role. Both paleontological and genomic evidence suggest that the axial arrest is the first step toward acquisition of the turtle body plan, which is estimated to have taken place after the divergence of a clade including turtles from archosaurs. The developmental relationship between the CR and the axial arrest remains a central issue to be solved in future.
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Affiliation(s)
- Tatsuya Hirasawa
- Laboratory for Evolutionary Morphology, RIKEN Center for Developmental Biology, Kobe, Japan
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Kaplinsky NJ, Gilbert SF, Cebra-Thomas J, Lilleväli K, Saare M, Chang EY, Edelman HE, Frick MA, Guan Y, Hammond RM, Hampilos NH, Opoku DSB, Sariahmed K, Sherman EA, Watson R. The Embryonic Transcriptome of the Red-Eared Slider Turtle (Trachemys scripta). PLoS One 2013; 8:e66357. [PMID: 23840449 PMCID: PMC3686863 DOI: 10.1371/journal.pone.0066357] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2013] [Accepted: 05/03/2013] [Indexed: 11/28/2022] Open
Abstract
The bony shell of the turtle is an evolutionary novelty not found in any other group of animals, however, research into its formation has suggested that it has evolved through modification of conserved developmental mechanisms. Although these mechanisms have been extensively characterized in model organisms, the tools for characterizing them in non-model organisms such as turtles have been limited by a lack of genomic resources. We have used a next generation sequencing approach to generate and assemble a transcriptome from stage 14 and 17 Trachemys scripta embryos, stages during which important events in shell development are known to take place. The transcriptome consists of 231,876 sequences with an N50 of 1,166 bp. GO terms and EC codes were assigned to the 61,643 unique predicted proteins identified in the transcriptome sequences. All major GO categories and metabolic pathways are represented in the transcriptome. Transcriptome sequences were used to amplify several cDNA fragments designed for use as RNA in situ probes. One of these, BMP5, was hybridized to a T. scripta embryo and exhibits both conserved and novel expression patterns. The transcriptome sequences should be of broad use for understanding the evolution and development of the turtle shell and for annotating any future T. scripta genome sequences.
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Affiliation(s)
- Nicholas J. Kaplinsky
- Department of Biology, Swarthmore College, Swarthmore, Pennsylvania, United States of America
| | - Scott F. Gilbert
- Department of Biology, Swarthmore College, Swarthmore, Pennsylvania, United States of America
| | - Judith Cebra-Thomas
- Department of Biology, Millersville University, Millersville, Pennsylvania, United States of America
| | - Kersti Lilleväli
- Department of Developmental biology, Institute of Molecular and Cell Biology, University of Tartu, Tartu, Estonia
- Department of Physiology, Faculty of Medicine, University of Tartu, Tartu, Estonia
| | - Merly Saare
- Department of Developmental biology, Institute of Molecular and Cell Biology, University of Tartu, Tartu, Estonia
| | - Eric Y. Chang
- Department of Biology, Swarthmore College, Swarthmore, Pennsylvania, United States of America
| | - Hannah E. Edelman
- Department of Biology, Swarthmore College, Swarthmore, Pennsylvania, United States of America
| | - Melissa A. Frick
- Department of Biology, Swarthmore College, Swarthmore, Pennsylvania, United States of America
| | - Yin Guan
- Department of Biology, Swarthmore College, Swarthmore, Pennsylvania, United States of America
| | - Rebecca M. Hammond
- Department of Biology, Swarthmore College, Swarthmore, Pennsylvania, United States of America
| | - Nicholas H. Hampilos
- Department of Biology, Swarthmore College, Swarthmore, Pennsylvania, United States of America
| | - David S. B. Opoku
- Department of Biology, Swarthmore College, Swarthmore, Pennsylvania, United States of America
| | - Karim Sariahmed
- Department of Biology, Swarthmore College, Swarthmore, Pennsylvania, United States of America
| | - Eric A. Sherman
- Department of Biology, Swarthmore College, Swarthmore, Pennsylvania, United States of America
| | - Ray Watson
- Department of Biology, Swarthmore College, Swarthmore, Pennsylvania, United States of America
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Evolutionary Origin of the Turtle Shell. Curr Biol 2013; 23:1113-9. [DOI: 10.1016/j.cub.2013.05.003] [Citation(s) in RCA: 88] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2013] [Revised: 04/03/2013] [Accepted: 05/01/2013] [Indexed: 11/30/2022]
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The draft genomes of soft-shell turtle and green sea turtle yield insights into the development and evolution of the turtle-specific body plan. Nat Genet 2013; 45:701-706. [PMID: 23624526 PMCID: PMC4000948 DOI: 10.1038/ng.2615] [Citation(s) in RCA: 285] [Impact Index Per Article: 25.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2012] [Accepted: 03/27/2013] [Indexed: 12/23/2022]
Abstract
The unique anatomical features of turtles have raised unanswered questions about the origin of their unique body plan. We generated and analyzed draft genomes of the soft-shell turtle (Pelodiscus sinensis) and the green sea turtle (Chelonia mydas); our results indicated the close relationship of the turtles to the bird-crocodilian lineage, from which they split ∼267.9-248.3 million years ago (Upper Permian to Triassic). We also found extensive expansion of olfactory receptor genes in these turtles. Embryonic gene expression analysis identified an hourglass-like divergence of turtle and chicken embryogenesis, with maximal conservation around the vertebrate phylotypic period, rather than at later stages that show the amniote-common pattern. Wnt5a expression was found in the growth zone of the dorsal shell, supporting the possible co-option of limb-associated Wnt signaling in the acquisition of this turtle-specific novelty. Our results suggest that turtle evolution was accompanied by an unexpectedly conservative vertebrate phylotypic period, followed by turtle-specific repatterning of development to yield the novel structure of the shell.
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Angielczyk KD, Feldman CR. Are diminutive turtles miniaturized? The ontogeny of plastron shape in emydine turtles. Biol J Linn Soc Lond 2013. [DOI: 10.1111/bij.12010] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Affiliation(s)
- Kenneth D. Angielczyk
- Department of Geology; Field Museum of Natural History; 1400 South Lake Shore Drive; Chicago; IL; 60605; USA
| | - Chris R. Feldman
- Department of Biology; University of Nevada, Reno; 1664 North Virginia Street; Reno; NV; 89557; USA
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Origin of the Turtle Body Plan: The Folding Theory to Illustrate Turtle-Specific Developmental Repatterning. VERTEBRATE PALEOBIOLOGY AND PALEOANTHROPOLOGY 2013. [DOI: 10.1007/978-94-007-4309-0_4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/13/2023]
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41
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Rieppel O. The Evolution of the Turtle Shell. VERTEBRATE PALEOBIOLOGY AND PALEOANTHROPOLOGY 2013. [DOI: 10.1007/978-94-007-4309-0_5] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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Lyson TR, Joyce WG. Evolution of the turtle bauplan: the topological relationship of the scapula relative to the ribcage. Biol Lett 2012; 8:1028-31. [PMID: 22809725 PMCID: PMC3497105 DOI: 10.1098/rsbl.2012.0462] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2012] [Accepted: 06/21/2012] [Indexed: 11/12/2022] Open
Abstract
The turtle shell and the relationship of the shoulder girdle inside or 'deep' to the ribcage have puzzled neontologists and developmental biologists for more than a century. Recent developmental and fossil data indicate that the shoulder girdle indeed lies inside the shell, but anterior to the ribcage. Developmental biologists compare this orientation to that found in the model organisms mice and chickens, whose scapula lies laterally on top of the ribcage. We analyse the topological relationship of the shoulder girdle relative to the ribcage within a broader phylogenetic context and determine that the condition found in turtles is also found in amphibians, monotreme mammals and lepidosaurs. A vertical scapula anterior to the thoracic ribcage is therefore inferred to be the basal amniote condition and indicates that the condition found in therian mammals and archosaurs (which includes both developmental model organisms: chickens and mice) is derived and not appropriate for studying the developmental origin of the turtle shell. Instead, among amniotes, either monotreme mammals or lepidosaurs should be used.
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Affiliation(s)
- Tyler R Lyson
- Department of Geology and Geophysics, Yale University, New Haven, CT 06511, USA.
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Chiari Y, Cahais V, Galtier N, Delsuc F. Phylogenomic analyses support the position of turtles as the sister group of birds and crocodiles (Archosauria). BMC Biol 2012; 10:65. [PMID: 22839781 PMCID: PMC3473239 DOI: 10.1186/1741-7007-10-65] [Citation(s) in RCA: 231] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2011] [Accepted: 07/27/2012] [Indexed: 11/24/2022] Open
Abstract
BACKGROUND The morphological peculiarities of turtles have, for a long time, impeded their accurate placement in the phylogeny of amniotes. Molecular data used to address this major evolutionary question have so far been limited to a handful of markers and/or taxa. These studies have supported conflicting topologies, positioning turtles as either the sister group to all other reptiles, to lepidosaurs (tuatara, lizards and snakes), to archosaurs (birds and crocodiles), or to crocodilians. Genome-scale data have been shown to be useful in resolving other debated phylogenies, but no such adequate dataset is yet available for amniotes. RESULTS In this study, we used next-generation sequencing to obtain seven new transcriptomes from the blood, liver, or jaws of four turtles, a caiman, a lizard, and a lungfish. We used a phylogenomic dataset based on 248 nuclear genes (187,026 nucleotide sites) for 16 vertebrate taxa to resolve the origins of turtles. Maximum likelihood and Bayesian concatenation analyses and species tree approaches performed under the most realistic models of the nucleotide and amino acid substitution processes unambiguously support turtles as a sister group to birds and crocodiles. The use of more simplistic models of nucleotide substitution for both concatenation and species tree reconstruction methods leads to the artefactual grouping of turtles and crocodiles, most likely because of substitution saturation at third codon positions. Relaxed molecular clock methods estimate the divergence between turtles and archosaurs around 255 million years ago. The most recent common ancestor of living turtles, corresponding to the split between Pleurodira and Cryptodira, is estimated to have occurred around 157 million years ago, in the Upper Jurassic period. This is a more recent estimate than previously reported, and questions the interpretation of controversial Lower Jurassic fossils as being part of the extant turtles radiation. CONCLUSIONS These results provide a phylogenetic framework and timescale with which to interpret the evolution of the peculiar morphological, developmental, and molecular features of turtles within the amniotes.
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Affiliation(s)
- Ylenia Chiari
- Institut des Sciences de l'Evolution, UMR5554-CNRS-IRD, Université Montpellier 2, Montpellier, France
- CIBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, Campus Agrário de Vairão, 4485-661 Vairão, Portugal
| | - Vincent Cahais
- Institut des Sciences de l'Evolution, UMR5554-CNRS-IRD, Université Montpellier 2, Montpellier, France
| | - Nicolas Galtier
- Institut des Sciences de l'Evolution, UMR5554-CNRS-IRD, Université Montpellier 2, Montpellier, France
| | - Frédéric Delsuc
- Institut des Sciences de l'Evolution, UMR5554-CNRS-IRD, Université Montpellier 2, Montpellier, France
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Nagashima H, Kuraku S, Uchida K, Kawashima-Ohya Y, Narita Y, Kuratani S. Body plan of turtles: an anatomical, developmental and evolutionary perspective. Anat Sci Int 2011; 87:1-13. [DOI: 10.1007/s12565-011-0121-y] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2011] [Accepted: 10/24/2011] [Indexed: 10/15/2022]
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Frazzetta TH. Flatfishes, Turtles, and Bolyerine Snakes: Evolution by Small Steps or Large, or Both? Evol Biol 2011. [DOI: 10.1007/s11692-011-9142-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Lima FC, Santos ALQ, Vieira LG, Coutinho ME. Sequência de ossificação do sincrânio e hioide em embriões de Caiman yacare (Crocodylia, Alligatoridae). IHERINGIA. SERIE ZOOLOGIA 2011. [DOI: 10.1590/s0073-47212011000200003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
O crânio representa uma estrutura única e complexa dos vertebrados, sendo foco relevante objeto de estudos morfológicos e sistemáticos. Embora os crocodilianos constituam um importante grupo representante dos Archosauria, nossos conhecimentos acerca de seu desenvolvimento e homologias ainda são escassos. Aqui descrevemos uma sequência detalhada de ossificação dos ossos do crânio de Caiman yacare (Daudin, 1802), objetivando contribuir com informações de foco anatômico. Coletaram-se ao acaso embriões em intervalos regulares durante todo o período de incubação, sendo estes posteriormente submetidos a protocolo de diafanização e coloração de ossos. O padrão de ossificação em C. yacare segue parâmetros gerais em répteis e outros tetrápodes. Os primeiros centros de ossificação correspondem aos ossos dérmicos, envolvidos com funções primárias como a alimentação e respiração (e.g. maxila, dentário, esplenial, angular, pterigoide, ectopterigoide e jugal, incluindo ainda os dentes). Os ossos da porção dorsal do neurocrânio se ossificam posteriormente, evidenciando uma fontanela cranial que permanece até o momento da eclosão. Os ossos parietal, frontal e opstótico possuem mais de um centro de ossificação que se fundem durante a ontogenia. O centro de ossificação do parisfenoide está ausente, e apenas um centro de ossificação está presente para o basisfenoide. A porção posterior do crânio é formada por centros de substituição do condrocrânio que se ossificam em estágios posteriores.
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Kawashima-Ohya Y, Narita Y, Nagashima H, Usuda R, Kuratani S. Hepatocyte growth factor is crucial for development of the carapace in turtles. Evol Dev 2011; 13:260-8. [PMID: 21535464 PMCID: PMC3121961 DOI: 10.1111/j.1525-142x.2011.00474.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Turtles are characterized by their shell, composed of a dorsal carapace and a ventral plastron. The carapace first appears as the turtle-specific carapacial ridge (CR) on the lateral aspect of the embryonic flank. Accompanying the acquisition of the shell, unlike in other amniotes, hypaxial muscles in turtle embryos appear as thin threads of fibrous tissue. To understand carapacial evolution from the perspective of muscle development, we compared the development of the muscle plate, the anlage of hypaxial muscles, between the Chinese soft-shelled turtle, Pelodiscus sinensis, and chicken embryos. We found that the ventrolateral lip (VLL) of the thoracic dermomyotome of P. sinensis delaminates early and produces sparse muscle plate in the lateral body wall. Expression patterns of the regulatory genes for myotome differentiation, such as Myf5, myogenin, Pax3, and Pax7 have been conserved among amniotes, including turtles. However, in P. sinensis embryos, the gene hepatocyte growth factor (HGF), encoding a regulatory factor for delamination of the dermomyotomal VLL, was uniquely expressed in sclerotome and the lateral body wall at the interlimb level. Implantation of COS-7 cells expressing a HGF antagonist into the turtle embryo inhibited CR formation. We conclude that the de novo expression of HGF in the turtle mesoderm would have played an innovative role resulting in the acquisition of the turtle-specific body plan.
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Affiliation(s)
- Yoshie Kawashima-Ohya
- Laboratory for Evolutionary Morphology, RIKEN Center for Developmental Biology (CDB), 2-2-3 Minatojima-minami, Kobe 650-0047, Japan
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Lima FC, Santos ALQ, Vieira LG, Da Silva-Junior LM, Romão MF, De Simone SBS, Hirano LQL, Silva JMM, Montelo KM, Malvásio A. Ontogeny of the Shell Bones of Embryos of Podocnemis unifilis (Troschel, 1848) (Testudines, Podocnemididae). Anat Rec (Hoboken) 2011; 294:621-32. [DOI: 10.1002/ar.21359] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2009] [Accepted: 11/26/2010] [Indexed: 11/08/2022]
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50
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Bonnet X, Delmas V, El-Mouden H, Slimani T, Sterijovski B, Kuchling G. Is sexual body shape dimorphism consistent in aquatic and terrestrial chelonians? ZOOLOGY 2010; 113:213-20. [PMID: 20832271 DOI: 10.1016/j.zool.2010.03.001] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2009] [Revised: 02/18/2010] [Accepted: 03/15/2010] [Indexed: 11/27/2022]
Abstract
Comparisons between aquatic and terrestrial species provide an opportunity to examine how sex-specific adaptations interact with the environment to influence body shape. In terrestrial female tortoises, selection for fecundity favors the development of a large internal abdominal cavity to accommodate the clutch; in conspecific males, sexual selection favors mobility with large openings in the shell. To examine to what extent such trends apply in aquatic chelonians we compared the body shape of males and females of two aquatic turtles (Chelodina colliei and Mauremys leprosa). In both species, females were larger than males. When controlled for body size, females exhibited a greater relative internal volume and a higher body condition index than males; both traits potentially correlate positively with fecundity. Males were more streamlined (hydrodynamic), and exhibited larger openings in the shell providing more space to move their longer limbs; such traits probably improve mobility and copulation ability (the males chase and grab the female for copulation). Overall, although the specific constraints imposed by terrestrial and aquatic locomotion shape the morphology of chelonians differently (aquatic turtles were flatter, hence more hydrodynamic than terrestrial tortoises), the direction for sexual shape dimorphism remained unaffected. Our main conclusion is that the direction of sexual shape dimorphism is probably more consistent than sexual size dimorphism in the animal kingdom.
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Affiliation(s)
- Xavier Bonnet
- Centre d'Etudes Biologiques de Chizé, Centre National de la Recherche Scientifique, UPR 1934, F-79360 Beauvoir sur Niort, France.
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