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Adán Pérez-garcía - One of the best experts on this subject based on the ideXlab platform.
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First evidence of a bothremydid turtle (crown Pleurodira) in the middle Cretaceous of Castile and Leon (Spain)
Journal of Iberian Geology, 2020Co-Authors: Adán Pérez-garcíaAbstract:The internal cast of a turtle shell, found near the town of Cabrejas del Pinar (Soria Province, Castile and Leon Autonomous Community, Spain), is presented here. It is the first fossil vertebrate recognized in the vicinity of that town. This specimen was found in a middle Cretaceous bed (Cenomanian), deposited in a coastal marine environment. It is recognized as attributable to a member of the crown group Pleurodira. No representative of this clade had so far been found in pre-Campanian strata in the Castile and Leon Autonomous Community. In fact, the pre-Campanian record of the crown Pleurodira is very limited in Laurasia. The hitherto known record of pre-Campanian turtles from Castile and Leon consisted of basal forms (members of the terrestrial clade Helochelydridae and of the freshwater Pleurosternidae) and of freshwater representatives of Eucryptodira, all of them found in layers older than that where the new turtle remain was found. The availability of characters in the analyzed specimen allows it to be recognized as compatible with the littoral bothremydid turtle Algorachelus . Se presenta aquí el molde interno del caparazón de una tortuga, procedente del término municipal de Cabrejas del Pinar (Provincia de Soria, Comunidad Autónoma de Castilla y León, España). El ejemplar corresponde al primer resto de un vertebrado fósil hallado en las inmediaciones de dicha población. Su hallazgo se produjo en un nivel del Cretácico medio (Cenomaniense), depositado en un ambiente marino costero. El espécimen es atribuible a un miembro del grupo corona Pleurodira. Ningún representante de este clado había sido previamente reconocido en niveles pre-campanienses de Castilla y León. De hecho, el registro pre-campaniense de Pleurodira es muy escaso en Laurasia. Las tortugas hasta ahora notificadas en los niveles pre-campanienses de Castilla y León estaban restringidas a formas basales (miembros del clado terrestre Helochelydridae y del acuático Pleurosternidae) y a representantes dulceacuícolas de Eucryptodira, todas ellas provenientes de niveles más antiguos que aquel del nuevo hallazgo aquí notificado. La disponibilidad de caracteres en el espécimen de Cabrejas del Pinar permite reconocerlo como compatible con el botremídido litoral Algorachelus .
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First evidence of a bothremydid turtle (crown Pleurodira) in the middle Cretaceous of Castile and Leon (Spain)
Journal of Iberian Geology, 2020Co-Authors: Adán Pérez-garcíaAbstract:The internal cast of a turtle shell, found near the town of Cabrejas del Pinar (Soria Province, Castile and Leon Autonomous Community, Spain), is presented here. It is the first fossil vertebrate recognized in the vicinity of that town. This specimen was found in a middle Cretaceous bed (Cenomanian), deposited in a coastal marine environment. It is recognized as attributable to a member of the crown group Pleurodira. No representative of this clade had so far been found in pre-Campanian strata in the Castile and Leon Autonomous Community. In fact, the pre-Campanian record of the crown Pleurodira is very limited in Laurasia. The hitherto known record of pre-Campanian turtles from Castile and Leon consisted of basal forms (members of the terrestrial clade Helochelydridae and of the freshwater Pleurosternidae) and of freshwater representatives of Eucryptodira, all of them found in layers older than that where the new turtle remain was found. The availability of characters in the analyzed specimen allows it to be recognized as compatible with the littoral bothremydid turtle Algorachelus.
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The African Aptian Francemys gadoufaouaensis gen. et sp. nov.: New data on the early diversification of Pelomedusoides (Testudines, Pleurodira) in northern Gondwana
Cretaceous Research, 2019Co-Authors: Adán Pérez-garcíaAbstract:Abstract One of the two lineages that constitute the crown group Testudines, Pan-Pleurodira, experienced an important radiation during the Early Cretaceous, from the Barremian or earlier. The origin of the two lineages that form the crown Pleurodira (i.e. Pan-Chelidae and Pelomedusoides) is related to this radiation. Pelomedusoides diversified in northern Gondwana in a relatively short period of geological time. The African Aptian fossiliferous region of Gadoufaoua (central Niger) is one of the most interesting fossiliferous areas for the study of the early diversity and evolution of Pelomedusoides, this being where the oldest African identification of the synchronic and sympatric presence of several Pleurodiran taxa is recognised. At least two lineages of Pelomedusoides are represented in Gadoufaoua, one being the extinct Araripemydidae. The second lineage had been recognised as related to Pelomedusidae or Podocnemidoidea, both clades representing part of the current biodiversity. A form from Gadoufaoua, hitherto poorly known and preliminarily presented almost 40 years ago, and currently determined as aff. Platycheloides sp., belongs to this second lineage. Its detailed study is performed here. It is defined as Francemys gadoufaouaensis gen. et sp. nov., constituting one of the few nominated pan-Pleurodiran taxa (i.e., about a dozen species) currently recognised in the Lower Cretaceous record. It is identified as being closely related to Podocnemidoidea, the clade that groups the common ancestor and all of the descendants of the abundant and diverse extinct bothremydids and extant podocnemidids.
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Identification of the Lower Cretaceous Pleurodiran turtle Taquetochelys decorata as the only African araripemydid species
Comptes Rendus Palevol, 2019Co-Authors: Adán Pérez-garcíaAbstract:Abstract Araripemydidae is a clade of freshwater Pleurodiran turtles originally described in South America, where it is represented by the Brasilian Aptian–Albian Araripemys barretoi. Two potential members of this lineage were defined in an Aptian level of Africa, in Gadoufaoua (Niger): Taquetochelys decorata, described from several isolated plates, and Lagaremys tenerensis, known from an almost complete skeleton. The review of the Araripemydidae record, and the analysis of the intraspecific variability present in that and in other clades of Pleurodira, allow me to refute their attribution to two different forms. ‘L. tenerensis’ is here recognized as a junior synonym of T. decorata. Therefore, the priority of T. decorata is demonstrated, as well as its attribution to Araripemydidae. The almost complete skeletal anatomy of the two currently recognized members of this Aptian–Albian clade (i.e. the African T. decorata and the South American A. barretoi) is well known, which is uncommon for the Cretaceous Pleurodiran turtles.
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A new member of Taphrosphyini (Pleurodira, Bothremydidae) from the Maastrichtian of Niger
Journal of African Earth Sciences, 2019Co-Authors: Adán Pérez-garcíaAbstract:Abstract A new Pleurodiran turtle, corresponding to a bothremydid Taphrosphyini, is described in this paper. This form, Ilatardia cetiotesta gen. et sp. nov., is represented by a large skull, with a length of about 20 cm. It is one of the few Mesozoic representatives of Taphrosphyini known by the skull. This new Maastrichtian taxon comes from the Mount Ilatarda area of the Tahoua Region, in south-western Niger. The detailed comparison of this form with the other Cretaceous and Paleogene representatives of this clade is carried out.
Stephen C. Donnellan - One of the best experts on this subject based on the ideXlab platform.
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A phylogeny for side‐necked turtles (Chelonia: Pleurodira) based on mitochondrial and nuclear gene sequence variation
Biological Journal of The Linnean Society, 1999Co-Authors: Arthur Georges, William P Mccord, Jeremiah Birrell, Kathleen M. Saint, Stephen C. DonnellanAbstract:Aspects of the phylogeny of Pleurodiran turtles are contentious, particularly within the Chelidae. Morphological analyses group the long-necked Australasian Chelodina and the long-necked South American Chelus and Hydromedusa into a single clade, suggesting a common derived origin of the long neck and associated habits that predated the separation of Australia from South America. In contrast, published analyses of 12S rRNA and cytochrome b sequences suggest that the long-necked Chelodina are more closely related to the short-necked Australasian genera than to either Chelus or Hydromedusa . This paper adds partial sequences of 16S rRNA and CO1 mitochondrial genes and partial sequences of the nuclear oncogene c- mos to test a range of previous hypotheses on the phylogenetic relationships among chelid turtles. In total, 1382 nucleotides were available for each of 25 taxa after elimination of ambiguously aligned regions. These taxa included representatives of all the genera of the turtle families Chelidae and Pelomedusidae, the three sub-genera of Phrynops , and recognized sub-generic groups of Elseya and Chelodina . Of the four genes examined, 12S rRNA was the most informative, followed by c- mos with 16S rRNA and CO1 the least informative. The molecular data support the currently accepted arrangement for pelomedusid genera, that is, a sister relationship between the African Pelusios and Pelomedusa and a clade comprising the South American Peltocephalus and Podocnemis with the Madagascan Erymnochelys . However, there is also support for Erymnochelys and Podocnemis as sister taxa to the exclusion of Peltocephalus (bootstrap values of 69–80%) which is at odds with the most commonly accepted arrangement. The South American chelids are monophyletic (76–82%). This clade includes the long-necked Chelus and Hydromedusa , but excludes the Australasian long-necked Chelodina . Furthermore, the South American long-necked chelids are not themselves monophyletic, with 98–100% bootstrap values for the node supporting Chelus and the remaining South American chelids to the exclusion of Hydromedusa . Hence, the hypothesis of a monophyletic grouping of the long-necked genera of South America and Australasia is not supported by the molecular data. Although reciprocal monophyly of the South American and Australasian chelid faunas was the most likely and the most parsimonious arrangement in all but one analysis, bootstrap support for the monophyly of the Australasian chelids was low (52–66%). The South American chelids, Chelodina and the short-necked Australasian chelids form an unresolved trichotomy. The genera Phrynops and Elseya are paraphyletic, leading to a recommendation to elevate the three sub-genera of Phrynops to generic status and support for previous suggestions to erect a new genus for Elseya latistermum and close relatives. A revised classification of the extant Pleurodira is presented, consistent with the phylogenetic relationships that emerge from this study.
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A phylogeny for side-necked turtles (Chelonia: Pleurodira) based on mitochondrial and nuclear gene sequence variation
Biological Journal of the Linnean Society, 1999Co-Authors: Arthur Georges, William P Mccord, Jeremiah Birrell, Kathleen M. Saint, Stephen C. DonnellanAbstract:Aspects of the phylogeny of Pleurodiran turtles are contentious, particularly within the Chelidae. Morphological analyses group the long-necked Australasian Chelodina and the long-necked South American Chelus and Hydromedusa into a single clade, suggesting a common derived origin of the long neck and associated habits that predated the separation of Australia from South America. In contrast, published analyses of 12S rRNA and cytochrome b sequences suggest that the long-necked Chelodina are more closely related to the short-necked Australasian genera than to either Chelus or Hydromedusa . This paper adds partial sequences of 16S rRNA and CO1 mitochondrial genes and partial sequences of the nuclear oncogene c- mos to test a range of previous hypotheses on the phylogenetic relationships among chelid turtles. In total, 1382 nucleotides were available for each of 25 taxa after elimination of ambiguously aligned regions. These taxa included representatives of all the genera of the turtle families Chelidae and Pelomedusidae, the three sub-genera of Phrynops , and recognized sub-generic groups of Elseya and Chelodina . Of the four genes examined, 12S rRNA was the most informative, followed by c- mos with 16S rRNA and CO1 the least informative. The molecular data support the currently accepted arrangement for pelomedusid genera, that is, a sister relationship between the African Pelusios and Pelomedusa and a clade comprising the South American Peltocephalus and Podocnemis with the Madagascan Erymnochelys . However, there is also support for Erymnochelys and Podocnemis as sister taxa to the exclusion of Peltocephalus (bootstrap values of 69–80%) which is at odds with the most commonly accepted arrangement. The South American chelids are monophyletic (76–82%). This clade includes the long-necked Chelus and Hydromedusa , but excludes the Australasian long-necked Chelodina . Furthermore, the South American long-necked chelids are not themselves monophyletic, with 98–100% bootstrap values for the node supporting Chelus and the remaining South American chelids to the exclusion of Hydromedusa . Hence, the hypothesis of a monophyletic grouping of the long-necked genera of South America and Australasia is not supported by the molecular data. Although reciprocal monophyly of the South American and Australasian chelid faunas was the most likely and the most parsimonious arrangement in all but one analysis, bootstrap support for the monophyly of the Australasian chelids was low (52–66%). The South American chelids, Chelodina and the short-necked Australasian chelids form an unresolved trichotomy. The genera Phrynops and Elseya are paraphyletic, leading to a recommendation to elevate the three sub-genera of Phrynops to generic status and support for previous suggestions to erect a new genus for Elseya latistermum and close relatives. A revised classification of the extant Pleurodira is presented, consistent with the phylogenetic relationships that emerge from this study.
Arthur Georges - One of the best experts on this subject based on the ideXlab platform.
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a complete mitochondrial genome sequence for the australian turtle chelodina longicollis obtained using 454 pyrosequencing
Conservation Genetics Resources, 2014Co-Authors: Xiuwen Zhang, Arthur GeorgesAbstract:The mitochondrial genome of the Australia eastern long-necked turtle Chelodina longicollis is 16,437 bp, containing 37 genes, with overall gene organisation and nucleotide composition typical of mitogenomes of other vertebrates. We identified a presumptive light strand replication initiation site (OL) in the WANCY region, a feature thought to be absent from the side-necked turtles (Pleurodira). The tRNAser2 of C. longicollis lacks a D-arm. This is the fifth mitogenome published for the Pleurodira, the third for the Chelidae and the first turtle mitogenome generated using next-generation sequencing. It will assist the development of primers and strategies for examining mitochondrial variation across the side-necked turtles.
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A phylogeny for side‐necked turtles (Chelonia: Pleurodira) based on mitochondrial and nuclear gene sequence variation
Biological Journal of The Linnean Society, 1999Co-Authors: Arthur Georges, William P Mccord, Jeremiah Birrell, Kathleen M. Saint, Stephen C. DonnellanAbstract:Aspects of the phylogeny of Pleurodiran turtles are contentious, particularly within the Chelidae. Morphological analyses group the long-necked Australasian Chelodina and the long-necked South American Chelus and Hydromedusa into a single clade, suggesting a common derived origin of the long neck and associated habits that predated the separation of Australia from South America. In contrast, published analyses of 12S rRNA and cytochrome b sequences suggest that the long-necked Chelodina are more closely related to the short-necked Australasian genera than to either Chelus or Hydromedusa . This paper adds partial sequences of 16S rRNA and CO1 mitochondrial genes and partial sequences of the nuclear oncogene c- mos to test a range of previous hypotheses on the phylogenetic relationships among chelid turtles. In total, 1382 nucleotides were available for each of 25 taxa after elimination of ambiguously aligned regions. These taxa included representatives of all the genera of the turtle families Chelidae and Pelomedusidae, the three sub-genera of Phrynops , and recognized sub-generic groups of Elseya and Chelodina . Of the four genes examined, 12S rRNA was the most informative, followed by c- mos with 16S rRNA and CO1 the least informative. The molecular data support the currently accepted arrangement for pelomedusid genera, that is, a sister relationship between the African Pelusios and Pelomedusa and a clade comprising the South American Peltocephalus and Podocnemis with the Madagascan Erymnochelys . However, there is also support for Erymnochelys and Podocnemis as sister taxa to the exclusion of Peltocephalus (bootstrap values of 69–80%) which is at odds with the most commonly accepted arrangement. The South American chelids are monophyletic (76–82%). This clade includes the long-necked Chelus and Hydromedusa , but excludes the Australasian long-necked Chelodina . Furthermore, the South American long-necked chelids are not themselves monophyletic, with 98–100% bootstrap values for the node supporting Chelus and the remaining South American chelids to the exclusion of Hydromedusa . Hence, the hypothesis of a monophyletic grouping of the long-necked genera of South America and Australasia is not supported by the molecular data. Although reciprocal monophyly of the South American and Australasian chelid faunas was the most likely and the most parsimonious arrangement in all but one analysis, bootstrap support for the monophyly of the Australasian chelids was low (52–66%). The South American chelids, Chelodina and the short-necked Australasian chelids form an unresolved trichotomy. The genera Phrynops and Elseya are paraphyletic, leading to a recommendation to elevate the three sub-genera of Phrynops to generic status and support for previous suggestions to erect a new genus for Elseya latistermum and close relatives. A revised classification of the extant Pleurodira is presented, consistent with the phylogenetic relationships that emerge from this study.
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A phylogeny for side-necked turtles (Chelonia: Pleurodira) based on mitochondrial and nuclear gene sequence variation
Biological Journal of the Linnean Society, 1999Co-Authors: Arthur Georges, William P Mccord, Jeremiah Birrell, Kathleen M. Saint, Stephen C. DonnellanAbstract:Aspects of the phylogeny of Pleurodiran turtles are contentious, particularly within the Chelidae. Morphological analyses group the long-necked Australasian Chelodina and the long-necked South American Chelus and Hydromedusa into a single clade, suggesting a common derived origin of the long neck and associated habits that predated the separation of Australia from South America. In contrast, published analyses of 12S rRNA and cytochrome b sequences suggest that the long-necked Chelodina are more closely related to the short-necked Australasian genera than to either Chelus or Hydromedusa . This paper adds partial sequences of 16S rRNA and CO1 mitochondrial genes and partial sequences of the nuclear oncogene c- mos to test a range of previous hypotheses on the phylogenetic relationships among chelid turtles. In total, 1382 nucleotides were available for each of 25 taxa after elimination of ambiguously aligned regions. These taxa included representatives of all the genera of the turtle families Chelidae and Pelomedusidae, the three sub-genera of Phrynops , and recognized sub-generic groups of Elseya and Chelodina . Of the four genes examined, 12S rRNA was the most informative, followed by c- mos with 16S rRNA and CO1 the least informative. The molecular data support the currently accepted arrangement for pelomedusid genera, that is, a sister relationship between the African Pelusios and Pelomedusa and a clade comprising the South American Peltocephalus and Podocnemis with the Madagascan Erymnochelys . However, there is also support for Erymnochelys and Podocnemis as sister taxa to the exclusion of Peltocephalus (bootstrap values of 69–80%) which is at odds with the most commonly accepted arrangement. The South American chelids are monophyletic (76–82%). This clade includes the long-necked Chelus and Hydromedusa , but excludes the Australasian long-necked Chelodina . Furthermore, the South American long-necked chelids are not themselves monophyletic, with 98–100% bootstrap values for the node supporting Chelus and the remaining South American chelids to the exclusion of Hydromedusa . Hence, the hypothesis of a monophyletic grouping of the long-necked genera of South America and Australasia is not supported by the molecular data. Although reciprocal monophyly of the South American and Australasian chelid faunas was the most likely and the most parsimonious arrangement in all but one analysis, bootstrap support for the monophyly of the Australasian chelids was low (52–66%). The South American chelids, Chelodina and the short-necked Australasian chelids form an unresolved trichotomy. The genera Phrynops and Elseya are paraphyletic, leading to a recommendation to elevate the three sub-genera of Phrynops to generic status and support for previous suggestions to erect a new genus for Elseya latistermum and close relatives. A revised classification of the extant Pleurodira is presented, consistent with the phylogenetic relationships that emerge from this study.
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The rate of mitochondrial 12S rRNA gene evolution is similar in freshwater turtles and marsupials
Journal of Molecular Evolution, 1998Co-Authors: John Michael Seddon, Peter R Baverstock, Arthur GeorgesAbstract:Assertions that the “conventional” rate of mitochondrial DNA (mtDNA) evolution is reduced in poikilotherms in general and turtles in particular were tested for side-necked turtles (Pleurodira: Chelidae). Homologous data sets of mitochondrial 12S rRNA gene sequences were used to compare the average divergence between the Australian and South American species for two Gondwanan groups: the chelid turtles and the marsupials. The mean nucleotide divergences between continental groups for both the turtles and the marsupials are remarkably similar. These data suggest that the rate of evolution of mitochondrial 12S rRNA gene is not substantially slower in turtles than in the homeothermic marsupials.
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Phylogenetic relationships of chelid turtles (Pleurodira: Chelidae) based on mitochondrial 12S rRNA gene sequence variation
Molecular Phylogenetics and Evolution, 1997Co-Authors: John Michael Seddon, Arthur Georges, Peter R Baverstock, William P MccordAbstract:Conflicting phylogenies have been proposed for the Chelidae (Testudines: Pleurodira), a family of sidenecked turtles found only in Australasia and South America. Sequence data from the mitochondrial 12S rRNA gene were used to test these phylogenies. In total, 411 nucleotides were sequenced for each of 16 chelid species, including all 11 recognized chelid genera and, as outgroups, 5 genera of Pelomedusidae (Testudines: Pleurodira). Analyses using parsimony and neighbor joining algorithms strongly support the division ofAustralian Chelidae into the three monophyletic groups initially suggested by Burbidge et al. (1974; Copeia 2: 392‐409): Chelodina (bootstrap value 99%), the Emydura group (87%), and Pseudemydura. The analyses suggest that the Australian chelids are a monophyletic lineage (64%), with the Australian longnecked turtles, Chelodina, more closely related to the Australian short-necked chelids than to the longnecked South American species. These relationships are in contrast to those of Gaffney (1977; Am. Mus. Novitates 2620: 1‐28). The species of Australian longnecked chelids consistently form a monophyletic clade, with Chelodina longicollis and Chelodina oblonga as sister taxa. The data failed to resolve relationships among theAustralian short-necked taxa:Emydura,the Elseya latisternum group, the Elseya dentata group, Rheodytes, and Elusor. Unlike Gaffney (1977), we find some weak support (58%) for Pseudemydura as the closest relative of the other Australian short-necked taxa. With the exception of Hydromedusa, the South American taxa are monophyletic and the subgenera of Phrynopsareparaphyletic. r 1997 Academic Press
Juliana Sterli - One of the best experts on this subject based on the ideXlab platform.
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New remains of Condorchelys antiqua (Testudinata) from the Early-Middle Jurassic of Patagonia: anatomy, phylogeny, and paedomorphosis in the early evolution of turtles
2019Co-Authors: Juliana Sterli, Marcelo S. De La Fuente, Guillermo W. RougierAbstract:ABSTRACT—New cranial and postcranial remains of the Early–Middle Jurassic turtle, Condorchelys antiqua, are described here in detail, providing new insights into the early evolution of turtles. Unconstrained and constrained cladistic analyses in addition to newly developed total-evidence Bayesian analysis were performed to explore large-scale turtle relationships and evolutionary trends. All the analyses show a similar resolution at the base of the tree, recovering several species of small-sized, fresh water turtles of the Early–Middle Jurassic at the base of the tree following the most basal, large-sized, terrestrial turtles from the Late Triassic. The calibration of the cladistic analyses and the tip-dating analysis provided similar results in the main nodes Testudines, Pan-Cryptodira, Cryptodira, Pan-Pleurodira, and Pleurodira, corroborating that the Jurassic is a key period for turtle evolution. The significant reduction in size in Early–Middle Jurassic stem turtles and the combination of certain characters (e.g., presence of fontanelles, loss of bones, loss of scutes) shown by those taxa suggests heterochronic changes, paedomorphosis in particular, at the base of the turtle tree. These morphological novelties could have trigged, or facilitated, the occupation of the aquatic niche as seen in Jurassic stem turtles. SUPPLEMENTAL DATA—Supplemental materials are available for this article for free at www.tandfonline.com/UJVP Citation for this article: Sterli, J., M. S. de la Fuente, and G. W. Rougier. 2019. New remains of Condorchelys antiqua (Testudinata) from the Early–Middle Jurassic of Patagonia: anatomy, phylogeny, and paedomorphosis in the early evolution of turtles. Journal of Vertebrate Paleontology. DOI: 10.1080/02724634.2018.1480112.
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Phylogeny & biogeography of Pleurodira from Phylogeny, biogeography and diversification patterns of side-necked turtles (Testudines: Pleurodira)
2018Co-Authors: Gabriel S Ferreira, Max C Langer, Mario Bronzati, Juliana SterliAbstract:Details and additional data of the phylogenetic, diversification and biogeographic analyses related to the publication "Phylogeny, biogeography and diversification patterns of side-necked turtles (Testudines: Pleurodira)" by Ferreira et al.
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phylogeny biogeography of Pleurodira from phylogeny biogeography and diversification patterns of side necked turtles testudines Pleurodira
2018Co-Authors: Gabriel S Ferreira, Max C Langer, Mario Bronzati, Juliana SterliAbstract:Details and additional data of the phylogenetic, diversification and biogeographic analyses related to the publication "Phylogeny, biogeography and diversification patterns of side-necked turtles (Testudines: Pleurodira)" by Ferreira et al.
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Multilocus phylogeny and statistical biogeography clarify the evolutionary history of major lineages of turtles
Molecular phylogenetics and evolution, 2017Co-Authors: Anieli G. Pereira, Juliana Sterli, Filipe R. R. Moreira, Carlos G. SchragoAbstract:Despite their complex evolutionary history and the rich fossil record, the higher level phylogeny and historical biogeography of living turtles have not been investigated in a comprehensive and statistical framework. To tackle these issues, we assembled a large molecular dataset, maximizing both taxonomic and gene sampling. As different models provide alternative biogeographical scenarios, we have explicitly tested such hypotheses in order to reconstruct a robust biogeographical history of Testudines. We scanned publicly available databases for nucleotide sequences and composed a dataset comprising 13 loci for 294 living species of Testudines, which accounts for all living genera and 85% of their extant species diversity. Phylogenetic relationships and species divergence times were estimated using a thorough evaluation of fossil information as calibration priors. We then carried out the analysis of historical biogeography of Testudines in a fully statistical framework. Our study recovered the first large-scale phylogeny of turtles with well-supported relationships following the topology proposed by phylogenomic works. Our dating result consistently indicated that the origin of the main clades, Pleurodira and Cryptodira, occurred in the early Jurassic. The phylogenetic and historical biogeographical inferences permitted us to clarify how geological events affected the evolutionary dynamics of crown turtles. For instance, our analyses support the hypothesis that the breakup of Pangaea would have driven the divergence between the cryptodiran and Pleurodiran lineages. The reticulated pattern in the ancestral distribution of the cryptodiran lineage suggests a complex biogeographic history for the clade, which was supposedly related to the complex paleogeographic history of Laurasia. On the other hand, the biogeographical history of Pleurodira indicated a tight correlation with the paleogeography of the Gondwanan landmasses.
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Contributions to Zoology, 79 (3) 93-106 (2010) Phylogenetic relationships among extinct and extant turtles: the position of Pleurodira and the effects of the fossils on rooting crown-group turtles
2016Co-Authors: Juliana SterliAbstract:The origin and evolution of the crown-group of turtles (Crypto-dira + Pleurodira) is one of the most interesting topics in turtle evolution, second perhaps only to the phylogenetic position of turtles among amniotes. The present contribution focuses on the former problem, exploring the phylogenetic relationships of extant and extinct turtles based on the most comprehensive phylogenetic dataset of morphological and molecular data ana-lyzed to date. Parsimony analyses were conducted for different partitions of data (molecular and morphological) and for the combined dataset. In the present analysis, separate analyses of the molecular data always retrieve Pleurodira allied to Trio-nychia. Separate analysis of the morphological dataset, by con-trast, depicts a more traditional arrangement of taxa, with Pleu-rodira as the sister group of Cryptodira, being Chelonioidea th
Pedro S. R. Romano - One of the best experts on this subject based on the ideXlab platform.
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Electronic Supplementary Material
2016Co-Authors: Pedro S. R. Romano, Valéria Gallo, Renato R. C. Ramos, Luzia AntonioliAbstract:Electronic Supplementary Material of the paper "Atolchelys lepida, a new side-necked turtle from the Early Cretaceous of Brazil and the age of crown Pleurodira
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The evolution of the fifth cervical vertebrae in Pelomedusoides (Testudines, Pleurodira): a preliminary analysis
2015Co-Authors: Thiago F Mariani, Pedro S. R. RomanoAbstract:Background. Crown-Pleurodira (i.e.: Cheloides and Pelomedusoides) possess a side-necked retraction mode with specialized cervical vertebrae (CV) anatomy. Moreover, there are distinctive ecological features among its lineages, as the convergent long neck in species of Chelidae and in the extinct pelomedusoid Araripemydidae. Also, the CV5-CV6 articulation is the major point of flexure in neck retraction and reflects a key point for the evolution of Pleurodira. Here we evaluated CV5 shape variation within some Pleurodira groups with emphasis on some Brazilian fossil species. Methods. We analyzed the fifth CV of eight species and 14 specimens comprising four Pleurodiran clades (Chelidae, Araripemydidae, Bothremydidae and Podocnemididae) in order to assess the shape variation via geometric morphometry. All specimens were photographed in caudal view under the same protocol, and eight landmarks (LM) were picked at the left side of each vertebrae using TPSDig2. Data were Procrustes superimposed and a Relative Warps Analysis (RWA) was performed using TPSRelw v1.49. Results. RW1 and RW2 summarized 68.63% of the shape variance. The scatter of the specimens revealed distinctiveness between Podocnemidoidea (Podocnemididae+Bothremydidae) and Araripemys+Chelidae paraphyletic group. Such variation is due to (1) a medial contraction of the surface of the postzygapophysis, (2) a taller neural spine and (3) a more rounded vertebral condile towards Podocnemidoidea. Podocnemididae showed greater variation: a Podocnemis sextuberculata specimen (MZSP3218) is more alike to Cearachelys placidoi (Procrustes Distances, PD=0.17) than other podocnemidids and Bauruemys elegans resembles P. unifilis (PD=0.11). Also, other P. sextuberculata specimen (MZSP3217) is more alike to the Araripemys-Chelidae group. Discussion. Previous works have noticed the anatomical similarities between both longnecked chelids and A. barretoi, considering it as a convergence since they are from different clades. Our data showed the same pattern and, assuming the current phylogenetic relationships of Pleurodira, this might indicates similar feeding behavior between living Hydromedusa and Chelus and Araripemys. The Podocnemidoidea morphospace variation is consistent with the phylogeny, since C. placidoi is nested among Podocnemis spp., and this might indicate a more specialized CV5 for the former and a possible convergence with some Podocnemis species. Also, the resemblance of P. unifilis CV5 with B. elegans seems to indicate a morphotype similar to the podocnemidid ancestor for this living species. Despite our scanty sample, it shows a notable variation in Podocnemis spp. and at least two convergences among CV5 within Pleurodira. Further studies with additional sampling might shed light on a more complex evolution of CV specializations in side-necked turtles than previously assumed.
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The evolution of the fifth cervical vertebrae in Pelomedusoides (Testudines, Pleurodira): a preliminary analysis
2015Co-Authors: Thiago F Mariani, Pedro S. R. RomanoAbstract:Background. Crown-Pleurodira (i.e.: Cheloides and Pelomedusoides) possess a side-necked retraction mode with specialized cervical vertebrae (CV) anatomy. Moreover, there are distinctive ecological features among its lineages, as the convergent long neck in species of Chelidae and in the extinct pelomedusoid Araripemydidae. Also, the CV5-CV6 articulation is the major point of flexure in neck retraction and reflects a key point for the evolution of Pleurodira. Here we evaluated CV5 shape variation within some Pleurodira groups with emphasis on some Brazilian fossil species.
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Atolchelys lepida, a new side-necked turtle from the Early Cretaceous of Brazil and the age of crown Pleurodira.
Biology letters, 2014Co-Authors: Pedro S. R. Romano, Valéria Gallo, Renato Rodriguez Cabral Ramos, Luzia AntonioliAbstract:We report a new Pleurodiran turtle from the Barremian Morro do Chaves Formation, Sergipe-Alagoas Basin, Brazil. We tested the phylogenetic position of Atolchelys lepida gen. et sp. nov. by including it in a comprehensive cladistic analysis of pleurodires. The new species is a basal member of Bothremydidae and simultaneously the oldest unambiguous crown Pleurodira. The biogeographic and chronostratigraphic significance of the finding has implications for the calibration of molecular clocks studies by pushing back the minimum age of crown Pleurodira by more than 12 Ma (ca 125 Ma). The reanalysis of Pelomedusoides relationships provides evidence that the early evolution and relationships among the main lineages of side-necked turtles can be explained, at least partially, by a sequence of vicariance events.
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ARE EXTANT PODOCNEMIDID TURTLES RELICTS OF A WIDESPREAD CRETACEOUS ANCESTOR
South American Journal of Herpetology, 2006Co-Authors: Pedro S. R. Romano, Sergio A.k. AzevedoAbstract:Abstract We re-analyzed the most recent morphological data matrix for Pleurodira with inclusion of the Upper Cretaceous Brazilian Pleurodiran turtle, Bauruemys elegans (Suarez, 1969), as new Operational Taxonomic Unit. An exhaustive search based on 50 characters for 11 taxa was performed to asses the phylogenetic relationships within the Pelomedusoides and a single most parsimonious tree of 64 steps was found. This new phylogenetic hypothesis places B. elegans as a basal form of Podocnemididae and is used to found a new biogeographic model for the Pelomedusoides. The biogeographical approach was performed with direct analysis of vicariance, using historical sequence of vicariance and phylogenetic information to construct an event-based model. Thus, inspection of distributions maps of Pelomedusoides and the phylogenetic arrangement proposed here were used to correlate cladogenesis and vicariance events during Cretaceous. Current biogeographic hypotheses suggest that living Pelomedusoides distribution and r...