Abstract
Pan-Chelidae (Testudines, Pleurodira) is a group of side-necked turtles with a currently disjointed distribution in South America and Australasia and characterized by two morphotypes: the long-necked and the short-necked chelids. Both geographic groups include both morphotypes, but different phylogenetic signals are obtained from morphological and molecular data, suggesting the monophyly of the long-necked chelids or the independent evolution of this trait in both groups. In this paper, we addressed this conflict by compiling and editing available molecular and morphological data for Pan-Chelidae, and performing phylogenetic and dating analyses over the individual and the combined datasets. Our total-evidence phylogenetic analysis recovered the clade Chelidae as monophyletic and as sister group of a clade of South American extinct chelids; furthermore Chelidae retained inside the classical molecular structure with the addition of extinct taxa in both the Australasian and the South American clades. Our dating results suggest a Middle Jurassic origin for the total clade Pan-Chelidae, an Early Cretaceous origin for Chelidae, a Late Cretaceous basal diversification of both geographic clades with the emergence of long-necked lineages, and an Eocene diversification at genera level, with the emergence of some species before the final breakup of Southern Gondwana and the remaining species after this event.
Highlights
Pan-Chelidae is one of the two main lineages of crown Pleurodira
The oldest fossils that could be attributed to PanChelidae are from the early Cretaceous (110 million years ago [mya]) from Argentina and Australia (Lapparent de Broin & de la Fuente, 2001; Lapparent de Broin & Molnar, 2001; Smith, 2010; de la Fuente et al, 2011), suggesting that they originated in the south region of the Gondwanan supercontinent (Broin & de la Fuente, 1993)
Following Gaffney (1977) and subsequent m orphological studies (Bona & de la Fuente, 2005; de la Fuente et al, 2015, 2017a, b; Maniel et al, 2018), long-necked chelids form a monophyletic group represented by the extant South American species Hydromedusa tectifera Cope, 1870, Hydromedusa maximiliani Mikan, 1825 and Chelus fimbriata Schneider, 1783, the extant Australasian species belonging to the genus Chelodina, and the South American extinct taxa H. casamayorensis de la Fuente & Bona, 2002, Yaminuechelys gasparinii de la Fuente et al, 2001, and Yaminuechelys maior Staesche, 1929, and probably, Chelodina alanrixi Lapparent de Broin & Molnar, 2001 and Ch. murrayi Yates, 2013
Summary
Pan-Chelidae is one of the two main lineages of crown Pleurodira (e.g., turtles that retract their neck inside the shell in a horizontal plane). Following Gaffney (1977) and subsequent m orphological studies (Bona & de la Fuente, 2005; de la Fuente et al, 2015, 2017a, b; Maniel et al, 2018), long-necked chelids form a monophyletic group (except in the study of de la Fuente et al, 2017a) represented by the extant South American species Hydromedusa tectifera Cope, 1870, Hydromedusa maximiliani Mikan, 1825 and Chelus fimbriata Schneider, 1783, the extant Australasian species belonging to the genus Chelodina, and the South American extinct taxa H. casamayorensis de la Fuente & Bona, 2002, Yaminuechelys gasparinii de la Fuente et al, 2001, and Yaminuechelys maior Staesche, 1929, and probably (because they have not being included in a phylogenetic analysis up to now), Chelodina alanrixi Lapparent de Broin & Molnar, 2001 and Ch. murrayi Yates, 2013 In this sense, the morphological hypothesis suggests that the origin of the long neck occurred only once in the evolutionary history of chelids. The presence of the long neck would have evolved independently in the South American and Australasian clades
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
