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Re: Pappochelys, new stem-turtle from the Middle Triassic of Germany + Gaffneylania, new horned turtle from Argentina

Read-only access to full Nature paper:


Smithsonian press release:


On Wed, Jun 24, 2015 at 10:14 AM, Ben Creisler <bcreisler@gmail.com> wrote:
> Ben Creisler
> bcreisler@gmail.com
> New papers that may be of interest:
> Rainer R. Schoch & Hans-Dieter Sues (2015)
> A Middle Triassic stem-turtle and the evolution of the turtle body plan.
> Nature  (advance online publication)
> doi:10.1038/nature14472
> http://www.nature.com/nature/journal/vaop/ncurrent/full/nature14472.html
> The origin and early evolution of turtles have long been major
> contentious issues in vertebrate zoology. This is due to conflicting
> character evidence from molecules and morphology and a lack of
> transitional fossils from the critical time interval. The
> ~220-million-year-old stem-turtle Odontochelys from China has a partly
> formed shell and many turtle-like features in its postcranial
> skeleton. Unlike the 214-million-year-old Proganochelys from Germany
> and Thailand, it retains marginal teeth and lacks a carapace.
> Odontochelys is separated by a large temporal gap from the
> ~260-million-year-old Eunotosaurus from South Africa, which has been
> hypothesized as the earliest stem-turtle. Here we report a new
> reptile, Pappochelys, that is structurally and chronologically
> intermediate between Eunotosaurus and Odontochelys and dates from the
> Middle Triassic period (~240 million years ago). The three taxa share
> anteroposteriorly broad trunk ribs that are T-shaped in cross-section
> and bear sculpturing, elongate dorsal vertebrae, and modified limb
> girdles. Pappochelys closely resembles Odontochelys in various
> features of the limb girdles. Unlike Odontochelys, it has a cuirass of
> robust paired gastralia in place of a plastron. Pappochelys provides
> new evidence that the plastron partly formed through serial fusion of
> gastralia. Its skull has small upper and ventrally open lower temporal
> fenestrae, supporting the hypothesis of diapsid affinities of turtles.
> News:
> http://www.npr.org/sections/thetwo-way/2015/06/24/416657576/how-the-turtle-got-its-shell
> http://www.ibtimes.co.uk/new-turtle-fossils-shed-new-light-evolution-its-shell-1507733
> In German:
> http://www.spiegel.de/wissenschaft/natur/aelteste-schildkroete-der-welt-bei-schwaebisch-hall-entdeckt-a-1040503.html
> http://www.swr.de/landesschau-aktuell/bw/heilbronn/ur-ahn-der-schildkroete-entdeckt-spektakulaerer-fossil-fund-bei-schwaebisch-hall/-/id=1562/did=15724232/nid=1562/1qwch7u/
> ====
> Also:
> Juliana Sterli, Marcelo S. de la Fuente and J. Marcelo Krause (2015)
> A new turtle from the Palaeogene of Patagonia (Argentina) sheds new
> light on the diversity and evolution of the bizarre clade of horned
> turtles (Meiolaniidae, Testudinata).
> Zoological Journal of the Linnean Society 174(3): 519–548
> DOI: 10.1111/zoj.12252
> http://onlinelibrary.wiley.com/doi/10.1111/zoj.12252/abstract
> In this contribution we present a new species of horned turtle,
> Gaffneylania auricularis gen. et sp. nov., from the Paleogene of
> Patagonia. The specimens come from the lower section of the Sarmiento
> Formation (Middle Eocene) at Cerro Verde (Cañadón Hondo area, Province
> of Chubut, Argentina). The level containing turtles and
> crocodyliforrmes is located at the base of the section and it consists
> of laminated, fine tuffs interpreted as shallow pond sediments. It
> underlies another fossiliferous level comprising lenticular, massive
> sandstones bearing skeletal remains of mammals, referred by previous
> authors to the Casamayoran SALMA. Gaffneylania auricularis represents
> one of the most complete meiolaniids from South America found to date
> and it is distinguished from other meiolaniids by the presence of a
> peculiar half-moon-shaped, thick rim surrounding the cavum tympani,
> the presence of three cranial scutes K and an unenclosed canalis
> chorda tympani mandibularis, among others. This new species sheds new
> light on the evolution and palaeobiogeographical history of the clade
> Meiolaniidae in Australasia and South America during the Cainozoic.
> The break up of southern Gondwana provoked major global climatic
> changes during the Cainozoic that probably influenced the evolution of
> meiolaniid turtles. The co-evolution of meiolaniids with other
> amniotes (e.g. chelid turtles, mammals) suggests a common
> palaeobiogeographical history of those clades in southern Gondwana.