A New Species of Bairdemys (Pelomedusoides: Podocnemididae) from the Oligocene (Early Chattian) Chandler Bridge Formation of South Carolina, USA, and Its Paleobiogeographic Implications for the Genus

Abstract

A new species of podocnemidid pleurodire turtle, Bairdemys healeyorum, is described from the upper Oligocene Chandler Bridge Formation of South Carolina, USA, on the basis of a nearly complete shell found with associated skull fragments, lower jaw, girdle elements, and limb elements. This is the first record of an Oligocene pleurodire turtle from North America. The shell and lower jaw are unique in detail but similar in overall morphology to equivalent parts of Bairdemys venezuelensis and B. sanchezi. The plastron of this new species also shares many features with the previously described Maryland Miocene species of podocnemidid, ''Taphrosphys'' miocenica, so the Miocene taxon is here referred to Bairdemys. In the Oligocene and Miocene, North and South America were separated by broad expanses of salt water, so Bairdemys probably was salt-water tolerant and reached North America by ''island hopping'' from South America across the Caribbean Sea.

A toothed turtle from the Late Jurassic of China and the global biogeographic history of turtles

“…10a). A number of marine dispersal events can be reconstructed between Africa, Europe, India, Madagascar, and North and South America within Bothremydinae [104, 105] and between Africa, India, Puerto Rico, and South and North America within Stereogenyina [106]. The question whether the current distribution of podocnemidids in South America and Madagascar is due to vicariance or dispersal remains unresolved (see discussion above).…”

Side-Necked Turtles (Testudines, Pleurodira) from the Ancient Gulf Coastal Plain of Florida During Middle Cenozoic Megathermals

“…The larger-bodied form may represent the genus Bairdemys, which had an extensive range across North America, some of the Caribbean Islands, and South America during the Miocene and likely dispersed freely across seawater. Bairdemys miocenica (Collins and Lynn 1936) is known from the Calvert Cliffs of Maryland (~16-15.7 Ma; Weems and Knight 2013), and records of this taxon are contemporaneous with the more abundant pleurodire records discussed here from the Willacoochee Creek and Midway LFs and only slightly younger or equivalent in age to pleurodires from Suwannee Springs, Camp Creek, and the Seaboard LF. It is unclear at this time, pending more complete fossils, if any of the Floridian pleurodires represent B. miocenica or a closely related taxon, but this scenario is not unlikely.…”

“…Gray bars indicate approximate temporal ranges of pleurodire records. Record of B. healeyorum after Weems and Knight (2013). Records of B. miocenica after Weems and George (2013).…”

“…The absence of cranial material makes classification at generic or specific levels dubious at this time. For example, a pleurodiran taxon from the Willacoochee Creek LF possesses neural bones, whereas, by contrast, the shell of B. venezuelensis lacks neurals (Gaffney and Wood 2002;Gaffney et al 2011), while some species of Bairdemys possessed neurals (Weems and Knight 2013;J.R.B., in prep.). The following specimen descriptions are organized in order of anatomical position (carapace: peripherals, costals, neurals; plastron: epiplastra, mesoplastron, hypoplastron, xiphiplastra).…”

Nostimochelone lampra gen. et sp. nov., an Enigmatic New Podocnemidoidean Turtle from the Early Miocene of Northern Greece

“…In accordance, Gaffney et al (2006) designated ''P.'' lata a nomen dubium because the holotype possessed no uniquely distinguishing features, and also regarded other reports of Miocene bothremydids from North America (Collins and Lynn 1936;Gaffney and Zangerl 1968; for an alternative reinterpretation see Weems and Knight 2012) and Oman (Roger et al 1994) to be inconclusive. The recent recovery of an articulated carapace and plastron belonging to a podocnemidoidean turtle from lower Miocene (Burdigalian) littoral marine sediments of the Zeugostasion Formation (or ''Zeugostasion Series'' sensu Wielandt-Schuster et al 2004) near the village of Nostimo in the Mesohellenic Basin of northwestern Macedonia (Fig.…”