Puentemys
- Cerrejon Formation, Colombia
- Puentemys mushaisaensis Cadena et al. 2,012
Puentemys is an extinct genus of turtles ( Testudines ), who lived on the present territory of Colombia in the Paleocene. As the only representative of her is attributed the type Puentemys mushaisaensis. She was up to 2 m length of the largest known representative of the Bothremydidae, an extinct family of the neck turner turtles ( Pleurodira ). Featuring a round, flat armored animals lived in freshwater and brackish water in coastal wetlands that were covered with tropical rainforest. The fossil remains of Puentemys were found in the coal mine El Cerrejón and come from the Seelandium and Thanetium. A group of paleontologists Edwin A. Cadena described it in 2012 as a new genus and species, the closest relatives of the genus among the known Bothremydidae are the Cretaceous genera Foxemys and Polysternon, suggesting that this family reached South America across the Atlantic.
Features
The skull of Puentemys has survived only in fragments. The pieces obtained belong to the posterior mandible region and leave - except for their dimensions and systematic implications - no conclusion as to the shape of the skull to. A characteristic feature of Puentemys is a shallow tank with almost round base area (maximum 141 × 135 cm), of the genus together with their relatively thin armor inner cortex ( cortical bone ) and a long Kontekt of Exocciptal and Os quadratum representing the Bothremydidae identifies. The carapace was not indented in the neck and had about the same size and shape as the plastron. It had a ridge made of seven vertebrae shields, which were flanked by eight pairs of elongate Pleuralschilde. The end of the carapace were eleven marginal plate pairs, a pygal and a Suprapygal. The plastron ( plastron ) had an almost square Entoplastron, which is flanked by two triangular Humeralia. The Pectoralia were shorter than the Humeralia, Abdominalia and femoralia in the middle of the plastron, what else was the case for any other Bothremydiden. The maximum total length of the animals is estimated to be about 2 m.
Locality, and palaeoecology of fossil material
The holotype of the species, with a carapace Hyoplastron (inventory number UF / IGM 50), was found in the La Puente- pit of the Colombian El Cerrejon mine. From the same pit originate various other back and belly tanks, armored fragments and the rear piece of a skull. The layers in which the fossils were found, are -10 to 310 m above sea level and are dated at 58-60 & nbspmya, which corresponds to the Paleocene stages of Seelandiums and Thanetiums. The habitat of Puentemys consisted of a large, coastal river system with tropical rain forest vegetation. The mean annual temperature of the Paleocene Cerrejón was estimated at 30-34 ° C, which resulted in a relatively large herpetofauna. Besides Puentemys were represented by Carbonemys, Titanoboa and Cerrenjonisuchus reptiles in it, which were far larger than their relatives living today.
Systematics and Taxonomy
The genus Puentemys and their only type have been described in 2012 by the paleontologist Edwin A. Cadena, Jonathan I. Bloch and Carlos A. Jaramillo in the Journal of Palaeontology. The genus name, the authors selected based on the locality, the La Puente- pit. The specific epithet refers to the Colombian town mushaisaensis Mushaisa reference, in which the Cerrejon coal mine is located.
Puentemys shows the construction of the coat with two distinct similarities Cretaceous Bothremydiden from France, Foxemys and Polysternon. Analysis of skeletal morphology associated Puentemys under the Bothremydidae Foxemys as sister taxon to. Together with Polysternon they form the monophyletic subtribe Foxemydina. Since the closest relatives of the genus lived each side of the Atlantic, Cadena and colleagues assume that the members of this group were able to long distances along coasts and ocean currents to cover and so to overcome the ocean.