Puentemys
| Puentemys | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Temporal occurrence | ||||||||||||
| Mittelpaläozän ( selandian ) to Spätpaläozän ( thanetian ) | ||||||||||||
| 60 to 58 million years | ||||||||||||
| Locations | ||||||||||||
| Systematics | ||||||||||||
|
||||||||||||
| Scientific name | ||||||||||||
| Puentemys | ||||||||||||
| Cadena , Bloch & Jaramillo , 2012 | ||||||||||||
| Art | ||||||||||||
|
||||||||||||
Puentemys is an extinct genus of tortoises (Testudines) that lived in the Paleocene in what is now Colombia . The only representative is the species Puentemys mushaisaensis . With a length of up to 2 m it was the largest known representative of the Bothremydidae , an extinct family of the turn-necked turtles (Pleurodira). The animals, equipped with a round, flat shell, lived in fresh and brackish water near coastal wetlands that were overgrown with tropical rainforest. The fossil remains of Puentemys were found in the El Cerrejón coal mine and come from the Seelandium and Thanetium . A group of paleontologists around Edwin A. Cadena described it as a new genus and species in 2012. The closest relatives of the genus among the known Bothremydidae are the Cretaceous genera Foxemys and Polysternon , which suggests that this family reached South America across the Atlantic.
features
The skull of Puentemys has only survived in fragments. The preserved pieces belong to the posterior region of the lower jaw and - apart from their dimensions and systematic implications - do not allow any conclusions about the shape of the skull. A characteristic feature of Puentemys is a flat carapace with an almost round base (maximum 141 × 135 cm), which together with its relatively thin carapace cortex (bone cortex) and a long contact of the Exocciptal and Os quadratum identifies the genus as a representative of the Bothremydidae. The back armor was not indented in the neck and was about the same size and shape as the belly armor. It had a ridge of seven vertebral shields, which were flanked by eight pairs of elongated pleural shields. The end of the carapace was made up of eleven pairs of marginal plates, a pygal and a suprapygal. The belly armor (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, which was not the case with any other bothremydid. The maximum total length of the animals is estimated at around 2 m.
Site, fossil material and paleoecology
The holotype of the genus, a carapace with hyoplastron (inventory number UF / IGM 50), was found in the La Puente pit of the El Cerrejón mine in Colombia . Various other back and abdominal armor, armor fragments and the back piece of a skull come from the same pit. The layers in which the fossils were found are between -10 and 310 m above sea level and are at an age from 58 to 60 mya dated what the Paleocene - stages of Seelandiums and Thanetiums equivalent. The habitat of Puentemys consisted of an extensive, coastal river system with tropical rainforest vegetation. The mean annual temperature of the Paleocene Cerrejón was estimated at 30–34 ° C, which led to a relatively large herpetofauna . In addition to Puentemys , reptiles such as Carbonemys , Titanoboa and Cerrenjonisuchus were represented, which were far larger than their relatives living today.
Systematics and taxonomy
The genus Puentemys and its only species were described in 2012 by paleontologists Edwin A. Cadena , Jonathan I. Bloch, and Carlos A. Jaramillo in the Journal of Palaeontology . The authors chose the generic name based on the place where it was found, the La Puente pit. The specific epithet mushaisaensis refers to the Colombian town of Mushaisa , where the Cerrejón coal mine is located.
In the construction of his tank, Puentemys shows clear similarities with two Cretaceous bothremydids from France, Foxemys and Polysternon . Analyzes of the skeletal morphology assigned Puentemys to the Bothremydidae Foxemys as sister taxon . Together with Polysternon they form the monophyletic subtribe Foxemydina. Since the closest relatives of the genus each lived across the Atlantic , Cadena and colleagues assume that the members of this group were able to cover long distances along coasts and ocean currents and thus cross the ocean.
swell
literature
- Edwin A. Cadena, Jonathan I. Bloch, Carlos A. Jaramillo: New Bothremydid Turtle (Testudines, Pleurodira) from the Paleocene of Northeastern Colombia. In: Journal of Paleontology 86 (4), 2012. doi : 10.1666 / 11-128R1.1 , pp. 688-698.
- Jason J. Head, Jonathan I. Bloch, Alexander K. Hastings, Jason R. Bourque, Edwin A. Cadena, Fabiany A. Herrera, P. David Polly, Carlos A. Jaramillo: Giant Boid Snake from the Palaeocene Neotropics Reveals Hotter Past Equatorial Temperatures. In: Nature 475 (532), 2009. doi : 10.1038 / nature10271 , pp. 715-718.