Denazinemys Explained

Denazinemys was a genus of baenid turtle that lived in the Late Cretaceous of New Mexico. The holotype specimen, which D. nodosa was based on, USNM 8345, consists of a partial carapace and plastron. It came from the De-na-zin Member of the Kirtland Formation, and therefore, Denazinemys lived in the Kirtlandian land-vertebrate age. Many specimens other than the holotype have been assigned to Denazinemys.

Numerous shell fragments from the Lower and the Middle Campanian were assigned to Denazinemys nodosa, based on the welted structure of the shell surface. However, a recent study calls into question the attribution of this material to Denazinemys nodosa, as the material is too fragmentary to distinguish differences in the structure of the welted shell surface. As it is not yet possible to identify these fragments precisely (several species of baenidae having this same feature on their shell surface), the researchers restricted Denazinemys nodosa to the Upper Campanian.

Distinguishing characteristics

Previously, Scabremys ornata was assigned to Denazinemys as D. ornata. Below are the features found in Denazinemys distinguishing the two genera:

• a carapace that is sub-triangular with widest dimension posteriorly;
• prepleurals present and touching the first vertebrae medially;
• the first vertebrae an irregular hexagonal shape with the greatest width posteriorly, contacting anterior second vertebrae;
• extracervicals lateral to the primary cervicals, the cervicals being sub-divided;
• and carapace nodes irregular and not forming distinct ridges.

Classification

Denazinemys is a baenid along with Plesiobaena, Boremys, Scabremys, Baena and Chisternon.

Below is a cladogram made by Sullivan et al. in 2013 showing the relations of Denazinemys: (note: Boremys pulchra is partly a junior synonym of Boremys grandis)

References

^{[1] [2]}

Notes and References

1. Book: Sullivan, R.M. . Jasinski, S.E. . Lucas, S.G. . 2013 . Re-Assessment of Late Campanian (Kirtlandian) Turtles from the Upper Cretaceous Fruitland and Kirtland Formations, San Juan Basin, New Mexico, USA . Brinkman, D.B. . etal . Morphology and Evolution of Turtles . Vertebrate Paleobiology and Paleoanthropology . 337–339 . 10.1007/978-94-007-4309-0_20 . 978-94-007-4308-3 . http://www.stevenjasinski.com/uploads/27_-_Sullivan_et_al__2012__Re-Assessment_of_Late_Campanian__Kirtlandian__Turtles_from_Upper_Cretaceous_Fruitland.pdf . 2014-02-19 . 2014-02-28 . https://web.archive.org/web/20140228225152/http://www.stevenjasinski.com/uploads/27_-_Sullivan_et_al__2012__Re-Assessment_of_Late_Campanian__Kirtlandian__Turtles_from_Upper_Cretaceous_Fruitland.pdf . dead .
2. Spicher, G.E.. Sertich, J.J.. Girard, L.C.. Joyce, W.G.. Lyson, T.R.. Rollot, Y.. 2023. A description of a Denazinemys nodosa specimen (Testudinata, Baenidae) from the Late Cretaceous Kaiparowits Formation of southern Utah. Fossil Record. 26. 2. 151–170 . 10.3897/fr.26.102520. free . 2023FossR..26..151S .