San Carlos quarry (Cretaceous of Mexico)

Also known as Austin limestone

Where: Coahuila, Mexico (29.1° N, 100.8° W: paleocoordinates 34.9° N, 73.5° W)

• coordinate stated in text

When: Austin Chalk Formation, Campanian (83.6 - 72.1 Ma)

Environment/lithology: marine; marl

• The San Carlos quarry, at the base of the outcrops, is composed of calcareous marls and yellowish-white chalks, and the upper part of them is composed of gray limestone and yellowish-brown marls. These lithologies are disposed in thin layers (decimeter). On the other hand, the thickness of the limestone varies between 40 and 60 cm, chalks and marls, between 20 and 100 cm, while shale thickness varies from a few centimeters to 40 cm. Studies made by Carrasco (1969) and Reeside (1927) in Jiménez, Coahuila suggested an early Campanian age for this unit, based on the presence of the ammonites Scaphites hippocrepis and Delawarella delawarensis. Also, many fish remains, shark teeth, bivalves, crabs and sea urchins, among others, have been recovered in this quarry (Silva-Martínez et al., 2014).

Size classes: macrofossils, mesofossils

Preservation: mold/impression

Collection methods: chemical, mechanical, ,

• The specimen described in this paper is housed at the Museo Paleontológico de Múzquiz, in Melchor Múzquiz, Coahuila, Mexico.

•The rocky matrix preserved on the bones was removed with pneumatic tools and dental needles. The bones and fossil impressions were hardened by applying a layer of plexygum dissolved in cyanoacrylate. In this study, the specimen was observed and measured directly and through photographs obtained under different conditions, including daylight and white and UV light of photo-studio.

Primary reference: O. A. Lopez-Conde, J. Sterli, J. Alvarado-Ortega, M. L. Chavarria-Arellano, and H. Porras-Muzquiz. 2019. The first record of Desmatochelys cf. D. lowii from the Late Cretaceous (Campanian)of Coahuila, Mexico. Journal of South American Earth Sciences [E. Vlachos/E. Vlachos]more details

Purpose of describing collection: taxonomic analysis

PaleoDB collection 201737: authorized by Evangelos Vlachos, entered by Evangelos Vlachos on 24.05.2019

Creative Commons license: CC BY (attribution)

Taxonomic list

• Studies made by Carrasco (1969) and Reeside (1927) in Jiménez, Coahuila suggested an early Campanian age for this unit, based on the presence of the ammonites Scaphites hippocrepis and Delawarella delawarensis. Also, many fish remains, shark teeth, bivalves, crabs and sea urchins, among others, have been recovered in this quarry (Silva-Martínez et al., 2014).
Show authors, comments, and common names
Reptilia
 Testudines - Protostegidae
Desmatochelys cf. lowii
Desmatochelys cf. lowii Williston 1894 sea turtle
MUZ-562 is a semi-articulated specimen represented only by postcranial elements preserved in ventral view.