Boletín de la Sociedad Geológica Mexicana Volumen 75, núm. 3, A140723, 2023 http://dx.doi.org/10.18268/BSGM2023v75n3a140723

Continental mollusks from the Olmos Formation (Upper Cretaceous), Coahuila, Mexico

Moluscos continentales de la Formación Olmos (Cretácico Superior), Coahuila, México

Naylet K. Centeno-González¹, Gerardo Zúñiga-Bermúdez¹, Emilio Estrada-Ruiz¹, Francisco J. Vega^2,*

¹ Departamento de Zoología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Prolongación de Carpio y Plan de Ayala s/n, 11340, CDMX, Mexico.

² Instituto de Geología, Universidad Nacional Autónoma de México, Ciudad Universitaria, Coyoacán, 04510, CDMX, Mexico.

* Corresponding author: (F.J. Vega) This email address is being protected from spambots. You need JavaScript enabled to view it.

How to cite this article:

Centeno-González, N.K., Zúñiga-Bermúdez, G., Estrada-Ruiz, E., Vega, F.J., 2023, Continental mollusks from the Olmos Formation (Upper Cretaceous), Coahuila, Mexico: Boletín de la Sociedad Geológica Mexicana, 75 (3), A140723. http://dx.doi.org/10.18268/BSGM2023v75n3a140723

Manuscript received: February 24, 2023; Corrected manuscript received: July 12, 2023; Manuscript accepted: July 17, 2023.

ABSTRACT

We describe freshwater mollusks from the Olmos Formation, Campanian, Upper Cretaceous. The results were obtained from several specimens of mollusks, identified with two families of gastropods: Viviparidae (Viviparus sp.) and Physidae (Mesolanistes sp.), and three families of bivalves: Limidae (Pseudolimea sp.), Unionidae (Proparreysia sp., Unio sp., Unionelloides? sp., Plesielliptio sp., and Ostreidae (Ostrea sp.). Based on this taxonomic recognition, along with the associated fossil flora, it was possible to get a preliminary of the environment where the mollusks lived. The interpretation of the paleoenvironment resemble freshwater bodies adjacent to an estuarine system. Furthermore, the mixing of specimens of brackish and freshwater environments is indicative of a transport of some of these mollusks. The general view of the paleoenvironment where the mollusks inhabited is that of a transitional freshwater-estuarine in the Olmos Formation during Campanian times.

Keywords:Mollusca, Campanian, Olmos Formation, NE Mexico.