Early Cretaceous mollusk-perforating sponges from central-western region of Mexico

Abstract

In the Huetamo region, located at the limit of the states of Michoacán and Guerrero, numerous specimens of nerineids, pectinids, ostreids and rudists, with multiple perforations made by bioeroding organisms, were collected in beds of the El Cajón (Aptian) and Mal Paso (Albian) Formations.

The borings have circular and hexagonal outlines, with diameters ranging from 1.0 to 1.5 mm, and depths ranging from 0.45 to 0.9 mm, the holes form semicircular galleries. On the basis of these characteristics, the boring activity is attributed to clionid sponges of the ichnospecies Entobia sp. and E. cretacea Portlock, 1843... In order to continue, download full text in PDF.