Sponges from the Wordian (middle Permian) of the Las Delicias Formation, Coahuila, northwestern Mexico

 

Authors: Galeana-Morán MA, Sánchez-Beristain F, Quiroz-Barragan J, Sour-Tovar F

Article in press: Received 17 June 2024; Accepted in revised form 5 April 2025; Online 17 May 2025

Keywords: Porifera, middle Permian, Sphinctozoan, petrography, SEM,

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Abstract

Eleven sponge species from the Las Delicias Formation, Coahuila, northern Mexico, are described. Seven are thalamid sponges: Amblysiphonella guadalupensis, Guadalupia zitteliana, Lemonea cylindrica, Imbricatocoelia paucipera, Discosiphonella mammilosus, Girtyocoelia sp., and Colospongia americana. In addition, we report the presence of three poriferan taxa: Chaunactis aff. foliata and Heliospongia sp. sponges related to Demospongia; and the chaetetid Chaetetes mackrothii. For the first time in Paleozoic specimens, in the descriptions of Amblysiphonella guadalupensis, the presence of siliceous monaxon spicules is reported. The fossils have a high grade of diagenesis and chemical replacement of microstructure, possibly in a context of high tectonic and diagenetic activity. The described species are closely related with others from Grandian localities such as the Guadalupe Mountains from Texas and New Mexico, and Mediterranean localities. Most abundant species in Las Delicias Formation are Amblysiphonella guadalupensis and Lemonea cylindrica, contrasting with Texas/New Mexico communities where Guadalupia species prevailed.