Acantholipan

Acantholipan is a genus of herbivorous dinosaur belonging to the nodosaurid family, known from fragmentary fossils discovered in Mexico. This dinosaur inhabited the region during the early Santonian age of the Late Cretaceous period.

Discovery and Naming

Fragmentary fossils of nodosaurids have been unearthed in northern Mexico. A partial skeleton, designated CPC 272, was excavated at Los Primos near San Miguel in Coahuila. Initially considered too incomplete for formal naming, subsequent evaluation determined the remains were distinct enough to warrant a binomial name. In 2018, the type species, Acantholipan gonzalezi, was formally described by Rivera-Sylva and colleagues. The genus name, Acantholipan, is a combination of the Greek word 'akanthos,' meaning "spine," and 'lipán,' a Spanish designation for the Lépai-Ndé people, an Apache tribe indigenous to the area where the fossils were found. The species name, gonzalezi, honors the Mexican paleontologist Arturo Homero González-González, who chaired the Museo del Desierto in Saltillo. Acantholipan holds the distinction of being the first ankylosaurian species to be named from Mexico.

Paleobiology and Fossils

The holotype specimen, CPC 272, was recovered from a marine layer of the Pen Formation and dates to the Santonian stage. This partial skeleton lacks a skull but includes several key elements. Among the found remains are a back vertebra, a tail vertebra, a piece of a rib, the underside of the left humerus, an upper left ulna, the underside of the left femur, and a spike-like osteoderm, likely originating from the posterior thorax. Acantholipan is classified within the Nodosaurinae subfamily and is considered the sister taxon to Nodosaurus. The fossil collection is housed at the Colección Paleontológica de Coahuila, Museo del Desierto, Saltillo.