A new homolid crab, Zygastrocarcinus carolinasensis n. sp., from the Cretaceous (Campanian) of NE Mexico: implications for paleobiogeography

Resumen

A new species of the
homolid crab, Zygastrocarcinus carolinasensis n. sp., is reported
from the Upper Cretaceous (upper Campanian) strata of Coahuila, NE
Mexico. Only the anterior part of the ~8 mm wide carapace was
preserved in addition to a part of the sternum (sternites 1-6). The
sternum is the oldest figured example of a fossil homolid sternum,
and also of the entire section of fossil Homoloida. The sternum
seems to be similar to extant homolids in general outline, and to an
earlier described Eocene homolid. Hitherto, Zygastrocarcinus spp.
were only known from the northern part of the USA (Wyoming, Montana,
and South Dakota). Thus, the new species extends the geographic
range of the genus during the Cretaceous to much of North America.
Additionally, this is the second fossil homolid known from
Mexico.