Ghost shrimps (Decapoda: Axiidea: Callianassidae) of the Maastrichtian (Late Cretaceous) Ocozocoautla Formation, Chiapas (Mexico)

Resumen

On the basis of newly
collected material, two ghost shrimp taxa from the lower
Maastrichtian Ocozocoautla Formation in Chiapas (Mexico) are
recorded. Callianassa burckhardti is reassigned to Eucalliax, which
extends the known fossil record of this genus to the early
Maastrichtian. A new species, Callianassa (s.l.) ocozocoautlaensis,
is described based on a single specimen whose state of preservation
does not enable a firm generic assignment, despite the fact that the
material exhibits striking similarities to extant Callianassa
modesta, occasionally treated as a member of the genus Cheramus. The
fossil record of ghost shrimps from Mexico is briefly reappraised
and their survival across the K/Pg boundary is discussed. The
conservative body plan of ctenochelid and callianassid taxa is
emphasized and it is postulated that virtually all major ghost
shrimp clades were already established well before the
Cenozoic.