Monday 12 January 2015

A new species of Icriocarcinid Crab from the End Cretaceous of California.

Icriocarcinid Crabs are a distinct group of Portunoid Crabs (the group that includes modern Swimming Crabs and Golden Crabs) known from the Late Cretaceous of North America and Europe. They had strong transverse ridges on their carapaces and spines on their limbs and mouthparts.

In a paper published in the journal Scripta Geologica in October 2014, Torrey Nyborg of the Department of Earth and Biological Sciences at Loma Linda University, Àlex Ossó of Tarragona in Spain and Francisco Vega of the Institutode Geología at Ciudad Universitaria, describe a new species of Icriocarcinid Crab from the End Cretaceous Moreno Formation in San Joaquin Valley, California.

The new species is placed in the genus Branchiocarcinus and given the specific name pacificus, in reference to the location where the fossils were found, on the Pacific Coast of North America; the only previously described species in the genus, Branchiocarcinu flectus, is known only from the Atlantic Coast of Mississippi, New Jersey and San Luis Potosí in Mexico, although specimens assigned to the genus but not to a species are known from British Columbia on the Pacific Coast.

Branchiocarcinus pacificus is described from three specimens from two different exposures. The specimens range from 25.7 mm to 30.5 mm in width, and are subtrapezoidal and twice as wide as long, being at their widest on their front third.

Specimen of Branchiocarcinuspacificus from the upper Maastrichtian, Tierra Loma Member of the Moreno Formation in Merced County, California. Nyborg et al. (2014).

See also… new species of Palaeocorystid Crab from the Late Cretaceous of Poitou-Charentes in southwest France.                                                      Palaeocorystid Crabs are widespread in sedimentary rocks from the Middle-to-Late Cretaceous across the world. They are interpreted as having been specialist back-burrowers, a lifestyle that requires several modifications to the bodyplan of normally sideways-moving Crabs, particularly narrowing of the body (which is wider than it is long in most Crabs) and reduction of the...
Frog Crabs, Raninoidia, are well represented in the fossil record across much of the globe in the Late Cretaceous and Cenozoic, but poorly recorded from the Early Cretaceous, when the group is thought to have originated. For a long time the majority of early Frog Crabs known were from Eurasia, leading to... A new species of Pea Crab from St. John’s Island, Singapore.                                                  Pea Crabs of the genus Indopinnixa are found living commensally in the burrows of Sipunculan Worms across South and Southeast Asia. They are morphologically quite variable, with different species having different carapace structures and numbers of fused segments, but all are quite small, which gets the...
Follow Sciency Thoughts on Facebook.