Monday 22 December 2014

A new species of Frog Crab from the Early Cretaceous of Colombia.

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 suggestions that they may have originated at high northern latitudes, but a number of new specimens have recently been reported from Colombia, leading to a re-evaluation of the groups origins, with the possibility that they may have originated in equatorial South America.

In a paper published in the journal Scripta Geologica in October 2014, Javier Luque of the Department of Biological Sciences at the Universityof Alberta and the Smithsonian Tropical Research Institute described a new species of Frog Crab from the Early Cretaceous Paja Formation of the Department of Santander in Colombia.

The new species is named Bellcarcinus aptiensis, where ‘Bellcarcinus’ means ‘Bell’s Crab’ honouring palaeontologist Thomas Bell (1792-1880) for his work on fossil Frog Crabs, and ‘aptiensis’ means ‘from the Aptian’, in reference to the Aptian Age (~125-113 million years ago), from which the fossils derive.

Bellcarcinus aptiensis, dorsal carapace. Luque (2014).

The new species is described from four specimens, ranging from 6.6 mm to 13 mm in length and from 8 mm to 16.1 mm in width. Luque suggests that Bellcarcinus aptiensis is probably a member of the Orithopsidae, making it the earliest occurrence of a group already thought to be one of the earliest Frog Crab families to appear, but notes that it also shows affinities to the Necrocarcinidae.

See also… 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...
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