Zanthopsis bispinosa was a true crab that lived in the warm seas covering southern Britain during the Early Eocene. Like other members of Zanthopsis, it had a broad, strongly built carapace and powerful claws. It probably lived on or near the sea floor, although its exact diet and behaviour cannot be determined from the fossils alone.

The species is particularly recognisable by the pair of short, flattened spines on each side of the carapace. These give the crab its name, bispinosa, meaning “two-spined”. The carapace is broad and oval, and noticeably wider than it is long.

Zanthopsis bispinosa is one of several closely related Zanthopsis crabs found in the London Clay. Complete specimens are easier to identify than isolated pieces, as the shape and ornamentation of the carapace are important for distinguishing it from species such as Zanthopsis nodosa, Zanthopsis unispinosa and Zanthopsis dufourii.