Mecochiro

This strange crustacean possessed in unusual appearance, mainly due to the length of the first pair of thoracic appendages (pereiopods), which were longer than the rest of the animal's body.
The latter, instead of bearing terminal claws as is the case in many crustaceans, were equipped with a simple, elongated segment, which was not counterbalanced by the classic fixed claw finger.
The elongated pereiopod was finely covered with tubercles and, at least in some species (e.g., Mecochirus germari), traversed by longitudinal and parallel keels.
The lower margin of the pereiopod had numerous denticles, and in many species there were true fine bangs (e.g., Mecochirus longimanatus).
The carapace was generally covered with a dense ornamentation of tubercles, with a short rostral margin lacking denticles, while the ocular incision was shallow.
The size of Mecochirus ranged from a few centimeters in length to more than 10 centimeters.