Pleistacantha kannu

Pleistacantha kannu is a species of spider crab in the family Oregoniidae.^[1] It is found on the coast of Southern India from the Bay of Bengal at depths of 129–530 m (423–1,739 ft).^[2]

Pleistacantha kannu has a pyriform carapace whose dorsal surface is covered with short, conical, broad-based spines and sharp tubercles.^[3] Its carapace is about as long postrostrally^[a] as it is wide,^[3] measuring up to 150 mm (5.9 in) long and up to 138 mm (5.4 in) wide.^[2] Its branchial region is strongly inflated, distinguishing it from similar Pleistacantha species such as P. moseleyi, P. pungens, and P. ori.^[3] It is the largest spider crab known to inhabit the Indian Ocean.^[2]

Its carapace ranges from orange to orange-red on the dorsal surface, its chelipeds and walking legs are reddish-brown with white fingers in males and orange and white in females, and its ventral surfaces are dirty white.^[3] Its walking legs end in a horn-like tip covered in setae, and they are covered in short tubercles and granules.^[3] Its abdomen lacks spines but is covered in numerous blunt and sharp tubercles.^[3]

Pleistacantha kannu was described in 2017 by carcinologists Peter Kee Lin Ng, Raveendhiran Ravinesh, and S. Ravichandran.^[3] It is named after T. Kannupandi, an Indian carcinologist at the Annamalai University.^[3] It is considered likely conspecific with a crab collected in 1997 from the Gulf of Aden.^[3]