A new species of the genus calaxiopsis (Decapoda: Thalassinidea: Calocarididae) from Japan

Abstract

A new species of calocaridid thalassinidean shrimp of the genus Calaxiopsis is described based on a single male specimen from Boso Peninsula, central Japan. It is related to C. serrata, but is readily distinguished from the latter in the unarmed submedian carinae on the gastric region, ventrally unarmed abdominal pleura, much shorter antenna! acicle and rudimentary podobranchs of the third maxilliped to third pereiopods, which lack normally developed gill filaments. The discovery of the new species shows that the development of the podobranchs on the third maxilliped to third pereiopods is variable within the genus. A check list of all known species of Axiidae and Calocarididae from the northwestern Pacific is included.