Crustacea Decapoda: Deep-sea shrimps of the genus Plesionika Bate, 1888 (Pandalidae) from French Polynesia, with descriptions of five new species

Abstract

Recent extensive deep-sea trappings in French Polynesian waters produced 21 species of shrimps belonging to the caridean genus Plesionika Bate, 1888. Seven of these have been described in detail before (CHAN & CROSNIER, 1991). The present report mainly deals with the remaining 14 species and has many interesting findings. P. ocellus (Bate, 1888) is actually a senior synonym of P. chacei Hayashi, 1986 and the name P. sindoi (Rathbun, 1906) has to be revived. P. macropoda Chace, 1939 and P. williamsi Forest, 1964 are distinct species and both occur, sometimes even sympatrically, in the Atlantic and Indo-Pacific. Abundant material belonging to the poorly known species P. nesisi (Burukovsky, 1986) is found in French Polynesia, and this species is c10sely related to P. laevis (A. Milne Edwards, 1883) and P. fenneri Crosnier, 1986. Furthermore, P. alexandri (A. Milne Edwards, 1883) and P. unicarinatus (Borradaile, 1915) also belong to the "P. làevis" group which is intermediate between the typical Plesionika and Heterocarpus. The exact differences between P. refiexa Chace, 1985 and P. ensis (A. Milne Edwards, 1881) are not c1ear, and it appears that the posterior spine on the abdomen somite III can be recurved or straight in the specimens from the Indo-Pacific but is always straight in the Atlantic material. Five new species were found in French Polynesia: P. erythrocyclus sp. nov., which is near to P. rostricrescentis (Bate, 1888) and also distributed in Taiwan; P. payeni sp. nov., which is somewhat affiliated to P. ocellus; P. picta sp. nov., which is distinct in lacking antennal spine and without epipod on the pereiopod IV; P. poupini sp. nov., which is very similar to P. carsini Crosnier, 1986; and P. protati sp. nov., which is closely related to P. sindoi. The other species reported from French Polynesia are P. edwardsii (Brandt, 1851), P. martia (A. Milne Edwards, 1883), P. semilaevis Bate, 1888 and P. spinidorsalis (Rathbun, 1906). Moreover, two probable postlarvae of P. fenneri Crosnier, 1986 were found and additional information is provided for this species.