REVISION OF THE GAMBA PRAWN 

 GENUS PSEUDARISTEUS, WITH DESCRIPTION OF TWO NEW SPECIES 



(CRUSTACEA: DECAPODA: PENAEOIDEA) 



Isabel Perez Farfante' 



ABSTRACT 



The genus Pseudaristeus (family Aristeidae) is widespread in the Indo-West Pacific where five species— P. 

 crassipes, P. gracilis, P. kathleenae n. sp., P. protensus n. sp., and P. sibogae—have been found at depths 

 between 719 and 1,785 m; another species, P. speciosus, occurs in the southwestern Atlantic, where it 

 was taken at 4,847 m. Females of Pseudaristeus possess a styliform, long rostrum, 0.70-1.40 as long 

 as the carapace; most males have shorter ones 0.20-0.57, but some have been found in which the rostrum 

 is as long as that of the females. This suggests that in this genus, as in AristeiLs, at certain stages of 

 the life cycle, males develop a long rostrum. Following a revised definition of the genus, a key to the 

 species, a synonymy, the location of the types, type-locality, and a list of specimens examined are given 

 for each species. Detailed morphological accounts, including intraspecific variation, accompany statements 

 of maximum sizes, and geographic and bathymetric ranges. The description of P. gracilis is the first 

 to take into consideration adult material. In discussing relationships, P. crassipes, P. kathleenae, and 

 P. protensTis, sympatric off the coast of India, are shown to constitute a rather homogenous group 

 somewhat distantly related to the other very distinctive members of the genus. 



The deep-sea "gamba prawns" of the genus Pseuda- 

 risteus are widely distributed at depths of 719-1,785 

 m in the Indo-West Pacific— from the Gulf of Aden 

 and off Natal, South Africa to the Philippines— 

 where five (P. crassipes, P. gracilis, P. kathleenae 

 n. sp., P. protensus n. sp., P. sibogae) of the six 

 species recognized herein are found. The sixth (P. 

 speciosus) occurs in the southwestern Atlantic, off 

 northeastern Argentina. It is unlikely that members 

 of the genus occur in the northwestern Atlantic, in- 

 cluding the Gulf of Mexico and the Caribbean, 

 where, although intensive collecting have been con- 

 ducted, no Pseudaristeus have been taken. 



The large gamba prawns (reaching as much as 

 47.5 mm carapace length, about 150 mm total 

 length) that occur at shallower depths might, in the 

 not too distant future, make a minor, but highly 

 esteemed, contribution to the commercial catches 

 of penaeoids in certain areas of the Indo-West 

 Pacific, as do members of other deep-sea genera 

 {Aristaeomorpha, Aristeus, and Plesiopenaeus) of 

 the family Aristeidae. 



The genus Pseudaristeus has been poorly under- 

 stood largely because the original descriptions of the 

 first three recognized species, P. speciosus, P. 

 gracilis, and P. crassipes, are inadequate for sep- 



^Systematics Laboratory, National Marine Fisheries Service, 

 NOAA, U.S. National Museum of Natural History, Washington, 

 DC 20560. 



arating them, and the illustrations of the latter two, 

 although well rendered, are of little help. Incomplete 

 descriptions and inadequate illustrations were pri- 

 marily responsible for subsequent assignment of 

 specimens of two new species described here to P. 

 crassipes, which, like them, occurs in the waters off 

 India. 



Availability of the rich collections of Pseudaristeus 

 made by the U.S. Bureau of Fisheries steamer 

 Albatross during the Philippine Expedition, 1907-10, 

 and the loan of critical material from several 

 museums have enabled me to make detailed studies 

 of all six species of the genus. Included in the ac- 

 counts of each are numerous diagnostic characters 

 which have not been previously recognized in the 

 four described species. One of these characters is 

 the sinuous ventral antennular flagellum found in 

 male P. gracilis, which not only allows a ready iden- 

 tification of these animals but constitutes another 

 significant element for the interpretation or a better 

 understanding of the relations of the members of 

 Pseudaristeus to those of the closely allied Aristeus. 



PRESENTATION OF DATA 



In the account of the species, most of the termi- 

 nology used follows that proposed and illustrated 

 by Perez Farfante (1969, 1977). The anterolateral 

 carina, a unique feature of one member of Pseuda- 

 risteus, which has not been cited by me previously, 



Manuscript accepted January 1987. 

 FISHERY BULLETIN: VOL. 85, NO. 2, 1987. 



311 



