FISHERY BULLETIN: VOL. 85. NO. 2 



short of mesial base of well-developed, sharp, disto- 

 lateral spine; third article not produced laterally; 

 dorsal flagellum extending to distal 0.2 of scapho- 

 cerite; ventral flagellum although incomplete, long, 

 and straight, not mesially curved (concave) just 

 distal to apex of dorsal flagellum. 



Scaphocerite extremely long, surpassing anten- 

 nular peduncle by as much as 0.4 its own length, 

 strong lateral rib ending in acutely pointed small 

 spine falling considerably short of distal end of 

 lamella. Antennal flagellum broken. 



Third maxilliped with ultimate article slender but 

 slightly broadening mesially from narrow base, then 

 tapering gently to blunt apex. 



Pereopods not covered with setae; first and sec- 

 ond pereopods with broad, depressed merus armed 

 with small, slender, distomesial spine. 



Abdomen with sharp dorsomedian carina extend- 

 ing full length of fourth somite through sixth, and 

 produced in spine on posterior margin of last 3 

 somites; sixth somite also bearing pair of minute 

 posteroventral spines and 2 elongate cicatrices. 

 Telson with median sulcus shallow anteriorly, in- 

 distinct posteriorly, and flanked by paired longitu- 

 dinal dorsolateral ridges (posterior part of telson 

 lacking in types). Lateral ramus of uropod surpass- 

 ing mesial ramus by about 0.3 its own length. 



Thelycum (Fig. 14) with setose plate of sternite 

 XIV very short, deeply excavate transversely, bear- 

 ing small anteromedian notch, and produced at 

 either side in elongate anterolateral hood; fossa im- 

 mediately anterior to plate very short and armed 

 with pair of small, oblique lateral ridges. Median 

 plate of sternite XIII very long (length 4.5-4.9 times 

 basal width), narrowly lanceolate (maximum width 

 0.4 length), strongly produced in sharp apical spine, 

 almost reaching anteromedian spine on sternite XII 

 and covered by very thickly set setae; posterolateral 

 margins of plate raised in slender ridges merging 

 with similar ones extending posteromesially before 

 curving laterally following margin of sternite XIII. 

 Sternite XII minutely setose, strongly raised and 

 bearing low median carina ending anteriorly in 

 minute spine. 



Geographic and bathymetric ranges.— Known only 

 from the type-locality, located in the Arabian Sea, 

 and from off Godavari, in the Bay of Bengal, at 

 depths of 1,569 and 869 m respectively (Fig. 9). 



Discission.— Like P. crassipes, P. kathleenae, and 

 P. gracillis but unlike P. sibogae, the anterodorsal 

 extremity of the groove dorsal to the posterior part 

 of the hepatic sulcus does not join the cervical sulcus 



in P. protensus; the optic calathus is relatively short, 

 and the pereopods are not covered by setae. Pseuda- 

 risteus protensus differs strikingly from all its 

 cogeners in several distinctive thelycal features: the 

 plate of sternite XIV is short, bears a small median 

 notch on the anterior margin, and is produced in 

 long anterolateral hoods; the median plate of ster- 

 nite XIII is very long (4.5-4.9 times the basal width, 

 rather than 1.8-3.5), almost reaching the antero- 

 median spine on sternite XII, and narrower (max- 

 imum width 0.40 instead of 0.45-0.75) than its 

 length. Moreover, it is very densely setose (more 

 so than in its cogeners) and bears a pair of very 

 conspicuous, vertically directed posterolateral 

 ridges. 



Although I have examined only two specimens of 

 P. protensus, distinct thelycal differences between 

 this gamba prawn and those of other members of 

 the genus leave no doubt that it represents a new 

 species. 



Etymology.— hsitm protensus, stretched forth, refer- 

 ring to the unusual length of the thelycal plate of 

 sternite XIII. 



Figure 14. —Pseudaristeus protensus, n. sp., holotype 9 40 mm 

 CL, west of Everal Gujarat, India. Thelycum. Scale = 2 mm. 



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