FISHERY BULLETIN: VOL. 85, NO. 2 



also covered with setae, moderately long (length 

 3-3.5 times basal width), falling considerably short 

 of spine on sternite XII, broadly lanceolate (max- 

 imum width 0.65-0.75 length), and flat or slightly 

 excavate; posterolateral margins of plate, some- 

 times turned ventrally, abutting slender ridges ex- 

 tending posteromesially before curving laterally on 

 margin of sternite XIII. Sternite XII minutely 

 setose, bearing median keel ending anteriorly in 

 anteroventrally directed sharp spine. 



Maximum lengths.— Msdes, 24 mm CL; females, 46.5 

 mm CL. 



Geographic and bathymetric ranges.— From west of 

 Cape Comorin, India, through Indonesia, and north- 

 ward to east of Luzon, Philippines (Fig. 9). It has 

 been obtained at depths between 549 and 1,225 m. 



Discussion.— This species differs from P. crassipes, 

 with which it has been confused previously, in the 

 following unique characteristics. In males, the third 

 article of the antennular peduncle is strikingly pro- 

 duced in a subtriangular or roughly ax-head shaped 

 lateral projection, and in females it is expanded 

 laterally in a broadly rounded prominence. This is 

 a feature by which the females of P. kathleenae can 

 be infallibly distinguished from those of P. crassipes 

 which, otherwise, are quite similar. In P. crassipes, 

 the third article of the antennular peduncle of both 

 sexes is uniform in width proximally and gradually 

 tapers distomesially. In males of P. kathleenae, the 

 penultimate article of the third maxilliped is com- 

 pressed distally and produced in a strong subellip- 

 tical or acuminate process which overhangs the 

 ultimate article; the latter is subspatulate, conspicu- 

 ously curved throughout, almost uniform in width, 

 and bears long rigid setae on the lateral surface. In 

 the males of P. crassipes the penultimate article of 

 the third maxilliped is subtriangular in cross section 

 throughout and does not project distally in a con- 

 spicuous process but instead is rounded distally; the 

 ultimate article is twisted, expanded basally, and 

 weakly to conspicuously so distally, and bears lateral 

 rows of spinules on its ventral surface. 



Pseudaristeus kathleenae differs further from P. 

 crassipes in features of the petasma. In the former, 

 the dorsolateral lobule is expanded distolaterally 

 before tapering to a subangulate mesial apex; also 

 the ventral costa is sinuous and does not turn strong- 

 ly distomesially from its basal part. In contrast, the 

 dorsolateral lobule is not expanded distolaterally in 

 P. crassipes, tapers to broadly elliptical apex, and 

 the ventral costa is almost straight basally before 



turning rather abruptly distomesially. Finally, in 

 females of P. kathleenae the median plate of ster- 

 nite XIII is broader than that in P. crassipes, its 

 maximum width ranging from 0.67 to 0.75 rather 

 than from 0.45 to 0.55 as it does in the latter. 



In females of Pseudaristeus the rostrum is long, 

 almost as long or considerably longer than the cara- 

 pace, whereas, in males it is usually short, less than 

 0.33 the length of the carapace. Among the 8 males 

 of P. kathleenae examined in this study, one pos- 

 sesses a rostrum that is 1.4 times the length of the 

 carapace (longer than that of any female examined), 

 and among the three available males of P. crassipes, 

 the rostrum of one, although proportionally not so 

 long, is 0.7 as long as the carapace. Perhaps these 

 males with long rostra are not as rare as one might 

 anticipate. This suggestion is based on a study by 

 Burukovsky and Romensky (1972) in which they 

 noted considerable variation in the length of the 

 rostrum in another aristeid, Aristeus varidens, 

 occurring in the eastern Atlantic from Ghana to 

 Angola. It was well known that in all genera of Aris- 

 teidae the rostrum of females is much longer than 

 that of males; however, they found that although 

 the majority of males of this gamba prawn have a 

 relatively short rostrum, in almost 30% of them it 

 is long. Also, they noted that in both sexes the 

 rostrum decreases proportionately with increasing 

 size (a fact well established for penaeoid species) and 

 that this age-dependent variation is different for the 

 sexes: in small females the rostrum may exceed 1.5 

 times the length of the carapace, whereas in large 

 ones it is about as long as the carapace; in small 

 males the length of the rostrum may be almost 1.5 

 times that of the carapace, but as they grow it 

 decreases to 0.1-0.5 times. Nevertheless, in individ- 

 uals of the same size they found that the range of 

 variation is smaller in females than in males. Their 

 study demonstrates that sexual dimorphism in the 

 length of the rostrum, thought to be typical of aris- 

 teids, disappears at least in small males of A. 

 varidens. This too might obtain in members of 

 Pseudaristeus, but because of the lack or paucity of 

 males of all 6 species I am unable to conduct a mean- 

 ingful investigation of variations in RL/CL. Because 

 no correlation was observed between variations in 

 the length of the rostrum and changes in the petas- 

 ma or in the structure of the gonads in males with 

 short and long rostrum which would indicate sex- 

 ual change, Burukovsky and Romensky suggested 

 that the reduction of the rostrum, more marked in 

 males than in females, might be associated with the 

 transition from a benthic to a bathypelagic existence 

 undergone by members of the family Aristeidae. 



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