PEREZ FARKANTE: AMERICAN SOLENOCERID SHRIMPS 



Petasma (Figure 22A, B) with row of cincinnuli 

 occupying proximal 0.35 of median line; ventro- 

 median lobule bearing two processes distally; 

 mesial one (disposed almost at right angle to 

 lobule) subrectangular, and armed with few long 

 spines, distolateral one (directed at about 45 

 degrees to lobule) unarmed, and produced prox- 

 imolaterally in small auricular process; distal flap 

 of ventrolateral lobule acuminate, large, extend- 

 ing as far as lateral process, and almost straight 

 rather than conspicuously inclined; ventral costa 

 projecting in strong rounded prominence at base 

 of flap. 



Appendix masculina (Figure 22C, D) with prox- 

 imal part produced into rounded lobe; distal part 

 extremely narrow and bearing lateral row of short 

 setae continuous with apical tuft of longer setae. 

 Appendix interna abruptly narrowing, setting off 

 distal part from rounded proximal part. Ventro- 

 lateral spur short, roughly semicircular in outline 

 distally. 



Thelycum (Figure 23) with median, longitudi- 

 nal ridge on sternite XIV; lamella at posterior 

 margin of sternite XIII rather flat, directed 

 anteriorly, with distal (cephalic) margin slightly 

 to deeply concave, and lateral margins convex 

 basally, straight or concave distally; lamella 

 flanked by pair of flattened, subtriangular to 

 rounded processes directed caudally; posterior 

 margin of sternite XII bearing paired, setose, 

 long horns, reaching almost midlength of sternite 

 XIII. 



Maximum size-Males: 18 mm cl; females: 27 mm 

 cl. 



Geographic and bathymetric ranges . -From south 

 of Cabo Blanco (5°30'N, 86°45'W), Costa Rica, 

 to northwest of Punta Galera and Islas Galapagos 

 (00°36'S, 86°46'W), Ecuador (Figure 20). It has 

 been found at depths between 1,271 and 3,279 m 

 (Figure 9). 



Affinities. -Hymenopenaeus nereus and H. doris 

 are very similar in external morphology. How- 

 ever, the external genitalia allow a ready separa- 

 tion of these two species as well as both from the 

 closely related H. laeuis and H. sewelli. Females 

 ofH. nereus are unique among the four species in 

 possessing a longitudinal ridge, instead of a large 

 protuberance, on sternite XIV; furthermore, the 

 median lamella of sternite XIII is directed an- 

 teriorly, its lateral margins tend to converge 

 proximally (posteriorly), and the lamella is 



FIGURE 23.— Hymenopenaeus nereus, syntype 9 21.5 mm cl, 

 south of Cabo Blanco, Costa Rica. Thelycum, ventral view. 



flanked by a pair of processes which are flattened 

 and directed caudally. In the other species, these 

 processes are lacking or, if present, are directed 

 anteroventrally. Males of H. nereus differ from 

 those of//, laevis in that the petasma of the latter 

 bears two, occasionally three, small, triangular 

 projections on the distomesial margin of the 

 ventromedian lobule instead of a single, sub- 

 rectangular process bearing spines distally. More- 

 over, the lateral process is small and extends 

 transversely rather than being directed disto- 

 mesially, and the distal part of the ventrolateral 

 lobule is broadly semicircular and strongly in- 

 clined toward the ventromedian lobule. 



Haliporotdes Stebbing 1914 



Peneopsis. Faxon 1893:212; 1895:185. 



Faxonia Bouvier 1905a:981 [part, excluding type- 

 species, Penaeopsis ocularis Faxon 1895 = 

 Pleoticus robustus (Smith 1885)]. 



Haliporus. Bouvier 1906b: 1 [part]; 1908:78 [part], 

 de Man 1911:31 [part]. Caiman 1925:9. 



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