PEREZ FARFANTE: AMERICAN SOLENOCERID SHRIMPS 



rigid, transversely elliptical process disto- 

 laterally; distal part of ventrolateral lobule 

 roughly elliptical and strongly trending toward 

 ventromedian lobule; ventral costa broad proxi- 

 mally, considerably narrower distally and, in 

 young, ending in minute marginal spine project- 

 ing from base of elliptical part of ventrolateral 

 lobule. 



Appendix masculina (Figure 14C, D) with prox- 

 imal part produced laterally into rounded lobe 

 bearing row of long setae on distal margin con- 

 tinuous with row extending along midventral line 

 of narrow distal portion; latter armed with apical 

 tuft of long setae; appendix interna abruptly 

 narrowing from rounded base and bearing apical 

 tuft of long setae; ventrolateral spur with distal 

 part subovate, bearing longitudinal submarginal 

 rib on dorsal surface. 



Thelycum (Figure 15) with median protuber- 

 ance on sternite XIV setose, pyramidal, and with 

 triangular base, its apical portion produced into 

 short ventrally directed projection; median la- 

 mella projecting vertically from posterior margin 

 of sternite XIII, flat, its distal margin slightly to 

 deeply emarginate (emargination angular or 

 curved), lateral margins straight or slightly 

 concave; posterior part of sternite XII bearing 

 paired, setose horns overreaching midlength of 

 sternite XIII. 



Maximum size. -Males: 15 mm cl; females: 22 mm 

 cl. 



Geographic and bathymetric ranges. -Western 

 Atlantic: from off Georges Bank, Mass. 

 (41°13'00"N, 60°00'50"W), to the Bahamas 

 (21°20'15"N, 71°13'20"W), including the Ber- 

 mudas (Figure 16). Eastern Atlantic: from west of 

 Mauritania to off Equatorial Guinea (Bate 1888). 

 Indo-West Pacific: in the Arabian Sea (Laccadive 

 Sea, Wood-Mason and Alcock 1891), the Bay of 

 Bengal (off Andaman Islands, Wood-Mason 1891; 

 Alcock 1901), and the Philippines (Bate 1888). If 

 the record oVHaliporus sp." by Lenz and Strunck 

 ( 1914) is actually one for this species, its range off 

 west Africa reaches farther south, at least to off 

 Liberia <0°39'N, 18°57'W). This shrimp has been 

 found at depths between 1,657 and 4,792 m 

 (Figure 9). Its habitat together with its small size 

 are most probably responsible for the few collec- 

 tions available. 



Affinities -Hymenopenaeus laevis is closely allied 



FIGURE 15. — Hymenopenaeus laevis, 2 17 mm cl, Turks Island 

 Passage, Bahama Islands. Thelycum, ventral view. 



to the American Pacific H. doris and H. nereus, 

 and to the Indo-West Pacific//, sewelli. These four 

 species form the compact section 2 of Burken- 

 road's group IV. They are the only members of the 

 genus which possess both branchiostegal and 

 pterygostomian spines. 



Females of//, laevis differ strikingly from those 

 of//, nereus in the structure of the thelycum. In 

 those of//, nereus, the median lamella of sternite 

 XIII is directed anteriorly, and has arched or sin- 

 uous lateral margins converging basally. Further- 

 more, in H. nereus the median lamella is flanked 

 by paired, caudally inclined processes, which are 

 lacking in H. laevis, and sternite XIV is raised in 

 a median longitudinal ridge, very different from 

 the strong pyramidal prominence present in 

 the latter. This shrimp, in turn, can be separated 

 readily from H. doris by the median lamella of 



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