PEREZ FARFANTE: AMERICAN SOLENOCERID SHRIMPS 



similar but the median protuberance of sternite 

 XIV tends to be broader in H. debilis than in H. 

 aphoticus. 



According to Burkenroad (1936), in this species 

 the proportion of the maximum diameter of the eye 

 to carapace length is even greater than that given 

 above, ranging between 19.3 and 26.9, x 22.3. My 

 measurements of specimens studied by Burken- 

 road resulted in proportions not exceeding 23.0. 

 This could be due to a slight reduction of the 

 cornea caused by the preservatives, or the cornea 

 is now deformed in the specimens with larger 

 corneae examined by me. 



Very similar to H. debilis is H. chacei which is 

 known only from off West Africa. According to 

 Crosnier and Forest (1969, 1973), these two 

 species differ in that in H. chacei the ventral 

 border of the rostrum is unarmed (actually, as 

 stated above, 39c of the individuals of//, debilis 

 examined by me lack such teeth), and no photo- 

 phores are present. The cornea of H. chacei is 

 narrower than that of//, debilis, in the former the 

 ratio of the greatest diameter to the carapace 

 length ranges from 13.2 to 16.0 (x 15.0), and it is 

 disposed such that its proximolateral extremity 

 lies slightly distal to the level of the medial 

 tubercle. 



A careful study of the western Atlantic speci- 

 mens in which the rostrum is ventrally unarmed 

 has left no doubt in my mind that they are H. 

 debilis. Hymenopenaeus chacei, which typically 

 lacks teeth on the ventral margin of the rostrum, 

 is not represented in the extensive collections 

 from the western Atlantic examined by me. 



I have found that in males of//, debilis the dis- 

 position of both the mesial and lateral processes of 

 the petasma varies from slightly to rather 



strongly inclined mesially, the former illustrated 

 herein (Figure 6A, B), and the latter, illustrated 

 by Crosnier and Forest ( 1973, plate 85, figure c-d, 

 a male from Morocco). This variation is not associ- 

 ated with the size of the animal, and occurs 

 throughout the entire range of the species in the 

 western Atlantic. Males in which the processes 

 are only slightly inclined mesially resemble those 

 of//, chacei in which, according to Crosnier and 

 Forest (1973), the roughly angular portion of the 

 lateral process is typically directed forward. The 

 males of the two species can still be distinguished 

 by the size and armature of the auricular process 

 of the petasma, which in H. debilis is very small 

 and unarmed but relatively large in//, chacei and 

 provided with marginal spinules (Crosnier and 

 Forest 1969:546, figure 2). 



Remarks. -The coordinates of the Talisman sta- 

 tions, cruise of 1883, where the material exam- 

 ined by me was collected, are given herein accord- 

 ing to the data presented by Crosnier and Forest 

 (1973). 



The disposition of the third syntype, from south- 

 east of Savannah Beach, Ga., caught at Blake 

 stn 317 is unknown. 



Hymenopenaeus aphoticus Burkenroad 1936 



Figures 4C, 8-12 



Hymenopenaeus aphoticus Burkenroad 1936:112, 

 fig. 62, 65, 66, 67 [holotype: 9 , YPM 4556; type- 

 locality: Turks Is Passage, 1,646-1,728 m, 

 21°15'40"N, 71°17'06"W, Pawnee stn 54]. 

 Yokoya 1941:52. Crosnier and Forest 1969:547. 



FIGURE 10. — Hymenopenaeus aphoticus. 9 18 mm cl, northwest of Peninsula de la Guajira, Colombia. Cephalothorax, lateral view. 



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