MORPHOLOGICAL STUDY OF DIAGNOSTIC CHARACTERS IN 



WESTERN ATLANTIC HEPOMADUS 



(CRUSTACEA, DECAPODA, PENAEIDAE) 



Isabel Perez Farfantei 



ABSTRACT 



The collections made during the expeditions of the Oregon, Oregon II, and the RV John 

 Elliott Pillshury almost tripled the number of specimens of Hepomadus previously 

 recorded from the western Atlantic. The taxonomic status of the material has been 

 assessed through a study of the external morphology and an investigation of variations of 

 morphological, morphometric, and meristic characters. It is demonstrated that intermediates 

 are present between extremes of variations and, consequently, all specimens are assigned 

 to a single species, Hepomadus tener Smith. 



The gap in our knowledge of the genus Hepo- 

 madus results from the great paucity of collec- 

 tions taken beyond the continental shelf of 

 America. Although recent material caught in 

 the course of the expeditions of the Oregon, 

 Oregon II, and the RV John Elliott PillsbKrij, 

 in addition to five specimens taken by the 

 Albatross in 1885 and 1886 which have not 

 been reported, have almost tripled the number 

 of specimens previously recorded from the 

 western Atlantic (18), the total number of 

 known specimens is only 51. 



The purpose of this paper is to demonstrate 

 that all specimens of Hepomadus that have 

 been taken in the western Atlantic (including 

 the Sargasso Sea, the Gulf of Mexico, and the 

 Caribbean) belong to a single species, Hepo- 

 madus te)ier Smith, 1884. My study has drawn 

 from the works of earlier investigators, and I 

 have corroborated their observations on the 

 great variation in many morphological and a 

 few morphometric and meristic characters 

 within this species. Additional material from a 

 greater number and more widely distributed 

 localities, however, have led me to conclude that 

 features which have been suggested as probably 

 useful in differentiating species of Hepomadus 



' Systematics Laboratory, National Marine Fisheries 

 Service, NOAA, U.S. National Museum, Washington, 

 DC 20560. 



in the region are not valid. Similarly, all other 

 characters analyzed here for the first time show 

 a wide range of variation, with intermediate 

 stages present between the extremes. One 

 meristic and two morphological characters, 

 however, have been found reliable for separating 

 H. te)ier and H. glacialis Bate, 1881, which is 

 known only from the western Pacific. 



PRESENTATION OF DATA 



The c.l. (carapace length — linear distance 

 between orbital margin and midposterior mar- 

 gin of carapace) and r.l. (rostral length — linear 

 distance from apex to orbital margin) are 

 measured to the nearest 0.5 mm. The ratios 

 presented in the tables are given to the nearest 

 0.05. Certain ratios are not given for every 

 specimen because the rostrum is damaged in 

 many of them, and, in some, the spine on the 

 third pleonic somite is broken. The ocean depths 

 have been recorded to the nearest meter. Finally, 

 the scales accompanying the illustrations are 

 in millimeters. 



The following abbreviations are used for 

 repositories of specimens: TAMU- Department 

 of Oceanography, Texas A&M University; 

 UMML- Institute of Marine Sciences, University 

 of Miami; USNM-National Museum of Natural 

 History, Smithsonian Institution; and YPM- 

 Peabody Museum of Natural History, Yale 

 University. 



Manuscript accepted September 1972. 

 FISHERY BULLETIN: VOL. 71, NO. 2. 1973. 



441 



