VARIATION IN THE FOURBEARD ROCKLING, 



ENCHELYOPUS CIMBRIUS, A NORTH ATLANTIC GADID FISH, 



WITH COMMENTS ON THE GENERA OF ROCKLINGS 



Daniel M. Cohen' and Joseph L. Russo^ 



ABSTRACT 



Enchelyopus cimbriun, the fourbeard rockling, is a gadid fish living around the rim of the North 

 Atlantic Ocean. It varies geographically in color pattern; anal, dorsal, and pectoral fin ray counts; and 

 vertebral and gill racker counts. There is a lack of overall concordance in patternsof vanation in color 

 and meristics. Morphometric characters do not distinguish populations from different geographical 

 areas, and the fourbeard rockling is considered to be a single species. 



New distributional records include the Gulf of Mexico, West Greenland, and West Africa. 



We classify the rockiings as a tribe, Gaidropsanni, of the subfamily Lotinae. Characters previously 

 used to separate rockiings into five genera — skull shape, vomerine tooth patch shape, number and 

 distribution of supratemporal pores, length of first dorsal fin ray, and size of jaw teeth — do not 

 distinguish nominal genera. Number of snout barbels divides rockiings into three groups that we 

 tentatively recognize as genera: Gaidropsarus. the threebeard rockiings, with two snout barbels; 

 Enchelyopus, the fourbeard rockling. with three snout barbels; and Ciliata, the fivebeard rockiings. 

 with four or more snout barbels. Onogadus and Antonogadus are referred to the synonymy of Gaidrop- 

 sarus. 



The correct generic name for the fourbeard rockling isEnckelyopus Bloch and Schneider 1801 , with 

 Rhinonemus Gill 1863 as a junior synonym. It is not preempted by Enchelyopus Gronovius 1760 in 

 Zoarcidae. which was used in a work that was not consistently binominal. 



The fourbeard rockling, Enchelyopus cimbritis, is 

 a locally abundant gadid fish found around the 

 margins of the North Atlantic Ocean. Although 

 this fish has been recorded in the literature for 

 more than 200 yr, many aspects of its biology are 

 obscure. Adults are sedentary bottom dwellers 

 taken at depths ranging from about 1 to 650 m [we 

 have been unable to verify depth records to 1,325 

 m given by Goode and Bean ( 1896) ]. There is some 

 indication that seasonal offshore-onshore move- 

 ments occur (Bigelow and Schroeder 1953; Tyler 

 1971). The pelagic larval stages are similar in 

 appearance to young hakes ( Urophycis ) and some- 

 times occur in silvery swarms near the surface 

 (Bigelow and Schroeder 1953). 



Recent collections discussed in this paper show 

 that fourbeard rockiings are more widely distrib- 

 uted than previously was known and that geo- 

 graphical variation is present. One of our objec- 

 tives in this paper is to describe, compare, and 



'Systematics Laboratory. National Marine Fisheries Service, 

 National Museum of Natural History, Washington, DC 20560. 



^Systematics Laboratory, National Marine Fisheries Service, 

 National Museum of Natural History, Washington, DC; pres- 

 ent address: Department of Biological Sciences, The George 

 Washington University, Washington, DC 20006. 



Manuscript accepted August 1978 

 FISHERY BULLETIN VOL 77. NO 1, IHTH 



evaluate geographical variation of selected 

 characters and to show that a single species is 

 represented throughout the range of the fish. 



The rockling group of the family Gadidae, which 

 is characterized by several distinctive features, 

 recently was divided into five genera (Wheeler 

 1969), although most ichthyologists have recog- 

 nized only three (albeit under a variety of names). 

 The second of our objectives is to show that at 

 present there are valid reasons for only three. 



The fourbeard rockling is currently named En- 

 chelyopus cimbrius by North American 

 ichthyologists and Rinonemus cimbrius by Euro- 

 peans. Our final objective is to show that En- 

 chelyopus is the correct generic name. 



METHODS 



All observations were made on museum speci- 

 mens listed in the Appendix. Counts of dorsal and 

 anal fin rays and vertebrae were taken from X-ray 

 photographs. Vertebral counts do not include the 

 terminal ural element. Gill raker counts include 

 all rakers on upper and lower arms of the first 

 arch. Head pores were examined with the aid of a 

 compressed air jet. Measurements and their 



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