Abstract.- Osteological differ- 

 ences confirm the validity of two spe- 

 cies of Grammatorcynus, G. bicari- 

 natus (Quoy and Gaimard 1825) and 

 the long-recognized G. bilineattis 

 (Riippell 1836). In addition to having 

 fewer gill rakers (12-15 vs. 18-24), 

 a smaller eye (3.1-4.6% vs. 4.0-6.0% 

 FL), small black spots on the lower 

 sides of the body, and reaching a 

 larger size (110cm FL vs. 60cm), G. 

 bicarinatus differs from G. biline- 

 atus in having a shorter neurocra- 

 nium, shorter parasphenoid flanges, 

 lower posterior edge of maxillary 

 shank, shorter quadrate process, 

 narrower first postcleithrum, wider 

 ethmoid, wider vomer, wider lach- 

 rymal, longer teeth, wider palatine 

 tooth patch, wider opercle, and a thin 

 posttemporal shelf between the 

 anterior processes. All but one of the 

 16 osteological differences previous- 

 ly found between Grammatorcynus 

 bilineatus and Scomberomorus and 

 Acanthocybium are confirmed with 

 the inclusion of G. bicarinatus in the 

 genus. Grammatorcynus bilineatus 

 is widespread in tropical and sub- 

 tropical waters of the Indo-West 

 Pacific from the Red Sea to Tokelau 

 Islands in Oceania. The range of G. 

 bicarinatus is restricted to the west- 

 ern and eastern coasts of Australia 

 and southern Papua New Guinea. 



Morphology, systematics, and biology 

 of the double-lined mackerels 

 [Grammatorcynus, Scombrldae) 



Bruce B. Collette 



Systematics Laboratory. National Marine Fisheries Service, NOAA 

 National Museum of Natural History, Washington, DC 20560 



Gary B. Gillis 



Observer Program, Alaska Fisheries Science Center, National Marine Fisheries Service 

 NOAA, 7600 Sand Point Way NE, Seattle, Washington 981 15-0070 

 Current address: Department of Ecology and Evolutionary Biology 

 University of California, Irvine, California 92715 



Manuscript accepted 18 December 1991. 

 Fishery Bulletin, U.S. 90:13-53 (1992). 



Until recently, most authors consid- 

 ered the genus Grammatorcynus to 

 be monotypic (Fraser-Brunner 1950, 

 Silas 1963, Zharov 1967, Collette 

 1979). Electrophoretic work (Lewis 

 1981, Shaklee 1983) indicated there 

 were two species of double-lined mack- 

 erels in Australia. This was confirmed 

 by Collette (1983) who showed there 

 are two species: the double-lined 

 mackerel or scad G. bilineatus, (Riip- 

 pell 1836), widespread in the Indo- 

 West Pacific, with more gill rakers 

 (18-24), a larger eye (4.0-6.0% FL), 

 and a smaller maximum size (60 cm 

 FL); and the shark mackerel G. bica- 

 rinatus (Quoy and Gaimard 1825), 

 restricted to the waters of northern 

 Australia and southern New Guinea, 

 with fewer gill rakers (12-15), a 

 smaller eye (3.1-4.6% FL), and a 

 larger maximum size (110 cm FL). All 

 morphological information concern- 

 ing Grafnimatorcynus in Collette 

 (1979) and Collette and Russo (1985b) 

 was based solely on G. bilineatus. 



The purposes of this paper are to 

 describe osteological differences be- 

 tween the two species of Gramma- 

 torcynus, redefine the genus and 

 both species, and summarize the 

 literature on both species. The paper 

 is divided into two parts. Part 1, 

 Comparative Morphology, contains 



descriptions and illustrations of mor- 

 phometry, meristic characters, soft 

 anatomy, and osteology of the two 

 species of Grammatorcynus; com- 

 parisons are made with Scombero- 

 morus and Acanthocybium- where 

 appropriate. Part 2, Systematics and 

 Biology, contains a generic descrip- 

 tion and accounts of both species, in- 

 cluding synonymy, types of nominal 

 species, diagnoses (based on char- 

 acters from the first section), size, 

 biology, interest to fisheries, geo- 

 graphic distribution, and material 

 examined. 



Methods and materials 



Methods are those used by Collette 

 and Russo (1985b) in a revision of 

 Scomberomorus, and by Collette and 

 Chao (1975) in a revision of the 

 bonitos (Sardini). 



Material of Grammatorcynus is 

 listed at the end of each species ac- 

 count; 80 specimens of G. bilineatus 

 and 11 G. bicarinatus. Abbreviations 

 of institutions housing the material 

 follow Leviton et al. (1985). Com- 

 parative material oi Scomberomorus 

 and Acanthocybium was listed in the 

 species accounts in Collette and 

 Russo (1985b). 



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