MORPHOLOGY, SYSTEMATICS, AND BIOLOGY OF 

 THE SPANISH MACKERELS (SCOMBEROMORUS , SCOMBRIDAE) 



Bruce B. Collette 1 and Joseph L. Russo 2 



ABSTRACT 



The Spanish mackerels and seerfishes of the genus Scorn beromorus constitute the most speciose 

 group of the 44 genera in six families that comprise the suborder Scombroidei. As in higher scom- 

 brids, Scomberomorus , Acanthocybium , and Grammatorcynus have a well-developed median keel 

 on the caudal peduncle, but there is no bony support as is present in the Sardini and Thunnini. 

 Acanthocybium and Scomberomorus share 17 osteological characters and are considered sister- 

 groups. The relationships of Grammatorcynus are not clear but it is clearly more primitive than 

 Scomberomorus; therefore, we have used it as the outgroup for a cladistic analysis of Scomberomorus. 

 Scomberomorus differ from all other scombrids in having a spatulate anterior extension of the 

 vomer. There are 18 species in the genus, nearly 40% of the 49 species of scombrids: Eastern At- 

 lantic — tritor (Cuvier); western Atlantic — brasiliensis Collette, Russo and Zavala-Camin, cavalla 

 (Cuvier), maculatus (Mitchill), and regalis (Bloch); eastern Pacific — concolor Lockington and 

 sierra Jordan and Starks; and Indo-West Pacific — commerson (Lacepede), guttatus (Bloch and 

 Schneider), koreanus (Kishinouye), lineolatus (Cuvier), munroi Collette and Russo, multiradiatus 

 Munro, niphonius (Cuvier), plurilineatus Fourmanoir, queenslandicus (Macleay), semifasciatus 

 (Macleay), and sinensis (Lacepede). A cladistic analysis of 58 characters shows six monophyletic 

 species-groups in Scomberomorus. The sinensis group is monotypic and is defined by the presence of 

 an abrupt downward curve in the lateral line under the first dorsal fin and by its retention of a swim 

 bladder. The commerson species-group contains commerson, niphonius, queenslandicus, and cavalla 

 and is defined by the presence of an intercalar spine of at least moderate length. Scomberomorus 

 cavalla and S. commerson share two additional specializations, the pterosphenoid bones are close 

 together and the lateral line curves abruptly downward under the second dorsal finlets. The munroi 

 species-group is monotypic and is defined by the loss of the anterior process on the outer surface of 

 the head of the maxilla. The semifasciatus species-group contains semifasciatus, plurilineatus, and 

 lineolatus, and is defined by the presence of a greatly expanded posterior end of the maxilla. Scom- 

 beromorus lineolatus and S. semifasciatus share an additional specialization, a wide parasphenoid, 

 but this character state appears independently in several other lines. The guttatus species-group 

 contains guttatus, multiradiatus, and koreanus and is defined by a high supraoccipital crest. Auxil- 

 iary branches extend off the anterior part of the lateral line in S. guttatus and S. koreanus. The 

 regalis species-group contains regalis, tritor, maculatus, concolor, sierra, and brasiliensis and is 

 defined by the presence of nasal denticles. All but the most primitive species in this group (S. tritor) 

 have an artery arising from the fourth left epibranchial artery. The four most advanced species (all 

 except tritor and maculatus ) have developed a long posterior process on the pelvic girdle. The three 

 most advanced species (sierra, brasiliensis, and regalis) have a coeliaco-mesenteric shunt connect- 

 ing the fourth right epibranchial artery with the coeliaco-mesenteric artery. 



The purposes of this paper are to define the 18 

 species of Scomberomorus, to clarify their rela- 

 tionships, and to assess the systematic position 

 of Scomberomorus within the Scombridae. The 

 methods used are similar to those of Collette and 

 Chao (1975) in a revision of the bonitos and of 

 Gibbs and Collette (1967) in a revision of Thun- 



1 National Marine Fisheries Service, Systematics Laboratory, 

 National Museum of Natural History, Washington, DC 20560. 



National Marine Fisheries Service, Systematics Laboratory, 

 National Museum of Natural History, Washington, DC 20560, 

 and Department of Biological Sciences, The George Washington 

 University, Washington, DC 20006; present address: Office 

 of Information Research Resource Management, Smithsonian 

 Institution, Washington, DC 20560. 



nus, and rely on previous work by Kishinouye 

 (1923), Munro (1943), Mago Leccia (1958), and 

 Devaraj (1977). 



The Spanish mackerels have been placed by 

 Collette and Chao (1975) and Collette and Russo 

 (1979) in a tribe (the Scomberomorini) along with 

 Acanthocybium and Grammatorcynus, interme- 

 diate between the more primitive mackerels 

 (Scombrini) and the more advanced bonitos (Sar- 

 dini). Acanthocybium is clearly the specialized 

 sister group of Scomberomorus, but the phylo- 

 genetic position of Grammatorcynus has been 

 unclear. 



Until recently, the number of valid species of 



Manuscript accepted November 1983. 

 FISHERY BULLETIN: VOL. 82, NO. 4, 1984. 



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