COLLETTE and RUSSO: SPANISH MACKERELS 



Scombrini, only 3 vertebrae supporting the caudal 

 fin and only 31 total vertebrae. Therefore, we have 

 used it as the outgroup for comparison with Scom- 

 beromorus. Of the 72 characters that differenti- 

 ated at least 1 taxon from the others, 14 were 

 autapomorphies of Acanthocybium. These cannot 

 contribute to an understanding of relationships 

 within Scomberomorus and were omitted from the 

 analysis. The remaining 58 characters were em- 

 ployed to generate a cladogram using a computer 

 program (WAGNER 78) written by J. S. Farris 

 (following Farris 1970 and Farris et al. 1970). The 

 order of the taxa was "shuffled" to determine if 

 another equally parsimonious tree would be gen- 

 erated. Another cladogram was produced with the 

 same total length, 112 steps. The first cladogram 

 has a deviation ratio (sum of the homoplasies 

 between all pairwise combinations of terminal 

 taxa divided by the sum of the character changes 

 between all pairwise combinations of terminal 

 taxa) of 0.24, the second 0.21. The difference is due 

 to characters 3 and 17. We feel that the first 

 cladogram (Fig. 70) more reasonably reflects our 

 concepts of evolution within the genus. A sum- 

 mary of the character states with references to the 

 relevant figures is presented as Appendix 1. 



We recognize six species groups within Scom- 

 beromorus (Fig. 70, Table 31): sinensis from node 

 17; commerson from node 15; munroi from node 11; 



semifasciatus from node 9; guttatus from node 8; 

 and regalis from node 5. 



The sinensis group is monotypic. It is defined by 

 the presence of an abrupt downward curve in the 

 lateral line under the first dorsal fin (character 19, 

 state 1). A similar abrupt downward curve is 

 present in two species of the commerson group but 

 the curve is under the second dorsal in those two 

 species. Scomberomorus sinensis is the only spe- 

 cies in the genus with a well-developed swim 

 bladder (character 18, state 0), but this is a plesio- 

 morphous character. This species is restricted to 

 the northwestern Pacific from Cambodia to Ja- 

 pan. There is no genus-group name available for 

 this group. 



The commerson group contains four species: 

 niphonius, queenslandicus , cavalla, and commer- 

 son. This group is defined by the presence of an 

 intercalar spine of at least moderate length (char- 

 acter 17, state 1). Three species (queenslandicus, 

 cavalla, and commerson) have a long (state 2) 

 intercalar spine. Scomberomorus cavalla and S. 

 commerson share two additional specializations: 

 the pterosphenoid bones are close together (char- 

 acter 13, state 1) and there is an abrupt downward 

 curve in the lateral line under the second dorsal 

 fin (character 19). Three of these species are Indo- 

 West Pacific: niphonius from China, Korea, and 

 Japan; queenslandicus from off northern Austra- 



FIGURE 70. — Cladogram of the Scomber- 

 omorini, node numbers refer to numbers 

 used in Table 31. 



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