CRESSEY ET AL.: COPEPODS AND SCOMBRID FISHES 



lochids were found in two species of Rastrelliger, 0. 

 aculeatus in the orbits, and N. kanagurta on the 

 gills. 



Matsui (1967) recognized three species of Rastrel- 

 liger: R. faughni Matsui from Taiwan, the Philippine 

 Islands, Indonesia, and western India; R. brachysoma 

 (Bleeker) in the same general area of the western 

 Pacific asi?. faughni but extending east to Fiji; andR. 

 kanagurta (Cuvier) which is widespread throughout 

 the Indo- West Pacific from Taiwan, the Philippines, 

 Samoa, and Australia east throughout the Indian 

 Ocean to Madagascar and the Red Sea. At least one 

 individual has gone through the Suez Canal into the 

 eastern Mediterranean Sea (Collette 1970). All but 

 one of our copepod records are from R. kanagurta 

 and R. faughni. Our only lernanthropid was a female 

 Lernanthropus kanagurta from a Bornean specimen 

 of/?, brachysoma. This is probably not a usual scom- 

 brid parasite (Cressey and Cressey 1980:45). 



Scomberomorini 



This is the most speciose tribe in the family, con- 

 taining 20 of the 48 species. Most of these (18 spe- 

 cies) belong to Scomberomorus, the Spanish mack- 

 erels and seerfishes; the other 2 species belong to the 

 monotypic genera Acanthocybium and Grammator- 

 cynus. Copepod fauna: 25 species in 8 genera. The 

 copepod genus most characteristic of the Scomber- 

 omorini is Shiinoa, found attached to the nasal ro- 

 settes of Acathocybium, Grammatorcynus, and 10 

 species of Scomberomorus. (Shiinoa was also found 

 on one specimen of Gymnosarda, but we do not be- 

 lieve Gymnosarda is a usual host for this copepod.) 



Scomberomorus Lacepede 



Scomberomorus differs from the other two genera in 

 the tribe, Acanthocybium and Grammatorcynus, by 

 usually lacking a swim bladder. The genus is com- 

 posed of 18 species (Collette and Russo 1 980). There 

 is one species in the Gulf of Guinea and Mediterra- 

 nean Sea — S. tritor (Cuvier); four in the western At- 

 lantic — cavalla (Cuvier), regalis (Bloch), maculatus 

 (Mitchill), and brasiliensis Collette, Russo, and Za- 

 valla-Camin; and two in the eastern Pacific — con- 

 color Lockington and sierra Jordan and Starks. The 

 remaining 1 1 species are in the Indo- West Pacific: 

 guttatus (Bloch and Schneider); koreanus (Kishinou- 

 ye); lineolatus (Cuvier); plurilineatus Fourmanoir; 

 commerson (Lacepede); sinesis (Lacepede); semifas- 

 ciatus (Macleay); queenslandicus Munro; niphonius 

 (Cuvier); munroi Collette and Russo; and 



multiradiatus Munro. Copepod fauna: 23 species in 7 

 genera. In addition to two species of Shiinoa, Scom- 

 beromorus is commonly parasitized by the pseudo- 

 cycnid genus Pseudocycnoides (buccata, armatus, 

 scomberomori) , the bomolochid genera Holobomolo- 

 chus (diuaricatus , asperatus, nudiusculus) , and Uni- 

 colax (U. ciliatus), and several species of Caligus 

 (especially C. biseriodentatus, C. infestans, and C. 

 cybii in the Indo-West Pacific, C. mutabilis and C. 

 productus in the western Atlantic, and C. omissus in 

 the eastern Pacific). The speciose nature of Scom- 

 beromorus and its copepod parasites requires further 

 discussion, by regions. 



ORIGINS AND EVOLUTION OF AMERICAN 

 SCOMBEROMORUS.— Six species of Scomber- 

 omorus occur in American waters. (Figs. 2, 3). Two of 

 these, S. sierra and S. concolor, are restricted to the 

 eastern Pacific from about lat. 10° to 40°N. Scom- 

 beromorus concolor presently occurs only in the Gulf 

 of California. The four Atlantic species areS. cavalla, 

 found from about lat. 30° S to 45°N; S. brasiliensis, a 

 southern coastal species (Belize to southern Brazil); 

 S. maculatus, a northern coastal species (Yucatan to 

 Massachusetts); and S. regalis, a largely insular 

 species (most abundant in the Bahamas and West 

 Indies). 



The six species of American Scomberomorus are 

 parasitized as a group by the following species of 

 copepods: H. asperatus (S. cavalla), H. nudiusculus 

 (S. sierra, S. concolor), H. divaricatus (S. brasiliensis, 

 S. maculatus, S. regalis), Shiinoa inauris (Scom- 

 beromorus maculatus, S. brasiliensis, S. regalis), C. 

 mutabilis (S. cavalla, S. brasiliensis, S. maculatus), C. 

 omissus (S. sierra, S. concolor), and P. buccata (all 

 species mentioned in this paragraph). 



To use parasitic copepods as indicators of host phy- 

 logeny we determined the pleisiomorphy-apomor- 

 phy of certain taxonomic characters. This is possible 

 within a closely related group of parasites based on 

 reduction and modification of characters for parasi- 

 tism. It seems reasonable to assume that, as species 

 of a parasite group evolve, the later (more recent) 

 species are more specialized or reduced than the old- 

 er species. If we assume that hosts and parasites 

 evolve together, the information on the evolution of 

 one group should provide evolutionary information 

 about the other group. Four genera of copepods para- 

 sitic on Scomberomorus lend themselves to analysis 

 and are discussed below. 



Three species oiHolobomolochus parasitic on Amer- 

 ican species of Scomberomorus and a fourth species 

 from Caranx hippos form a subgroup of the genus 

 (see Cressey and Cressey 1980:8). In these species, 



233 



