Smith-Vaniz and Carpenter; Review of the Coronx hippos complex with a description of a new species from West Africa 221 



Comparisons Although long confused with Caran.x 

 fischeri. as discussed under "Comparisons and relation- 

 ships" in the account of that species, C. hippos is easily 

 distinguished. However, C. hippos and C. caninus are so 

 similar externally that many authors considered them 

 to be taxonomically identical or only subspecifically 

 distinct. They have broadly overlapping mensural (Figs. 

 6-7) and meristic values (Tables 2-4), but the pattern 

 of hyperostosis (Table 1) is surprisingly different in the 

 two species. They differ in four character states (Table 

 1, characters 2-4, 6) and share three others (Table 1, 

 characters 5-6), although even in one of these (Table 

 1, character 5), the relative degree of hyperostosis is 

 different (Fig. 11), namely the expansion of the first 

 dorsal-fin pterygiophore being more pronounced in C. 

 caninus. The color of the anal fin of a living fish is 

 lemon yellow in C. hippos and is either uniformly white 

 or brownish-orange in C. caninus. The underside of the 

 caudal peduncle in adults of C. hippos is mostly yellow, 

 a trait that C. Caninus lacks. 



Distribution This species is found on both sides of the 

 Atlantic Ocean but is largely restricted to continen- 

 tal shelf areas (Fig. 2). In the western Atlantic it is 

 found from Nova Scotia only as rare waifs (Scott and 

 Scott, 1998) to Rio de la Plata, Uruguay (Devincenzi, 

 1924), but is absent from Bermuda (Smith-Vaniz et 

 al., 1999) and most of the Lesser Antilles. Confirmed 

 insular locality records based on museum specimens 

 include those for Jamaica and the Bahamas (Andros 

 Island), and we have photographic documentation for 

 the Virgin Islands (St. Thomas) near the southern end 

 of the shallow Puerto Rico shelf, where the species is 

 relatively common. Caran.x hippos is a regular summer 

 visitor as far north as Woods Hole, Massachusetts 

 (Klein-MacPhee, 2002), and young-of-the-year inhabit 

 temperate estuaries of New York and New Jersey 

 from July to November. McBride and McKown (2000) 

 presented data indicating that these juveniles are 

 spawned in subtropical latitudes and, aided by the 

 Gulf Stream, disperse northward to coastal nurser- 

 ies. Although the species is incapable of surviving the 

 winter north of Cape Hatteras, growth rates and sea- 

 sonal changes in distribution of this species indicate 

 that some individuals successfully migrate southward 

 to suitable over-wintering habitat and retain their 

 potential contribution to the spawning population. 



In the eastern Atlantic C. hippos is known from 

 Mauritania to Angola, but historical records for the 

 Mediterranean Sea (Tortonese, 1952, 1975) are based 

 on misidentifications of C. fischeri, as presumably 

 are additional unconfirmed records cited by Papacon- 

 stantinou (1988) and Bilecenoglu et al. (2002). The 

 photograph (Debelius. 1997, p. 159) of a large school 

 of adult Caran.x. identified in the caption as C. hip- 

 pos and stated to have been taken at the Balearic Is- 

 lands, Spain, may have been a substitution and this 

 locality record for the species could not be confirmed 

 (Debelius^). Reports of C. hippos from the Canary Is- 

 lands are based on misidentifications of C. latus; and 



records of the species from the Azores (Arruda, 1997), 

 Cape Verde Islands (Osorio, 1911), and St. Helena 

 (Melliss, 1875; Edwards and Glass, 1987; Edwards, 

 1990) are unreliable and can not been confirmed. 



Adults are found inshore and frequently in upstream 

 brackish waters (Klein-MacPhee, 2002) but are most 

 common in salinities higher than 30 ppt (Gunter, 1945). 

 Juveniles appear to use estuaries as nurseries in both 

 temperate and tropical areas. Most reports of the spe- 

 cies from freshwater are unreliable because of previous 

 confusion with C. fischeri or are misleading (Herald 

 and Strickland, 1949) because Homossassa Springs, 

 Florida, has high alkalinity from the ionic composition 

 of bicarbonate spring effluents. Gunter (1945) recorded 

 juveniles and adults from Texas in salinities from 4.8 to 

 36.4 ppt. Smith (1985) reported that crevalle jacks are 

 common summer residents in the Lower Hudson River, 

 New York, and "in 1982 they were especially abundant 

 as far upstream as River Mile 68 in early October and 

 were still present at River Mile 66 in early November." 

 McBride and McKown (2000) observed individuals in 

 the Hudson River during July-October 1986-1993 at 

 the freshwater interface (about 1 ppt), about 90-100 

 km inland. 



Geographic variation Juveniles and adults of C. hippos 

 from opposite sides of the Atlantic Ocean are virtu- 

 ally identical externally, including life coloration (Fig. 

 8, D-E), but differ notably in relative development of 

 hyperostosis of the first pterygiophore of the dorsal 

 fin. This bone is much less robust in adults of eastern 

 Atlantic C. hippos (Figs. 11, 12). There is some variation 

 in relative development of this pterygiophore in large 

 western Atlantic specimens, but in all those we have 

 examined (including a number of partially articulated 

 skeletons at the AMNH not listed below) it is dorsolater- 

 ally expanded in marked contrast to the slender profile 

 of the bone in eastern Atlantic specimens (Fig. 12). The 

 basal halves of the neural spines of some of the anterior 

 vertebrae (usually vertebrae 5-12) are also consistently 

 and strongly expanded (Fig. 9, B-C) in large adults from 

 the western Atlantic. The neural spines are only slightly 

 hyperossified in a 56-cm-FL specimen (Figs. lOB, 13) 

 from Senegal. They were more expanded (although much 

 less so than in similar-size western Atlantic specimens) 

 in a 90-cm specimen from Angola that had been partially 

 dissected and photographed at our request so that we 

 could ascertain the condition of the neural spines. 



Caran.x hippos has an essentially continental distri- 

 bution (there are no confirmed records from any oce- 

 anic island) and populations on opposite sides of the 

 Atlantic presumably are isolated and have little ge- 

 netic connectivity, thus some geographic differentiation 

 might be expected. Caran.x senegallus and C. fischeri 

 are both eastern Atlantic endemics, but other Atlantic 

 species of Caran.x with amphi-Atlantic distributions (C. 



■' Debelius, H. 2004. Personal commun. IKAN-Underwasser- 

 arehiv, Waldschulstrasse 166, 65933, Frankfurt, Germany. 



