DEVELOPMENT AND STRUCTURE OF FINS AND FIN SUPPORTS 



IN DOLPHIN FISHES CORYPHAENA HIPPURUS AND 



CORYPHAENA EQUISELIS (CORYPHAENIDAE)^ 



Thomas Potthoff^ 



ABSTRACT 



The development and structure of the fins and fin supports were studied from a cleared and stained size 

 series of about 400 Coryphaena hippurus and about 400 C. equiselis. Coryphaena hippurus and 

 C equiselis differ in all aspects of fin ray and fin support development; C . equiselis is always more 

 advanced than equal-sized C. hippurus during development. The species differ in number of fin rays in 

 the single dorsal fin. The pterygiophores of the single dorsal fin each develop from a single cartilage in 

 both species. The cartilage then ossifies to proximal and distal radials. Each fin ray is serially 

 associated with a distal and proximal radial, and each ray is secondarily associated with the following 

 (posterior) proximal radial. Exceptions were found at the anteriormost and posteriormost parts of the 

 dorsal fin. The two species differ only slightly in anal fin ray counts. The pterygiophores of the anal fin 

 are similar in development and structure to those of the dorsal fin. The species do not differ in caudal fin 

 ray counts. The caudal fin rays are supported by some of the bones of the caudal complex, which 

 contains one neural spine, one specialized neural arch, two autogenous haemal spines, one autogenous 

 parhypural bone, five autogenous hypural bones, two paired uroneural bones, and two epural bones. 

 During development, hjrpurals one and two and hypurals three and four fuse, forming the dorsal and 

 ventral hypural plates. The two epurals fuse into one and the two pairs of uroneurals form one pair. 

 Both species have the same number of pectoral fin rays. In both species, pectoral fin rays are directly 

 supported by the scapula and four radials, and indirectly by the cleithrum and the coracoid. 

 The pectoral suspensorium, which consists of seven bones, connects the pectoral bones to the skull. 

 The posterior process of the coracoid develops as a prominent larval structure that disappears during 

 development. The pelvic fins of both species have one spinous and five soft rays. These fin rays 

 are supported on each side by the pelvic basipterygium. The basipterygium develops in similar fashion 

 to a pterygiophore. 



The development and anatomy of the fins and fin 

 supports for Coryphaena hippurus and C. equi- 

 selis have not been described. The purpose of this 

 study was to document the development and 

 anatomy of the fins and fin supports for the family 

 Coryphaenidae and to point up differences in 

 meristic counts and arrangement of fin rays and 

 supporting bones between the two species of Cory- 

 phaena using cleared and stained material. 



No complete study of the fins and fin supports 

 for the two Coryphaena species has been done. 

 Studies on the osteology and meristic counts exist 

 without use of cleared and stained material. 

 Jordan and Evermann (1896), Nichols (1909), 

 Gibbs and Collette (1959), Rothschild (1964), 

 Miller and Jorgenson (1973), and Shcherbachev 

 (1973) have published meristic counts for the two 



'Contribution No. 80-03M, Southeast Fisheries Center Miami 

 Laboratory, National Marine Fisheries Service, NOAA. 



^Southeast Fisheries Center Miami Laboratory, National 

 Marine Fisheries Service, NOAA, 75 Virginia Beach Drive, 

 Miami, FL 33149. 



species. Clothier (1950) gave the meristic counts 

 and an illustration of the head and the vertebral 

 column for C. hippurus. Potthoff (1971), using 

 cleared and stained material, studied meristic 

 counts of C. equiselis. Collette et al. (1969) re- 

 ported the vertebral numbers of the two species, 

 and Gregory (1933) depicted the skull of C. hip- 

 purus and commented on the phylogenetic rela- 

 tionship of C. hippurus. Starks' (1930) description 

 of the pectoral girdle of C hippurus was presented 

 without illustrations. 



Many publications deal with the biology (age, 

 growth, reproduction, food) of Coryphaena spp., 

 usually C. hippurus (Schuck 1951; Williams and 

 Newell 1957; Gibbs and Collette 1959; Kojima 

 1961, 1963a, b, 1964; Beardsley 1967; Rose and 

 Hassler 1968, 1974; Shcherbachev 1973; Taka- 

 hashi and Mori 1973). Others document the distri- 

 bution of Coryphaena spp., most often that of C. 

 hippurus (Williams 1953; Morrow 1954; Pew 1957; 

 Gibbs and Collette 1959; Kojima 1960, 1964; Tibbo 

 1962; Shcherbachev 1973; Takahashi and Mori 



Manuscript accepted November 1979. 

 FISHERY BULLETIN: VOL. 78, NO. 2, 1980. 



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