314 



ONTOGENY AND SYSTEMATICS OF FISHES-AHLSTROM SYMPOSIUM 



Table 87. Meristic Variation in Selected Species of Carapid Fishes. Abbreviations used are: N — number of specimens examined; D,o— 

 number of dorsal rays whose bases lie anterior to 31st vertebra; Ajo— number of anal rays whose bases he anterior to 31st vertebra; P, — pectoral 

 rays; P^— pel vie rays; PCV—precaudal vertebrae; NVD— number of vertebrae to dorsal origin; NVA— number of vertebrae to anal origin; ARDO— 



number of anal rays to dorsal ongin; NA— not applicable. 



Species N D^ A^ P^ p] PCV NVD NVA ARDO 



gut migrates forward by 2-4 myomeres during formation of the 

 gut coil (Gordon, 1982). By 8-10 mm NL, the haemal arches 

 are closed allowing accurate determination of the vertebral for- 

 mula in cleared and stained larvae. Rays of the dorsal and anal 

 fins develop from posterior to anterior. Development begins at 

 7-10 mm NL and is complete by 15-20 mm SL. The adult 

 complement of nine caudal rays and seven branchiostegal rays 

 is present by 10 mm NL in most species. These structures do 

 not appear until 1 5 to 20 mm SL in the elongate O. selenops. 

 The number of pectoral fin rays ranges from 16-28, with sizes 

 at which the first rays appear ranging from 1 3-20 mm SL. The 

 pectoral fin is complete in some species by 18-20 mm SL. 



Traditionally, meristic characters have not been widely used 

 in adult descriptions of carapids (Arnold, 1956) and conse- 

 quently, some easily observed and useful characters such as 

 pectoral fin ray counts (Cohen and Nielsen, 1978; OIney and 

 Markle, 1979) can not be obtained from the literature. Inno- 

 vative meristics, partly borrowed from eel systematics (Nielsen 

 and Smith, 1978), are useful aids to identification of larval and 

 adult carapids (OIney and Markle, unpublished data). Table 87 

 summarizes some of these meristic characters for selected species 

 of carapids. 



Morphology. — Except for the larvae of O. selenops and O. no- 

 comis, known ophidiine larvae show little variation in size, 

 shape and development (Figs. 159, 160). The larvae, which 

 hatch at 2-3 mm NL, are moderately elongate and taper slightly 

 from the head to the end of the notochord. The eyes are round 

 and conspicuous; the mouth is oblique. Larvae become more 

 laterally compressed with growth. In all species examined by 

 Gordon (1982), the gut is straight at hatching and develops a 

 single coil at 5-7 mm NL as a downward loop twists, displacing 

 the more posterior portion of the gut to the right. 



Carapid vexillifers (Figs. 161-163) are elongate larvae with a 

 moderately sized head, large eye and nasal rosette, coiled gut, 



short preanal length, and tapered body frequently ending in a 

 broken filament, and an elongate larval dorsal fin ray (vexillum) 

 in front of the first adult dorsal fin ray (OIney and Markle, 1979; 

 Govoni et al., 1 984). Larvae of Pyramodon and Snyderidia (Fig. 

 1 63) have a somewhat deeper head and trunk, shorter pre-dorsal 

 distance, relatively long anal fin pterygiophores, and more pec- 

 toral fin rays than other carapid larvae (Markle and OIney, 

 1980). Variations in gross morphology in carapine larvae are 

 limited to variation in gut shape and fin ray or vexillum position 

 (Figs. 161, 162; Table 87). 



Pigmentation. — VxgmenXdiXion of ophidiine larvae is useful for 

 identifying species and species groups though care must be taken 

 since ontogenetic changes occur (Gordon, 1 982). Head pigmen- 

 tation typically consists of two or three melanophores present 

 distally on the suspensorium near the articulation with the lower 

 jaw. Abdominal pigmentation is usually variable within species 

 and consists of melanophores scattered ventral to the gut. Pig- 

 mentation on the posterior half of the body is the most useful 

 for taxonomic purposes. All Lepophidium larvae have 2-10 

 large spots placed medially along the base of the anal finfold 

 and 1-2 spots dorsally in the caudal peduncle region. Unlike 

 Lepophidium, larvae of Ophidion, Otophidium and Chilara have 

 patterns of small stellate melanophores present laterally on the 

 body. Several species of these genera can be recognized on the 

 basis of postanal pigmentation. Some species have larvae which 

 are very similarly pigmented: O. selenops and O. nocomis; O. 

 welshi and O. marginatum. Larvae of other species cannot be 

 distinguished using pigmentation or meristic characters (Gor- 

 don, 1982): Ophidion Type 1 (Fig. 159B) which represents O. 

 holbrooki, O. beani and unidentified Ophidion species; Ophidion 

 Type 2 (Fig. 1 59C) O. welshi and O. grayi; and Lepophidium 

 Type 1 (Fig. 160D) L. graellsi and L. jeannae. 



Carapid vexillifers are sparsely to moderately pigmented (Figs. 

 161-163). Red chromatophores have been noted in fresh ma- 



Fig. 161 . (A) Urva of Echiodon drummondi, 76.5 mm TL, ZMUC uncat., DANA St. 8371, 5 r29'N, 1 2''50'W. (B) Urva of Echiodon rendahli. 

 72 mm TL, CSIRO uncat., Warreen Cruise, Sta. 266/39, 36°17'S, 150°25'E. (C) Dorsal fin and vexillar supports of Echiodon dawsoni. 4.2 mm 

 HL and 10 mm HL. Abbreviations used are vex — vexillum, fdp— first dorsal pterygiophore. (D) Dorsal fin and vexillar supports of Echiodon 

 drummondi. 4.6 mm HL and 24.3 mm HL. Abbreviations as in Fig. 16 IC. 



