1032 



Fishery Bulletin 97(4), 1999 



Eggs, larvae, and juveniles (except those used ex- 

 clusively for radiography) were measured to the near- 

 est 0.04 mm by using a Wild M-5 binocular micro- 

 scope equipped with an ocular micrometer. Dimen- 

 sions measured for eggs included chorion diameter, 

 maximum yolk diameter, and lengths of the shortest 

 and longest intact chorionic filaments, and for lar- 

 vae andjuveniles, body length (BL), preanal length 

 (PAL), head length (HL), snout length (SnL), barbel 

 length (BbL), eye diameter (ED), head width (HW), 

 body depth (ED), and lengths of the pectoral (PjL) 

 and pelvic (P2L) fins. All these dimensions, except 

 chorionic filament length (measured along the axis 

 of the filament from its point of attachment on the 

 chorion to its free tip), are defined by Moser (1996). 

 Larval lengths refer to formalin-preserved body 

 length. All descriptions of pigmentation refer solely 

 to melanistic pigment. 



One late embryo (3.3 mm) dissected from the egg 

 and eight larvae (2.9-16.8 mm) were cleared and 

 stained with alcian blue and alizarin red S accord- 

 ing to the method of Taylor and VanDyke (1985) to 

 elucidate the development of the axial skeleton and 

 fins and to aid in making counts. Illustrations were 

 made with a Wild M-5 microscope equipped with a 

 camera lucida. 



Identification 



Specimens were identified by the series method. A 

 size series of larvae andjuveniles, linked by shared 

 morphological, meristic, and pigmentation charac- 

 ters, was traced down to recently hatched larvae from 

 juveniles that could be identified by using known 

 juvenile and adult characters. The smallest larvae 

 shared a pigmentation pattern with late-stage em- 

 bryos that allowed identification of the eggs. 



Of the eight fiyingfish genera in the eastern tropi- 

 cal Pacific (Parin, 1995; Dasilao et al., 1996), only 

 Cheilopogon has paired mandibular barbels during 

 at least part of the larval and juvenile stages (Parin, 

 1961a, 1961b; Collette et al., 1984). {Parexocoetus 

 brachypterus develops a pair of mandibular barbels, 

 and a small beak as well, during the juvenile stage: 

 Collette et al., 1984.) Of the nine Cheilopogon spe- 

 cies in and near the area (Table 1; Parin, 1995), lar- 

 vae are known for five: (C. atrisignis: Chen, 1987, 

 1988; C. furcatus: Hildebrand and Cable, 1930; C. 

 heterurus hiibbsi: Barnhart, 1932; Watson, 1996; C. 

 pinnatibarbatus californicus: Hubbs and Kampa, 

 1946; Watson, 1996; and C. spilonotopterus: Kova- 

 levskaya, 1977; Chen, 1987, 1988). All five differ from 

 the series treated here. Cheilopogon rapanouiensis 

 was eliminated from consideration by its higher ver- 



tebral, pectoral-fin ray, and predorsal scale counts 

 (45-46 vs. 43, 16-17 vs. 13-15, and 31-33 vs. 27-28, 

 respectively). Cheilopogon papilio was eliminated 

 because of its lower dorsal-fin ray count (9-10 vs. 

 12-13), usually lower pectoral-fin ray count (12-13 

 vs. 13-15), because of separate rather than fused 

 barbels and much heavier pectoral- and pelvic-fin 

 pigmentation in the juvenile stage, and because of 

 restricted distribution in coastal waters and the lower 

 Gulf of California (Parin, 1995). The remaining two 

 species, C. dorsomaculata and C. xenopterus, are 

 widely distributed in the eastern tropical Pacific 

 (Parin, 1995), are quite similar in appearance as 

 small (<ca. 40 mm) juveniles, and both were consid- 

 ered as possible identifications for the present se- 

 ries. Predorsal scale counts from the largest series 

 juveniles (27-28 scales) are consistent with C. 

 xenopterus and slightly high for C. dorsomaculata 

 (Table 1 ). Pectoral-fin ray counts for series specimens 

 having full complements of rays (>9 mm; 13-15 rays) 

 match the range for C. xenopterus and fall below to 

 within the lower half of the range for C. dorso- 

 maculata (Table 1). Juvenile C. dorsomaculata typi- 

 cally have less pelvic-fin pigment than C. xenopterus, 

 and in this character the larger series specimens are 

 consistent with C. xenopterus. Thus, 1 concluded that 

 the series is C. xenopterus. 



Specimens examined 



Listings are given as cruise and station number or 

 SIO catalogue number, and in parentheses number 

 of specimens and size range. Specimens listed with 

 cruise numbers are housed at the National Marine 

 Fisheries Service Southwest Fisheries Science Cen- 

 ter; specimens with SIO numbers are housed at the 

 Scripps Institution of Oceanography Marine Verte- 

 brates Collection. 



Cheilopogon xenopterus (Gilbert, 1890). 



Eggs: 8910JD: 3-100 (3: 1.8-1.9 mm), 3-102 (7: 1.8- 

 1.9 mm), 4-107 (1: 1.7 mm); 9210JD: 1-001 (4: 1.8- 

 1.9 mm), 1-008 (4: 1.8-1.9 mm), 3-047 (1: 1.8 mm). 



Larvae; 8710JD: 1-009 ( 1: 15.2 mm), 2-016A ( 1: 2.8 

 mm), 3-046 (6: 3.4-4.8 mm), 3-054 (1: 2.9 mm), 3- 

 056 (1: 4.9 mm), 3-075 ( 1: 2.9 mm), 3-078 (2: 5.3, 14.3 

 mm); 8710M4: 1-003 (1: 4.1 mm); 8810JD; 2-049(1: 

 8.0 mm), 3-086 (1: 7.5 mml, 3-118 (5: 8.7-13.6 mm), 

 4-153 ( 1: 8.3 mm); 8910JD: 1-015 ( 1: 2.9 mm), 1-019 

 (1:6.4 mm), 1-021(1: 13.7 mm), 2-056 (1: 6.8 mm), 3- 

 104(1: 4.8 mm); 8910M4: 1-010(1: 12.5 mm), 1-012 

 (1: 3.4 mm), 4-143 (2: 9.8, 13.9 mm); 9010JD: Manta 

 54(1: 13.4 mm), Manta 65(1: 6.4 mm), Manta 74(1: 

 22.8 mm); 9210JD: Manta 2 (1: 8.1 mm), Manta 9 



