Diagnosis: Modal fin-ray counts of D-VI,10 A-10 and Pect-18-20 with fused pelvic fins indicate the 10/10 Coryphopterus sand gobies, i.e. Coryphopterus eidolon, C. glaucofraenum, C. tortugae, C. bol , C. dicrus, and C. thrix. The distinguishing features of adult C. eidolon are mostly not present on recruits and small juveniles.
Analogues: The 10/10 sand goby clade share fin-ray counts, morphology, and most markings as larvae and new recruits. Transitional C. eidolon and C. thrix develop scattered spots on the top of the head vs. short stripes on most other sand gobies, as well as a prominent melanophore(s) at the 7-8 o'clock position on the orbital rim, often early in transition. Both species have no jaw angle melanophores, at least as recruits (larval pattern uncertain). C. thrix juveniles larger than about 12 mm SL diverge from C. eidolon as they develop the characteristic speckling of small patches of melanophores (some 0.05-0.1 mm) over the dorsal aspect of the eye vs. a few large round and comma-shaped patches (0.3-0.5 mm) in C. eidolon (and other sand gobies). An additional difference between the small juveniles (>10 mm SL) of these two very similar species is the uniform size of the head melanophores in C. eidolon vs. C. thrix, where the lowest melanophores, just behind the eye, are larger than the adjacent sets of dorsal melanophores. Transitional recruits of the hovering gobies Coryphopterus personatus, C. hyalinus, and C. lipernes also do not have the stripes on the head at transition; nevertheless they can be distinguished from transitional sand gobies by developing melanophores around the vent and in a wide band from the eye to the maxilla.
Description: Based on transitional recruits, the larvae of C. eidolon may or may not have the jaw-angle or thoracic midline melanophores characteristic of other sand goby larvae. The caudal fin of transitional recruits have melanophores at the base of the central fin rays, and not at the lowest two or three segmented rays. Otherwise the larvae would look similar to other sand goby larvae: body relatively thin, long and narrow with a large eye and a terminal mouth. Pectoral fins long, dorsal and anal-fin bases relatively short, caudal peduncle long and narrow, procurrent caudal-fin rays 8-9 (7-8 spindly). Melanophores in a paired row along the anal-fin base, usually between the third and eighth element (often merged into a streak on each side). Then, after a space, there are several midline melanophores extending along the ventral caudal peduncle ending near the start of the procurrent caudal-fin rays. Internal melanophores are present at the base of the saccule and often above the saccule and sometimes several around the rear braincase, along the dorsal surface of the swim bladder, and around the gut near the vent. Transitional recruits develop a scattering of melanophores on the dorsal aspect of the head, not forming stripes. There is usually a conspicuous one or two large melanophores at 7-8 o'clock on the orbital rim and two or three oblong and comma-shaped collections of melanophores on the membrane overlying the dorsal aspect of the eyeball. The pelvic fins have not developed the short innermost fin rays and notched outline (rays equal in length). The lower portion of the head and the thorax are unmarked, as is the base of the pectoral fin. Melanophores cover the membranes of both dorsal fins and the anal fin. A bar of melanophores develops at the base of the caudal fin, concentrated at the base of the central caudal-fin rays. Fine melanophores speckle the distal portions of the lower segmented caudal-fin rays and, to a lesser extent, the central and upper rays.
Coryphopterus eidolon, the pallid goby, is a species of goby found in the Western Atlantic Ocean from southern Florida and the Bahamas all the way to Brazil.[1]
This species reaches a length of 6.0 cm (2.4 in).[2]
Coryphopterus eidolon, the pallid goby, is a species of goby found in the Western Atlantic Ocean from southern Florida and the Bahamas all the way to Brazil.
This species reaches a length of 6.0 cm (2.4 in).
