Hetereleotris caudilinea (Randall, 2005)

Douglass F. Hoese & Helen K. Larson, 2005, Description of two new species of Hetereleotris (Gobiidae) from the south Pacific, with a revised key to species and synonymization of the genus Pascua with Hetereleotris., Zootaxa 1096, pp. 1-16 : 5-8

Hetereleotris caudilinea (Randall, 2005)

(Fig. 3, Tables 1-3)

Pascua caudilinea Randall, 2005 : 21, figs. 1-4 (Easter Island).

Material Examined (all from Easter Island): AMS I.17452-001, 1(25 mm SL) ; AMS I.43246-001, 1(24) + I.43246-002, 3(22-27), cleared and stained ; BPBM 6745, 11(21- 28) ; BPBM 17213, 4(18-29) ; BPBM 31956, 1(27) ; CAS 24290, 1(28) ; LACM 6560-42, 1 (32) ; LACM 6560-43, 4(25-29) ; SIO 68-433, 3(26-29), one specimen cleared and stained) ; UBC 65-417, 1(23) ; USNM 203814, 4(23-30) .

Diagnosis. Pelvic fins widely separated at base, rays I,5, fifth ray unbranched or branched once at tip, distance between bases of inner rays of two fins about equal to base of either fin. One head pore by each posterior nostril, a single anterior interorbital pore, a single posterior interorbital pore, a supraorbital pore behind eye, an infraorbital pore below supraorbital pore behind eye, a lateral canal pore behind infraorbital pore, a terminal lateral-canal pore over preopercular margin, and two preopercular pores (Fig. 2). First gill-arch connected by a membrane to inside of gill cover. Gill opening restricted to depth of pectoral base. Anterior nostril at end of short tube; posterior nostril a simple pore, sometimes with an elevated anterior rim. First two dorsal spines in males prolonged into short filaments. First dorsal fin with a basal black line just above body. Second dorsal-fin rays normally I,9.

Description. First dorsal-fin spines VI (in 14); second dorsal-fin rays usually I,9; analfin rays I,8; pectoral-fin rays 18-22; pelvic-fin rays I,5 (in 14); segmented caudal-fin rays 17 (in 14); branched caudal-fin rays 13-15; unsegmented caudal-fin rays 6-8 above and 6 below. Branchiostegal rays 5. Vertebrae 10+17 = 27 (14). Longitudinal scale count 23-26. Transverse scale count (TRB) 8(3), 9(6). Variation of some of the meristics are indicated in Tables 1-3.

Head as broad as deep, rounded; compressed body tapering slightly posteriorly; mouth moderately oblique, forming an angle of 15° to 20° with body axis; posterior margin of mouth below a point between middle and posterior margin of pupil. Lower jaw projecting slightly. Snout length about 1.2 in eye length. Eye separated from upper jaw by less than pupil diameter. Fleshy interorbital less than 0.5 mm in largest adults. Anterior nostril tubular; posterior nostril a pore, in contact with anterior margin of orbit, sometimes with an elevated anterior margin. Lower margin of gill-opening just under ventral margin of pectoral base. Tongue truncated to slightly emarginate, never bilobed. No rakers on outer face of first gill-arch; 5-6 rakers on inner face of first arch and rakers on remaining arches composed of small clusters of spines.

Inner (fifth) pelvic ray usually unbranched, but occasionally branched once at tip. Second dorsal and anal spines each about two-thirds body depth at anal origin. In males, posterior rays longest, but in females all rays of about equal length. In males, first two dorsal spines prolonged well beyond spine of second dorsal fin. In females, first three spines of approximately same length, and first not reaching spine of second dorsal fin. Remaining dorsal spines decreasing in length posteriorly. First dorsal fin membrane ending just before second dorsal origin or narrowly connected to based of spine of second dorsal fin. Dorsal and anal rays, all but one or two pectoral rays, and four pelvic rays, branched. Middle and longest pectoral rays reaching to or beyond anus. Fourth (longest) pelvic ray reaching to or slightly beyond anus. Fifth pelvic ray shorter than third and fourth rays, and longer than second. Rounded caudal 0.9 of head length.

Urogenital papilla short and rounded in females, elongate and flattened with short lateral lobes at distal tip in males; urogenital papilla 2.5 to 4 times as long as broad in males, and 1 to 2 times as long as broad in females. The pores and papillae of the lateralis system are shown in Figure 2.

Squamation. Scales confined to body, ending anteriorly at a line from second or third dorsal spine to upper base of pectoral fin (Fig. 2). Scales ctenoid on sides of body, but cycloid on belly. Scales on midline of belly smaller than those on either side. At base of caudal fin two modified scales, with enlarged ctenii (Fig. 1). Anterior to base of pelvic fins, on midline, two cycloid scales in a longitudinal row. Because most of the specimens examined had lost their scales, the transverse rows could not be counted accurately for much of the material.

Teeth of upper jaw. Teeth of outer row curved, enlarged, and wide-set. Occasionally smaller teeth inserted between enlarged ones. Inside this row, smaller conical teeth in 3 rows, converging posteriorly into a single row. Inside these rows, on each side, 3 or 4 enlarged teeth near anterior part of jaw.

Teeth of lower jaw. An outer row of 10 to 12 enlarged, curved, closely spaced teeth on each side extending half length of jaw. Inside this row a single series of smaller teeth extending full length of jaw, and inside this series a row of 7 to 8 curved teeth, on each side, becoming larger posteriorly and extending full length of jaw.

Osteology. No free dorsal postcleithrum. Mesopterygoid and posterior process of pelvic girdle absent. Head canals surrounded by bony ridges. Dorsal process of short sphenotic meets lateral wing of supraoccipital. Crested supraoccipital is as long as wide; its lateral wings extending to outer margin of epiotics; its posterior flange covering inner part of epiotics, but not exoccipital; anterior flange extending forward under frontal. Frontal also covering lateral wings of supraoccipital, sphenotic flange, and anterior parts of pterotics and epiotics. Elongate ventral metapterygoid process extending over part of quadrate. Posterior wing of hyomandibular with a ventral process, articulating with dorsal and proximal part of preoperculum. Glossohyal spatulate. Coracoid well developed below and anterior to lower pectoral radial. Rudimentary scapula fused to cleithrum. Anterior 6 and posterior 5 or 6 vertebrae with well developed zygapophyses. A single epural, one epaxial and one hypaxial element, and two hypural plates, with upper only fused to urostyle.

Coloration in alcohol. Head and body light brown. An oblique bar extending from anteroventral margin of eye to above middle of upper jaw. Less than a pupil diameter behind middle of eye, a dark-brown spot, about as large as pupil. A series of small longitudinal spots extending along mid-sides from pectoral base to caudal base. In young, these spots square or rounded. Ten blotches on side, 3 under and 7 behind pectoral fin (in some specimens a few spots faded and not discernible). A vertical bar crossing entire base of caudal fin. Three faint blotches extending a short distance downward from base of first dorsal; 4 blotches at base of second dorsal. Ventral surface of body with 7 blotches from anal origin to caudal base. Upper two-thirds of caudal fin with 5 or 6 faint wavy bands, becoming less distinct posteriorly; lower third of fin clear to dusky, with scattered melanophores. On basal fourth of first dorsal, a horizontal bar, with little pigment between bar and body. Distal part of first dorsal fin clear, with scattered melanophores. Faint oblique bars, on second dorsal fin slope downward posteriorly. Anal fin dusky, darkest near tip. Pelvic fin dusky to black in males; clear and without melanophores in females. Triangular area between base of pelvic fin and branchiostegal membrane densely covered by melanophores in males, but unmarked in females. Basal two-thirds of urogenital papilla of males covered laterally with pigment. In females, a lateral group of melanophores at base of papilla on each side.

Remarks. The species is known only from Easter Island.

The species was collected from rocky areas, often with rubble in depths of 1-6 m. The species is known from 13 males (22-30 mm SL) and 19 females (18-27 mm SL).

Randall (2005) considered the unbranched fifth pelvic ray to be a generic characteristic. As noted above the pelvic is branched at the tip in some specimens.