Soleichthys serpenpellis, Munroe & Menke, 2004

Munroe, Thomas A. & Menke, S. B., 2004, Two New Soleid Flatfishes (Pleuronectiformes: Soleidae: Soleichthys) from Australian Waters, With a Re-description of Soleichthys microcephalus (Günther), Records of the Australian Museum 56 (2), pp. 247-258 : 253-255

Soleichthys serpenpellis n.sp.

Figs. 2, 3; Tables 1, 3

Snakeskin sole

Type Material. HOLOTYPE, AMS IB. 7211, 122.7 mm SL, Gulf of Carpentaria , 12– 18°S 139– 143°E. P ARATYPES: AMS I.15557-066, 2(103.4–125.3 mm SL), Gulf of Carpentaria , 17°29'S 140°45'E, 4 m; QM I. 11204, 117.8 mm SL, Gulf of Carpentaria , 16°35'55"S 140°48'20"E, 9 m; WAM P5739 , 100.0 mm SL, Delambre Island, Dampier Archipelago off northwestern Australia, 21°S 117°E.

Distinguishing characters. Soleichthys serpenpellis is readily distinguished from all congeners by its combination of: low meristic features (44–46 vertebrae, 76–84 dorsalfin rays, 64–71 anal-fin rays, and 83–95 lateral-line scales),

a series of six incomplete, diamond-shaped crossbands on the ocular surface that are widest in their mid-sections and wider than respective interspaces between crossbands, with small, brown spots scattered in the interspaces between ocular-side crossbands, with three crossbands on the head, in having two white spots in longitudinal series along the midline of the ocular-side body, in its two elongated ocularside pectoral-fin rays of nearly equal length or with the second fin ray longer than the first, and in having small scales present on bases and proximal halves of elongated ocular-side pectoral-fin rays.

Description. Meristic and morphometric features for the holotype and four paratypes are summarized in Tables 1 and 3. Body moderately elongate with nearly straight dorsal contour anteriorly, greatest depth (about 2.75 in SL) at a point in the anterior 33–50% of body length; taper gradual in posterior one-fifth of body; body thick, especially in region of pectoral fins. Head ca. 0.44 BD; wider than long (HW ca. 1.2–1.5 HL) with its ventral contour gently sloping posteriorly. Snout bluntly rounded, smaller than ED; snout tip on horizontal line through centre of fixed eye. Blindside head with a few widely-spaced cirri also present along posterior margin of opercle. Ocular-side anterior nostril extending to about anterior margin of fixed eye when depressed posteriorly. Posterior margin of jaws at vertical through anterior margin of pupil of fixed eye. Lips fleshy, with longitudinal plicae. Eyes large (ED> SNL) and conspicuous, oval. Gill cover with fleshy membranous attachment to bases of three dorsalmost pectoral-fin rays on ocular side; on blind side, gill cover broadly connected by thick membrane to dorsalmost two or three pectoral-fin rays for nearly one-half their lengths. Ocular-side gill cover without obvious cirri; blind-side gill cover with cirri present along posterior border. Ocular-side lateral line anteriorly with small, curved portion posterior to migrated eye and extending dorsal to horizontal at dorsal margin of migrated eye. Dorsal-fin origin on body midline usually at vertical anterior to anterior margin of migrated eye. Dorsal-fin pterygiophore formula 1-1-2 (holotype and 3 paratypes) or 1-0-2 (1 paratype). Middle dorsal-fin rays slightly longer than those in other regions of fin. Both sides of dorsal-fin rays from a point anterior to mid-point of fin with a single row of ctenoid scales on their proximal halves; at approximately body mid-point to posterior end of dorsal fin, both sides of fin rays covered for nearly four-fifths their lengths with single row of small ctenoid scales. Proximal halves of both sides of anal-fin rays in anterior one-fifth of fin covered with single row of ctenoid scales; scales gradually increasing in number (but not rows) posteriorly and eventually covering nearly proximal four-fifths of fin rays in posterior portions of anal fin. Caudal fin broadly rounded and relatively large, with 18–19 fin rays. Proximal three-fourths of ocular side of caudal fin scaly; scales covering only proximal half of blind side of caudal fin. Ocular-side pectoral fin long, pointed, with 8–9 fin rays, the two dorsalmost rays elongate with remainder decreasing in size progressively. Second ocular-side pectoral-fin ray slightly longer than first and nearly equal to head length; elongated pectoral-fin rays scaly for proximal one-third of their lengths; remainder of fin scaly only on basal region. Blind-side pectoral fin rounded, with 6–8 relatively short fin rays; two dorsalmost rays longer than remainder, which are nearly equal in size; pectoral-fin base about equal to length of longest blind-side fin ray; blind-side pectoral-fin rays not noticeably scaly, but with some scales on blindside pectoral-fin base. Blind-side pelvic fin nearly on body midline; ocular-side pelvic fin with anteriormost ray on body midline and with remainder of fin rays dorsal to midline on right side. Scales on body small, strongly ctenoid, rhomboid, with ctenii in centre of scale more strongly developed than those on dorsal or ventral margins. Lateral-line scales small, rounded, cycloid, and with slightly raised pore.

Pigmentation (in alcohol, Fig. 3). Ocular-side background coloration generally light- to medium-brown with a series of 9–10 prominent darker crossbands from snout tip to base of caudal fin and with two conspicuous, rounded, white spots equal to, or slightly larger than, eye diameter in longitudinal series on body midline. Anterior spot situated between first and second crossband on body; posterior spot between crossbands 3 and 4. Body usually with 6–7, darkbrown, complete or nearly complete, crossbands covering body from base of dorsal fin to base of anal fin; crossbands in mid-body region of some specimens generally broader than others, with central regions wider than areas nearer bases of dorsal and anal fins. Body crossbands broader and more darkly pigmented than respective light-tan interspaces. Crossbands in anterior one-half of body nearly straight across vertical axis of body, whereas borders of posterior crossbands often with wavy appearance. Crossbands not bordered by spots, but interspaces between crossbands on body and on head posteriorly with numerous, round darkbrown spots and irregular blotches. Head with three, darkbrown, continuous crossbands; the first on anterior snout and chin, second crossing region between middle and posterior margin of eyes and third crossband located posteriorly on head and gill cover. Ocular-side anterior nostril uniformly brown throughout its length. Mouth lining black. Inner opercular linings and isthmus on both sides with dense concentration of melanophores. Blind side uniformly yellowish-white, with scattering of pepperdot melanophores on scales along pterygiophore regions of dorsal and anal fins. Basal halves of ocular sides of dorsal and anal fins light tan similar to background coloration on body. Ocular sides of dorsal- and anal-fin rays with dense concentrations of melanophores throughout lengths of fin rays. Pigment intensifying on distal thirds or less of ocular sides of dorsal- and anal-fin rays, exclusive of tips, and forming continuous or nearly continuous longitudinal darkbrown to blackish band throughout entire lengths of fins. Longitudinal band solid in some regions and in others comprised of two parallel rows of irregular spots covering several fin rays and joining membrane; spots frequently coalesce into larger, darkly pigmented blotches in some areas of these fins. Distal band darkest on posterior onethird of dorsal and anal fins. Distal tips of dorsal- and analfin rays in anterior region of fin whitish. Blind sides of dorsal and anal fins with melanophores throughout length of fin rays and with dark, blackish-brown band on distal two-thirds of fins in anterior two-thirds of body, and with band on distal one-third of fins in posterior region of body. Ocular side of caudal fin with medium-brown band on proximal one-third of fin rays; middle one-third of caudal fin tancoloured with lighter concentration of melanophores; and distal one-third of fin with dark (blackish) band continuous with that of dorsal and anal fins. Blind side of caudal fin white basally, with dark melanophores on middle third, and with more solid blackish-brown pigment on distal one-third of fin. Ocular-side pectoral fin with uniformly brown pigment throughout length of fin rays, with distal tips of elongated fin rays white, and with darker, nearly black, pigment streaks on membrane between elongated fin rays; blind-side pectoral fin with pepperdot melanophores on fin and sometimes also with pepper dots on body scales immediately behind blind-side pectoral fin. Pelvic fins blackish-brown with membrane more darkly pigmented than most fin rays.

Distribution and habitat ( Fig. 2). Tropical waters of northern Australia; four specimens were taken in the Gulf of Carpentaria, Queensland (18°S – 16°35'S), and a single specimen was captured east of Delambre Island, Dampier Archipelago, northwestern Australia (21°S 117°E). The available specimens were captured in depths of 4– 9 m.

Etymology. From the Latin, serpen, snake, and pellis, skin; in reference to the distinctive ocular-side pigmentation pattern in this species that is reminiscent of a snake-skin colour pattern.

Comparisons. Soleichthys serpenpellis is readily differentiated from S. heterorhinos , S. nigrostriolatus , S. multifasciatus and S. lineatus by its lower meristic features (44–45 vs. 48–53 total vertebrae, 76–84 vs. 85–105 dorsalfin rays, 64–71 vs. 74–91 anal-fin rays and 83–95 vs. 100–

124 lateral-line scales in these other species, respectively) and in its pigmentation pattern including fewer (6–7), wider crossbands on its body (vs. 17–31 crossbands in these others). It differs from S. heterorhinos , S. nigrostriolatus , and S. multifasciatus in having only three crossbands on its head (vs. usually five or more in these others). Soleichthys serpenpellis differs from S. microcephalus and S. oculofasciatus (see below) in having incomplete, diamondshaped crossbands on the body (vs. complete bands of different shape in these other species), in having fewer total ocular-side crossbands than these others, and in having numerous brown spots distributed among ocular-side crossbands (vs. brown spots lacking in these others). Soleichthys serpenpellis is further distinguished from S. oculofasciatus in having only two, conspicuous white spots situated mid-laterally in a horizontal series on the ocular side (vs. four white spots with two arranged in vertical series), in having the second elongated pectoral-fin ray as long as or longer than the first (vs. second elongated pectoral-fin ray shorter than first), and in having scales on elongated rays of the ocular-side pectoral fin (vs. scales lacking on elongated pectoral-fin rays). Soleichthys serpenpellis also differs from S. oculofasciatus in having a shorter and wider head and a shorter caudal fin (compare respective data in Tables 3 and 4). Soleichthys serpenpellis differs from S. siammakuti and S. maculosus in lacking spots on the fins characteristic of these other species. Soleichthys tubiferus is most easily distinguished from the new species by its uniformly pigmented ocular side (vs. prominent crossbands in S. serpenpellis ).