Hetereleotris dorsovittata Kovačić & Bogorodsky, 2014

Kovačić, Marcelo, Bogorodsky, Sergey V. & Mal, Ahmad O., 2014, A new species of Hetereleotris (Perciformes: Gobiidae) from Farasan Island (Red Sea), Zootaxa 3846 (1), pp. 119-126 : 120-125

Hetereleotris dorsovittata Kovačić & Bogorodsky , sp. nov.

(Figs. 1 & 2)

Holotype. SMF 35229, male, 21.7 + 6.3 mm, Red Sea, Saudi Arabia, Farasan Archipelago, Farasan Island, 16°43.083' N, 42°03.934' E, coral patch in lagoon, 1 m, coll. S.V. Bogorodsky & T. Alpermann, 20 March 2012.

Diagnosis. Dorsal-fin rays VI + I,12; anal-fin rays I,11; pectoral-fin rays 14, all rays branched; pelvic-fin rays I,5, the fin separated and without fraenum, 5th ray unbranched; body without scales; no head canals; suborbital rows of papillae with 4 transversal rows; no tentacle above eye; anterior nostril a long tube without flap at its tip, posterior nostril short tube, no more than ½ length of anterior nostril; body and head with irregular mottling above midlateral, both dorsal fins with black submarginal bands (Figs. 1A & B).

Description. Body moderately elongate, laterally compressed posteriorly, the depth at pelvic-fin origin 17.1% SL, at anal-fin origin 14.3% SL, width at pectoral-fin origin 18.0% SL. Preanal length 58.1% SL, predorsal length 36.9% SL and prepelvic length 29.0% SL. Head length 29.0% SL, head depressed (its depth 75.6% width), head width 20.7% SL, head depth 15.7% SL. Snout with moderately sloping profile, rounded from lateral view, 7.4% SL. Anterior nostril tubular, long, extending anteriorly to upper lip, without flap at its tip. Posterior nostril tubular and short, not more than ½ length of anterior nostril. Eyes dorsolateral and small, eye diameter is 7.8% SL, 27.0% head length. Interorbital narrow. No tentacle above eye. Mouth terminal, oblique, and lower jaw slightly projecting. Upper jaw extending posteriorly below anterior margin of pupil. Rows of pointed teeth in both jaws, outer row largest. Tongue truncate. No mental frenum, surface smooth along midventral from lower lip backwards. Branchiostegal membranes fused to isthmus, gill openings restricted to pectoral-fin base. Lower limb of first gill arch joined to gill cover by membrane, first gill slit completely closed. No spines on preopercle. Caudal-peduncle depth 12.6% SL and caudal-peduncle length 16.1% SL.

Fins. First dorsal fin VI, second dorsal fin I,12; anal fin I,11; pectoral fins 14 (14/14), all rays branched, upper rays no more free at tips than other rays; branched caudal-fin rays 15, segmented 17; pelvic fins I,5, completely separate and without fraenum, 5th ray unbranched. Distance between first and second dorsal fin origins 18.4% SL; second dorsal-fin base (35.0% SL) and anal-fin base (30.4% SL) long. Spines of first dorsal fin not elongate or filamentous, fourth to sixth spine of first dorsal fin reaching to origin of second dorsal fin when folded down; third spine of first dorsal fin longest, length 14.7% SL. Fin membrane from last spine of first dorsal fin not connected with second dorsal-spine base, small gap present. Origin of first dorsal fin behind vertical of pectoral-fin base. Origin of anal fin slightly posterior to vertical at origin of second dorsal fin i.e. opposite first segmented ray of second dorsal fin. Length of ninth segmented ray in second dorsal fin 13.8% SL, length of eighth segmented rays in anal fin 12.9% SL. Pectoral fins extending posteriorly below second dorsal fin and almost to a vertical of origin of anal fin, length 24.4% SL. Pelvic fins length 21.7% SL, pelvic fins ending slightly in front of anus, shorter than pectoral fins. Caudal fin rounded, slightly shorter than head, 96.8% head length, 28.1% SL.

FIGURE 1. Hetereleotris dorsovittata sp. nov. Holotype: SMF 35229, male, 21.7 mm SL, Farasan Island, Saudi Arabia, Red Sea. A: freshly collected specimen; B: preserved specimen. Photos by S.V. Bogorodsky (A), M. Kovačić (B).

Squamation. No scales. The holotype is covered with mucus and a superficial look could easily misidentify mucus granules for small cycloid scales. The stain confirmed lack of any scales on the body.

Cephalic sensory systems (Fig. 2). No head canals. Rows of head sensory papillae were counted on the left side except for the oculoscapular rows which were better visible on the right side, and therefore counted there and transferred on the drawing on the left side (Fig. 2). Rows of head sensory papillae reduced and additional individual larger papillae present on the position of absent head canals. Preorbital: snout with two median preorbital series, upper row r (4) at middorsal between eyes and posterior nostrils, and lower row s3 as three longitudinally arranged papillae above upper lip. Lateral series c in three parts: superior (c2) horizontal row between anterior and posterior nostril (4); inferior rows: upper horizontal c2 (4) and lower horizontal c1 (2) between upper lip and suborbital row 1. Suborbital rows: no row a. Row b (6) longitudinal, anteriorly beginning close to transversal row 4 and near vertical of posterior edge of eye. Four transverse suborbital rows (1-4) of sensory papillae, row 1 longer, reaching upper lip, row 2 short and distant from eye, ending ventrally close to row d, row 3 longer, spreading from eye to near row d, row 4 long, extended below level of row d (1: 10, 2: 5, 3: 9, 4: 22). Row d (7 + 8) is above upper lip, and on cheek, ending backwards below posterior part of eye and near transversal row c4. Preoperculo - mandibular rows: external row e (21 + 17) longitudinal and uniserial, divided into anterior and posterior sections; internal row i anteriorly with transversal proliferations, first three papillae tripled, fourth papilla doubled and remaining three papillae of anterior section single, posterior section longitudinal and uniserial (9); mental row f longitudinal (8). Oculoscapular rows: larger papillae longitudinally arranged on position of missing oculoscapular canal: one papilla anteriorly, one single and one transversally doubled papillae in middle and one papilla posteriorly; anterior upper longitudinal row x1 (5+2) short, looks divided; anterior lower transversal row z (5); transversal axillary rows as1 (4), as2 (3), as3 (4) present; other oculoscapular rows not visible. Opercular rows: one larger papilla in middle of position of missing preopercular canal; transverse row ot (15); superior longitudinal row os (7); and inferior longitudinal row oi (4). Anterior dorsal rows: single papilla behind eye on position of the missing anterior oculoscapular canal, row n as three transversally arranged papillae, row o absent, row g (4) longitudinal; row m absent; row h longitudinal, and short (5). Interorbital rows: two pairs of larger papillae present in interorbital, one anteriorly and one posteriorly.

FIGURE 2. Hetereleotris dorsovittata sp. nov. Cephalic sensory papillae: holotype, SMF 35229, male, 21.7 mm SL. Terminology in text. Drawing by M. Kovačić.

Colour. Immediately after death (Fig. 1A): semitransparent, to some degree dusky whitish, with upper part and sides of body and head mottled with dark greenish brown, most densely on predorsal area, with melanophores irregularly scattered without recognisable pattern on body. In addition to melanophores, tiny whitish and yellowish orange spots cover head and body. A small dark brown spot above pectoral-fin base. An internal series of three large, horizontally-elongated, black blotches along vertebral column are visible below second dorsal fin. Head mottled with greenish brown dorsally, densely on snout and nape and few round melanophores on cheek, with oblique dark brown bar from upper lip to pupil, continuing faintly on iris dorsoposteriorly, and oblique dark brown bar extending from eye ventroposteriorly, making 90° angle with anterior bar and ending on upper half of cheek. Red gills visible through thin gill cover. Eyes brown green, with black pupil. First dorsal fin more or less transparent basally on its half, with a broad black submarginal band and broad white upper margin, brown pigmentation somewhere extending basally onto some spines; second dorsal fin is more or less transparent with whitish dots, more densely along rays, and with longitudinal black submarginal band less intensive compared to the first dorsal fin, brown pigmentation somewhere extending basally onto rays. Anal fin mostly transparent except whitish distally. Caudal fin transparent with vertical dark brown bar at base and few melanophores in the anterior half of the fin. Pectoral fins transparent, with irregular brown mark at basal part of upper rays proceeding on the fin-lobe and with whitish pigment at lower basal part. Pelvic fins whitish.

In alcohol (Figs. 1B): body opaque and yellowish white with brown pigmentation on upper part of head and body. Upper and middle parts of head and body mottled, with melanophores irregularly scattered without recognisable pattern and no other pigments visible. Predorsal area more intensively pigmented, mottled with brown pigment. Head with irregularly scattered melanophores in upper part, oblique brown bar from upper lip to pupil less visible compared to oblique brown bar going backwards and down from eye, making 90° angle with anterior bar. Cheek and opercle with a few scattered melanophores in upper part. Eyes dark, including pupil. The dark longitudinal bands in upper half of dorsal fins still the most prominent coloration pattern on the preserved specimen. The rest of each dorsal fin transparent, except extension of brown pigmentation from skin surface onto fin lower parts. Anal fin transparent; caudal fin transparent with vertical dark brown band at caudal-rays base; pectoral fins transparent, with irregular brown mark over basal part of upper rays and fin-lobe; pelvic fins transparent.

Etymology. The species is named dorsovittata , a noun in apposition derived from the combination of the Latin nouns dorsum = back and vitta = band in reference to the distinctive longitudinal black submarginal bands on the first and second dorsal fins.

Habitat. The single specimen was collected in the large inner lagoon of main island of Farasan Archipelago, at the base of an isolated small coral patch, at a depth of 1m.

Remarks. The new species lacks one character noted in diagnosis of the genus Hetereleotris by Hoese (1986), the single-lobed mental frenum; however, Hoese (1986) has not added this character to the short descriptions of any of 13 species known at that time and in his revision of the genus Hetereleotris . Regarding three Hetereleotris species described after 1986: there is no mentioning of single-lobed mental frenum in the description of H. georgegilli ( Gill 1998) ; Shibukawa (2010) wrote in his description of H. exilis that mental frenum is weakly developed, forming a small bump just behind the lower-jaw symphysis; the mental frenum is also absent in H. psammophila ( Kovačić & Bogorodsky 2014) . Considering the lack of a well-developed single-lobed mental frenum in Hetereleotris species described in last thirty years and the lack of data on this character in the diagnosis and descriptions of the previously known 13 species, the single-lobed mental frenum should be excluded as a diagnostic character for the genus Hetereleotris .

Hetereleotris dorsovittata shares with four of 16 known species of the genus, a completely scaleless head and body: H. caminata ( Smith, 1958) , H. diademata (Rüppell, 1830) , H. psammophila , and H. vulgaris (Klunzinger, 1871) (Figs. 3A-C). It differs from H. caminata and H. vulgaris by the absence of head pores. Therefore, the new species is unique among the species of the genus Hetereleotris , except for H. diademata and H. psammophila , in the combination of absence of head canals and lack of squamation. Hetereleotris dorsovittata , with a low count of pectoral-fin rays (14), only overlaps in this character with H. psammophila (14 or 15) of the 16 known species of the genus Hetereleotris (pectoral-fin rays 15–18).

The most informative published data on morphology of H. diademata are descriptions in Smith (1958) based on the holotype, and in Hoese (1986) based on the holotype and additional material; these descriptions are, however, short and without characters that are significant among Hetereleotris species. The new species differs FIGURE 3. A. Hetereleotris diademata , PMR VP2479, female, 27.2 mm SL, Hurghada, Egypt, Red Sea. B. Hetereleotris vulgaris , PMR VP2478, female, 20.9 mm SL, Hurghada, Egypt, Red Sea. C. Hetereleotris psammophila , PMR VP3054, female, 26.9 mm SL, Dahab, Egypt, Red Sea. Photos by S.V. Bogorodsky.

from H. diademata in having fewer pectoral-fin rays and in their structure, in larger eyes, very long anterior nostrils, longer jaws, third dorsal-fin spine, and pelvic fin, and in coloration: pectoral-fin rays 14 in H. dorsovittata vs. pectoral-fin rays 15–17 in H. diademata ( Smith 1958; Hoese 1986; comparative material); all pectoral-fin rays branched in H. dorsovittata vs. lowermost and uppermost rays simple, remaining rays branched in H. diademata ( Smith 1958; comparative material); eye diameter 3.7 in head length in H. dorsovittata vs. eye diameter 4.2 in head length in H. diademata ( Smith 1958; comparative material); anterior nostril tubular and long, posterior nostril tubular and short, no more than half length of anterior nostril in H. dorsovittata vs. anterior nostril only slightly longer than posterior nostril in H. diademata ( Hoese 1986; comparative material with posterior nostril length fourfifths of length of anterior nostril); upper jaw extending posteriorly below anterior margin of pupil in H. dorsovittata vs. upper jaw extending below anterior margin of eye in H. diademata ( Smith 1958; comparative material); pelvic fins ending slightly in front of anus in H. dorsovittata vs. pelvic fins ending well before from anus in H. diademata ( Smith 1958; comparative material); length of third spine of first dorsal fin 14.7% SL in H. dorsovittata vs. 11.4–12.0% SL in H. diademata ( Smith 1958; comparative material); body and head with irregular brown mottling above midlateral in H. dorsovittata vs. intensively pigmented head, body, and fins, with broad vertical dark bars on body and the bar under the first dorsal fin darker than other bars in H. diademata (Fig. 13 in Smith 1958; Hoese 1986, comparative material); oblique dark brown bar extending ventroposteriorly from eye short, ending on upper half of cheek in H. dorsovittata vs. oblique, broad, dark brown bar extending ventroposteriorly from eye to the lower margin of opercle in H. diademata (Fig. 13 in Smith 1958; comparative material); anal fin transparent in H. dorsovittata vs. anal fin with a broad longitudinal black submarginal band similar to dorsal fins in H. diademata (comparative material) (Figs. 1 and 4).

The new species differs from H. psammophila in the higher count of soft rays in dorsal and anal fins, the papillae arrangement in preoperculo - mandibular row i and in coloration: second dorsal-fin rays I,12 and anal-fin rays I, 11 in H. dorsovittata vs. second dorsal-fin rays I,10 and anal-fin rays I, 9 in H. psammophila ; internal row i with transversal proliferations in anterior section: first three papillae tripled, fourth papilla doubled and the remaining three papillae of the anterior section single in H. dorsovittata vs. internal row i longitudinal and uniserial in H. psammophila ; body and head with irregular brown mottling above midlateral and dorsal fins with longitudinal dark submarginal bands in H. dorsovittata vs. H. psammophila transparent in life with a scattered tiny white and brownish orange spots on body and the dorsal fins mostly transparent, with scattered whitish and brown pigments basally and scattered melanophores along margin. Some morphometric values differ in the single specimen of H. dorsovittata from values of H. psammophila by 10% or more, so the specimen of H. dorsovittata has smaller eyes (eye diameter 7.8% SL in H. dorsovittata vs. 9.7–10.1% SL in H. psammophila ), head more depressed (head depth 75.6% head width in H. dorsovittata vs. 83.9–85.2% head width in H. psammophila , shorter caudal peduncle (caudal peduncle length 16.1% SL in H. dorsovittata vs. 19.4–20.4% SL in H. psammophila ), longer second dorsal-fin base (35.0% SL in H. dorsovittata vs. 28.7–29.4% SL in H. psammophila ), and anal-fin base (30.4% SL in H. dorsovittata vs. 22.7–23.9% SL in H. psammophila ), and shorter pelvic fin (21.7% SL in H. dorsovittata vs. 23.8–24.3% SL in H. psammophila ), compared to the types of H. psammophila ; however, to confirm the degree of morphometric differences between two species larger samples of both sexes from both species are needed.