Oxyurichthys omanensis, Zarei & Al Jufaili & Esmaeili, 2022

Zarei, Fatah, Al Jufaili, Saud M. & Esmaeili, Hamid Reza, 2022, Oxyurichthys omanensis sp. nov., a new Eyebrow Goby (Teleostei: Gobiidae) from Oman, Zootaxa 5182 (4), pp. 361-376 : 365-371

Oxyurichthys omanensis sp. nov.

English name: Oman’s Eyebrow Goby

( Figs. 2–5 , Table 3 )

Holotype. ZM-CBSU S105-19, male, 58.9 + 30.7 mm; Oman: Muscat: Yeti (Yiti) mudflat/estuary at Yeti village, 23°31’52”N 58°39’51”E; H. R. Esmaeili, S.M. Al-Jufaili, and A.H. Masoumi, 14 March 2022.

Paratypes. ZM-CBSU S105, 9 males, 2 females, 44.7 + 21.6–63.2 + 28.0 mm; the collecting data same as holotype .

Additional material. ZM-CBSU S105, 22 specimens, Oman: the collecting data same as holotype .

Material used in the mitochondrial COI analysis. Molecular IDs: 3561, 3567, 3599, 3600, 4 specimens (all from additional material, ZM-CBSU S105), Oman: the collecting data same as holotype (GenBank accession numbers: OP006725 – OP006728 ) .

Diagnosis. Oxyurichthys omanensis sp. nov. is diagnosed among all currently recognised congeners by the following combination of character states: elongate tentacle on dorsoposterior surface of the eye; nape with welldeveloped membranous crest; nape scaled to above anterior half of opercle along sides with naked median along membranous crest, scales never reaching to above preopercle; opercle and pectoral base naked; scales ctenoid laterally on trunk posterior to base of second dorsal fin 3rd element; lateral scale rows 51–58, usually 51–56; transverse forward scale rows 23–29, usually 24–28; transverse rearward scale rows 14–16, usually 14–15; upper lip usually constricted at premaxillary symphysis; infraorbital transverse papillae row 2 reaching eye margin dorsally and markedly short of longitudinal row d ventrally; additional short transverse papillae rows between rows 2 and 3i present; dark saddle present over caudal peduncle; snout length 34.9–45.4% HL; second dorsal-fin longest ray 1.1–1.6 head depth; pelvic fin always reaching or passing anal-fin origin.

Description. All morphometric values in the text are presented as holotype first and paratypes, if different, in parentheses.

General morphology ( Figs. 2–5 ). Body proportions in Table 3 . Body moderately elongate, its depth at pelvicfin origin 5.1 (4.2–5.7) in SL, at anal-fin origin 5.4 (4.3–5.8) in SL, laterally compressed posteriorly, with caudal peduncle deep, caudal-peduncle depth 1.0 (0.8–1.0) of caudal-peduncle length. Head large, length 3.9 (3.2–3.9) in SL, width 5.3 (4.6–5.9) in SL, its depth 5.7 (4.5–5.7) in SL and 0.9 (0.9–1.1) of width. Postorbital profile almost horizontal. Snout short and rounded, oblique, convex, longer than eye, its length 1.4 (1.4–1.9) of eye diameter, 2.7 (2.2–2.9) in head length.Anterior naris tubular, short, placed close to upper lip, rim with no processes; posterior naris an oval open pit, midway between eye and anterior naris. Eyes lateral, high on head, extending above dorsal profile, eye diameter 3.8 (3.8–4.3) in head length. Elongate tentacle on dorsoposterior eye. Well-developed membranous crest on nape. Interorbital narrow, 2.4 (2.2–2.9) in eye diameter. Mouth directed obliquely upwards, forming an angle of about 45° with body axis. Jaws reach to vertical through mid-orbit. Upper lip in ~70 % of material examined variably constricted at premaxillary symphysis, 1/2–1/4 of greatest lip width ( Fig. 5 ); not constricted in other specimens. Upper jaw teeth in single row, about 20 on each side of symphysis; small gap at symphysis. Lower jaw teeth in two rows, about 25–30 in outer row each side of mandibular symphysis, innermost row with about 12–13 strong recurved canines on each mandible. Strong canine teeth in upper jaw, about twice size of lower jaw teeth in outer row. Branchiostegal membranes fused to isthmus along the entire lateral margin of isthmus, gill opening limited to pectoral fin base.

Fins. D1 VI; D2 I/12; A I/12–I/13 (holotype I/13; paratypes: I/12:1, I/13:10); P 21–22 (holotype, left side: 21; paratypes, left side: 21:10, 22:1); V I/5+5/I; CSR 8/9; CBR 7/8. Morphometric characters are given in Table 3 . First dorsal fin with filamentous spines, first spine longest, spines decreasing in size backwards to sixth spine. First spine 1.1 (0.8–1.2) of head length, reaching just beyond third to fifth second dorsal-fin element when appressed. Second dorsal-fin and anal-fin rays moderately long, anal fin slightly lower, posteriormost rays in both longest, longer than head depth, 1.1–1.6 of head depth, reaching past caudal-fin base when appressed. Interdorsal space between D1 VI and D2 I narrow, completely covered with interdorsal membrane. Anal-fin originates below D2 I. Pectoral fin oval, central rays longest, extending to vertical between fourth and fifth anal-fin elements, 0.3 (0.3–0.4) of SL. Pelvic disc complete, oval, originates markedly anterior of vertical through D1 origin, always reaching or slightly passes analfin origin, 1.09 (1.05–1.23) of abdomen length; rear edge of pelvic fin anterior membrane (frenum) villose. Caudal fin elongate, pointed, longer than head length, 2.0 (1.4–2.0) of HL.

TABLE 3. (Continued)

Squamation. Nape scaled with small cycloid scales along sides with naked median along membranous crest backwards to D1 base; scales terminate above anterior half of opercle, never reaching above preopercle. Opercle, cheek and pectoral base naked. Abdomen scaled with cycloid scales. Ctenoid scales on side of body behind a line connecting base of third D2 element to anal-fin origin, becoming cycloid and smaller anteriorly. Scales on entire caudal peduncle enlarged. LL 51–58 (holotype, left side: 51; paratypes, left side: 51:2, 52:3, 54:1, 55:2, 56:2, 58:1), TFR 23–29 (holotype, left side: 24; paratypes, left side: 23:1, 24:2, 25:2, 26:3, 28:2, 29:1), TRB 14–16 (holotype, left side: 14; paratypes, left side: 14:5, 15:5, 16:1), PD 10–16 (holotype 11; paratypes: 10:1, 11:3, 12:5, 15:1, 16:1).

Lateral line system ( Fig. 6 ). Cephalic canals. Anterior oculoscapular canal present, carrying 11 pores: a pair of anterior nasal pores A’, a pair of posterior nasal pores B, a pair of interorbital pores C, single interorbital pore D, and paired F and H’. Posterior oculoscapular and preopercular canals and pores absent. Head sensory papillae. Preorbital: median series in four rows: row r as long oblique row opposite posterior nostril; midline of snout anterior of pore C free of neuromasts; row s 1 as short oblique row medial to posterior nostril; row s 2 as transverse row posterior to pore A’; row s 3 above upper lip, anterior to row s 2 and medial to pore A’; lateral series in three rows: row c 2 as two oblique rows between anterior and posterior nostrils, with lower row much longer than upper; rows c 1 and c 2 as long joint transversal row c 1 + c 2 starting lateral of anterior nostril on c 1 position, curving down in middle and going posterior to suborbital row 1 on c 2 position; row c 1 as short oblique row, ventral of posterior c 1 + c 2 and posteriorly close to suborbital row 1. Suborbital: five transverse rows (1–5) and two longitudinal rows (b, d) on cheek, rows 1–2 before longitudinal row b, long, dorsally starting close to eye, row 1 ventrally extending to level of row d, row 2 ventrally not reaching row d; rows 1 and 2 above and anterior to rear edge of jaws; rows 3 and 4 divided by row b in short superior (3s, 4s) and longer inferior (3i, 4i) sections; row 3i slightly behind jaws angle, starting close above longitudinal row d and ending close below longitudinal row b, row 4i ventrally extending to level of row d, ending slightly below level of row b; rows 3i and 4i almost confluent with each other. Small additional rows (1–4 rows) made of 1–4 neuromasts, always anteriorly shorter, posteriorly longer, situated below row b between rows 2 and 3i. Also a short transverse row between rows 3i and 4i present in all specimens. Sometimes, small additional rows (1–2 rows) made of 2–3 neuromasts between rows 3i and short transverse row anterior to row 4i present. Row 5 only as upper row 5s, short (2–3 neuromasts), immediately anterior of pore F; row b long, anteriorly reaching row 2 and to below anterior end of pupil, and posteriorly reaching edge of preopercle and row i 2; row d long, reaching row e 2 posteriorly, anteriorly reaching ventral end of row 1. Preoperculo-mandibular: three rows, e, i and f; external row e divided at articulation of lower jaws in anterior mandibular (e 1) and posterior preopercular (e 2) sections; anterior and posterior sections of internal row i (i 1, i 2) discontinuous, their separation at articulation of lower jaws distinct; both usually without additional papillae (i.e., without doubled parts of row) and row i 1 continuous with symphyseal row f. Oculoscapular: five main transverse rows (z, trp, y, as 1 and as 2) and three longitudinal rows (x 1, x 2, la 1); row x 1 long, extending from behind eye to posterior third of opercle; row x 2 above posterior half of opercle, behind row x 1, anteriorly overlapping above posterior part of row x 1; row z dorsally reaching close to pore H’; row trp long and posterior to pore H’, extending ventrally slightly below upper edge of opercle and dorsally to horizontal level of midpoint between pores F and D; row y short and immediately behind x 2; row u proliferated in 10–13 short vertical rows above upper edge of opercle; transversal axillary rows as 1 and as 2 long, small additional rows between rows as 1 and as 2 and behind row as 2 present; longitudinal axillary series represented by one long row (la 1) extending from row as 1 anteriorly to above row as 2 posteriorly. Opercular: three rows, one transverse row (ot), and two longitudinal rows (os, oi) rows; row oi reaching row ot anteriorly, row os short of row ot anteriorly, both backwards extend to opercular posterior edge. Anterior-dorsal (occipital): three rows, one transverse row (n) and two longitudinal rows (g, m); row n behind eye and long; row g posterior and lateral of row n, passing it anteriorly; row m parallel and below to row g, reaching row n anteriorly.

Colouration ( Figs. 2–5 ). No distinct sexual dichromatism evident on specimens.

Colour in life: head and body soft yellowish grey, ventral side of head and breast whitish to pinkish white. Nape with brown to greyish brown crescent behind each eye; crescents may meet in dorsal midline (before crest); some specimens with pale area before and after dark crescent. Orbital tentacle coppery orange, darker at tip. Nape crest grey to bluish white with distinct narrow black margin. Five large brown saddles on back below the dorsal fins and over caudal peduncle, posteriormost over caudal peduncle darkest. Row of five or six elongated brown blotches along midline, anteriormost blotches beneath pectoral fin larger, more vertical, irregular and more distinct; posteriormost mid-lateral blotch on caudal-fin base almost triangular and darkest of all blotches. Vertical bars on body of variable width, soft grey, starting at saddles and most of them passing through lateral blotches; vertical bars on anterior half of body slightly oblique, opaque to dark grey. “Comma-shaped” mark on pectoral-fin base dark brown, with bluish spot dorsally to it; pale area on centre of base appears bluish grey. Anterior narial tube with dense black spot medially, posterior naris with brownish rim. Rectangular “tear-shaped” mark along ventral edge of eye down and forward to upper lip, with pale opalescent line along anteroventral edge of blotch and sometimes bluish spot anterodorsal edge of blotch. Dorsal fins elements narrowly edged with golden; dorsal fins membranes translucent with dark brown spots and streaks. Anal fin dusky grey to pinkish grey anteriorly and dusky grey posteriorly with bright white distal margin. Caudal fin with ventral half dusky to grey, dorsal half with 6–9 rows of brownish to dark grey short streaks across fin, rows of whitish to transparent short streaks alternate with dark streaks, ventral edge whitish. Pectoral fin translucent dusky, with rows of blackish spots on ventral half; fin margin bright to bluish white. Pelvic disc whitish with dark grey on membrane by fin rays, fin margin bright white.

Colour in preservative: head and body yellowish to greyish brown, paler ventrally, with five or six diffuse oval brown blotches along midside of body; posteriormost blotch, on caudal-fin base, darkest and triangular, rounded in some specimens. Nape with brown to greyish brown crescent behind each eye before crest with pale area before and after dark crescent. Orbital tentacle dusky to greyish, darker at tip. Nape crest grey with distinct narrow black margin. Large grey brown saddles on back, posteriormost saddle over caudal peduncle darkest. Upper body with reticulate greyish brown pattern from scale margins narrowly outlined with grey brown, more prominent anteriorly. Eight to nine narrow greyish bars present on lateral body side posterior to anal-fin origin; bars confluent with midlateral blotches and dorsal saddles. Interorbital and snout greyish brown. Anterior narial tube with dense black spot medially, posterior naris with dusky to blackish rim. Opercle plain or mottled dusky to brownish. Oblique short and broad stripe, grey brown, continues from nape cresent, along ventral edge of eye goes down to upper lip. Upper lip grey to greyish brown. Lower lip grey. Isthmus and chin light brownish to greyish brown. Breast pale to dusky. Pectoral base with brown to blackish brown curved “comma-shaped” mark, curving from dorsal part of fin base along most of pectoral ray origins. Abdomen yellowish white to white; black peritoneum usually showing through body wall at midline. First dorsal fin greyish, with four or five wavy dark grey lines crossing fin; lines may break up into short streaks, especially posteriorly; leading edge of first spine plain greyish or with indistinct spot at commencement of each wavy line. Second dorsal fin greyish, with four to eight slightly oblique rows of oval blotches (proximal) and spots (distal). Caudal fin with ventral half grey, dorsal half with 6–9 rows of brownish to dark grey short streaks across fin, rows of whitish to transparent short streaks alternate with dark streaks. Anal fin plain grey to blackish. Pectoral fin greyish, usually with rows of diffuse dark grey spots crossing ventral half of fin. Pelvic disc greyish with dark grey to brown streaks along membrane beside each ray.

Sexual dimorphism. Urogenital papilla conical in males with pointed posterior edge, and wider and rounded in females.

Etymology. Named for Oman, where the species occurs.

English name. Oman’s Eyebrow Goby.

Distribution and habitat. Oxyurichthys omanensis is known only from its type locality, a shallow mudflat at Yeti, near the mouth of Wadi Aday ( Muscat Area, northern Oman), which drains into the Gulf of Oman ( Figs. 7– 8 ). Sympatric fish species were Favonigobius reichei (Bleeker, 1854) , Cryptocentroides arabicus (Gmelin, 1789) , Planiliza klunzingeri (Day, 1888) and Terapon jarbua (Forsskål, 1775) .

Figures

FIGURE 2. Oxyurichthys omanensis, ZM-CBSU S105-19, male, holotype, 58.92 mm SL, collected from Yeti, northern Oman.

FIGURE 3. Oxyurichthys omanensis, paratypes, A: ZM-CBSU S105-14, male, 63.25 mm SL, B: ZM-CBSU S105-10, male, 46.36 mm SL, collected from Yeti, northern Oman.

FIGURE 4. Live specimens of Oxyurichthys omanensis collected from Yeti, northern Oman. Upper) ZM-CBSU S105-1, 54.5 mm SL, male, paratype; lower) ZM-CBSU S105-3, 61.9 mm SL, male, paratype.

FIGURE 5. Head dorsal view of Oxyurichthys omanensis, showing the upper lip constriction at premaxillary symphysis. A) ZM-CBSU S105-2, stained; B) ZM-CBSU S105-4; C) ZM-CBSU S105-8; and D) ZM-CBSU S105-3, paratypes.

FIGURE 6. Head lateral line system (left side, composite drawing based on more than one specimen) of Oxyurichthys omanensis collected from Yeti, northern Oman. Terminology is given in the text.

FIGURE 7. Geographic distribution of Oxyurichthys omanensis (yellow circle: Yeti, northern Oman), O. cornutus and O. ophthalmonema [records from Froese & Pauly (2022), Pezold & Larson (2015), Isari et al. (2017), Chang et al. (2017), and Viswambharan et al. (2015)].

FIGURE 8. Habitat of Oxyurichthys omanensis, Yeti estuary, northern Oman.