Trimma quadrimaculatum, Hoese, Douglass F., Bogorodsky, Sergey V. & Mal, Ahmad O., 2015

Hoese, Douglass F., Bogorodsky, Sergey V. & Mal, Ahmad O., 2015, Description of a new species of Trimma (Perciformes: Gobiidae) from the Red Sea, with a discussion of the generic separation of Trimma and Priolepis, with discussion of sensory papillae terminology, Zootaxa 4027 (4), pp. 538-550 : 540-545

Trimma quadrimaculatum , n. sp.

Four-spotted Pygmygoby ( Figures 1 & 2 )

Material examined. All specimens collected from Saudi Arabia, Red Sea.

Holotype. SMF 35720, female, 16.7 mm SL, cave of steep slope, Obhur creek (Sharm Obhur), Jeddah, 21°42’31.00”N, 39°05’45.00”E, 14 m, 13 November 2014, S.V. Bogorodsky & T.J. Alpermann.

Paratypes. AMS I.46503–001, female, 16.0 mm SL, fringing reef with some small caves, 30 km south off Al Wajh, 26°03'30.36"N 36°38'34.98"E, 10–12 m, 14 June 2013, S.V. Bogorodsky & T.J. Alpermann; AMS I.46503– 0 0 2, male, 14.9 mm SL (cleared and stained), fringing reef with some small caves, 30 km south off Al Wajh, Saudi Arabia, 26°03'30.36"N, 36°38'34.98"E, 10–12 m, 14 June 2013, S.V. Bogorodsky & T.J. Alpermann; AMS I.46504–001, female, 14.3 mm SL (cleared and stained), coral wall with many caves in the bay at Diba (Duba), Saudi Arabia, 12–16 m, 27°20'44.22"N, 35°41'42.12"E, 21 June 2013, S.V. Bogorodsky; KAUMM 320, 3 females (16.2 mm SL, 15.9 mm SL and 16.2 mm SL), fringing reef with some small caves, 30 km south off Al Wajh, Saudi Arabia, 26°03'30.36"N, 36°38'34.98"E, 10–12 m, 14 June 2013, S.V. Bogorodsky & T.J. Alpermann; KAUMM 321, female, 16.8 mm SL, fringing reef with some small caves, 30 km south off Al Wajh, Saudi Arabia, 25°37'01.80”N, 36°53'17.20”E, 10 m, 16 June 2013, S.V. Bogorodsky & T. J. Alpermann; KAUMM 322, female, 15.6 mm SL, cave of steep slope, Obhur creek (Sharm Obhur), Jeddah, Saudi Arabia, 21°42’31.00”N, 39°05’45.00”E, 15 m, 0 3 July 2013, S.V. Bogorodsky; SMF 35530, female, 16.0 mm SL, bay with reef wall with many small caves, 60 km south of Diba (Duba), Saudi Arabia, 26°57'47.00''N, 35°57'59.20''E, 10 m, 20 June 2013, S.V. Bogorodsky; SMF 35531, male, 15.9, mm SL, bay with reef wall with many small caves, 60 km south of Diba (Duba), Saudi Arabia, 26°57'47.00''N, 35°57'59.20''E, 10 m, 20 June 2013, S.V. Bogorodsky; SMF 35532, 3 females (14.9 mm SL, 15.1 mm SL and 16.1 mm SL), 1 male (16.1 mm SL), fringing reef with some small caves, 30 km south off Al Wajh, Saudi Arabia, 26°03'30.36"N, 36°38'34.98"E, 10–12 m, 14 June 2013, S.V. Bogorodsky & T.J. Alpermann; SMF 35533, male, 15.9 mm SL taken with KAUMM 321.

Diagnosis. Dorsal-fin rays VI + I,8; anal-fin rays I,7; pectoral-fin rays 15–17, most rays unbranched; longitudinal scale series 23–25; transverse scale series counted forward 7; median predorsal scales 6–8 (usually 7 or 8), scales reaching to just behind eye. Eyes slightly elevated resulting in a shallow pit in interorbital area and a shallow groove along dorsoposterior margin of eye. Pectoral-fin base covered with two large cycloid scales (and 1 or 2 smaller scales). Prepelvic area covered with about 3–6 rows of cycloid scales. Reduced transverse pattern of sensory papilla rows on cheek ( Fig. 2 ). Nape with one or two modified elongate papillae behind each eye. Pelvic fins connected to form a plate, no interspinal membrane, fifth ray with 2 dichotomous branches. Head and body with broad, irregular, brown bars, last bar posteriorly on caudal peduncle extending basally onto rays of caudal fin; head with three dark brown bars below eye; basal quarter of second and third membranes of first dorsal fin with diffuse dark blotch; two subcutaneous dark brown spots along anal-fin base, and two similar spots ventrally on caudal peduncle behind rear base of anal fin.

Description. Based on 16 specimens (14.3–16.8 mm SL). First dorsal VI* (in 16); second dorsal fin-rays I,8* (16); anal-fin rays I,7* (16); pectoral-fin rays 15 (1), 16* (10), 17 (4), most rays unbranched; segmented caudal-fin rays 9/8* (16); branched caudal-fin rays 7/6 (4), 6/6* (12); midline predorsal scales 6 (1), 7* (5), 8 (9); longitudinal scale series 23 (2), 24 (8), 25* (6); transverse scale series TRF 7* (16), TRB 6* (12), 7 (4); pterygiophore formula 3(22110) (in 2); vertebrae 10+17 (2).

Head more or less rounded in cross section, head depth subequal to width at posterior preopercular margin, length 34.1% SL in holotype (range 29.6–39.2% SL). Cheeks only slightly bulbous. Head width at posterior preopercular margin 19.2 (18.8–21.9% SL). Depth at posterior preopercular margin 20.4 (19.5–22.0% SL). Postorbital length subequal to distance from tip of snout to posterior middle of eye. Snout slightly convex in side view, rounded in dorsal view, slightly over half of eye diameter (0.55–0.59 of eye diameter). Mouth oblique, with lower jaw protruding slightly beyond tip of upper jaw, with jaws forming an angle of 42–50º with body axis. Posterior end of jaws just below a point between behind mid-eye to posterior quarter of pupil; anterior margin of jaws in line with a point just below pupil; upper jaw length 15.6 (15.4–18.1% SL). Interorbital very narrow, with eyes almost touching. Suborbital region between eye and upper lip narrow, about one-third to one-quarter eye diameter. Eye diameter 11.4 (10.7–12.2% SL). Mental frenum indistinct, not elevated and no lobes. Anterior nostril at end of short tube about one nostril diameter above upper lip. Posterior nostril at end of elevated rim just before and not in contact with anterior margin of eye, about 1–2 nostril diameters from anterior nostril. Gill opening broad, extending forward to below a point just before posterior margin of pupil. Gill rakers on outer face of first arch slender and very long; rakers at angle longer than filaments, rakers running full length of arch, inner margin of rakers smooth, without odontids; rakers on inner face of first arch and rakers on other arches short and denticulate. Tongue tip with shallow notch at anterior margin. Body compressed, tapering posteriorly. Urogenital papilla of male elongate; rounded with free lobe on each side in female.

Dentition. Teeth conical and slightly curved. Teeth in outer row of upper jaw wide-set and slightly enlarged, reaching to near posterior end of premaxilla; 1–2 inner rows of small teeth tapering laterally to 1 row; an innermost row of slightly enlarged inwardly directed teeth. Teeth in outer row of lower jaw wide-set, confined to anterior half of dentary; an inner row of small teeth becoming larger anteriorly at side of dentary, followed posteriorly with a row of very small conical teeth.

Fins. Dorsal-, anal- and pelvic-fin segmented rays branched, except first segmented ray in second dorsal fin unbranched in some specimens. First dorsal fin origin above a point behind pelvic-fin insertion; first dorsal fin low and rounded, without filamentous spines; fourth and fifth dorsal-fin spines extending beyond others when fin adpressed. Pectoral fins reaching to above a point between origin of anal fin to third segmented anal-fin ray, length 26.3 (25.9–30.8% SL). Inner rays of two pelvic fins connected by thin membrane to tips of fifth pelvic rays, without interspinal membrane; pelvic fins reach to a point below and between anus and third segmented anal-fin ray, origin below a point just before lower pectoral-fin insertion, length 29.3 (25.5–31.5% SL); fifth pelvic ray with 4 terminal tips, two branches dichotomous, length about 70–90% length of fourth pelvic ray. Caudal fin with rounded margin, about 25.1 (23.6–29.4% SL).

Squamation. Body scales ctenoid, except for cycloid scales on midline of belly, pectoral-fin base and prepelvic area, and a few scales of nape. Predorsal scales small, arranged in 6–8 (usually 7 or 8) irregular median rows, scales largely ctenoid, except for one or two scales on midline cycloid, scales reaching forward to above posterior margin of eye, apparently no scale in predorsal region between posterior half of eyes, no naked patch immediately before first dorsal fin. Belly completely scaled. Pectoral-fin base with two large cycloid scales arranged vertically, in some specimens with a smaller third upper scale (holotype) or one or two very small scales before or behind large scales. Prepelvic area fully covered with small cycloid scales in 3–6 rows, with a single scale between pelvic spines. Cheek and operculum without scales. Base of caudal fin with 2–3 rows of small ctenoid scales.

Head papilla pattern ( Fig. 2 ). Reduced transverse pattern of sensory papilla rows. Three LL papillae in line on each side medial to nostrils; interorbital region with pair of papillae at level of anterior margin of pupil and a second pair at level just behind posterior margin of pupil; two supraorbital papillae along dorsoposterior margin of eye with axis of papillae along margin of eye (all interorbital and postorbital papilla = row p of Winterbottom (2011), posterior papilla flap-like and slightly prolonged in some preserved specimens. A modified elongate papilla behind dorsoposterior margin of eye, just behind posterior supraorbital papilla, prolonged in some specimens into a short slender flap; base of papilla elongate parallel to axis of body (TT) (not shown in Winterbottom 2011). Three papillae on each side of nape irregularly arranged (LT1) or forming a horizontal line slightly diverging from line on opposite side of nape (rows g and o of Winterbottom); anterior-most (probably papilla o) flap-like and elongate in some specimens, with height about 3–4 times width at base, but typically smaller than post orbital papilla (TT). Rows r and cs (on snout) of Winterbottom (2011) not observed in any of the specimens. Side of head with four VT papillae below eye, one below front of pupil and one below middle of pupil, one behind middle of pupil, one along posteroventral margin of eye (collective as row a in Winterbottom (2011) or two papillae below pupil possibly row c). A single line of VT papillae forming an oblique row with 3 papillae probably representing vertical line 5 in Winterbottom (2011, Fig. 2 B), but with upper labelled as a and lower as cp in Winterbottom (2011, Fig. 2 A). An upper LTU line (row b) extending from VT row to near end of preoperculum. A short lower LTB line (row d) extending from near posterior end of jaws to below a point under posterior end of eye. A single papilla at posteroventral margin of eye. Lower LT line on operculum (row oi) not seen in any specimens. Inner (ia and ip) and outer (ea and ep) preopercular mandibular papillae lines with a gap behind posterior margin of jaws, a common feature in Priolepis and Trimma . A single row of papillae on each side of chin converging posteriorly forming a V, but not meeting (row f in Winterbottom 2011). Other papillae are shown in Fig. 2 .

Live coloration, based on holotype SMF 35720, female, 16.7 mm SL and SMF 35532, female 15.1 mm SL ( Figs. 1 A & B). Head and body with alternating bands or mottling of dark brown and white forming bars and blotches; a very dark brown oblique bar, less than pupil diameter in width, becoming broader ventrally, extending from ventral margin of eye to posterior end of jaw; second dark brown bar of similar width extending from posteroventral margin of eye to over middle of preoperculum followed by a broader white, diffuse in some specimens, slightly oblique bar from posterior end of eye extending ventrally to ventral side of preoperculum; white areas on head suffused with minute dark brown spots; a series of more or less vertical alternating white and dark brown bars on body, often partly constricted, giving bars an irregular shape; first oblique white bar extending from below first dorsal-fin origin, second below posterior end of first dorsal fin, third below middle of second dorsal fin, fourth just behind second dorsal fin and fifth near posterior end of caudal peduncle, followed posteriorly by large brown vertical bar extending onto base of caudal fin; a series of four subcutaneous dark brown spots ventrally, first just above anal-fin origin, second above rear anal-fin base, third on caudal peduncle a short distance posterior to rear anal-fin base; fourth small subcutaneous spot ventrally on caudal peduncle obscured by brown peduncular bar; dark body coloration extending onto base of first dorsal fin anteriorly, forming basal blotch between second and third membranes, with white to clear spot on lower anterior margin of fin, similar markings on anterior base of second dorsal fin; body pigment also extending onto base of second dorsal fin near posterior end of fin; scattered melanophores forming two irregular oblique lines on second dorsal fin; anal fin with pigment similar to body pigment forming basal spot on anterior and posterior part of fin; basal half of anal fin with scattered melanophores giving fin a dusky to brown appearance; pectoral and pelvic fins largely clear to white; pectoral-fin base with two dark brown spots (slightly less than pupil diameter); caudal fin translucent with very thin wavy brown bands becoming obscure posteriorly (faint in holotype).

Coloration of freshly collected material, based on photo of paratype SMF 35530 ( Fig. 1 C). Head and body with alternating white and brown bars and blotches; a white oblique bar, less than pupil diameter in width, extending from anteroventral margin of eye to about middle of jaw, followed by a dark brown bar from ventral margin of eye to posterior end of jaws; second white bar of similar width extending from posteroventral margin of eye to just behind posterior end of jaws, followed by dark brown bar; a broader white, diffuse, oblique bar from posterior end of eye extending ventrally to ventral side of preoperculum and operculum; a series of more or less vertical white irregular bands on body interspersed between dark brown bars, first oblique white bar thin, extending below from first dorsal-fin origin; second white bar a small spot below second dorsal-fin origin or a bar interrupted by brown, with ventral portion displaced forward, third below middle of second dorsal fin, fourth beginning dorsally as a white spot fading to a faint band just behind second dorsal fin and fifth a vertical band near posterior end of caudal peduncle, followed posteriorly by distinct brown vertical bar extending onto base of caudal fin; a series of subcutaneous dark brown spots ventrally, first just above anal-fin origin, second above rear anal-fin base, third on caudal peduncle a short distance posterior to rear anal-fin base; fourth small subcutaneous spot ventrally on caudal peduncle obscured by brown peduncular bar, with a faint small fifth spot at base of caudal fin; dark body coloration extending onto base of first dorsal fin anteriorly, with white to clear spot on lower anterior margin of fin and similar white spot at base of middle of fin; similar markings on anterior and middle base of second dorsal fin, body pigment also extending onto base of second dorsal fin near posterior end of fin; second dorsal fin dark gray to brown, with scattered melanophores forming two irregular oblique lines; anal fin dark gray or brown; pectoral and pelvic fins largely clear, with scattered brown pigment; pectoral-fin base with two dark brown spots (slightly less than pupil diameter); caudal fin dusky with very thin, faint, wavy brown bands becoming obscure posteriorly.

Coloration of preserved material. Overall marking similar to fresh coloration; subcutaneous spots ventrally on body more distinct and overall coloration generally lighter than in fresh material. Contrast between dark marks and lighter mottling less prominent, fin coloration dusky to translucent.

Osteology. No mesopterygoid. Branchiostegal rays 5. Caudal fin usually with 9 dorsal and 8 lower segmented rays, uppermost articulating with epural, second with hypural 5; 7 segmented rays articulating with upper hypural plate, 6 segmented rays articulating with lower hypural plate, 1 segmented caudal ray articulating with parhypural and lowermost articulating with haemal arch of penultimate vertebra. Haemal arch of first caudal vertebra fused below centrum (Type B of Winterbottom & Zur 2007). Dorsal and ventral postcleithra absent. Lower hypural plate with articulation joint connecting to urostyle but not fused with urostyle or upper hypural plate. Urohyal slender and elongate without transverse shelf on ventral margin. Basihyal spatulate. Scapula partly ossified dorsally, cartilaginous ventrally with distinct foramen. One epural. Interneural gap (interneural space without pterygiophore) between 2 dorsal fins, pterygiophores formula 3(22110). Two pterygiophores precede first haemal spine. Frontal very narrow between orbits. Preoperculum widely separate from symplectic, with thin, largely cartilaginous process connecting to upper end of symplectic. Inner preoperculum with ossified process extending dorsally and articulating with posterior wing of hyomandibular. Symplectic slender. Metapterygoid very broad, not overlapping quadrate.

Distribution and habitat. Trimma quadrimaculatum is known from the northern to central Red Sea along coast of Saudi Arabia, from Al Wajh bank to Obhur creek, Jeddah. It is typically found in small groups in small caves in the reef wall of fringing reefs in seaward reefs and bays at a depth range of 10– 16 m.

Etymology. From the Latin quadrus = four fold + maculatus = spotted referring to the four prominent subcutaneous spots above anal fin and ventral caudal peduncle.

Remarks. Trimma quadrimaculatum differs from other species of the genus in details of the color pattern, such as the presence of alternating white and dark bars on the body, three dark brown bars below the eye, and the presence of four subcutaneous dark brown spots along the anal-fin base and ventrally on the caudal peduncle. In addition, T. quadrimaculatum differs from Red Sea congeners T. avidori , T. barralli , T. filamentosus , T. sheppardi , T. taylori , and T. tevegae in the low count of soft rays in second dorsal and anal fins (8 and 7 versus 9–10 and 8–10 respectively). It differs from T. fishelsoni in the low count of longitudinal scales series and predorsal scales (23–25 and 6–8 versus 26–28 and 11–14 respectively), and no elongate spine in first dorsal fin versus second dorsal-fin spine elongate and filamentous in both sexes in T. fishelsoni . The new species is similar to T. mendelssohni (Fig. 3A) in that both possess a of pair of modified elongate papillae on the nape, each behind postorbital groove, and dark bars below eye. The new species differs from that species in having fewer dorsal- and anal-fin soft rays (8 and 7, versus usually 9 and usually 8 respectively); spine in the first dorsal fin not elongate (versus second dorsal-fin spine slightly prolonged in both sexes); the posterior nostril is well before eye (versus posterior nostril on anterior edge of orbit); in lacking a deep trench between the eyes (versus a deep longitudinal groove in interorbital that bifurcates posteriorly to a Y-shape, one branch around rear of each orbit); no scales on operculum (versus operculum with several scales) and in having broad brown bars on the body (versus six narrow white bars dorsally on the body).

Trimma quadrimaculatum is also similar morphologically to T. flavicaudatum (Fig. 3B), a species restricted to the Red Sea and Gulf of Aden. The two species share low counts for the rays in the second dorsal, anal, and pectoral fins, the scales in longitudinal series, and predorsal scales, 3–4 large scales on the pectoral fin base and no elongate dorsal-fin spines. That species differ considerably in coloration, with Trimma flavicaudatum having a light caudal peduncle with no ventral spots along the anal fin and caudal peduncle. In addition to the distinct coloration, the new species differs in having of pair of elongate papillae on the nape (versus no elongate papillae); a narrower interorbital space which is less than 50% pupil diameter (versus about 50–70% pupil diameter); and a fifth pelvic-fin rays with two dichotomous branches (versus fifth pelvic-fin ray branched once dichotomously). The nine examined specimens of Trimma flavicaudatum also differ in having anal rays of I,8 (versus I,7) and 5 or 6 predorsal scales (versus 6–8). Winterbottom (1995) reported an anal-fin ray count of I,7–8 for Trimma flavicaudatum , but all specimens we examined have I,8 and Goren (1982) reported I, 8 in the type specimens. The pectoral-fin ray count is 15 in specimens of Trimma flavicaudatum examined, while the count is usually 16 in T. quadrimaculatum , but too few specimens have been examined to determine if the difference is significant.

Trimma quadrimaculatum is more similar in coloration to Priolepis than to Trimma , especially Priolepis randalli (Fig. 3C), known from the Gulf of Aqaba, southern Oman, and the Arabian Gulf, as both have dark broad bars on the body, dark bars below the lower margin of the eye, a somewhat round black mark at the base of the first dorsal fin, and dark spot on the upper base of pectoral fin (also in Trimma mendelssohni ); Trimma quadrimaculatum differs in having four subcutaneous dark brown spots ventrally on the posterior body, two above the anal-fin base and one posterior to the rear of the anal-fin base and on the caudal peduncle (versus no spots ventrally on body); dark brown bar posteriorly on the caudal peduncle extending on to the base of the caudal-fin rays (versus no bars at caudal-fin base); low counts of segmented rays in the second dorsal and anal fins 8 and 7 (versus 9 and 8 respectively); the low counts of the longitudinal scales series and the predorsal scales 23–25 and 6– 8 (versus 25–28 and 14–16 respectively); and no scales on head (versus cycloid scales dorsally on the operculum). Trimma quadrimaculatum also shows considerable similarity to the group of Priolepis , reviewed by Winterbottom & Burridge (1993) which have a reduced transverse papilla pattern and predorsal scales. The new species differs from all species in that group in having a second dorsal count of I,8 (versus I,9–12). Priolepis inhaca ( Smith, 1949) and P. limbatosquamis ( Gosline, 1959) have a dorsal-fin ray count of I,9, while other species in the group usually have I,10–12. The pectoral-fin ray counts of 15–17 in T. quadrimaculatum is also similar to that of P. inhaca (versus usually 18–22 in the other species). It differs from P. i n ha c a in having fewer predorsal scales and broader bands on the head (6–8 versus 12–17 predorsal scales in adult P. inhaca , but such scales often absent in juveniles). It also possibly differs in having papilla row z continuous with row ot on the operculum versus, not meeting.

Figures

FIGURE 1. Trimma quadrimaculatum, n. sp. A. live coloration of holotype SMF 35720, female, 16.7 mm SL; B. live paratype SMF 35532, female, 15.1 mm SL; C. Freshly collected paratype SMF 35530, 16 mm SL. Photos by S. V. Bogorodsky.

FIGURE 2. Sensory papillae in Trimma quadrimaculatum, n. sp., composite based on holotype and several paratypes. A. Top view; B. Side view.