Tomiyamichthys levisquama, Hoese & Shibukawa & Johnson, 2016

Hoese, Douglass F., Shibukawa, Kochi & Johnson, Jeffrey W., 2016, Description of a new species of Tomiyamichthys from Australia with a discussion of the generic name, Zootaxa 4079 (5) : -

Tomiyamichthys levisquama new species

Figs. 1–6 . Table 1

Material examined. Holotype. NTM S.17974-002, 42.9 mm SL male, Vestey’s Beach Reef, Darwin Harbour , Northern Territory, 31 October 2015, M. Hammer and party.

Paratypes. Northern Territory: NTM S.10423–001, 1(36), Mindil Beach mudflats, Darwin , 13 November 1981, R. Hanley ; NTM S.10429–034, 3(10–26), Channel Island, Darwin Harbour 24 May 1982, H. Larson & party ; NTM S.10718–047, 2(18–37), Creek at Pearl Rafts, East Arm , Darwin , 1.5 m, 31 December 1982, H. Larson & party ; NTM S.11506–016, 2(36–39), Gunn Point, Northeast of Shoal Bay , 0–0.5 m, 26 October 1984, H. Larson ; NTM S.14255–001, 1(19), Channel Island, Darwin Harbour 2 m, 7 July 1993, Marine Ecology Unit. Queensland: QM I.16708, 69 mm SL male, 1.5 miles NE of Mud Island, Moreton Bay, trawled, 23 February 1967, Zoology Department University of Queensland; QM I.17913, 65 mm SL, off Redcliffe, Moreton Bay, January 1978, W. Croft; QM I.29226, 62 mm SL male, Moreton Bay off Tangalooma , 27°12'S 153°22'E, 10 February 1993, T. Cribb; QM I.30165, 69 mm SL female, Moreton Bay east of Shorncliffe , 27°19'S 153°10'E, 20 October 1995; QM I.31282, 18 mm SL juvenile, Lower reaches of Daintree River , 16°17'S 145°26'E, 23 November 1995.

Diagnosis. Mental fraenum truncate, with straight posterior margin. Mouth large; reaching to point below posterior quarter of eye; jaws forming angle of 35–45° with body axis; upper margin of upper jaw in line with point just below eye. A distinct groove behind eye formed by elevated eyes and triangular projection of skin from nape. Cheeks slightly bulbous. Interorbital very narrow, less than pupil diameter. Gill opening reaching to below point just behind posterior preopercular margin. Head papillae in longitudinal pattern. Scales entirely cycloid. Predorsal area partly scaled, midline naked, or rarely with one scale before first dorsal fin, sides of nape scaled forward in an arch from first dorsal origin to above middle to anterior part of operculum. Cheek and operculum naked. Pectoral fin base naked; prepelvic area scaled, except for small area anteriorly, scales embedded and not easily seen. Belly covered with cycloid scales, except for small naked area just behind pelvic fin insertion. First dorsal fin low, with rounded to slightly pointed margin, third to fifth spines longest and not filamentous; spines 3–5 extending beyond other spines when fin depressed. First dorsal fin sometimes with a small black spot on membranes between distal tips of third and fourth spines ( Figs. 1 and 3 ). Pelvic disc with a median dark stripe ( Fig. 4 ). Body with three slightly oblique dark bands and rounded spot at end of caudal peduncle extending onto caudal fin. Second dorsal fin rays I,10; anal fin rays I,10; pectoral fin rays usually 18–19; longitudinal scale count 50–70; predorsal scale count 0–4; transverse scale count (TRB) 23–25.

Description. Based on 15 specimens (6 males, 4 females and 5 immature), 19–70 mm SL. Counts and proportions of holotype indicated by asterisk. Numbers after counts indicate the number of specimens with that count; numbers after proportions indicate range of proportions in other specimens. Data not taken on four smallest and damaged or dehydrated specimens.

First dorsal spines VI(11)*; second dorsal rays I,10(11)*; anal rays, I,10(11)*; pectoral rays; 17(2)*, 18(6), 19(3); longitudinal scale count Northern Territory 50(2), 54(2), 57(2)*; Queensland 65(1), 68(1)*, 70(1); midline predorsal scale count 0(7), 1(1), 3(2), 4(1); transverse scale count (TRB) Northern Territory 19(3), 20(1), 21(1)*, 22(1); Queensland 23(2), 24(2), 25(1); gill rakers on outer face of first arch 1+1+4(1), 2+5(1); segmented caudal rays 9/8(11)*; branched caudal rays 7/6(6), 7/7(2)*, 8/6(1); 8/7(1).

Head slightly compressed, 28.0 (in holotype)* (range 25.7–29.4)% SL. Head depth at preopercular margin 17.5* (15.5–17.5)% SL. Head width at preopercular margin 14.4* (14.2–15.8)% SL. Snout rounded in dorsal view; slightly convex in side view; 6.1* (5.3–7.1)% SL. Eye moderate and slightly elevated, with shallow groove behind, about equal to snout, 7.9* (7.3–8.1)% SL in specimens from 36–43 mm SL, 6.9–7.7% SL in specimens 62–70 mm SL. Anterior nostril at end of short tube, one-half to one nostril diameter above upper margin of upper lip. Posterior nostril a large pore about 2–3 nostril diameters behind anterior nostril, above and much closer to eye than upper lip. Preoperculum short, distance from end of eye to upper posterior preopercular margin subequal to distance from snout to middle of pupil. Postorbital short, subequal to distance from tip of snout to just behind eye. Body slender, depth at anal origin 17.9* (15.2–18.0)% SL. Upper jaw 12.4* (10.0–12.4)% SL. Teeth conical. Teeth in upper jaw: outer row of teeth curved, enlarged and wide-set, largest anterior to angle of jaw; four to five rows of smaller, depressible teeth anteriorly, tapering to two to three rows posteriorly; posteriormost rows pointing inward into mouth and slightly larger than teeth in other inner rows. Teeth in lower jaw: teeth in outer row slightly curved, enlarged, conical, wide-set, covering anterior end of dentary only, ending in single outwardly directed enlarged canine; four to five inner rows of smaller conical teeth anteriorly and two to three rows posteriorly. Tongue tip truncate to slightly rounded. Gill rakers on outer face of first arch slender, denticulate on posterior margin, rakers shorter than filament length and confined to posterior part of arch, anterior part connected by membrane to inner gill cover. Rakers on inner face of first arch and other arches short and denticulate at distal tip. Body covered with cycloid scales. Depressed first dorsal fin reaching to about second to fourth segmented ray of second dorsal fin in males and usually to before second dorsal to first segmented ray in females (first dorsal fin height 23.1% in holotype, 22.7–29.7% SL in other males and 18.5–21.7% SL in females), origin above a point well behind pelvic fin insertion. Second dorsal fin base 31.7* (26.3–32.3.0)% SL. Anal fin base 24.2* (23.3–26.5)% SL. Pectoral fin with rounded margin, reaching to beyond pelvic fin tip, to well before anus; length 21.4* (21.4–25.1)% SL. Pelvic disc small, reaching just beyond middle of abdomen, well before anus, pelvic length 17.5* (17.2–21.4)% SL. Caudal fin with acute posterior margin, central rays longest; length 28.4* (26.6–30.5)% SL.

Head pores. Posterior nasal pore just median and slightly above posterior nostril (B’); median anterior interorbital pore above front quarter of eye (C); median posterior interorbital pore just behind eyes (D); postorbital pore behind upper quarter of eye (E); infraorbital pore below and before postorbital pore (F), behind middle of eye; lateral canal pore above a point just behind middle of preoperculum (G); terminal lateral canal pore above posterior preopercular margin (H); a short tube or pores above middle of operculum (L’ & K’); two preopercular pores (M’ & O’), upper in line with lower quarter of eye.

Papillae. Head papilla pattern longitudinal ( Fig. 5 ). Cheek with a VT line from anterior margin of eye extending to middle of upper jaws and following upper lip margin and extending posteriorly onto cheek as an LT line (row d); an upper LL line (a) from below and just before middle of eye upward to infraorbital pore; second line an LT line (b) from below anterior pupil extending to posterior end of preoperculum; a third line (LT or c) extending from near end of jaws upward and posteriorly to near end of preoperculum, usually with a ventral branch posteriorly; inner preopercular mandibular row (e) with a gap behind jaws; inner preopercular mandibular row continuous onto chin; a transverse row of papillae (with axis of papillae along axis of row) along posterior margin of the mental frenum; top of head with short longitudinal row extending from near postorbital pore and a second medial line over preoperculum; no transverse line behind eye on top of head. Other papillae as shown in Fig. 5 ; some papillae not shown, due to condition of specimens examined.

Coloration in alcohol (based on Queensland specimens, Fig. 2 ). Head and body light brown. Head with a series of light bars and oblique oblong spots ( Fig. 6a ), bordered by dark brown pigment; first a broad bar from anterior margin of eye to anterior part of upper lip; second a thin bar extending from eye to upper lip; cheek and operculum with 3 lines of thin bars, typically broken into separate oblique spots. Upper lip white posteriorly continuous with white on lower surface of head; posterior tip of jaws with dark brown pigment. Top of head light brown, with 2–3 oblong darker spots just before first dorsal fin, first continuous with dark upward extension from operculum; ventral surface of head white, except for dark brown pigment anteriorly on lower lip. Body with 4 oblique bars; first bar faint and formed by a series of dark brown spots extending from the upper margin of the operculum to just before the first dorsal fin; second a prominent dark brown bar extending almost vertically from below posterior half of first dorsal fin onto sides of belly, sloping slightly forward ventrally; third bar very oblique, extending from just before middle of second dorsal fin ventrally to near anus and slightly overlapping anal fin origin; fourth bar very oblique, extending from posterior rays of second dorsal fin ventrally to before posterior rays of anal fin; bars sometimes intensifying on midside, forming an oval spot; bars much narrower than lighter interspaces. A large round dark brown to black spot subequal to eye size on midside at posterior end of caudal peduncle and extending onto base of caudal fin. First dorsal fin translucent with an oval black spot, smaller than pupil diameter between tips of third and fourth spine; second dorsal fin faded in most specimens, one specimen with faint brown spots; caudal fin translucent with grey pigment posteriorly, often more prominent ventrally; anal fin translucent with concentrated melanophores distally forming a faint band over approximately one third of fin; proximal base of upper pectoral-fin rays with a dark brown to black spot smaller than pupil diameter, with a stripe extending forward on to pectoral fin base. Pelvic membranes between spines forming black stripes in both sexes, three central stripes darkest, lateral and distal margins of fin white.

Specimens from the Northern Territory are faded, with little pigment, although the body coloration appears generally similar to that of specimens from Queensland. The black spot is continuous with black pigment extending forward over much of the first dorsal fin and the bands are narrower than those in specimens from Queensland. However the band widths vary considerably in Queensland specimens ( Fig. 2 ). The light bars are absent from the head in most specimens from the Northern Territory, but prominent in the holotype ( Fig. 6b ). One faded specimen from Queensland also lacks the bars.

Live and Fresh Coloration (based on holotype). Head and body light yellowish-brown in life, coming whitish shortly after preservation. Head with a series of yellow bars, edged with dark brown and oblique oblong spots, also edged with dark brown ( Fig. 1 ); first a broad dark brown bar from anterior margin of eye to anterior part of upper lip, without a dark margin; second a thin bar extending from eye to upper lip faint and merged with anterior dark bar; cheek and operculum with 3 lines of thin bars, broken into separate oblique spots on one side of head in holotype; a short faint fourth bar on operculum. Upper lip with yellow anteriorly and yellowish-white posteriorly (in freshly preserved holotype) continuous with white on lower jaw and lower surface of head; posterior tip of jaws with yellow and dark brown pigment. Top of head white to light brown, with scattered dark edged yellow spots; ventral surface of head white, except for grey to brown pigment anteriorly on lower lip. Body with 4 oblique bars; first bar faint with yellowish brown tint extending from the upper margin of the operculum to just before the first dorsal fin; second a prominent dark brown bar extending almost vertically from below posterior half of first dorsal fin onto sides of belly, sloping slightly forward ventrally, interrupted by white just above midside; third bar dark brown, very broad dorsally, very oblique, extending from just before middle of second dorsal fin ventrally to near anus and slightly overlapping anal fin origin; fourth bar very oblique, extending from posterior rays of second dorsal fin ventrally to before posterior rays of anal fin; bars much narrower than lighter interspaces. A large round dark brown to black spot slightly smaller than eye size on midside at posterior end of caudal peduncle and extending onto base of caudal fin. First dorsal fin a translucent grey with several small yellow spots ventrally; an oval black spot, much smaller than pupil diameter between tips of third and fourth spine. Second dorsal fin in life with a thin blue submarginal stripe and scattered blue and yellow pigment over much of fin, a series of small brown spots ventrally on fin in a horizontal line, blue pigment rapidly disappearing in preserved holotype; caudal fin yellowish blue, with yellow spots forming four wavy bands near dorsal base of fin, ventrally fin becoming grey; anal fin (not visible in live individual) pale near body with scattered yellow pigment, becoming dark grey distally. Proximal base of upper pectoral-fin rays with a dark brown to black spot smaller than pupil diameter, formed with melanophores over a background of yellow pigment; a yellow stripe bordered by dark pigment extending forward on to pectoral fin base.

Distribution. Known only from Darwin area, Northern Territory and from Daintree River to Moreton Bay, Queensland, from 0.5–25 m, found over mud bottom, often trawled.

Comparisons. Morphological characteristics showing differences between described species of Tomiyamichthys are shown in Tables 2 and 3. Species of Tomiyamichthys broadly fall into two groups based on the height of the first dorsal fin. In one group the first dorsal fin has two or more very elongate spines, with the dorsal fin height much higher than the body depth and a second group, in which the dorsal fin height is subequal to or slightly higher than the body depth. This latter group includes the current species and T. gomezi , T. russus , T. nudus , T. oni and T. zonatus . Tomiyamichthys levisquama is most similar to T. russus in general body form and fin ray counts. It differs from that species in having entirely cycloid scales (versus scales ctenoid posteriorly on body in 10–18 rows, below posterior part of second dorsal fin and on caudal peduncle), the third to fifth dorsal spine longest (versus first) and in having fewer scale rows on the body (50–70 versus 74–95 in T. russus ). Morphometrics do not show apparent differences ( Table 1). However too few specimens were available of both species for a precise comparison. The dorsal fin appears higher in photographs in T. russus , but in the few specimens examined of T. levisquama the fin is slightly higher in males than in females. Most of the specimens of T. russus examined were females. Live color variation is unknown in T. levisquama and a detailed comparison of coloration cannot be made. However, we note that T. russus appears to lack the dark medial bar on the pelvic fin and usually has rounded light spots on the head rather than elongate bars ( Figs. 5c and 7 ).

Shibukawa et al. (2005) redescribed and figured freshly collected specimens of T. russus from Japan. They noted that the species has been recorded under various names, such as Cryptocentrus polyophthalmus in Kuiter & Tonozuka (2001) and Flabelligobius sp. 2 in Senou et al. (2004). Several names are tentatively included here as synonyms of F. russus (see comparative material examined above). We noted considerable variation in scale counts in that species and coloration ( Fig. 7 ), comparable to that found by Shibukawa et al. (2005). Also some specimens have two preopercular pores and others three and some two on one side and three on the other. We have not been able to resolve species differences in the material that we examined. All material from outside Australia had ctenoid scales on the caudal peduncle.

Remarks. As noted above, specimens from the Northern Territory differ slightly from Queensland specimens in coloration and in scale counts. We note that there is also a wide range of variation in coloration and scale counts in Tomiyamichthys russus and the differences noted between Australian localities may not be significant. Etymology. From the Greek levis = smooth + squama = scale, alluding to the cycloid scales, treated as a noun in apposition.

Figures

FIGURE 1. Holotype of Tomiyamichthys levisquama— NTM S. 17974 - 002, 42.9 mm SL male. A. Live coloratioN. B. Fresh coloratioN shortly after collectioN. Photos M. Hammer.

FIGURE 2. Types from QueeNslaNd showiNg variatioN iN coloratioN of preserved material. Tomiyamichthys levisquama— A. QM I. 30165, 69 mm SL female. B. QM I. 17913, 65 mm SL female. C. QM I. 16708, 69 mm SL male. D. QM I. 29226, 62 mm SL male.

FIGURE 3. First dorsal fiN of Tomiyamichthys levisquama. A. NTM S. 11506 – 016, 40 mm SL female, B. 37 mm SL male.

FIGURE 4. Pelvic fiN of Tomiyamichthys levisquama, NTM S. 11506 – 016, 37 mm SL male.

FIGURE 5. SeNsory papillae oN head of Tomiyamichthys levisquama, composite, based primarily oN QM 16708; A. side view. B. dorsal view. C. veNtral view.

FIGURE 6. Head of Tomiyamichthys. A. QM I. 29226, T. levisquama, B. Holotype of T. levisquama. NTM S. 17974 - 002, NTM S. 17974 - 002; C. T. russus USNM 263350.

FIGURE 7. Live coloratioN of Tomiyamichthys russus. A. female from Alotau, MilNe Bay, Papua New GuiNea, iN 16 m depth, photo G. AlleN. B. BLIP 20060963, juveNile iN aquarium from Sedake, Ohura-waN Bay, OkiNawa-jima IslaNd, JapaN, photo D. Hoese.