Pseudogobius cinctus, Larson & Hammer, 2021

Larson, Helen K. & Hammer, Michael P., 2021, A revision of the gobiid fish genus Pseudogobius (Teleostei, Gobiidae, Tridentigerinae), with description of seven new species from Australia and South-east Asia, Zootaxa 4961 (1), pp. 1-85 : 21-25

Pseudogobius cinctus n. sp.

Banded snubnose goby

urn:lsid:zoobank.org:act:81B7ABA7-FA4D-4D2B-8FD7-41C33A32BF89

Figs 1 and 8 , Tables 2–5, 8

Pseudogobius sp. A ‘banded’— Hammer et al. 2021: 4 (northern Australia, Wyndham to Maningrida [diagnosable at nuclear and mitochondrial markers])

Material examined. Holotype: NTM S.18268-001 (ex AMS I.20890-001), 25 mm SL male, Little Horse Creek , Victoria River, Northern Territory, Australia, D.F. Hoese, 12 June 1978 . Paratypes: NORTHERN TERRITORY: AMS I.20890-001, 36(9–27.5), same data as holotype; NTM S.17346-005, 12(11–21.5), first creek upstream from Maningrida, Liverpool River, M. Hammer and Waterhouse Club, 16 May 2012 ; NTM S.15537-006, 5(18–21.5), creek at Middle Point beach, West Alligator Head, H.K. Larson and party, 9 June 2001 ; NTM S.13036-001, 1(20.5), freshwater, Darwin River, P. Hurley, December 1990 . WESTERN AUSTRALIA: AMS I.25522-003, 3(22–22.5), creek by caravan park, King Sound, Derby , Western Australia, D.F. Hoese and D. Rennis, 21 September 1985 ; AMS I.25538-022, 5(21–30.5), Parry Creek , 7.5. km from road, Wyndham , Western Australia, D.F. Hoese and D. Rennis, 28 September 1985 ; WAM P.34040-003, 3(23–24.5), Bindoola Creek at junction with Pentecost River , Western Australia, Bush Blitz Survey BBK-14-008, M. Hammer and G. Moore, 1 June 2014 .

Additional material (no data taken). NORTHERN TERRITORY: AMS I.18392-003, 6, Tomkinson River , J. Taylor, 3 May 1975 ; NTM S.14025-014, 12, Nyarnpi Creek, Roper River , H. Larson and R. Williams , 9 September 1994 ; NTM S.10720-004, 1, Cannon Hill Lagoon, East Alligator River , H. Midgley, 20 February 1973 ; NTM S.14024-017, 6, small creek north side Roper River , HL 94-16, H.K. Larson and R.S. Williams , 8 September 1994 ; NTM S.14390-008, 13, small creek, Melville Island , HL 96-9, H.K. Larson and G.M. Dally, 6 October 1996 ; NTM S.14885-001, 200, Middle Point, Adelaide River , B. Richards and H. Sakurai, 21 November 1996 ; AMS I.24683- 005, 74, Blackmore River , D. Hoese and party, 8 September 1984 ; NTM S.16054-006, 4, Keep River , SITE 13 , D. Buckle and party, 25 July 2004 . QUEENSLAND: AMS I.22789-006, 1, Norman River , G.S. and M. Hardy, 6 July 1980 ; AMS I.23277-013, 1, Mission River mouth, Wallaby Island , Weipa, D. Hoese and D. Rennis, 9 October 1982 .

Diagnosis. A moderate-sized Pseudogobius with second dorsal rays I,6–8; anal rays I,6–8; pectoral rays 15–18; 16 segmented caudal rays in 9/7 pattern; lateral scales 24–28; TRB 7–81/2; predorsal scales 7–8; opercle usually with three rows of cycloid scales, 1–2 cycloid scales on cheek close behind eye; shoulder girdle with smooth bony edge; tongue short, tip blunt or bluntly rounded; in males, upper jaw teeth in outer row long, evenly sized and evenly spaced, fairly straight and slightly flattened with pointed tips, while in females, upper jaw teeth of small to mediumlength (not as long as in males), compressed, slender, teeth often close-set but may be slightly apart, tips blunt or sharp; scale margins on upper three-quarters of body edged with brown, 3–6 small brown blotches along mid-side of body with posteriormost blotch at hypural crease, caudal fin with two distinct round or almost square dark brown spots, just above and below mid-lateral line (upper spot may coalesce with spot on hypural crease); known only from estuarine to fresh waters of northern Australia.

Description. Based on 29 specimens, 15.5–30.5 mm SL. An asterisk indicates the counts of the 25 mm SL holotype ( Fig. 8D ).

First dorsal VI*; second dorsal I,6–8 (usually I,7*); anal I,6–8 (usually 7*); pectoral rays 15–18 (usually 17*); segmented caudal rays 16*, in 9/7 pattern; branched caudal rays 7/6–9/7, modally 8/7*; lateral scale count 24–28 (usually 25*); TRB 7–8½ (usually 8*); predorsal scale count 7*–8 (usually 7).

Body slender, compressed. Body depth at anal origin 17.4–21.4% SL (mean 19.7%). Head wider than deep, HL 21.3–28.4% SL (mean 26.0%). Head depth at posterior preopercular margin 56.8–67.7 HL (mean 62.5%). Width at posterior preopercular margin 66.1–79.6% HL (mean 71.7%). Mouth small, subterminal, almost horizontal; jaws reaching to vertical from about mid-eye in adult males and to anterior half of eye in females; upper jaw 27.7–51.5% HL (mean 34.7%); lips relatively thin, lower lip broadly fused to chin anteriorly. Eyes lateral, high on head, top usually forming part of dorsal profile, 27.6–33.3% HL (mean 30.0%). Snout rounded and slightly inflated, 22.4–31.8% HL (mean 26.4%). Interorbital moderate, 15.3–21.5% HL (mean 18.7%). Caudal peduncle compressed, length 26.2–32.6% SL (mean 30.3%). Caudal peduncle depth 11.9–14.9% SL (mean 13.6%).

First dorsal fin low, rounded, first to third spines longest. Appressed first dorsal fin length 14.4–20.4% SL (mean 18.2%), fin falling short of second dorsal in both sexes. First dorsal spine length 14.1–17.3% SL (mean 15.6%). Second dorsal spine length 13.5–15.4% SL (mean 14.7%). Third dorsal spine length 11.2–15.6% SL (mean 14.3%). Second dorsal fin taller than first; anal fin height moderate; both fins slightly pointed posteriorly, posteriormost rays longest, fins falling well short of caudal fin base when appressed. Pectoral fin oval, central rays longest, extending back to vertical above anus or just before, 19.2–23.8 % SL (mean 21.0%). Pelvic fins rounded, reaching just over halfway to anus, 15.1–20.0% SL (mean 18.0%). Caudal fin broad, rounded posteriorly, 16.0–32.0% SL (mean 28.2%).

Anterior nostril in short tube, oriented down over upper lip. Posterior nostril rounded, with very low rim, placed at mid-level of eye. Gill opening extending forward to just under opercle; rarely to under mid-opercle. Shoulder girdle with smooth bony edge. Tongue short, tip blunt or bluntly rounded. In males, upper jaw teeth in outer row long, evenly sized and spaced, fairly straight and slightly flattened with pointed tips, teeth in the 1–2 inner rows very small, close-set and sharp; lower jaw with two rows of teeth, outermost teeth slightly flattened, pointed or blunt and may have orange tips, a pair of curved canine teeth behind all rows. In females, upper jaw teeth in two rows, small to medium-length (not as long as in males), compressed, slender, teeth often close-set but may be slightly apart, tips blunt or sharp; lower jaw teeth similar but teeth always shorter.

Body scales ctenoid to behind or above pectoral fin base but no further forward; cycloid scales on predorsal and pectoral fin base; opercle usually with three rows of cycloid scales, 1–2 cycloid scales may be present on cheek close behind eye; belly scales ctenoid anteriorly and cycloid on posterior half; midline may be all cycloid. Lateral canals, pores and sensory papillae pattern similar to that of P. hoesei n. sp. ( Fig. 12 ).

Coloration of preserved material. Head and body yellowish white or pale brownish (depending on preservation), with scale margins on head and upper three-quarters of body narrowly edged with brown, 3–6 small brown round or elongate blotches along mid-side of body, posteriormost at hypural crease, and a few scattered small brown spots on predorsal area. Three to five indistinct oblique brown small saddles or short bars across dorsum, longest (at middle of first dorsal fin) reaching down to first mid-lateral brown blotch (dorsal saddles are remnants of dusky brown bars when fish alive). Interorbital and snout plain brownish, with pale bar from eye to lip, covering nostrils; behind pale bar a dark brown bar from eye to middle of jaw. Cheek and opercle with variable brown mottling and small blotches, may form oblique wedge across opercle ending in dark brown blotch at upper rear corner of opercle. Chin and lips dusky grey in adult males; chin unpigmented in females. Breast and belly faintly dusky grey in males, unpigmented in females.

In males, first dorsal fin evenly dusky grey with transparent submarginal stripe; second dorsal fin dusky grey basally or may have a series of vertical dark grey streaks beside base of each fin element, a narrow dark grey median stripe present with broad transparent stripe above it and a mostly dusky grey margin; anal fin pale to dark grey with translucent margin. Females with similar pattern on dorsal fins but fins more transparent and with much less pigmentation; anal fin mostly translucent with faintly grey submarginal stripe. Caudal fin (in both sexes) with two distinct round or almost square dark brown spots, one just above mid-lateral line and other spot ventral to mid-lateral line; upper spot may partly coalesce with posteriormost mid-lateral brown spot at hypural crease; small dark brown spot at middle of procurrent rays; in male rest of fin dusky grey to plain brownish, darkest anteriorly; in females rest of fins translucent with scattered melanophores. Pectoral fin transparent with indistinct grey or brown blotch at upper base extending onto upper fin rays. Pelvic fins translucent.

Coloration of fresh material. Based on photos of fresh dead and live fish ( Fig. 8 ). Colour pattern very similar to preserved specimens. Head and body translucent pale brownish or yellowish white, scale margins thinly outlined with melanophores. Markings on head and body dark brown to blackish. Transparent stripe on dorsal fins replaced by bright yellow or pinkish yellow. Dark brown stripe on cheek (from eye to rear of preopercle) distinct; brown bar from eye to jaw less so. Opercle with bluish white speckling on ventral half. Pectoral fin base with iridescent white area below dorsal brown blotch. Peritoneum silvery white, blackish dorsally. Iris pinkish gold.

Comparisons. This species is distinctive in having at least one scale on the upper cheek behind the eye, 4–5 dusky grey vertical bars along the side of the body and a black-bordered yellow band on the outer part of both dorsal fins. It is restricted to northern Australia, known from Derby, Western Australia , to Weipa, Queensland.

Distribution. Endemic to northern Australia, known only from northern Western Australia, the Northern Territory and north-west Queensland (Gulf of Carpentaria and western Cape York).

Ecology. Estuarine to freshwater, found in tidal rivers, mangrove creeks and muddy tide-pools, at depths of 0–1 m, with substrate of sandy mud, mud and mangrove roots and leaf litter. Typically co-occurs with P. aquilonius and other local Pseudogobius species other than P. jeffi n. sp.

Etymology. Named cinctus (from the Latin for belt or girdle) in reference to the distinctive vertical dark bars or bands on the body in this species.

Figures

FIGURE 1A. Distribution maps of species in the genus Pseudogobius, based upon material examined and inspected (circles) with the type localities indicated (squares).

FIGURE 8. Pseudogobius cinctus n. sp., northern Australia, (A) captive male, Blackmore River, Tumbling Waters; (B) captive female, Blackmore River, Tumbling Waters; (C) fresh male (top) and female, NTM S.17346-005, from Liverpool River, Maningrida; (D) preserved holotype, 25 mm SL male, NTM S.18268-001, Little Horse Creek, Victoria River. Photos by MPH.

FIGURE 12. Pseudogobius hoesei n. sp., sensory papillae and lateral canal pores, 34 mm SL female, WAM P.31299-004, Timika, Papua, Indonesia (note that cheek scale behind eye often absent). Drawing by HKL.