Pseudogobius aquilonius, 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 : 10-16

Pseudogobius aquilonius n. sp.

Northern snubnose goby

urn:lsid:zoobank.org:act:9ED71CE8-B3E6-483E-9119-3979542FEA71

Figs 1 , 4–5 , Tables 2–6

Goby sp.— Midgley 1973: appendix B (Cannon Hill Lagoon).

Pseudogobius sp.— Davis 1988: 164 (Buffalo Creek, Leanyer Swamp); Blaber et al. 1992: 9 (Groote Eylandt).

Pseudogobius sp. 2— Larson 1992: 9 (Home Creek); Larson & Williams 1997: 370 (Ludmilla Creek; N side Channel Island; creek at Elizabeth River mouth); Larson 1997: 41 (Kakadu); Larson 1998: 36 (creek S of Pickertaramoor, Maxwell Creek, Melville Island); Larson 1999b: 44 (Kakadu).

Pseudogobius poicilosoma —Larson 1996: 11 (Roper River; Nayarnpi Creek; Towns River); Hoese et al. 2006: 1680 (NT; N coast); Larson 2001: 203 (in part; Indonesia; Papua New Guinea; Northern Territory, Queensland).

Pseudogobius sp. 2 (cf poicilosomus )— Larson 2000: 49 (Sandfly Beach); Larson 2002: 40 (Middle Beach; Sandfly Beach).

Pseudogobius poicilosomus — Larson et al. 2013: 207 (Cannon Hill Lagoon; Buffalo Creek; Leanyer Swamp; Groote Eylandt; Home Creek; Ludmilla Creek; N side Channel Island; creek at Elizabeth River mouth; Kakadu; creek S of Pickertaramoor, Maxwell Creek, Melville Island; Roper River; Nayarnpi Creek; Towns River; Sandfly Beach; Middle Beach; creek on E side Vanderlin Island; Field Island, Northern Territory).

Pseudogobius sp. B ‘plain’— Hammer et al. 2021: 4 (northern Australia, Broome to Brisbane [diagnosable at nuclear and mitochondrial markers]).

Material Examined. Holotype: NTM S.13518-004, 28 mm SL male, east arm of Bing Bong Creek, Gulf of Carpentaria , Northern Territory, Australia, H. Larson and party, 5 September 1992 . Paratypes: WESTERN AUSTRALIA: AMS I.25538-010, 16(23.5–25.5), Parry Creek , 7.5 km from road, Wyndham, D. Hoese and D. Rennis, 28 September 1985 ; AMS I.30005-001, 1(28), Dampier Salt Ponds, J. Tyler, 1987 ; WAM P.25668-015, 4(21–26), Walsh Point, Port Warrender , B. Hutchins and Duyker, 22 October 1976 . NORTHERN TERRITORY: NTM S.12429-015, 63(15–25), creek on east side Vanderlin Island , H. Larson and W. Houston, 22 July 1988 ; NTM S.13518-015, 88(12–33), east arm of Bing Bong Creek, Gulf of Carpentaria , H. Larson and party, 5 September 1992 . QUEENS- LAND: QM I.39298, 15(14.5–30.8), Boggy Creek, Brisbane River mouth, J. Johnson and party, 12 July 1988 ; ROM 38801, 6 (29–32.5), Saunders Beach, N of Townsville , R. Winterbottom , 4 October 1981 ; CSIRO B.2511, 5(15–32), freshwater creeks and swamps at various localities, Cairns, Army Survey, August 1940 ; CSIRO B.2512, 23(7–22), Cabbage Tree Creek , Sandgate, Brisbane, 7 March 1938 .

Additional material (no data taken). QUEENSLAND: AMS I.23277-005, 7, Mission River mouth, Wallaby Island, D. Hoese and D. Rennis, 9 October 1982 ; NTM S.17877-006, 3, Sand Hills Creek, Bowen, 16 September 2014 ; S.18130-002,19, Auckland Creek , Gladstone, P. Unmack and party, 14 April 2015 ; NTM S.18265-002, 19, Round Hill Creek estuary, near Gladstone, PU 15-20 , P. Unmack and party, 14 April 2015 ; NTM S.18127-002, 2, Railway drain, Barron River tributary, Cairns, M. Hammer, 25 July 2015 ; NTM S.18129-002, 2, Railway drain, Barron River tributary, Cairns, GM14-15, G. Moore and party, 30 January 2014 ; NTM S.18267-001, 2, Weipa foreshore tide pools, M. Hammer and party, 23 November 2015 ; QM I.39298, 14, Boggy Creek, Brisbane, J. Johnson, 12 July 1988 ; QM I.28574, 7, Pine River Mouth, R.J. McKay and J. Johnson, 26 November 1993 ; NTM S.15585-004, 2, Tin Can Bay, B. Hansen, 30 November 1996 ; NTM S.18273-002, 3, Portsmith drain, Cairns, MH 19-02 , M. Hammer and G. Moore, 24 January 2019 ; ROM 68486, 3 , Blacksand Creek , S of Townsville, RW94-01, Winterbottom and party, 14 June 1994 . NORTHERN TERRITORY: NTM S.16746-003, 8, Inburrkul Creek, Mountnorris Bay, H. Larson and party, 8 August 2008 ; NTM S.12990-001, 26, creek at Vesteys Beach, Darwin , R. Williams and D. White, 27 May 1991 ; NTM S.14692-002, 2, Leanyer sewage plant, D. Wilson, 12 September 1993 ; NTM S.14962-012, 14, Sandfly Beach, West Alligator Head, H. Larson and party, 8 September 1999 ; NTM S.10694-005, 142, Gunn Point, H. Larson and R. Williams, 20 September 1982 ; NTM S.17658-001, 1, Buffalo Creek, Shoal Bay, M. Hammer and party, 28 September 2012 ; NTM S.17346-007, 1, first creek upstream from Maningrida, Liverpool River , Northern Territory, M. Hammer and Waterhouse Club, 16 May 2012 ; NTM S.14042-041, 8, creek at Towns River mouth, H. Larson and R. Williams, 13 September 1994 ; NTM S.14025-012, 3, Nyarnpi Creek, Roper River , H. Larson and R. Williams, 9 September 1994 ; NTM S.15715-009, 46, Rapid Creek, Darwin, D. Rennis, 5 August 1983 ; NTM S.15036-014, 41, Lake Alexander, Darwin Harbour, H.K. Larson and party, 7 May 1998 ; NTM S.11366-002, 2, Settlement Beach, Milingimbi, HL 84-31, H.K. Larson and P.G. Horner, 26 July 1984 ; NTM S.18302-001, 14, Rapid Creek, Darwin, MH 19-04 , M. Hammer, 5 March 2019 ; USNM 257127 , 6 , creek west of Yirrkala , R. Miller and party, 8 August 1948 . WESTERN AUSTRALIA: AMS I.25521-001, 37, Crab Creek, Broome, D. Hoese and D. Rennis, 20 September 1985 ; AMS I.25511-002, 2, mangroves at Cossack, D. Hoese and D. Rennis, 15 Sept 1985 ; WAM P.27672-003, 9, Broome, G. Allen, 30 July 1982 ; WAM P.34990-002, 1, Exmouth Gulf, G. Moore and party, 20 June 2019 .

Diagnosis. A moderate-sized Pseudogobius with second dorsal rays I,6–8; anal rays I,6–7; pectoral rays 14–17; 15–16 segmented caudal rays in 9/7 pattern; lateral scales 24–27; TRB 7–9; predorsal scales 6–8; opercle with at least 2 rows of cycloid scales, rarely with a cycloid scale on cheek right behind eye; shoulder girdle smooth or with narrow bony flange; tongue short and may be greatly reduced; in males, teeth in outer row of upper jaw slightly flattened, blunt-tipped or pointed, with two curved symphyseal canines behind anterior tooth rows, while in females, outer row teeth of upper jaw small, compressed and blunt-tipped; scale margins edged with brown, about 5–6 small brown elongate blotches along mid-side of body with posteriormost blotch at hypural crease extending onto caudal fin and coalescing with narrow vertical dark bar on fin base; known from estuarine to fresh waters of northern Australia.

Description. Based on 52 specimens, 20–33.0 mm SL. An asterisk indicates counts of the holotype ( Fig. 5E ).

First dorsal VI *; second dorsal I,6*–8 (usually I,7); anal I,6–7 (usually 7*); pectoral rays 14–17 (usually 16*); segmented caudal rays 15–16*, in 9/7 pattern; branched caudal rays 7/6–9/7, modally 8/7; lateral scale count 24–27 (usually 26, 25 in syntype); TRB 7*–9 (usually 8); predorsal scale count 6–8 (usually 7*) .

Body rounded or slightly compressed anteriorly, compressed posteriorly. Head wider than deep, but not greatly so, HL 23.9–29.8% SL (mean 27.2%). Head depth at posterior preopercular margin 58.0–74.7% HL (mean 63.2%). Head width at posterior preopercular margin 63.9–85.3% HL (mean 72.4%). Mouth small, subterminal, slightly oblique; jaws reaching to vertical through mid-eye in large adults and to anterior half of eye in females, with males usually having longer jaws; upper jaw 26.3–48.2% HL (mean 36.4%); lips relatively thin, lower lip broadly fused to chin anteriorly. Eyes lateral, high on head, top usually forming part of dorsal profile, eye width 26.7–33.3% HL (mean 29.7%). Snout rounded and somewhat inflated, 22.8–36.1% HL (mean 28.6%). Interorbital moderate, 16.7– 22.9% HL (mean 19.9%). Body depth at anal origin 19.2–22.4% SL (mean 20.5%). Caudal peduncle compressed, length 26.1–34.6% SL (mean 30.3%). Caudal peduncle depth 12.3–15.4% SL (mean 13.4%).

First dorsal fin low, triangular, second to third spines longest (fourth spine longest in one male). Appressed first dorsal fin falling short of second dorsal in both sexes, fin length 16.1–20.0% SL (mean 18.0%). Second dorsal spine length 13.5–17.3% SL (mean 15.0%). Third dorsal spine length 13.6–16.1% SL (mean 14.9%). Second dorsal and anal fin heights moderate, fins rounded posteriorly with first few rays longest, rays falling well short of caudal fin base when appressed. Pectoral fin oval, central rays longest, extending back to vertical just short of anus, 18.8–23.5% SL (mean 21.6%). Pelvic fins oval, short, reaching short of anus, 16.1–20.0% SL (mean 18.3%). Caudal fin broad, rounded posteriorly, 25.0–33.6% SL (mean 28.9%).

Anterior nostril in short tube, oriented down over upper lip. Posterior nostril oval, with very low rim, placed at mid-level of eye. Gill opening relatively narrow, extending usually to under opercle. Shoulder girdle smooth or with narrow bony flange. Tongue short, may be greatly reduced, tip blunt or bluntly rounded. Upper jaw teeth in 3–4 rows, in males, teeth in outer row slightly flattened, blunt-tipped or pointed; in females, outer row teeth small, compressed and blunt-tipped; teeth in 2–3 inner rows always very small, close-set and sharp. Lower jaw teeth in 2–3 rows; in males, outer row teeth stout and with rather blunt or pointed tips; two curved symphyseal canines behind anterior tooth rows; females with compressed or somewhat flattened evenly sized blunt-tipped teeth in outer row; teeth in inner 2–3 rows same as in upper jaw.

Body scales ctenoid to pectoral fin base, cycloid scales on predorsal, breast and pectoral fin base; opercle with at least two rows of cycloid scales, rarely with a cycloid scale on cheek right behind eye; belly scales cycloid on posterior half at least, may be ctenoid scales anteriorly or most of belly with ctenoid scales. Lateral canals, pores and sensory papillae pattern as in Fig. 4 .

Coloration of preserved material. Head and body with scale margins on head and body narrowly edged with brown, usually only on upper half in females, and about 5–6 small brown elongate blotches along mid-side of body, posteriormost at hypural crease where it extends onto caudal fin and coalesces with narrow vertical bar on fin base; small brown spots on predorsal area; specimens from Broome pale, with only short horizontal brownish bar and no dark spots at caudal base. Males with more defined scale margins and head and nape may be darker, or entire head and body darker than in females. Three to five indistinct brown small cross-hatched bars across dorsum; brown bar under first dorsal fin broadest and may be darkest, in some specimens extending down side of body to mid-side (most defined in small specimens). Dark brown elongate blotch or series of irregular spots above pectoral fin base and partly extending onto rear corner of opercle; may be series of less distinct brown spots extending from this dark blotch along upper part of body below first dorsal fin. 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; cheek with broad wedge-shaped bar from lower edge of eye ending behind jaws, and another very short brown bar from behind eye angled obliquely toward rear of preopercle. Chin and lips speckled with scattered melanophores or quite greyish in adult males; chin unpigmented in females. Breast faintly greyish; belly unpigmented. Thin blackish to dense black mid-ventral line running from middle (or insertion) of anal fin to end at first ventral procurrent ray. Black peritoneum may be visible through body wall.

First dorsal fin greyish brown with diffuse blackish spot at rear of fin; dark brownish pigment may cover most of fin or form a broad, generally central, band; margin usually narrowly brownish. Second dorsal fin transparent with diffuse brownish band across centre and greyish margin; fin more heavily pigmented in adult males. Anal fin transparent with few scattered brownish speckles. Caudal fin grey or pale brownish, paling to transparent posteriorly; may have 2–3 diffuse dark brown spots near base. Pectoral fin with transparent membranes, rays speckled with brown. Pelvic fins translucent.

Coloration of fresh material. Head and body translucent pale yellowish to greyish yellow, with brown crosshatching along scale margins scattered irregularly over body and nape and 5–6 X-shaped to elongate small brown blotches along mid-side of body (blotches may be paired) ( Fig. 5 ). Posteriormost blotch on body ending at hypural crease and coalescing with two brown spots on caudal fin. Iridescent pale gold to pinkish gold pigment may be scattered along scale edges along abdominal region. Four internal blackish brown short bars along mid-ventral line starting at mid-base of anal fin, with fourth bar (posteriormost) slightly more widely separated from others. Snout translucent or pale brownish, with two short brown bars, one before and after nostril area, which is pale. Cheek translucent with diffuse brown bar from below eye usually ending mid-cheek and second brown bar from behind eye diagonally back toward upper part of preopercular margin. Opercle dusky brown above with blue-white iridescent speckling on lower half. Iris golden, darker near pupil. Lips pale, narrowly edged with brown. Abdomen silvery white, peritoneum dense black.

First dorsal fin translucent with broad diffuse brown band across most of fin; may be submarginal whitish to pale bluish stripe present. Second dorsal fin translucent with dusky brown speckling; may have whitish to pale bluish stripe across mid-fin and narrow bluish margin. Anal fin dark brown or golden with broad whitish or bluish white margin. Caudal fin translucent with two brown spots close together at base and coalescing with posteriormost brown body blotch; area over procurrent rays may be pale bluish. Pectoral fins transparent. Pelvic fins white, greyish near bases of rays.

Comparisons. This species is most similar to P. hoesei n. sp. and P. jeffi n. sp., both of which have one or two cycloid scales on the cheek behind the eye (these scales absent in P. aquilonius ). It differs in live and preserved colour especially on the caudal peduncle and caudal fin; the vertical dark bar on the fin base of P. aquilonius is unique among its congeners (compare Figs 5 , 13 and 15 and see Comparisons under P. hoesei n. sp.).

Distribution. Endemic to northern Australia (from Dampier, Western Australia to Brisbane, east coast Queensland). May occur in adjoining areas of southern New Guinea (no samples found).

Ecology. Shallow-water estuarine, 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, logs and leaf litter. Found among a variety of mangroves, e.g. Aegialitis, Avicennia, Ceriops, Exoecaria and Rhizophora and often in marginal habitats such as small drainage creeks running through exposed salt flats. Co-occurs at its microhabitat or location with all other species recorded in northern Australia (including minor overlap with P. eos n. sp. around Brisbane).

Etymology: From the Latin aquilonius , north or northerly, in reference to this Australian species’ distribution around the north coast of the country.

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 4. Lateral canal pores and sensory papillae in Pseudogobius aquilonius n. sp., 29 mm SL female, NTM S.12990-001, Vesteys Beach, Darwin, Northern Territory. Drawing by HKL.

FIGURE 5. Pseudogobius aquilonius n. sp., northern Australia, (A) captive male, Chinaman Creek tributary, Cairns; (B), captive female, Rapid Creek, Darwin; (C) fresh male, NTM S.18273-002, Chinaman Creek tributary, Cairns, (D) fresh female, NTM S.18302-001, Rapid Creek, Darwin; (E) preserved holotype, 28 mm SL male, NTM S.13518-004, Bing Bong Creek, Gulf of Carpentaria. Photos by MPH.

FIGURE 13. Pseudogobius hoesei n. sp., New Guinea and north-eastern Australia (A) captive male, Aru Islands, Indonesia, photo by G. Allen; (B) captive female, Aru Islands, Indonesia, photo by G. Allen; (C) fresh male (top) and female, NTM S.18266-01, Weipa, Queensland, Australia, photos by MPH; (D) preserved 27 mm SL holotype male, QM I.40993, Bellvue Creek, Weipa, Queensland, Australia, photo by D. Hoese.

FIGURE 15. Pseudogobius jeffi n. sp., north-easternAustralia, (A) captive male, Chinaman Creek tributary, Cairns; (B) captive female, Chinaman Creek tributary, Cairns; (C) fresh male (upper) and female, NTM S.18273-001, Chinaman Creek tributary, Cairns; (D) preserved holotype, 26 mm SL male, QM I.40992, Auckland Creek, Gladstone. Photos by MPH.