Pseudogobiopsis festivus, Larson, 2009

Larson, Helen K., 2009, Review Of The Gobiid Fish Genera Eugnathogobius And Pseudogobiopsis (Gobioidei: Gobiidae: Gobionellinae), With Descriptions Of Three New Species, Raffles Bulletin of Zoology 57 (1), pp. 127-181 : 155-157

Pseudogobiopsis festivus new species

( Figs. 22–24 ; Plate 2A; Tables 13–17)

Calamiana sp. nov. – Kottelat & Lim, 1995: 247. Eugnathogobius sp. nov. – Larson, 2001: 66–68.

Material examined. – HOLOTYPE - ZRC 40279, 34.5 mm SL male, 8.6 km after turnoff to Sungei Cina Matang after entrance to Matang Reserve , near Kuching, Sarawak, Malaysia, THH 9554, H. H. Tan & D. C. J. Yeo, 4 Sep.1995 . PARATYPES - MALAYSIA, SARAWAK: ZRC 40280, 6 (20.5–27.0), same data as holotype ; NTM S.14299-001, 7(19.5–29.5), same data as holotype ; ZRC 27842-3 , 2 (14.5–24.4), 7 km on Kuching-Batu-Kawa Road, M. Kottelat & K. Lim, 3 Jul.1992 ; ZRC 29082-3 , 2 (19.0–20.5), 7 km on Kuching-Batu-Kawa Road, M. Kottelat & K. Lim, 3 Jul.1992 ; ZRC 50715, 9 (18–33), stream 1, Ulu Assam , Bako National Park, Kuching, K. Lim, 30 Jun.1994 ; ZSM \ KEW 538 , 5 (16–24), NW of Bau, Batang Kayan River basin, Sungai Stunggang, C. Kettner, K.-E. Witte & R. Krumenacher , 24 Mar.1988 ; CMK 8401 (12 will go to ZRC), 26(11–27), Sungei Bejit , road from Balai Ringin to Simunjan, M. Kottelat, K. Lim & P. Ng, 2 Jul.1992 .

Other material examined (but not used in description). SARAWAK: ZRC 40281, 3, Sungei Stok Muda, Lundu; ZRC 26026-27, 2, drain off road to Simundjan; ZRC 40282, 4, about 10 km from Kuching; NTM S.14301-001, 3, Sungei Stok Muda, Lundu; NTM S.14300-001, 3, Sungei Cina Matang, Matang; ZSM /KEW 1031, 1, field label lost.

Diagnosis. – A moderately slender Pseudogobiopsis with second dorsal rays I,7; anal rays modally I,7; pectoral rays 17–19; longitudinal scales 28–32; TRB 8-9; predorsal scales 8–13, reaching up to behind eyes; jaws enlarged in mature males; some headpores present, preopercular pores and posterior portion of oculoscapular canal absent; first spine of dorsal fin longest, occasionally filamentous in males; light sandy yellow with brown saddles and mottling, fins red in life, dorsal fins and caudal fins with rows of black or dark brown spots; known only from fresh waters in Sarawak.

Description. – Based on 33 specimens, 14.5–34.5 mm SL. An asterisk indicates counts of holotype ( Fig. 22 ).

First dorsal VI*; second dorsal rays always I,7*; anal rays I,7*–8 (strongly modally I,7); pectoral rays 17*–19 (mean 18), segmented caudal rays 16–18 (mean 17*); caudal ray pattern 6/6 to 9/6 (modally 7/7*); branched caudal rays 12–16 (mean 14*); unsegmented (procurrent) caudal rays 9/9 (in one); longitudinal scale count 24–26 (mean 25*); TRB 8–9 (mean 8*); predorsal scale count 8–13 (mean 10*); circumpeduncular scales always 12*. Gill rakers on outer face of first arch 2+5 to 3+7 (modally 2+7). Pterygiophore formula 3-12210 (in three). Vertebrae 10+16 (in seven). Neural spine of second vertebra blunt or broadened at tip (in one), or slender and pointed (in one). One (in two) or two (in four) epurals. Two (in seven) anal pterygiophores before haemal spine of first caudal vertebra. Palatine not reaching quadrate. Metapterygoid relatively low, well separated from quadrate. Quadrate shallowly forked. Dentary short. Anterior margin of preopercle pointed. Scapula unossified. Six ossified gill rakers.

Body slender, somewhat compressed posteriorly, less so anteriorly. Body depth at anal fin origin 15.6–19.2% (mean 16.9%) of SL. Head rounded, almost cylindrical, wider than deep, but not greatly so, HL 25.3–30.3% (mean 28.4%) of SL; cheeks may be somewhat inflated in large males. Depth at posterior preopercular margin 50.0–62.1% (mean 55.1%) of HL. Width at posterior preopercular margin 56.8–75.5% (mean 65.7%) of HL. Mouth terminal, slightly oblique, forming angle of about 20° with body axis; jaws reaching past rear preopercular margin in large males (such as holotype) and to below mid-eye in females. Lips smooth, without fleshy fimbriae on edges; lower lip narrowly free at sides, fused across front. Upper jaw 31.8–66.0% (mean 35.8% in females, 46.2% in males) of HL. Eyes dorsolateral, high on head, forming part of dorsal profile, 21.6–34.6% (mean 28.3%) of HL. Snout short, flattened, 19.6–27.3% (mean 22.9%) of HL. Interorbital moderately broad to narrow, 9.8–29.4% (mean 16.9%) of HL. Caudal peduncle compressed, length 28.2–33.8% (mean 30.3%) of SL. Caudal peduncle depth 11.7–13.5% (mean 12.4%) of SL.

First dorsal fin triangular, first or second spines longest or subequal, occasionally filamentous, first spine modally longest; spines slightly longer in males than females; spines falling short of second dorsal fin origin when depressed, even in large males (unless spines filamentous). First dorsal spine length 14.4–24.8% (mean 19.3% in males, 17.3% in females) of SL. Second dorsal spine length 14.4–22.7% (mean 17.5% in males, 16.1% in females) of SL. Second dorsal and anal fins short-based, lower than first dorsal fin, posteriormost rays longest, rays falling well short of caudal fin base when depressed. Pectoral fin slender, pointed, central rays longest, 23.7–29.7% (mean 25.7%) of SL; rays usually all branched. Pelvic fins long, oval, usually reaching to anus, 21.1–24.8% (mean 22.8%) of SL. Caudal fin slender, pointed to slightly rounded, 27.0–31.9% (mean 29.3%) of SL.

No mental fraenum, chin smooth to slightly bulbous. Anterior nostril tubular, placed at preorbital edge, tube oriented down and forward, preorbital often slightly curved to accommodate nostril. Posterior nostril round to oval, placed close to front centre margin of eye. Gill opening extending forward to under opercle. Inner edge of pectoral girdle smooth (in nine) or with knobby ridge or bony flange, which may support flaps (in 21), two specimens with distinct fleshy knobs. Gill rakers on outer face of first arch very short and unspined, longest rakers near angle of arch; rakers on inner face of first arch not much longer than those on outer face; inner and outer rakers on other arches similar to rakers on first arch. Tongue long, tip usually blunt to slightly concave; occasionally folded longitudinally. Outer teeth across front of upper jaw largest, sharp and curved, largest teeth toward side of jaw (considerably larger in males); behind this row, two or three rows of small sharp teeth; only one or two rows at side of jaw; teeth may be absent from posterior half of jaw; tips of teeth (mostly outer row) often tinted translucent orange to brown. Lower jaw with four or five rows of small sharp teeth across front; teeth toward sides largest and stoutest (enlarged and curved in males); usually only one row of teeth along side of jaw; tips of teeth often tinted translucent orange or brown.

Predorsal scales moderate, evenly sized, reaching forward to behind eyes or at least halfway between rear preopercular margin and eyes. Operculum with two to four cycloid scales on upper half. Cheek always naked. Pectoral base covered with cycloid scales. Prepelvic area covered with cycloid scales. Belly with cycloid scales, occasionally naked anteriorly, underneath pelvics. Ctenoid scales on side of body extending up to pectoral base.

Gut simple, S-bend shape.

Genital papilla in male relatively short, flattened, tip blunt to rounded, with one or two fine lobes present; in female, short, rounded and indented at tip.

Headpores present, with pair of anterior interorbital scales, single posterior interorbital pore, and infraorbital and postorbital pores behind each eye. Rear portion of oculoscapular canal absent. No preopercular pores.

Sensory papillae pattern longitudinal, as in Fig. 23 . Papilla row b broken well behind eyes, rear portion with two to four papillae. Three s rows, of one papilla each. Mental f row consisting of one papilla on each side of symphysis.

Colouration of fresh material. – From colour slides by Peter Ng and Heok Hui Tan of fresh specimens. Colouring very similar to preserved specimens, but upper part of head and body with scattered orange-red spots, dorsal and anal fins with orange-red to red wash over black and dark brown spots and streaks; pectoral and caudal fins reddish, not as bright as dorsal fins (Plate 2A).

Colouration of preserved material. – Head and body yellowish-white to pale yellowish-brown, with scattered dark brown to blackish spots, some scale margins partly outlined with dark brown, especially on lower half of body, and five oblique to nearly vertical dark brown bars crossing back and sides, evenly spaced from just before first dorsal fin origin to just before upper procurrent rays of caudal fin; occasionally brown blotch on centre of nape ( Fig. 24 , Plate 2A). Oblique bars becoming diffuse and ending on midside of body; indistinct midlateral brown streak, formed by two to three rows of pale scales with brown spots on or near their centres, sometimes present. Brown spots on body of variable intensity, usually very fine and partly outlining scale margins, especially on lower half of body. At midbase of caudal fin, oblique elongate blackish blotch present, extending down and back onto lower segmented caudal rays. Pectoral base dusky with short dark brown bar extending obliquely from upper third of base onto upper ray bases. Ventral midline of caudal peduncle with thin black line sometimes visible; midventral line of body with five narrow black blotches, evenly spaced, from anus to just before lower procurrent rays of caudal fin; anteriormost black blotch (at anus) sometimes obscure.

Side of head with many dark brown to blackish oblique lines, often vermiculate or broken into rows of short streaks or spots; opercle usually with rows of spots. Anteriormost two lines darkest, extending from margin of eye across preorbital to front of jaws, crossing jaws to meet counterparts on lower lip and chin. Upper lip pale, barred with dark brown (continuation of oblique stripes on head); lower lip pale to dusky, often with few brown bars or spots anteriorly. Rear of opercle and branchiostegal membranes dusky with small brown blackish spots in males; pale with short brown to blackish oblique lines in females. Nape and interorbital with small brown blotches and small spots. Underside of head and belly plain pale whitish to dusky brownish; scales with margins outlined in dark brown forming dark patch on breast just anterior to pelvic fins in males.

First dorsal fin translucent to dusky, with broad dark grey to blackish streak across centre of fin, diffuse black spot within streak toward rear sometimes present; brownish narrow stripes or dusky streaks along fin above and below central broad dark streak; tips of several dorsal spines with dense black spot, usually on first, third and fourth; first dorsal spine always pale with two to three small dark brown to black spots on membrane just behind spine. Second dorsal fin whitish to translucent, with five to seven rows of small dark brown to black round to oval spots; unsegmented spine always pale with two black spots, fin margin plain dusky. Anal fin plain dusky to brownish. Pectoral fins translucent dusky to pale brownish, rays becoming darker toward tips; fins distinctly darker in males. Pelvic fins plain dusky grey to brownish. Caudal fin translucent whitish to pale dusky with many rows of vertically oriented, dark brown to black small spots or short lines, spots becoming smaller distally; short lines closest to fin base sometimes joining to form one or two oblique to vertical dark lines on lower half of fin; lowermost edge of caudal with broad plain dusky to greyish margin; one to three black spots along upper edge of fin, crossing dorsal procurrent rays.

Males distinguished from females in being darker, on pectoral fins especially, and in having darker and more complex vermiculate oblique lines on head ( Figs. 23 , 24 , Plate 2A).

Sensory papillae often orange-tipped. Peritoneum pale with broad brown dorsal saddle and scattered brown spots (as in colour pattern of surrounding skin).

Comparisons. – Most similar to P. paludosus ; most easily distinguished by the presence of headpores and in the oblique dark lines on the side of the head (vs. headpores absent and brown blotches on side of head).

Distribution. – Specimens are only known so far from rainforest freshwater streams of Sarawak, Malaysia.

Ecology. – One specimen lot was recorded as being from a slightly turbid blackwater stream, with leaf litter and aquatic vegetation present.

Etymology. – From the Latin, festivus , meaning cheerful, delightful or humorous, all words which relate to the elongate smiling jaws of mature males.

Remarks. – This species and P. paludosus share a synapomorphy: cheek papilla row b is broken into two sections, with a wide gap behind the eyes.

Figures

Fig. 22. Pseudogobiopsis festivus, new species, holotype, 34.5 mm SL, male, ZRC 40279, near Kuching, Sarawak, Malaysia.

Fig. 23. Pseudogobiopsis festivus, new species, papillae pattern. 26 mm SL female, CMK 8401, Sungei Bejit, Sarawak: A, lateral view; B, dorsal view. Scale bar = 1 mm.

Fig. 24. Pseudogobiopsis festivus, new species, female paratype, 29.5 mm SL, ZRC 40280, Kuching, Sarawak, Malaysia.