Pseudogobiopsis paludosus ( Herre, 1940 )

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 : 163-166

Pseudogobiopsis paludosus ( Herre, 1940)

( Figs 27–30 ; Tables 13–16, 19)

Ctenogobius paludosus Herre, 1940: 23 , Pl. 18 (north of Kota Tinggi, Johore, Malay Peninsula).

Calamiana sp. undet. – Roberts 1989: 168.

Rhinogobius paludosus – Kottelat 1989: 19.

Eugnathogobius paludosus – Larson 2001: 70.

Material examined. – MALAYSIA: Holotype of Ctenogobius paludosus, CAS 32998, 1(30.5), 5 miles (8 km) north of Kota Tinggi, Johore, A. W. Herre, May 1937. ZRC 8411 , 1 (30), Sungai Sedili, Johore, 22 Feb.1968; CMK 7384 , 8 (12.5–29.0), Sungai Mupor, Johore, M. Kottelat, P. K. L. Ng & K. Lim, 22 Jan.1991; NTM S.16416-001, 2(18–25), C&S, same data as previous. INDONESIA: USNM 230332 , 3 (18–23), West Kalimantan, Sungai Gentu, near confluence with Kapuas River, T. Roberts, 16 Aug.1976; CAS 49462, 58 (7.5–28.0), Sungai Mandai Kecil, near confluence with Kapuas River , 18 km west-south-west of Putissibau, T. Roberts and S. Woerjoatmodjo, 1 Aug.1976; CMK 9009 , 5 (13–21), Sumatra, Riau district, Sungai Kalesa , north of Seberida , A. J. Whitten, 22 Feb.1992.

Other material examined (but not used in description). MALAYSIA: ZRC 8405 , 1 , by Gunung Panti , Johore ; ZRC 17095, 1 , by Gunung Panti , Johore ; ZRC 14011, 1 , Kota Tinggi . INDONESIA: USNM 230333 , 7 , Kapuas River tributary, Borneo ; USNM 230331 , 7 , Sungei Seriang, Sungei Palin tributary ; CMK 6933 , 1 , Sungai Sibau , Kalimantan Barat ; CMK 6761 , 3 , Kapuas River tributary, Kalimantan Barat ; CMK 11598, 1 , Sungai Letang, Kapuas River tributary, Kalimantan Barat ; CMK 10141 ,

14, Sungai Piyam, Nanga Empanang , Kalimantan Barat ; CMK 11781, 1 , Sungai Barito , Kalimantan Tengah ; MHNG 2537.36 , 2 , N of Sempit , Kalimantan Tengah ; CMK 9674 , 1 , Sungai Serdang , Sumatra, Riau Province .

Diagnosis. – Slender Pseudogobiopsis , somewhat rounded anteriorly, with second dorsal rays I,7–10 (modally I,8); anal rays I,6–7 (modally I,7); pectoral rays 13–16; longitudinal scales 23–27; TRB 7–9; predorsal scales 5–9, small, reaching to above preopercular margin; headpores absent; mouth enlarged in males; scales on body mostly ctenoid; caudal fin pointed; head and body yellow to whitish with scattered brown spots and five brown bars crossing back and sides, caudal and dorsal fins with rows of fine black spots; single very broad epural; known from fresh waters of Indo-Malaysian Archipelago.

Description. – Based on 23 specimens, 16–30.5 mm SL. An asterisk indicates counts of holotype of Ctenogobius paludosus ( Fig. 27 ).

First dorsal V (in one), VI* (in 21), VII (in one); second dorsal I,7–10 (mean I,8*); anal I,6–7 (mean I,7*), pectoral rays 13*–16 (mean 15), segmented caudal rays 15–17*; caudal ray pattern 6/6 to 8/8 (modally 7/6*); branched caudal rays 12–16 (mean 14, 13 in holotype); unsegmented (procurrent) caudal rays 5/5 to 6/5; longitudinal scale count 23-27 (mean 25, 24 in holotype); TRB 7*–9 (mean 8); predorsal scale count 5–9 (mean 8*); circumpeduncular scales always 12*. Gill rakers on outer face of first arch 1+6 to 3+6 (modally 2+6). Pterygiophore formula 3-12210 (in eight). Vertebrae 10+15 (in three), 10+16 (in nine), 10+17 (in one). Neural spines of first few vertebrae slender, pointed (in 10). One (in 10) very broad epural; two in one specimen. Two (in 11) anal pterygiophores before haemal spine of first caudal vertebra. Palatine not in contact with quadrate. Pterygoid long, equal to or longer than palatine. Metapterygoid low to moderate, well separate from quadrate in female, slightly overlapping quadrate in adult male (suspensorium shifted back and shortened by enlarged jaws) ( Fig. 28 ). Quadrate shallowly forked. Dentary short, narrow. Pectoral radials poorly ossified. Scapula unossified.

Body slender, compressed, more rounded anteriorly. Body depth at anal fin origin 15.4–19.5% (mean 17.1%) of SL. Head rounded to slightly depressed, wider than deep, but not greatly so, HL 30.5–33.7% (mean 31.9%) of SL; cheeks may be considerably inflated in males. Depth at posterior preopercular margin 47.8–56.9% (mean 51.7%) of HL. Width at posterior preopercular margin 56.9–71.6% (mean 65.3%) of HL. Mouth terminal, lower jaw tip anteriormost, oblique, forming angle of about 25–30° with body axis; jaws reaching past rear of eye in males and to below front half of eye in females (well past rear of eye in holotype). Lips smooth, usually narrow in males; without fleshy fimbriae along edge; lower lip free at sides, broadly fused across front. Upper jaw 32.1–62.5% (mean 34.3% in females, 52.4% in males) of HL. Eyes dorsolateral, close to snout tip, high on head forming part of dorsal profile, 22.1–35.2% (mean 29.3%) of HL. Snout short, flattened, 17.7–27.4% (mean 23.7%) of HL. Interorbital flat, moderate to narrow, 8.5–22.7% (mean 18.8% in males, 14.4% in females) of HL. Caudal peduncle long, compressed, length 22.1–30.1% (mean 26.6%) of SL. Caudal peduncle depth 10.0–12.9% (mean 11.7%) of SL.

First dorsal fin triangular, pointed, third to fifth spines longest or subequal, sometimes elongate, especially in large males (first dorsal spine longest in one female), second or third spine longest in females, third modally longest in males; spines slightly longer in males than females; spines usually reaching second dorsal fin origin when depressed. Second dorsal spine longest in some females, length 15.3–17.3% (mean 16.5%) of SL. Third dorsal spine length 14.0–15.7% (mean 15.1%) of SL. Fourth dorsal spine length in males 15.0–27.3% (mean 22.8%) of SL. Fifth dorsal spine length in males 19.2-35.0% (mean 25.8%) of SL. Second dorsal and anal fins short-based, pointed posteriorly, rays falling well short of caudal fin base when depressed. Pectoral fin pointed, slender, central rays longest, 23.3–31.3% (mean 26.5%) of SL; rays usually all branched. Pelvic fins long, oval, usually reaching to anus, 20.0–25.9% (mean 23.8%) of SL. Caudal fin slender, pointed, 25.2–34.8% (mean 29.7%) of SL.

No mental fraenum, chin blunt, smooth, slightly protuberant. Anterior nostril in very slender tube, placed just at preorbital edge, tube oriented forward and slightly downward, preorbital occasionally produced forward to accommodate nostril. Posterior nostril small, oval, placed about midway between front centre margin of eye and anterior nostril. Gill opening extending forward to just under opercle. Inner edge of pectoral girdle with smooth narrow edge (in 14) or with smooth bony flange (in nine) which may be angled outward, rarely with low flat lobes or flaps present. Gill rakers on outer face of first arch usually short knobs, occasionally slender or reduced, shortest rakers on upper limb; rakers on inner face of first arch of similar size but stouter; outer and inner rakers on other arches similar to those of first arch. Tongue long, tip blunt to rounded, occasionally slightly pointed.

Upper jaw teeth in male: teeth in outermost row, across front of jaw to midside of jaw, large, sharp and curved, largest teeth grouped at midside of jaw, rear third or less of jaw without teeth; inner three or four rows consisting of small, curved, sharp teeth. Upper jaw teeth in female: about three rows of small curved sharp teeth across front; one row of teeth at side of jaw. In males, lower jaw with band of five to seven rows of curved sharp teeth across front, band broader toward side of front of jaw and one or two large curved outer teeth at each side. Lower jaw teeth arrangement similar in females, but with four or five rows of curved sharp teeth across front of jaw; one or two slightly enlarged teeth outermost, toward each side of lower jaw. Tips of teeth in both sexes sometimes tinted translucent orange or brown.

Predorsal scales cycloid, moderately sized, reaching forward to at least preopercular margin or to between preopercular margin and rear of eyes. Operculum naked or with one to few cycloid scales. Cheek always naked. Pectoral base naked or with one or two cycloid scales. Prepelvic area usually with few cycloid scales, occasionally naked. Belly with cycloid scales, occasionally naked. Side of body with ctenoid scales extending up to behind pectoral base. Anteriormost scales on side of body larger than those on caudal peduncle.

Gut short, S-bend shape. Female genital papilla quite large, swollen and rounded, with two lobes at tip (size probably due to large size of ripe ova). Male genital papilla small, flat and pointed.

Head pores absent.

Sensory papillae pattern longitudinal, as in Fig. 29 . Papillae in row p few, widely spaced. Papillae in cheek rows a, c and cp enlarged, widely separated; other papillae very small and fine. Cheek row b broken into two short sections, with wide gap. Three s rows of papillae on snout, of one papilla each. Mandibular f row of one papilla on each side. Papillae in row i along dentary few, widely separated.

Colouration of fresh material. – Colour slide by Maurice Kottelat, of freshly dead specimens, showing colour very like that of preserved material: pale yellowish-white with blackish to dark brownish grey markings on body and blackish markings on fins.

Colouration of preserved material. – Head and body yellowish-white to pale yellowish-brown, covered with small dark brown round spots 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 ( Fig. 30 ). Oblique bars usually ending on lower side of body, often intensified on midside of body forming row of square dark brown blotches, slightly offset from oblique bar. Dark brown spots on body of variable intensity, sometimes very fine and partly outlining scale margins; on side of head, spots usually large and rounded. At midbase of caudal fin, triangular to oblique elongate dark brown blotch present; if oblique, blotch extending down and back onto lower segmented caudal rays. Underside of head and belly plain pale whitish to pale brownish; small patch of dark brown spots on breast just anterior to pelvic fins in males. Ventral midline of caudal peduncle with thin black line and three (occasionally four) narrow black blotches, evenly spaced, from midbase of anal fin to just before lower procurrent rays of caudal fin.

Side of head with two short oblique dark brown bars from rear of eye extending down and backward, ending on middle of cheek; and one bar extending from lower front margin of eye to middle of jaws, crossing jaws to meet its counterpart on chin; bars blotchy and often nearly indistinguishable from small dark brown spots covering head. Opercle with dark brown spots often coalescing into dark blotches. Lips nearly uniform brown or with small dark brown spots. Nape and interorbital with small brown blotches and small spots. Pectoral base pale with scattered dark brown round spots.

First dorsal fin translucent to whitish, with broad dark grey to black band across centre, intense black spot within band toward rear of fin usually present, and short narrow oblique blackish streak from base of first dorsal fin crossing bases of first three spines; first dorsal spine always pale with two small dark brown to black spots (regardless of intensity of blackish bands on rest of fin). Second dorsal fin whitish to translucent, with three to five rows of small dark brown to black round to oval spots; unsegmented spine always pale with two black spots. Anal fin plain dusky to brownish, darker toward base. Pectoral fins translucent dusky to pale brownish, rays darkest at bases. Pelvic fins plain dusky grey to brownish. Caudal fin translucent whitish to pale dusky with five to seven rows of vertically oriented, dark brown to black small spots or short lines; spots or short lines closest to fin base sometimes joining to form one or two wavering vertical dark lines.

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

Comparisons. – This species is most similar to P. festivus , new species from Sarawak; see Comparisons under that species. There may be another undescribed species related to this species-group, see Remarks below.

Distribution. – Specimens are known from Peninsular Malaysia, western Borneo and the Riau Archipelago, Sumatra.

Ecology. – Known from freshwater habitats, including clear, swift “blackwater” (brown to reddish tinted) streams ( Roberts, 1989).

Roberts (1989) gives information on reproductive condition of the specimens obtained during the Kapuas River survey, e.g. a 19.5 mm female specimen (out of CAS 49462) had 30 eggs, of 1.5 mm diameter .

Remarks. – This species was described from “the type and only specimen, 30 mm. long” ( Herre, 1940 a). His illustration of the type, despite its simplicity, gives a good impression of the species, and it is apparently the only published illustration of the species. A specimen presently labelled as paratype (CAS 32988) is a species of Pseudogobius and is not a type specimen.

Twenty small specimens from Sanggau and Sintan on the Kapuas River drainage in western Kalimantan (CMK 6735, CMK 6799 and CAS 49461) were initially referred to this species. However, they have some headpores, but are lacking preopercular canals and the posterior portion of oculoscapular canal. Three very small specimens in CMK 6735 have no pores or exhibit open canals only. All these specimens are similar in that the colour pattern shows narrow brown scale margins over the pale back and sides, forming an irregular network pattern, and the five brown saddles and lateral bars are rather indistinct. Additional material, including mature males, is required to determine the status of these specimens, which probably represent an undescribed species. These specimens are not dealt with further in this paper.

Figures

Fig. 27. Pseudogobiopsis paludosus. Holotype of Ctenogobius paludosus Herre, CAS 32998, 30.5 mm SL male, Kota Tinggi, Johore, Malaysia.

Fig. 28. Jaws and suspensorium of Pseudogobiopsis paludosus. A, male, ex CAS 7384, Sungei Mupor, Johore, Malaysia; B, female, CMK 6735, Kalimantan Barat, Borneo (specimens from this lot possibly represent a separate species). Scale bar = 1 mm.

Fig. 29. Pseudogobiopsis paludosus, papillae pattern. 29 mm SL male, CMK 7384, Johor, Malaysia. Scale bar = 1 mm.

Fig. 30. Pseudogobiopsis paludosus, CMK 7384, 20 and 29.5 mm SL, Johor, Malaysia. From colour slide by Maurice Kottelat.