Platygobiopsis hadiatyae, Helen K. Larson1* & Teguh Peristiwady4, 2020

Helen K. Larson 1 *, Zeehan Jaafar 2, Tan Heok Hui 3 & Teguh Peristiwady 4, 2020, Platygobiopsis hadiatyae, a new species of deepwater gobiid from Indonesia (Teleostei, Gobiidae, Gobiinae), Raffles Bulletin Of Zoology 68, pp. 14-18 : 14-17

Platygobiopsis hadiatyae , new species Renny’s Flat Goby

2 Department of Biological Sciences, 14 Science Drive 4, National University of Singapore, Singapore 117543, Singapore; Email: [e-mail]

( Figs. 1—4 )

3 Lee Kong Chian Natural History Museum, National University of Singapore, 2 Conservatory Drive, Singapore 117377; Email: [e-mail]

Holotype. MZB 17230 , 43.0 mm SL male; East Sunda Strait, along Panaitan Strait, off southern end of Panaitan Island, SJADES- 2018 station DW 19 , 6°42.551'S, 105°11.143'E to 6°42.762'S, 182— 172 m depth, mud and clay substrate, dredge, 27 March 2018 .

4 Bitung Marine Life Conservation Unit,Research Center for Oceanography,Indonesian Institute of Sciences,Tandurusa,Aertembaga, Bitung 97255, North Sulawesi, Indonesia; Email: [e-mail]

© National University of Singapore ISSN 2345-7600 (electronic) | ISSN 0217-2445 (print)

Diagnosis. Avery elongate, slender member of Platygobiopsis with flattened head and body, distinguished from congeners by the following combination of characters: total number of vertebrae 26; dorsal pterygiophore pattern 3-12210; sensory papillae on head in longitudinal pattern, with most papillae fleshy and forming two low fleshy ridges or folds on side of head; sensory pores on head absent; lateral scales 56; scales absent from head, predorsal, pre-pelvic area and belly; no barbels on underside of head; I,12 dorsal-fin rays; I,13 anal-fin rays; 17 pectoral-fin rays; translucent pinkish when fresh, upper part of head and body with fine dark brown speckling, fins translucent with variable brown speckling.

Description. Based on holotype ( Figs. 1—4 ). Where morethan one count is given, this refers to left and right side of body. First dorsal VI; second dorsal I,12; anal I,13; pectoral 17; segmented caudal rays 17; branched caudal rays 8/7; caudal ray pattern 9/8. Longitudinal scale count 56; TRB 10; circumpeduncular scales 9. Vertebrae 10+16. First dorsal pterygiophore pattern 3-12210, 1 broad epural, 2 pre-anal pterygiophores ( Fig. 4 ).

Body greatly elongated, slender, depressed anteriorly and becoming less depressed andnarrower posteriorly; body depth at anal origin 4.6% of SL, body width at anal origin 9.3% of SL. Head length 8.5% of SL; wider than deep, considerably flattened; head depth at posterior preopercular margin 2.8% of HL; head width at posterior preopercular margin 6.5% of HL. Mid-dorsal low ridge of skin from dorsal-fin origin to back of cranium. Mouth slightly oblique, terminal but with chin anteriormost, reaching back to below anterior part of eye; lips smooth, lower lip free at sides, narrrowly fused across front, with slightly raised fleshy pad on chin, lacking barbels. Papilla rows b and d supported by low fleshy ridge. Upper jaw 32.9% of HL. Eyes small, mostly dorsally angled, forming part of dorsal profile, 17.6% of HL. Snout short, rounded, 9.4% of HL. Interorbital broad, flat, 15.3% of HL. Caudal peduncle long, flattened, length 18.1% of SL. Caudal peduncle narrow, depth 3.5% of SL.

First dorsal fin low, short, 13.2% of SL. Second dorsal and anal fins low, long-based (second dorsal-fin base 33% of SL), damaged from trawl, rays falling well short of caudalfin base when depressed. Low mid-dorsal groove on trunk from behind first dorsal-fin origin to caudal peduncle (to accommodate dorsal fins when folded). Pectoral fin slender, pointed, central rays longest, 16.7% of SL; rays branched but for upper and lowermost. Pelvic fins fused, oval, reaching about halfway to anus, 15.0% of SL; thin frenum present. Caudal fin probably pointed (as in congeners), damaged from trawl; what remains is 20.6% of SL.

Anterior nostril placed at preorbital edge, in short tube projecting anteriorly. Posterior nostril oval, placed close behind anterior nostril tube. Gill opening extending forward to posteror margin of preopercle. Tongue moderate in size, free, with blunt tip. Teeth in both jaws caniniform, in 2—3 rows, outermost row teeth large, more than twice the size of the inner row teeth, innermost row with small teeth except for 2 large, recurved teeth near symphysis, the latter are same size as outermost teeth.

Cycloidscales on side of body extending forward to pectoralfin base, with only 1—2 scales just above base; head naked. Pectoral-fin base, prepelvic area and belly naked.

Genital papilla elongate, narrowing toward tip.

Sensory papillae pattern longitudinal, as in Fig. 3 . Cheek rows a, c and cp composed of large and fleshy, widely spaced papillae, and rows b and d of smaller, more numerous and closely spaced papillae. Two mandibular f rows of three small papillae, placed just behind fleshy pad on chin; no barbels present. On opercle, row os is vertical and meets the oi row (this arrangement is present in all other species of the genus). Head pores absent.

Colouration of fresh material. Head and body translucent pinkish, pinkish white ventrally on abdomen; head and upper part of body with scattered dark brown fine speckles ( Fig. 1 ). Lips and anterior nostril tube darker brown than remainder of head; rim of posterior nostril margined with dark brown. Scale pocket margins on body with narrow dark brown margins except for scale pockets on ventral surface, which are unpigmented. Some of the fleshy sensory papillae on head with pale red-brown pigment, and papillae in row b alternately pale brown and red. Iris golden, darker gold dorsally. First dorsal-fin membranes damaged; what remains is translucentwith scattered pale brownish speckling; anteriormost edge offirst dorsal spine with narrow brown line. Second dorsal fin similar but rays brown at least on lower half. Caudal fin translucent pale brownish, rays darker brown than membranes. Anal-fin rays whitish to pink, membranes damaged. Pectoral fin transparent; rays with narrow line of brown along them. Pelvic fins translucent whitish.

Colouration of preserved material. Head and body whitish with fine pale brown speckling over top of head and upper part of cheek; most of opercle unpigmented; scale pocket edges on upper half of body outlined in pale brown; widely scattered very small blackish spots over ventral part of body ( Fig. 2 ). Lips and fleshy pad on chin more heavily pigmented than rest of head.

Most fin elements whitish; membranes transparent to hyaline; small pale brownish spots present on some dorsal-fin rays; narrow blackish lines along caudal-fin rays and few scattered dusky grey spots basally. Ventral midline of caudal peduncle with indistinct small greyish blotches at anterior base of each fin ray. Prepelvic area with few very small blackish spots forming indistinct broken line in midline, from isthmus to base of pelvic fins. Underside of body plain whitish.

Comparisons. This species is unlike its three congeners by lacking scales from the chest, pectoral-fin base, and belly (the others have these areas covered in cycloid scales), as well as having the predorsal region scaleless (vs. at least some predorsal scales present).

Distribution. Indonesia, currently only known from Panaitan Strait along the Sunda Strait.

Ecology. Large polychaetes, many tube worms, molluscs, crustacea, and ophiuroids came up in the dredge with the goby. The dredge started at 182 m and was lifted at 172 m (after 14 minutes of bottom time), over mud and clay bottom.

Etymology. This species is named for our dear colleague Renny Kurnia Hadiaty, who died too soon (21 August 1960 to 30 January 2019). She co-authored 19 gobioid species names in addition to many other taxa.

Figures

Fig. 1. Platygobiopsis hadiatyae, new species, MZB 17230, holotype, 43.0 mm SL, photographed soon after collection; Indonesia, Panaitan Strait along the Sunda Strait. Photographs by Tan Heok Hui.

Fig. 2. Platygobiopsis hadiatyae, new species, MZB 17230, holotype, 43.0 mm SL; fixed specimen, lateral view. Right pectoral fin dissected. Photographs by Tan Heok Hui.

Fig. 3. Platygobiopsis hadiatyae, new species, MZB 17230, holotype, 43.0 mm SL; line drawing of head (lateral view) showing sensory papilla pattern. Scale bar equal to 8 mm. Drawing by Helen Larson.

Fig. 4. Platygobiopsis hadiatyae, new species, MZB 17230, radiograph of holotype, 43.0 mm SL; lateral view.