Rasbora patrickyapi, Hui, 2009

Hui, Tan Heok, 2009, Rasbora Patrickyapi, A New Species Of Cyprinid Fish From Central Kalimantan, Borneo, Raffles Bulletin of Zoology 57 (2), pp. 505-509 : 505-509

Rasbora patrickyapi , new species

( Figs. 1A–D )

Material examined. – Holotype: MZB 10707, 41.8 mm SL; Central Kalimantan: Rungan-Kahayan basin, Sungei Rijak, km 84 along road from Palangkaraya to Telakin (01°37.319'S 113°37.560'E, 54 m asl); P. Yap et al., 18 Sep.2007.

Paratypes – ZRC 51748, 11 ex. , MZB 10708, 4 ex., CMK 21508, 5 ex., 29.8–42.2 mm SL; same locality data as holotype . – ZRC 51749, 20 ex., 31.9–44.5 mm SL; Central Kalimantan: Rungan- Kahayan basin, from aquarium fish trade; P. Yap, 24 Jul.2007 . – MZB 5334 , 11 ex., paratypes, 23.6–57.0 mm SL; Central Kalimantan: Katingan River basin, Kecamatan Katingan ilir, Sungei Hampalit; A. Jaim, 18 Mar.1984 . – ZRC 51750, 5 ex., 23.8–46.5 mm SL; Central Kalimantan: Katingan River basin, stream before Tumbang Samba ; T. Idei , 2004 .

Diagnosis. – Rasbora patrickyapi is differentiated from its congeners in the following combination of characters: in life, body with iridescent, black midlateral stripe bordered by a white stripe above it, reddish unpaired fins, sides of body with violet sheen, dorsum with golden sheen. Lateral line complete with 28 scales; distinct symphyseal knob; body depth at dorsal fin origin 23.9–26.1% SL; predorsal scales 12–13 (modally 13); transverse scales 5.1.2; circumpeduncular scales 15; predorsal length (54.0–56.6% SL).

Description. – General body shape and appearance as shown in Fig. 1 ; meristics and morphometrics in Table 1. Head broadly pointed, relatively short (head length 27.8–29.0% SL), relatively narrow (head width 47.8–49.1% HL) and deep (head depth 58.6–63.1% HL). Mouth terminal and slightly upturned, symphyseal knob distinct; no tubercels present. Orbit relatively large (27.7–30.4% HL), situated nearer to tip of snout than opercle edge. Interorbital width large (33.3–37.2% HL), dorsal profile a gentle slope to slight concavity. Slope of nape gentle from head to body, body cylindrical, compressed laterally, relatively slender, deepest at dorsal fin origin (23.9–26.1% SL), most slender at caudal peduncle (13.5–14.9% SL). Lateral line complete, running diagonally from opercle edge towards pelvic fin origin and to just below the middle of caudal base. Dorsal and anal fins placed relatively far back (54.0–56.6% SL and 68.7–70.8% SL respectively).

Dorsal fin triangular, with 2 simple and 7 branched rays, last two rays articulate on the same pterygiophore; origin above lateral line scale 7 or 8 (modally 8), behind origin of pelvics. Caudal fin forked, with upper lobe longer than lower lobe, ratio of length versus caudal peduncle depth 1.54–1.66. Anal fin triangular, with 2 simple and 5 branched rays, last two rays articulate on the same pterygiophore; origin below lateral line scale 13 or 14 (modally 13). Pelvic fin triangular, with 1 simple and 7 branched rays, adpressed fin does not reach anal-fin origin; origin below lateral line scale 6 or 7 (modally 7); pelvic axillary scales present, just longer than base of pelvic fin. Pectoral fin triangular, with 1 simple and 12 branched rays, adpressed fin not reaching pelvic-fin origin, axillary lobe present, about equal length with pectoral-fin base. Two scale rows between lateral line and pelvic-fin origin.

Predorsal scales 12–13 (modally 13), transverse scales at anus 5.1.2, transverse scales at dorsal-fin origin 6.1.2, lateral scales 28 (+ 2 on caudal fin), caudal peduncle scales 4.1.2.

Sample size 1 5

Standard length (mm) 41.8 39.3–41.8

% Standard length

Total length 130.1 129.6–133.2

Trunk length 72.2 71.5–73.6

Predorsal length 56.2 54.0–56.6

Preanal length 70.8 68.7–70.8

Prepelvic length 51.9 50.3–51.9

Head length 27.8 27.8–29.0

Body depth at dorsal fin origin 23.9 23.9–26.1

Body depth at anus 20.3 20.3–21.5

Caudal peduncle depth 13.9 13.5–14.9

Caudal peduncle length 22.5 21.1–23.8

Dorsal fin base length 12.2 11.6–12.2

Anal fin base length 12.7 10.9–12.7

Pelvic fin length 18.4 16.8–18.6

Pectoral fin length 24.4 22.6–24.4

Upper caudal lobe length 31.8 31.4–36.4

Middle caudal length 20.6 16.8–20.6

Lower caudal lobe length 28.0 28.0–34.1

% Head length

Head depth 58.6 58.6–63.1

Head width 48.3 47.8–49.1

Snout length 29.3 27.7–29.7

Orbital diameter 28.4 27.7–30.4

Interorbital width 37.1 33.3–7.2

Vertebral count: 17–18 + 15–16, total = 32–34 (mode 33, n = 10).

Live coloration. – See Figs.1A–B . Dorsum of head and body dark brown with gold sheen. Top of eye goldenorange. Black stripe running from lower jaw, through eye to opercle edge, continuing onto midlateral black stripe (margins are irregular) to caudal base and through to tips of middle caudal fin rays; with green iridescence. A white stripe above midlateral black stripe posterior to opercle edge to caudal base. A black suparanal blotch above anal fin origin. Body with violet sheen throughout. All unpaired fins reddish, pelvic fin reddish and pectoral fin yellowish. Dorsal fin anterior base to mid area with black pigments.

Coloration in preservative. – See Figs. 1C–D . Freshly preserved specimens with colours as in life, but muted and lacking iridescence and sheen ( Fig. 1C ). Specimens stored in ethanol were discoloured, with no red colouration ( Fig. 1D ). Body cream, with dark brown dorsum and black central stripe. The midlateral black stripe is broadest at the middle of the body, sometimes interrupted with cream patches above the region between the pelvic and anal fins. Mid-dorsal black stripe present, mid-ventral black stripe present on caudal peduncle.

Distribution. – Rasbora patrickyapi is currently known only from the lowland peat swamps and degraded heath forest of the Katingan and Kahayan river basins of Central Kalimantan, Borneo ( Fig. 4 ).

Field notes. – Rasbora patrickyapi inhabits shallow, slow-flowing swampy areas next to the flowing blackwater streams. At the type locality ( Fig. 5 ), and is sympatric with Rasbora kalochroma . Other fishes include: Cyprinidae – Osteochilus pentalineatus , O. spilurus , O. bleekeri , Rasbora cephalotaenia , Sundadanio cf. axelrodi , Systomus rhomboocellatus , S. johorensis , S. trifasciatus ; Cobitidae – Kottelatlimia hipporhynchos , K. pristes ; Nemacheilidae – Nemacheilus sp. ; Siluridae – Ompok supernus , Silurichthys phaiosoma ; Clariidae – Clarias leiacanthus ; Hemiramphidae – Hemirhamphodon chrysopunctatus ; Nandidae – Nandus nebulosus ; Osphronemidae – Betta anabatoides , B. foerschi , Luciocephalus pulcher , Sphaerichthys selatenensis ; Channidae – Channa bankanensis ; Mastacembelidae – Macrognathus circumcinctus . The lowland swamplands around Palangkaraya have mainly been logged, and the vegetation is secondary. The habitat is heath forest interspersed with peat swamp. The substrate are a mixture of peat and silica sand.

Etymology. – Named for Patrick Yap Boon Hiang, a long-time supporter of the museum and freshwater fish enthusiast and exporter, who has generously donated much fish material for the author’s research.

Remarks. – Rasbora patrickyapi belongs to the R. einthovenii group(as defined by Brittan, 1954) but displays characters of both R. eithovenii and R. kalochroma .

Brittan (1954) listed four species belonging to the R. einthovenii group, and these are R. einthovenii , R. cephalotaenia , R. tubbi and R. jacobsoni . The basis for this species group is not very clearly defined, Brittan (1954) only listed the following characters: circumpeduncular scale rows 12 (except for R. tubbi , with 14); and an overall morphological similarity. He also mentioned the variable lateral line scale counts ( R. einthovenii 29–32, R. cephalotaenia 32–34, R. tubbi 34–35, and R. jacobsoni 24–27). From the present study, the circumpeduncular scale rows are counted based on a slightly different technique, and R. einthovenii has 13 and R. patrickyapi has 15. The overall morphology of R. patrickyapi places it with the R. einthovenii group.

Rasbora patrickyapi differs from R. einthovenii in the following characters: body with violet sheen in life (vs. absence); reddish unpaired fins in life (vs. hyaline to pale yellow); well demarcated broad white stripe above black midlateral stripe (vs. weakly marked, see Fig. 3); absence of reticulate pattern on edge of body scales along dorso-lateral area above pectoral to pelvic fin region (vs. presence); lower margin of midlateral black stripe indistinct (vs. conspicuous in lower half of body); dorsal and anal fins without marking (vs. sub-distal black bars); dorsal profile of body a gentle slope (vs. more arched); presence of supra-anal black blotch (vs. absence); more pelvic-fin rays (1, 7, vs. 1, 6); more lateral scales (28 +2, vs. 23–24 +2); more circumpeduncular scales (15 vs. 13); smaller predorsal length (54.0–56.6% SL, vs. 56.7–58.6); smaller pectoral fin length (22.6–24.4% SL, vs. 24.3–26.4); smaller head width (47.8–49.1% HL, vs. 49.5–54.3); smaller interorbital width (33.3–37.2% HL, vs. 40.7–46.0).

Rasbora patrickyapi differs from its sympatric congener, R. kalochroma in the following characters: presence of black midlateral stripe (vs. absence of stripe, instead having two black rounded blotches, one above the pectoral fin and the other above the anal fin, see Fig. 2 ); body with violet sheen in life (vs. red); pectoral, pelvic and anal fins without distal tip of second ray extending beyond interradial membrane (vs. tips of second ray extending beyond interradial membrane); presence of supra-anal black blotch (vs. absence); more pectoral-fin rays (1, 12 vs. 1, 11); more tranverse scales at dorsal-fin origin (6.1.2 vs. 5.1.2); more circumpeduncular scales (15 vs. 12); dorsal, anal and pelvic fins placed more anterior in relation to lateral scale number (dorsal:7–8 vs. 10; anal: 13–14, vs. 16–16½; pelvic: 6–7, vs. 8); smaller preanal length (68.7–70.8% SL, vs. 70.8–73.1); more slender body (body depth 20.3–21.5 % SL vs. 21.9–23.0); more slender caudal peduncle (its depth 13.5–14.9% SL vs. 15.3–17.1; its length 21.1–23.8 % SL vs. 18.3–21.2); larger ratio of length versus caudal peduncle depth (1.54–1.66 vs. 1.12–1.27); smaller pelvic fin length (16.8–18.6% SL vs. 18.7–22.1); smaller pectoral fin length (22.6–24.4% SL vs. 25.0–29.3); smaller head width (47.8–49.1% HL vs. 50.0–56.4); smaller interorbital width (33.3–37.2% HL vs. 41.3–47.3).

Rasbora patrickyapi can be differentiated from the rest of striped rasboras occurring in Borneo (namely R. agyrotaenia , R. cephalotaenia , R. dusonensis , R. gracilis , R. rutteni , R. sarawakensis , R. tornieri and R. trifasciata ) by the following characters: it is a stenotopic inhabitant of peat swamps (vs. riverine habitat of R. agyrotaenia , R. dusonensis and R. tornieri ; vs. hill stream habitat of R. rutteni , R. sarawakensis and R. trifasciata ; vs. swamp forest habitat of R. cephalotaenia and R. gracilis ), lateral scale count of 28 (vs. 24–27 of R. sarawakensis and R. trifasciata ; vs. 29–35 of R. dusonensis , R. cephalotaenia , R. agyrotaenia , R. gracilis and R. tornieri ), presence of black supra-anal blotch (vs. black supra-anal stripe of R. sarawakensis , R. cephalotaenia , R. agyrotaenia , R. tornieri and R. gracilis ; vs. absence in R. dusonensis and R. rutteni ) (data extracted from Brittan, 1954, and Kottelat et al., 1993).

Comparative material. – Rasbora einthovenii – ZRC 50123, 5 ex., 26.4–34.7 mm SL; West Kalimantan: Sambas [type locality] basin, Sungei Sinabar, blackwater tributary of Sambas River ( Fig. 3). Rasbora kalochroma – ZRC 51451, 10 ex., 33.3–60.2 mm SL; Central Kalimantan: Kahayan basin, Rungan River , aquarium trade . – ZRC 51751, 14 ex., 37.8–52.5 mm SL; Central Kalimantan: Katingan basin, Kasongan east area . – ZRC 51752, 4 ex., 25.7–39.7 mm SL; Central Kalimantan: Rungan-Kahayan basin, Sungei Rijak, km 84 along road from Palangkaraya to Telakin ( Fig. 2 ) .

Figures

Fig. 1. Rasbora patrickyapi, A, ZRC 51749, paratype, ca. 40 mm SL, life colouration; B, ZRC 51749, paratype, ca. 40 mm SL, life colouration; C, ZRC 51748, paratype, 41.4 mm SL, freshly preserved; D, MZB 10707, holotype, 41.8 mm SL, preserved material, Central Kalimantan: Rungan.

Fig. 4. Map of Borneo showing distribution of Rasbora patrickyapi (circle); type locality of Rasbora einthovenii (square); type locality of Rasbora kalochroma (triangle).

Fig. 5. Type locality of Rasbora patrickyapi (March 2008).

Fig. 2. Rasbora kalochroma. ZRC 51752, 37.9 mm SL; Central Kalimantan: Rungan.