Oryzias javanicus, (BLEEKER, 1854)

Parenti, Lynne R., 2008, A phylogenetic analysis and taxonomic revision of ricefishes, Oryzias and relatives (Beloniformes, Adrianichthyidae), Zoological Journal of the Linnean Society 154 (3), pp. 494-610 : 565-567

ORYZIAS JAVANICUS ( BLEEKER, 1854)

JAVANESE MEDAKA

FIGURES 19A , 26B , 43

Aplocheilus javanicus Bleeker, 1854: 323–324 [type locality: Indonesia: Panimbang R., Perdana, Java].- Weber & de Beaufort, 1922: 372–373 [comparisons, distribution].- Aurich, 1935: 104 [listed, key].- Smith, 1945: 425 [comparison with Oryzias minutillus ].

Aplocheilus mcclellandi Bleeker, 1854: 323–324 [comparisons with figure of Aplocheilus javanicus in McClelland, 1839].

Haplochilus javanicus .- Günther, 1866: 311 [classification in Haplochilus ].

Haplochilus javanicus var. trilineata Popta, 1911: 13–14 [description of new variety from Lombok ].

Panchax javanicus .- Fowler, 1938: 71, 254 [listed].

Oryzias javanicus .- Alfred, 1961: 13 [Seletar and Serangoon rivers, Singapore].- Rosen, 1964: 227 [classification in family Oryziatidae ].- Alfred, 1966: 43–45 [characters, synonymy, report from Singapore].- Schrey, 1978: 335 [taxonomy of Oryzias ].- Iwamatsu et al., 1982: 190 [report from Pontianak, West Kalimantan, Indonesian Borneo].- Sakaizumi, 1985: 521– 522 [electrophoretic comparisons].- Magtoon, 1986: 859–865 [distribution in Thailand, relationships, karyotype].- Uwa, 1986: 867–875 [cytogenetic comparisons].- Hori, Phang & Lam, 1988: 1770–1772 [salinity tolerance].- Uwa & Parenti, 1988: 159 [morphometric and cytogenetic comparisons].- Roberts, 1989: 1 [conclusion that presence in Pontianak is an introduction].- Lim & Ng, 1990: 82 [photo, characters, Singapore].- Mok & Munro, 1991: 235) [ecological observations in Singapore].- Kottelat et al., 1993: 89 [listed; characters; distribution in Sundaland, Sulawesi, Lombok].- Hamaguchi, 1996: 757–763 [description and comparison of testis structure].- Soeroto & Tungka, 1996: 1–5 [distribution].- Seegers, 1997: 15, 19 [listed, photographs].- Roberts, 1998: 223 [characters, relationships, distribution].- Parenti, 2000a: 2150 [listed].- Parenti, 2000b: 600 [listed].- Kakuno, Fujii & Koyama, 2001: 35–37 [gonad development].- Tan & Lim, 2004: 110 [report from Natuna archipelago, Indonesia].

Oryzias javan .- incorrect spelling; Travers, 1981: 857 [absence of interarcual cartilage].

Oryzias melastigmus .- Labhart, 1978: 53 [listed in synonymy].

Differential diagnosis: Oryzias javanicus is a small Oryzias , in a group including O. dancena , O. haugiangensis and O. carnaticus that share closed rather than open lacrimal sensory canals (as does O. hubbsi ) and a pelvic bone with a lateral strut that is needlelike and elongate, rather than blunt. Oryzias carnaticus , O. hubbsi , O. haugiangensis and O. javanicus have enlarged, bilobed urogenital papillae in females. Oryzias javanicus is like O. carnaticus in having enlarged teeth posteriorly on the premaxilla of both sexes, and is distinct in having an ethmoid cartilage anterior margin that is straight, rather than irregular and indented anteromedially, and having yellowish caudal fin margins.

Description: Small, maximum size of specimens examined 33.6 mm SL. Body compressed laterally, body depth 24–30. No pronounced abdominal concavity between pelvic fins and anal fin. Mouth terminal, jaws subequal or lower jaw projecting slightly beyond upper jaw. Dorsal body profile relatively straight from head to dorsal-fin origin; ventral body profile somewhat convex from head to anal-fin origin. Dorsal surface of head slightly convex just anterior to orbits. Head length 23–27; snout length 6–7; eye moderate, 8–9, orbits meet dorsal surface of head. Single-lobed testis on right side of body of males. Basal portion of dorsal and anal fin do not project significantly beyond primary body profile. Scales relatively large, cycloid; 27–30 in a lateral series. Elongate, filamentous dorsal- and anal-fin rays in males; anal-fin rays with bony contact organs. Medialmost pelvic-fin ray connected to body via a membrane along its proximal portion. Caudal fin truncate. Male with a short, tubular urogenital papilla; female with relatively large, bilobed urogenital papilla.

Premaxilla short and broad with distinct ascending process; premaxilla and dentary with two irregular rows of caniniform teeth; males with two to five enlarged posterior teeth on the premaxilla and dentary; females with two or three enlarged posterior teeth on the premaxilla only; tooth tips project through lips. No preethmoid cartilage; ossified portions of mesethmoid disc-shaped; anterior border of ethmoid cartilage straight. No flanges on the ventral surface of the palatine and the quadrate. Dorsal ramus of hyomandibula not distinctly bifid, single cartilage articulates with sphenotic and pterotic. Lacrimal sensory canal largely bone-enclosed and covered by epidermis. First pleural rib on parapophysis of third vertebra; first epipleural bone attaches to parapophysis of first vertebra dorsal to, and not in horizontal line with, posterior epipleural bones; lateral process of pelvic bone attaches to third pleural rib. Caudal skeleton with two epural bones; one ventral accessory bone and a second accessory cartilage or bone. Fifth ceratobranchial toothplates subtriangular, with teeth in irregular rows anteriorly, followed by six discrete rows of unicuspid teeth, including a small, incomplete posterior row. Basihyal bone relatively short and triangular, basihyal cartilage elongate and rectangular. Epibranchial elements fully ossified; epibranchial two notably smaller than the other epibranchial elements.

Dorsal-fin rays 6–8. Anal-fin rays 18–25. Pelvic-fin rays 5–6. Pectoral-fin rays 10–13. Principal caudal-fin rays i,4/5,i. Procurrent fin-rays, dorsal 4, ventral 5. Vertebrae 27–31 (10–13 + 17–18). Branchiostegal rays 5.

Cytogenetic data: Oryzias javanicus has a monoarmed chromosome constitution (Uwa, 1986, 1991b) and is characterized by having a diploid chromosome number of 48, comprising 23 acrocentric and one subtelocentric pair, and a chromosome arm number of 48 ( Table 2). Genome size is recorded as 1.7 pg DNA per nucleus.

Colour in life: Body translucent, and with melanophore pattern as described below in alcohol. Females with a subrectangular, males with a smaller, subtriangular silvery peritoneum and both sexes with a silvery operculum. Caudal fin with yellowish dorsal and ventral submarginal band.

Colour in alcohol: A diffuse row of melanophores from the dorsal surface of the head to the dorsal-fin origin, a discrete midlateral black line from the head to base of the caudal fin that continues onto the caudal fin on the membrane just dorsal and ventral to the first ray above and below the midline, respectively. Body translucent, and with melanophore pattern as described below in alcohol. Females with a subrectangular, males with a smaller, subtriangular black peritoneum. A discrete black line along the anal-fin base. Dorsal and anal fin interradial membranes with scattered melanophores. Specimens from Lombok (e.g. ZMA 100.570) are uniformly faded to a pale yellow, with silvery abdomen and faint melanophores.

Distribution and habitat: Broadly distributed in brackish waters throughout Thailand, Peninsular Malaysia, Singapore, and Indonesia (Sumatra, Java, Borneo, Bali, Lombok, Sulawesi).

Remarks: Bleeker (1854: 323–324) compared his new species, Aplocheilus javanicus , with a species referred to as Aplocheilus mcclellandi Bleeker , known from a figure in McClelland (1839). Bleeker stated that A. javanicus was nearly identical to A. mcclellandi , but differed by having fewer anal-fin rays and a narrower body depth. I do not designate a lectotype from among the syntypes because I have been unable to locate the entire type series and am uncertain of the type status of some of the specimens catalogued as types. The RMNH catalogue, for example, lists RMNH 6979 as a paratype lot, whereas Eschmeyer’s online database lists BMNH 1866.5.2.101 as syntypes. Morphometric and meristic data are supplemented by those in Iwamatsu et al. (1982) and Uwa & Parenti (1988). Another common name for this species is Javanese ricefish ( Seegers, 1997: 21).

A report of O. javanicus from Pontianak, Kalimantan, Indonesian Borneo by Iwamatsu et al. (1982) was considered an introduction by Roberts (1989). This species is abundant in recent collections from southeastern Kalimantan (D. Lumbantobing, pers. comm., 2007; material, below); I conclude that it is native to Borneo.

Material examined: 997 specimens (6.2–33.6 mm SL). Syntypes. INDONESIA. Panimbang R., Perdana, RMNH 6979 (7 males, 6 females), BMNH 1866.5 .2.101 (male) .

Non-type specimens. INDONESIA. Java: about 20 mi. SE of Surabaja , CAS-SU 68380 , 11 (8.0– 18.5 mm), J. P. Heath, ix.1961 ; Pulau Edam , 13 km N of Jakarta, semi-stagnant pool, CAS 73123, 1 (25.8 mm), CAS 35626, 8 (24.5–28.5 mm), F. B. Steiner, 8.xi.1975 , CAS 35689, 4 (25.9–27.2 mm), F. B. Steiner, 20.xii.1975 . Lombok: river near Labuan Tring, west coast of Lombok (8°44.5′S, 116°2.5′E), ZMA 100.570 , 10 (20.5– 28.0 mm), M. Weber, 19–21.iii.1899 ; Praya , RMNH 10518 , 1 (female?, 22.5 mm), Sunda Expedition 1909– 1910 (Dr. J. Elbert), 27.vi.1909 . Borneo : Kalimantan Selatan: Desa Pulau Salak, Kecamatan Kintap Hilir, road to Pagatan , (03°37.114′S; 115°52.664′E), 29 m alt., USNM 391946 , 53 (13–25 mm), D. Lumbantobing, D. Rudaya & A. Daely, 17.viii.2007 ; River on Magalau-Sungaikupang road, between Kaliaman R. and Cantung R. (02°51.696′S, 116°03.959′E), 36 m alt., USNM 391947 , 1 (22.5 mm), D. Lumbantobing, D. Rudaya & A. Daely, 20.viii.2007 . Bali: NSMT-P 67703 , 5 (9.2–23.2 mm), K. Shibukana, 3.xi.2003 .

THAILAND. Phuket Is.: Nai-Han , CAS 58033, 10 (13.0– 21.5 mm), N. Tawimsunnuk, H. Uwa & W. Magtoon, 2.ii.1985 ; Patong Bay , USNM 246908 , 530 (6.2–33.6 mm), USNM 246912 , 1 (28.7 mm), USNM 246913 , 5 (6.1–26.5 mm), ANTON BRUUN, 22.iii.1963 .

MALAYSIA. Penang, Pulau Penang, CAS-SU 32783 , 2 (15.8–23.5 mm), A. W. Herre, 24.iii.1937 .

SINGAPORE. CAS-SU 35670 , 45 (18–26 mm), A. W. Herre , 11.iii.1937 , CAS-SU 31134 , 18 (13.2–24.3 mm, 2 of which have been cleared and counterstained), A. W. Herre, 1934 , CAS 7476 , 1 (18 mm, dehydrated and faded), E. Wigham, 1934; Sg. Mandai , FMNH 47156 , 3 (males, 21.5–22.5 mm), A. W. Herre , 14.iii.1934 , CAS 58026, 50 (17.6–26.1 mm, 4 of which have been cleared and counterstained), G. Loy , R. Hori & H. Uwa, 12.ii.1985 ; Poyan R., BMNH 1970.7.22 : 38–39, 68 (17–27 mm, adult female 21.8 mm carrying embryo cluster), 28.vi.1966; Sg. Buloh, just outside of nature reserve, small stream entering Straits of Johore , USNM 348513 , 224 (9.4–23.9 mm, 14 of which have been cleared and counterstained), L . R. Parenti, H. K. Larson, K. Lim & N. Sivasothi , 5.ix.1997 .

Figures

Figure 19. A, O. javanicus, juvenile, USNM 348513, 18.5 mm SL; B, O. matanensis, CMK 6195, female, 44.5 mm SL. Detail of ethmoid region of skull and oral jaws. Note closed lacrimal canal in O. javanicus, open canal in O. matanensis.

Figure 26. A, Oryzias setnai, CAS 56255, male, 18 mm SL, SEMX134. B, Oryzias javanicus, CAS 58026, adult male, 26 mm SL, SEMX53. C, Oryzias celebensis, CAS 58034, adult female, 29 mm SL, SEMX40, teeth on right half of toothplate dislodged during specimen preparation. D, Oryzias bonneorum, ZMA 123.863, female, 40 mm SL, SEMX23. SEM of a right fifth ceratobranchial bone and toothplate. Anterior is up.

Figure 43. Oryzias javanicus (Bleeker, 1854), Java, Indonesia, CAS 35626, male, 28.5 mm SL.