Oryzias sinensis, CHEN ET AL., 1989

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 : 587-589

ORYZIAS SINENSIS CHEN ET AL., 1989

CHINESE MEDAKA

FIGURE 56

Oryzias latipes .- Nichols, 1943: 234 [in subgenus Oryzias , synonymy; characters in specimens from Shandong (Shantung), China].- Uwa & Parenti, 1988: 159–164 [population from Kazahkstan].- Uwa et al., 1988: 332–340 [karyotype; distribution in southwestern China].- Roberts, 1998: 221 [as synonym of O. latipes , comparisons].- Lin et al., 1999 [ Taiwan population compared with ricefish from Japan and mainland China].- Tzeng et al., 2006: 285, 291–293 [population demographics and distribution].

Aplocheilus sp. - Abdil’dayev & Dubitskiy, 1974: 287– 289 [report of a population from the Ili River basin, Kazakhstan].

Oryzias latipes sinensis Chen et al., 1989: 239 [type locality: China: Kunming, Yunnan Province; as subspecies of O. latipes ( Temminck & Schlegel, 1846) ].- Chen, 1990: 227–228 [distribution in Yunnan].- Yu, 1996: 30 [listed in checklist of vertebrates from Taiwan].- Uwa, 1991a: 361–367 [karyology, relationships].- Seegers, 1997: 15 [listed].- Tzeng et al., 2006: 288, table 1, fig. 2 [population demographics and distribution].

Oryzias sinensis .- Kottelat, 2001a: 10, 56, fig. 120 [expected to be in Vietnam; characters].- Kottelat, 2001b: 144–145, fig. 408 [characters, distribution].- Kim & Park, 2002: 302 [ Korea].- Youn, 2002: 219, 545 [ Korea].- Jang et al., 2003: 119 [distribution in South Korean national parks].

Oryzias spec. ‘China’, possibly = sinensis Chen et al., 1989 .- Seegers, 1997: 22 [photographs of male and female from southern China].

Differential diagnosis: Oryzias sinensis is a miniature species of Oryzias (maximum size recorded by Chen et al., 1989 is 26 mm) and member of the biarmed chromosome group of Uwa (1986), along with O. luzonensis , O. latipes , O. curvinotus and the miniature O. mekongensis that have anal-fin rays of approximately the same length, forming a ‘parallelogram-shaped’ fin, and chromosome arms numbering 58 or more. Oryzias sinensis and O. mekongensis both have the first pleural rib on the second, rather than the third, vertebra. They are like O. latipes and O. luzonensis , and differ from Oryzias curvinotus by having bony processes on the pectoralfin rays. Oryzias sinensis is distinguished from all other ricefish species with a biarmed chromosome constitution by having a diploid chromosome number of 46, as opposed to 48 ( Table 2).

Description: Miniature, maximum size of specimens examined 26 mm SL. Body compressed laterally, body depth 18–21. 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 slightly convex from head to anal-fin origin. Dorsal surface of head slightly convex just anterior to orbits. Head length 24–29; snout length 6–9; eye moderate, 7–9, orbits meet dorsal surface of head. Basal portion of dorsal and anal fin project somewhat beyond primary body profile. Scales relatively large, cycloid; 29–30 in a lateral series. Elongate, filamentous dorsal- and anal-fin rays in males; anal- and pectoral-fin rays with bony contact organs. Medialmost pelvic-fin ray connected to body via a membrane along its proximal portion; pelvic fins meet or extend beyond anal-fin origin in some specimens. Caudal fin rounded to truncate. Male with a short, tubular urogenital papilla; female with bilobed urogenital papilla.

Premaxilla short and broad with distinct ascending process; premaxilla and dentary with two irregular rows of caniniform teeth; males with two or three enlarged posterior teeth on the premaxilla and dentary; tooth tips project through lips. No preethmoid cartilage; ossified portions of mesethmoid discshaped; 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 carried in open bony groove. First pleural rib on parapophysis of second 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 fourth 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 three irregular rows anteriorly, followed by three discrete rows of unicuspid teeth and no incomplete posterior row. Basihyal bone relatively short and triangular, basihyal cartilage extremely elongate and rectangular. Epibranchial elements fully ossified; epibranchial 2 notably smaller than the other epibranchial elements.

Dorsal-fin rays 6–7. Anal-fin rays 16–20. Pelvic-fin rays 6. Pectoral-fin rays 8–10. Principal caudal-fin rays i,4/5,i. Procurrent fin-rays, dorsal 5–6, ventral 6. Vertebrae 28–30 (10–11 + 18–19). Branchiostegal rays 5.

Cytogenetic data: Oryzias sinensis has a biarmed chromosome constitution, with 2 n = 46 chromosomes, comprising three metacentric, eight or nine submetacentric, one or two subtelocentric and nine, ten or 13 acrocentric pairs. One large chromosome pair has been reported in populations from Kunming, Shanghai and west Korea. Chromosome arm number (NF) ranges from 68 to 70. Cell size was recorded as 1.7 pg DNA per nucleus ( Chen et al., 1989; Uwa, 1991a; Table 2).

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.

Colour in alcohol: A diffuse row of melanophores from the dorsal surface of the head to the dorsal-fin origin, a 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. Females with a subrectangular, males with a smaller, subtriangular black peritoneum. A faint black line along the anal-fin base. Dorsal and anal fin interradial membranes with scattered melanophores. I have examined five lots of Oryzias from Taiwan, ANSP 76433, CAS-SU 23166, CAS-SU 23115 and FMNH 59113, all now dehydrated and distorted, and USNM 356076, collected in 1999. One specimen in the ANSP lot, an adult male, 26 mm, has a unique colour pattern: the midlateral black line prominent in many ricefish species is interrupted, i.e. formed by individual blotches along the midlateral portion of the body from approximately the second scale posterior to the pectoral-fin base to the caudal peduncle where the blotches are small and indistinct. There is an irregular row of indistinct blotches dorsal to, and two irregular rows of blotches ventral to, the midlateral row.

Distribution and habitat: Widely distributed throughout continental Eurasia from as far west as Kazakhstan, Mekong basin in Laos, Thailand and Yunnan, Irawaddy, Salween, Yuan Jiang and Nanpang Jiang basins, south-western China, Taiwan and west Korea in clear water swamps ( Kottelat, 2001b: 144; my personal observation in Taiwan).

Remarks: Oryzias latipes sinensis was included by Yu (1996: 30) in a checklist of the vertebrates of Taiwan. Ricefish had long been thought to be extinct in Taiwan, but were rediscovered there in 1993 ( Lin et al., 1999; Tzeng et al., 2006). Meristic data are supplemented by those in Chen et al. (1989). Another common name for this species is Chinese ricefish ( Seegers, 1997: 22). I have not examined the type specimens which are maintained at the Kunming Institute of Zoology (holotype no. 8610002).

The material listed below includes the collections of ricefishes made in China in the 1920s and 1930s and sent to the Smithsonian Institution by David Crockett Graham and now housed in the USNM. Graham was a missionary and naturalist who made or oversaw extensive, historically valuable natural history collections in mountainous south-west China. Many of his collections are from the vicinity of ‘ Suifu’ , now Yibin , at the confluence of the Mi and Jinsha (a tributary of the Yangtse or Chang Jiang) rivers, in Sichuan Province near the border with Yunnan.

Material examined: 800 specimens (7.8–26 mm SL).

CHINA (no specified locality or province unknown). USNM 112459 , 1 (21 mm), Y. T. Chu, USNM 86529 , 21 (12.8–19.2 mm), D. C. Graham, 14.ii.1924; West China. USNM 87388 , 3 (21.9–24 mm), D. C. Graham, 1925 .

CHINA. Yunnan Prov.: Hua-gong Yuan, type locality near Kunming Institute of Zoology, USNM 309183 , 10 (17.2–23.4 mm, 2 of which, 17.2–18.5 mm, have been cleared and counterstained); Huahongdong , Kunming , CAS 60238, 12 (18- 21 mm), H. Uwa, R.- F. Wang, and Y.- R. Chen, 27.x.1986 ; Baoshan Prefecture, Tengchong market, C. J. Ferraris & X.-Y. Chen, 24.x.1998 , CAS 207735 , 39 (12–21.8 mm); Baoshan Prefecture, Longchuanjiang trib. at Longkou , Qushi township , 25°26′4″N, 98°35′30″E, C. J. Ferraris & X.-Y. Chen, 25.x.1998 , CAS 207736 , 80 (13.7– 22.6 mm); Lang Yun Yuan , USNM 89212 , 3 (22.5– 25.7 mm), Y. Ching, 23.vi.1928 .

Chongqing (Chungking) Prov. , USNM 130054 , 1 (13.5 mm), D. C. Graham,. ix.1930 , USNM 91706 , 1 (female, 22.7 mm), D. C. Graham, 6–27.v.1930 . USNM 91702 , 4 (16.7–20.7 mm), D. C. Graham, 6–27.v.1930 . Yenchingkou, near Wanxian ( Wanshien ), AMNH 10483 , 1 (17 mm), Third Asiatic Expedition, W. Granger, xi.1921 – i.1922 .

Sichuan ( Szechuan ) Prov.: Chengdu (Chengtu) , USNM 102373 , 1 (14.5 mm) , USNM 102985 , 9 (all dried), D. C. Graham, 1–6.i.1936 , USNM 91662 , 1 (18 mm), D. C. Graham, 1.iv.1930 – 14.vi.1930 . Qianwei (Chien Way) , USNM 89207 , 11 (14–21 mm), D. C. Graham, 4.i.1928 . Yibin (Suifu) , USNM 130191 , 9 (16–21 mm), D. C. Graham, 1922 , USNM 86523 , 7 (14–22 mm), D. C. Graham, 17.i.1924 , USNM 87453 , 98 (11–18 mm), D. C. Graham, x.1924 , USNM 89152 , 32 (11–20 mm), D. C. Graham, 1.iii.1928 , USNM 89153 , 1 (22 mm), D. C. Graham, iv.1928 , USNM 89154 , 1 (22 mm), D. C. Graham, v.1928 , USNM 89205 , 39 (13–20 mm), D. C. Graham, 31.i.1928 , USNM 89206 , 6 (13–20 mm), D. C. Graham, 30.xii.1927 , USNM 89208 , 20 (12–21 mm), D. C. Graham, 18–24.i.1928 , USNM 89311 , 3 (17– 22 mm), D. C. Graham, 21.vi.1928 , USNM 89337 , 1 (15 mm), D. C. Graham, 24.x.1928 , USNM 91630 , 163 (14–22 mm, 4 of which have been cleared and counterstained), D. C. Graham, 15.iii–15.iv.1929 , USNM 91597 , 1 (15 mm), D. C. Graham, 20.iv.1929 , USNM 91605 , 2 (19–26 mm), D. C. Graham, 1.vi.1929 , USNM 130147 , 1 (18 mm), D. C. Graham, 1.vi.1929 , USNM 91644 , 2 (18–20 mm), D. C. Graham, 25–26.xi.1929 , USNM 130055 , 2 (19–21 mm), D. C. Graham, 16.xii.1929 , USNM 91693 , 3 (18–21 mm), D. C. Graham, 1930 , USNM 130056 , 6 (distorted), D. C. Graham, 25–29.iii.1930 , USNM 130057 , 3 (16– 21 mm), D.C. Graham, 1.iv.1930 . Changlin-Chien , USNM 89312 , 1 (19 mm), D. C. Graham, 17.vi.1928 . Yashan , USNM 86673 , 2 (16–18 mm), D. C. Graham, iii.1924 . Ya’an (Yachow) , USNM 89328 , 12 (7–18 mm), D. C. Graham, 8–11.vii.1928 .

Shandong (Shantung) Prov., Hwang He (Yellow R.), Jinan (Tsinan), AMNH 10344, 72 (18.7–26 mm, 6 of which have been cleared and counterstained), Third Asiatic Expedition, W. Granger, Summer, 1924.

Shanghai Prov., Shanghai, CAS 58031, 24 (20.5– 25.5 mm), Univ. Tokyo laboratory stock .

TAIWAN. Shori : FMNH 59113 , 6 (14–17 mm), M. Oshima, no date; I-Lan Co.; USNM 356076 , 15 (7.8– 20.8 mm, 2 of which, a female, 20.8 mm, and a male, 16.5 mm, have been cleared and counterstained), L. R. Parenti, S.-M. Lin & G. Shang, 18.iii.1999 .

KAZAKHSTAN. Alma Alta : Iri R., AMNH 38404 , 16 (10–25 mm, 2 of which, 21.9–23.7, have been cleared and counterstained), N. V. Parin, 21.vi.1974 .

Figures

Figure 56. Oryzias sinensis Chen et al., 1989, Hua-gong Yuan, Yunnan Province, China, USNM 309183, male, 22.9 mm SL.