Oryzias woworae Parenti and Hadiaty, 2010
- Biogeographic Region: Australasia
Oryzias woworae is a small, remarkably colorful ricefish, described in 2010 from a freshwater habitat on Muna Island off the southeastern coast of the main island of Sulawesi, Indonesia. Its brilliant red and blue color pattern has already attracted attention from conservation biologists and aquarists (See link, below). Reaching a maximum size of 28 mm (just over one inch) Standard Length, it is the smallest known ricefish from Sulawesi, a large, geologically complex island in the Indo-Australian Archipelago (Parenti and Hadiaty, 2010). It's common name in English is "Daisy's Ricefish" in honor of the collector of the new species and the person for whom it is named, Dr. Daisy Wowor, an Indonesian crustacean biologist. More photos and a report of its being bred in the aquarium trade are available here.
Conservation and Management
Oryzias woworae is so far known only from the type locality, a small stream on Muna Island. Because of its attractive and distinctive color pattern, it may serve as an icon to generate interest in the endemic freshwater fishes of Sulawesi and encourage their conservation.
Oryzias woworae is distinguished from all other known ricefishes by a remarkable color pattern of both sexes in life: the ventral surface of head and body anterior to the pelvic fins, dorsal portion of pectoral fins, dorsal-fin base, posterior portion of anal-fin base, caudal peduncle, and dorsal and ventral portions of caudal fin are brilliant red; the midlateral scales from just posterior to the eye to the caudal-fin base and the body scales anterior to the anal fin and ventral to midlateral scales are steel blue; the blue coloration is most prominent in adult males (Parenti and Hadiaty, 2010)
Body compressed laterally, slender to somewhat deep-bodied. Mouth subterminal, lower jaw extends slightly beyond upper jaw. Dorsal and ventral body profile gently arching from head to dorsal- and anal-fin origins. Dorsal surface of head slightly convex just anterior to orbit. Head small to moderate; Snout short; Eye moderate to large, orbit projects somewhat beyond dorsal surface of head. Basal portion of dorsal and anal fin do not project significantly beyond primary body profile. Scales of moderate size, cycloid, and somewhat deciduous; 30–33 in a lateral series. Elongate, filamentous dorsal- and anal-fin rays in males; anal-fin rays lack bony contact organs. Innermost pelvic-fin ray connected to body via a membrane along its proximal half. Caudal fin truncate. Male with a short, slightly conical, 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 one to two rows of external conical teeth on the upper and lower oral jaws. No preethmoid cartilage; ossified portions of mesethmoid somewhat hour-glass shaped with no cartilage on midlateral margins; anterior border of ethmoid cartilage irregular. 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 third vertebra; first epineural bone attaches to parapophysis of first vertebra dorsal to, and not in horizontal line with, posterior epineural bones; lateral process of pelvic bone attaches to third pleural rib (attached to fifth vertebra). Dorsal-fin origin over vertebra 21 or 22. Caudal skeleton with two epural bones; one ventral accessory bone. Anterior procurrent caudal-fin rays slightly hooked at their base. Fifth ceratobranchial toothplates subtriangular, with pavement dentition anteriorly, followed by four to five discrete rows of unicuspid teeth; no small, incomplete posterior row of teeth. Basihyal bone triangular, basihyal cartilage elongate and rectangular. Epibranchial elements incompletely to fully ossified; epibranchial two notably smaller than the other epibranchial elements. Dorsal-fin rays 8. Anal-fin rays 18–19 . Pelvic-fin rays 6. Pectoral-fin rays 9–10. Principal caudal-fin rays i,5/6,i. Procurrent fin rays, dorsal 3–4, ventral 4–5. Vertebrae 29–30. Branchiostegal rays 5–6 (minute, anteriormost ray on left side in one of eight specimens.
Only known from the type locality, a freshwater stream, pH 6-7.
Endemic to Mata air Fotuno, a freshwater stream in the village of Wakumoro, districit of Parigi, in the Muna Regnecy, Muna Island, Indonesian state of Sulawesi Tenggara.
Lives with a halfbeak, Nomorhampus sp.
Evolution and Systematics
Systematics and Taxonomy
Oryzias woworae is a member of the genus Oryzias in the beloniform family Adrianichthyidae (sensu Parenti, 2008). It shares with congeners an array of synapomorphies including reaching no more than 60 mm in Standard Length, having 34 or fewer vertebrae, and a hyomandibula with a single, rather than bifid, head articulating with the otic region of the skull.
Although the sister species of Oryzias woworae is unknown, it is hypothesized to be a member of a large clade of ricefishes united by the unambiguous synapomorphy of a truncate, rather than lunate or emarginate, caudal fin (Parenti, 2008)