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| Pseudomugil ivantsoffi - photo© Charles Nishihira |
Allen and Renyaan, 1999
Ivantsoff Blue-eye
Description
Head and body of males semitransparent, often with bluish hue; opercle, abdomen and swim bladder region silvery; upper half of first dorsal and anterior half of second dorsal fins, and edge of anal fin bright red; dorsal and ventral contour posterior to second dorsal and anal fins edged with similar red; upper and lower third of caudal fin also red; head with reddish suffusion; pelvic fins pink. Iris of eye intensely blue; edges of some scales on abdomen with narrow black margins. Females overall semitransparent, lacking bright red shades of male; opercle, abdomen and swim bladder region silvery; some scales on anterior half of body with faint, fine black margins; fins mainly translucent to faintly yellowish, the outer tips of the first and second dorsal fins yellow.
This fish was initially identified as Pseudomugil reticulatus, based on the close resemblance of females from the Timika area to the single known example of that species. However, recent collections near the type locality of Pseudomugil reticulatus, which lies some 900 km northwest of Timika, revealed that the two populations are distinctive.
Distribution
Tributaries of the Ajkwa, Iwaka and Kopi Rivers in the Timika-Tembagapura region of West Papua.
Habitat & Ecology
The habitat consisted of small (1-2 m wide), shallow, slow-flowing streams in dense rainforest. Water clarity was excellent, but some were tannin stained, and aquatic vegetation was generally sparse. Bottom conditions included sand, gravel, cobble, and rocks. Water temperature and pH values ranged from 24 - 28°C and pH 6.7 - 7.8 respectively. Other fishes collected from this habitat included Pseudomugil pellucidus, Melanotaenia goldiei, and Melanotaenia ogilbyi.
When first collected in July-August 1995 this species was common in several creeks. The same species and habitat conditions were encountered in January 1997, but by the following year, after a prolonged El Niño related drought, the two species of Pseudomugil, as well as the melanotaeniid Melanotaenia ogilbyi, could not be found in any of the former areas. The Kuala Kencana housing development and recent forest destruction near the Kopi river sites may well have caused the local extinction of these species. However, they no doubt will continue to survive in primary forest to the immediate east and west of the Timika region. Pseudomugil ivantsoffi is a small species, slender and laterally compressed, growing to a length of around 3 cm SL.
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| Pseudomugil ivantsoffi - photo© Charles Nishihira |
Remarks
Named "ivantsoffi" in honour of Walter Ivantsoff, of Macquarie University, Sydney, Australia, in recognition of his valuable contributions to our knowledge of atherinoid taxonomy. Although live specimens have been collected, it is currently rare in the aquarium hobby.
© Copyright Adrian R. Tappin
Updated January, 2007.
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