Paedocypris
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P. micromegethes |
Paedocypris is an Indonesian genus of fish in the family Cyprinidae (carps, minnows), subfamily Danioninae.[1], It includes two species, Paedocypris progenetica and Paedocypris micromegethes.
Paedocypris progenetica has been claimed to be the smallest known species of fish and vertebrate in the world. The smallest mature female measured 7.9mm and the largest known individual 10.3mm.[2]
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[edit] Etymology
Paideios is Greek for children; Cypris is Greek for Venus, a common suffix for cyprinid genera indicating gender feminine. Progenetica i.e. progenetic is used as an adjective.
[edit] Discovery
Both species were first discovered and identified by ichthyologists Maurice Kottelat from Switzerland and Tan Heok Hui from the Raffles Museum of Biodiversity Research and the National University of Singapore in 1996, but it was first formally described and named in 2006.[2] Their osteology was studied by Ralf Britz at London's Natural History Museum.
In 2006, WWF International explored the "Heart of Borneo" and discovered paedocypris micromegethes, which is 0.35 inch long.
The creature, which gets its name from the Greek words for children and small, is tinier than all other vertebrate species on Earth except for its slightly more minuscule cousin, a 0.31-inch-long fish found on the Indonesian island of Sumatra, according to WWF.
Paedocypris micromegethes was found on the Malaysian part of the island, living in the slow-flowing blackwater streams and peat swamps.
[edit] Appearance
The smallest mature female is only 7.9 mm, smaller than any other female vertebrate species. The largest known individual is 10.3 mm.
Their miniature transparent body lacks typical features characteristic of adult fish, for instance a bony skull structure around its brain, and it retains the post-anal larval-fin-fold along the ventral edge of the caudal peduncle, characteristic of fish larvae. They have a unique sexual dimorphism: The males have highly modified pelvic fins, with the first ray terminating with a hook-like projection of keratinized skin, supported by hypertrophied pelvic musculature. Males also have a pad of keratinized skin in front of the pelvic fins. It is hypothesized that these modified fins are used to grasp the female during mating, or to keep position over a spawning surface.
[edit] Habitat
Paedocypris progenetica lives in the dark colored peat swamps of the Indonesian island of Sumatra.[2] [3] Paedocypris micromegethes lives in the peat swamps of Sarawak (Borneo). Their small size helps them to survive through extreme droughts, as they can live in small remaining puddles of acid water (pH as low as 2.9, at least 100 times more acidic than rainwater). Their habitat is threatened by forest fires, logging and plantations.
[edit] Other "smallest" fish
Male individuals of the species anglerfish Photocorynus spiniceps have been documented to be 6.2-7.3mm at maturity, and thus claimed to be a smaller species. However, these survive only by sexual parasitism[4] and the female individuals reach the significantly larger size of 50.5mm.[3]
[edit] External links
- BBC: Scientists find 'smallest fish'
- BBC: Is it really the smallest fish after all?
- Pharyngula: Paedocypris
- Raffles Museum of Biodiversity Research, National University of Singapore
- Scientists discover world's smallest fish
[edit] References
- ^ T. R. Roberts: The "Celestial pearl danio", a new genus and species of colourful minute cyprinid fish from Myanmar (Pisces: Cypriniformes) The Raffles Bulletin of Zoology, 2007 55(1): 131-140
- ^ a b c Maurice Kottelat, Ralf Britz, Tan Heok Hui, Kai-Erik Witte, 2005. "Paedocypris, a new genus of Southeast Asian cyprinid fish with a remarkable sexual dimorphism, comprises the world's smallest vertebrate." Proceedings of the Royal Society B 10.1098/rspb.2005.3419. Abstract
- ^ a b Raffles Museum news, 2006. "RMBR: So which is the smallest species of fish in the world? (Part II)"
- ^ Sandra Hines, 2006. "Flap over fishes: Who's the smallest of them all?" University of Washington News
