Paedocypris

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(Redirected from Paedocypris progenetica)

Paedocypris is an Indonesian genus of fish in the family Cyprinidae (carps, minnows). 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.<ref name=kottelat>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</ref>

1 Etymology
2 Discovery
3 Appearance
4 Habitat
5 Other "smallest" fish
6 External links
7 References

[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.<ref name="kottelat" /> Their osteology was studied by Ralf Britz at London's Natural History Museum.

[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.<ref name=kottelat/> <ref name=rmnews/> 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<ref>Sandra Hines, 2006. "Flap over fishes: Who's the smallest of them all?" University of Washington News</ref> and the female individuals reach the significantly larger size of 50.5mm.<ref name=rmnews>Raffles Museum news, 2006. "RMBR: So which is the smallest species of fish in the world? (Part II)"</ref>