title: Paedocypris, a new genus of Southeast Asian cyprinid fish with a remarkable sexual dimorphism, comprises the world's smallest vertebrate.
abstract: Paedocypris is a new genus of paedomorphic cyprinid fish from highly acidic blackwater peat swamps in Southeast Asia. It includes two new species, one of which (Paedocypris progenetica) appears to be the smallest fish and vertebrate known, with the smallest mature female measuring a mere 7.9 mm. Paedocypris has many 'larval' features typically associated with paedomorphic fish (e.g. narrow frontals that leave the brain unprotected dorsally by bone and a precaudal larval-fin-fold), but, uniquely among fishes, males also possess highly modified pelvic fins with hypertrophied muscles and a keratinized pad in front of the pelvic girdle, which, we hypothesize, function together as a clasping or holding device, thereby suggesting an unusual reproductive mode. Unfortunately, habitat destruction jeopardizes the survival of these fishes and thus opportunities for further research.
authors.affiliation: Raffles Museum of Biodiversity Research, Department of Biological Sciences, National Universityof Singapore, Singapore. mkottelat@dplanet.ch
authors.forename: Maurice
authors.initials: M
authors.lastname: Kottelat
authors.forename: Ralf
authors.initials: R
authors.lastname: Britz
authors.forename: Tan Heok
authors.initials: TH
authors.lastname: Hui
authors.forename: Kai-Erik
authors.initials: KE
authors.lastname: Witte
mesh_terms: D000818:Animals; D001210:Asia, Southeastern; D049628:Body Size; D003530:Cyprinidae / Q000033:anatomy & histology* / Q000145:classification / Q000502:physiology; D004777:Environment; D005247:Feeding Behavior; D005260:Female; D008297:Male; D012727:Sex Characteristics