Paedocypris, a new genus of Southeast Asian cyprinid fish with a remarkable sexual dimorphism, comprises the world's smallest vertebrate.
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.
Kottelat
Maurice
M
Raffles Museum of Biodiversity Research, Department of Biological Sciences, National Universityof Singapore, Singapore. mkottelat@dplanet.ch
Britz
Ralf
R
Hui
Tan Heok
TH
Witte
Kai-Erik
KE
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