First Find of Epigonichthys maldivensis (Cooper) and Rediscovery of E. lucayanus (Andrews) from Nanwan Bay, Southern Taiwan (Cephalochordata)

Two species of tropical lancelet, Epigonichthys maldivensis (Cooper) and E. lucayanus (Andrews), were collected from bottom sand dredged by SCUBA-divers at depths of 10-14m among coral reefs in Nanwan Bay, southern Taiwan, in June, 1996. The average density, inclusive of both species, was roughly 25 ind. m-2, with E. maldivensis in the minority. Many individuals of both species longer than 13mm were sexually mature. The present specimens represent the second record from Taiwan of the circum-tropical E. lucayanus after a gap of 20 years and the first find in Taiwan of the Indo-West Pacific E. maldivensis. SEM observations of the gut contents and material extracted from the sandy bottom of the habitat suggest that the lancelets may feed on surface detritus. Some morphological notes and a key to 5 East Asian lancelet species are also given.