PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASHINGTON 116(3):710-718. 2003. Early zoeas of Athanas parvus De Man, 1910 (Decapoda: Caridea: Alpheidae) reared in the laboratory Hoi Jeong Yang and Chang Hyun Kim (HJY) Department of Life Sciences, Silla University, Busan 617-736, Republic of Korea, e-mail: [email protected]; (CHK) Department of Biology, Pusan National University, Busan 609-735, Republic of Korea Abstract. — Early zoeas of Athanas parvus De Man are described and illus-trated in detail, based on laboratory-hatched eggs from females collected in Sangju, Korea. This is the first record of the genus Athanas Leach from Korean waters. The zoeal characteristics of Athanas species are compared with those of species of the other four alpheid genera for which larvae are known. Based on morphological similarity, larval characters of Athanas species support a close relationship between the Alpheidae and Palaemonidae. The small shrimps of the genus Athanas Leach, 1814 are usually found in dead coral heads, pools under rocks, and sandy or muddy beaches. Some species are found in permanent association with sea urchins, liv-ing between the spines on the oral surface (Banner & Banner 1973). Ten species of the family Alpheidae, belonging to four genera have been recorded from Korean waters (Yang & Anker 2003). However, species of the genus Athanas have not been reported from Korean waters to date. Larvae of three species of Athanas have been described so far: A. djiboutensis Cou-tiere, 1897, first zoea obtained from Ghar-daqa (Gurney 1938); A. dimorphus Ort-mann, 1894, first zoea based on plankton material from the Red Sea (Gurney 1927) and first three zoeal stages from India (Bhu-ti et al. 1977); and A. nitescens (Leach, 1814), first three zoeal stages from the U.K. (Lebour 1932), and other descriptions based on plankton material (Sars 1906, William-son 1915, Webb 1921, Kurian 1956, Bour-dillon-Casanova 1960, Williamson 1967). This study describes and illustrates in de-tail the early zoeal stages of A. parvus De Man, 1910, and compares morphological characteristics of the zoea of species of Athanas with those of the other four alpheid genera for which larvae are known. Material and Methods On 21 July 1997, ovigerous females of Athanas parvus were collected from oyster raft cultures in Sangju, Korea (34°43'00"N, 127°59'30"E). Ten newly hatched zoeas were removed and placed in each of six glass bowls containing 33.3%o filtered sea-water, and kept in a growth chamber at 25°C. Larvae were fed daily with the mi-croalga Dunaliella tertiolecta Butcher, and some specimens in each stage were pre-served in 7% neutral formalin. Drawings were made with the help of a camera lucida. Measurements and setal counts were based on the mean of ten specimens for each zoeal stage. Total length (TL) was mea-sured from the rostral tip (postorbital mar-gin for the first zoea) to the posteromedian margin of the telson, excluding posterior se-tae. Carapace length (CL) was measured from the postorbital margin to the postero-median margin of the carapace. The setal armature of appendages is described from proximal to distal segments. The chromato-phore pattern was determined by observa-tion of living zoeas.