Morphological Description of Flying Fish, Cypselurus hiraii Larvae (Pisces: Exocoetidae)

제비날치(Cypselurus hiraii) 자어의 형태기재

This study was conducted in order to investigate the growth and morphological development of Cypselurus hiraii larvae and to obtain basic data for taxonomic research. Specimens for this study were collected using a scoop net (aperture Ø60 cm) at the Geomun Island in Yeosu-si, Jollanam-do in July and August of 2013, and the mean water temperature was $20.6{\pm}1.84^{\circ}C$ and the mean salinity was $32.1{\pm}0.46$‰ during the collection. In post-larvae of total length 9.58~9.69 mm (average $9.63{\pm}0.04mm$, n=5), the mouth was opened, and the maxilla was shorter than the mandible. The length of the dorsal fin did not exceed that of the ventral fin, and the dorsal fin was on the same line as that of the ventral fin. In post-larvae of total length 18.0~18.5 mm (average $18.2{\pm}0.22mm$, n=5), with the growth accelerated, the pectoral fin was developed broadly and their caudal fin was differentiated into the heterocercal tail. These characteristics suggest the development of swimming ability and resultant active feeding activities. In post-larvae of total length 22.4~23.0 mm (average $22.7{\pm}0.21mm$, n=5), striped melanophores deposited in the pectoral fin, and small spot-like melanophores expanded in the processes formed on the mandible. The dorsal and anal fins were on the same line, and the anal fin was situated behind the dorsal fin.

본 연구는 제비날치 자어의 크기에 따라 형태발달을 조사하여 분류학적 연구의 기초자료로 이용하고자 실시하였다. 시료확보를 위해 2013년 7월부터 8월까지 전남 여수시 거문도에서 뜰채 (망목 Ø60 cm)를 이용하여 채집하였고, 채집당시 평균 수온은 $20.6{\pm}1.84^{\circ}C$였으며, 평균 염분은 $32.1{\pm}0.46$‰이었다. 전장 9.58~9.69 mm (평균 $9.63{\pm}0.04mm$, n=5)의 후기자어는 입이 열려 있었고, 위턱이 아래턱보다 짧았다. 등지느러미의 길이는 배지느러미를 넘어서지 않았고, 등지느러미는 배지느러미와 같은 선에 위치하였다. 전장 18.0~18.5 mm (평균 $18.2{\pm}0.22mm$, n=5)의 후기자어는 성장함에 따라 가슴지느러미의 폭이 넓게 발달하였고, 꼬리지느러미가 부정미로 분화하는 것으로 보아 유영능력의 발달로 인해 먹이 섭취활동이 활발해진 것으로 보인다. 전장 22.4~23.0 mm (평균 $22.7{\pm}0.21mm$, n=5)의 후기자어는 가슴지느러미에 줄무늬 형태의 흑색소포가 침착되었고, 아래턱에 형성된 돌기에는 작은 반점 모양의 흑색소포가 확장되었다. 같은 선에 위치한 등과 뒷지느러미는 뒷지느러미가 등지느러미보다 뒤쪽으로 위치하였다.