DESCRIPTION OF THE FIRST PHYLLOSOMA STAGE OF THE JUAN-FERNANDEZ LOBSTER, JASUS-FRONTALIS, CHILE

The recently hatched larvae of Jasus frontalis corresponds to a naupli osoma larvae. It presents a rounded body with its appendices folded un der the body. After 20 min of swimming the naupliosoma moults to origi nate the first stage of phyllosoma. The phyllosoma is strongly phototr opic. The body is strongly flattened dorso-ventrally, cephalic field p iriform and the abdomen rudimentary and each side terminated in a shor t spine and three setae. Non pedunculated eyes. It presents three pair s of pereiopods, an uniramous antenna and a biramous antennule. The fi rst and second pair of pereiopods present an exopodite with six pairs of plumosae setae. The third pereiopod, the antennulae, the second and third pair of maxilipeds, are all uniramous. Mandible with three inci sive teeth, a serrate lateral border and a molar with numerous little teeth. The first stage of phyllosoma of J. frontalis present a close r esemble to the first stage of phyllosoma of Syllarus americanus and Ja sus verreauxi, however they differ in the spines of the distal end of abdomen and longitude of the antenna of the first species and the firs t maxilliped of the second species.