The Complete Larval Development of the Sand Lobster, Scyllarus Americanus (Smith), (Decapoda, Scyllaridae) in the Laboratory, with Notes on Larvae from the Plankton

Phyllosoma larvae of the scyllarid lobster, Scyllarus americanus, were hatched in the laboratory and reared through metamorphosis to the postlarval stage on a diet of brine shrimp nauplii, this being the first time that it has been possible to study the complete larval development of any scyllaridean lobster in the laboratory. The larval life consists of six or seven phyllosoma stages and is of relatively short duration. Postlarvae were obtained at 25°C in a minimum of 32 and a maximum. of 40 days after hatching. At 25°C, final-stage phyllosomas were obtained in various salinities ranging from 23.2 to 38.6‰. Seven phyllosoma stages and the postlarva are described and illustrated.

Specific differences can be recognized among the larvae of many species of Scyllarus. Phyllosomas of S. americanus in the earliest stages can be distinguished from larvae of other western Atlantic species by the possession of only three apical setae on maxilla 2, the relatively large number of pairs of natatory setae on the exopod of pereiopod 2, and the relatively great total length. Subsequent stages are characterized by the subcircular outline of the cephalic shield. The sequence of stages reported by Baisre (1966) from Cuban waters belongs undoubtedly to S. americanus. The small, immature scyllarid described by Smith (1881) under the name Arctus depressus cannot be considered a postlarval stage of S. americanus, nor can the specimen described as such by Bouvier (1925).

Distributional data indicate that larval development of S. americanus takes place in relatively shallow coastal waters. Although species of Scyllarus appear to have a comparatively short larval life, evidence reviewed suggests that certain other scyllarid lobsters may have a larval life as long as, if not longer than, that of palinurid lobsters.