The First Larval Stage of Microprosthema semilaeve (von Martens, 1872) (Crustacea: Decapoda: Stenopodidea) Obtained in the Laboratory

The first larval stage of Microprosthema semilaeve (von Martens, 1872) is described from ovigerous females collected off Sombrero Key, Florida Keys, USA, and Guana Island, British Virgin Islands, Caribbean. The larvae are characterized by a broad, triangular telson bearing posterolateral spines and an “anomuran seta,” a first maxilliped that differs markedly from the very similar (to each other) second and third maxillipeds, and the presence of the first pereiopod as a swimming appendage upon hatching, as is apparently true of all stenopodidean first stage larvae. Characters of the larvae are compared to those described from the Indian Ocean by Raje and Ranade (1978) and mistakenly attributed to this same species, and to those of stenopodidean larvae described by Lebour (1941) from Bermuda plankton. Problems in identifying adult specimens of Microprosthema from the Caribbean are discussed.