Abbreviated larval development of the pea crab Orthotheres barbatus (Decapoda : Brachyura : Pinnotheridae) described from laboratory-reared material, with notes on larval characters of the Pinnotherinae

The pea crab Orthotheres barbatus is one of seven species of the family Pinnotheridae reported from Venezuelan marine waters. Larval life histories are not known for any species of the genus Orthotheres. Ten ovigerous females of O. barbatus were obtained from their host gastropod, Cittarium pica, at Los Roques Archipelago, Venezuela. Larvae of O. barbatus were reared in the laboratory from hatching to the first crab stage. This species exhibits abbreviated development in both the number of larval stages (two zoeal stages preceding a megalopa) and the duration of development (minimum of four days from hatching to first crab). The number of zoeal stages for pinnotherid species described to date ranges from 3 to 5, with only Tunicotheres moseri, Pinnotheres taylori, and Nepinnotheres pinnotheres known to also have only two zoeal stages. Morphology of the larval stages of O. barbatus is described, illustrated and compared to that previously described for larvae of the Pinnotherinae. Selected larval characters are proposed as typical larval features for this subfamily and are used to support separation of this group from the rest of Pinnotheridae.