The earliest record of Crustacea in phytotelmata was published by Müller (1879), who described the ostracod Metacypris bromeliarum for Brazilian bromeliads. Ostracoda, sometimes called seed shrimps or mussel shrimps, are frequently found in phytotelmata. In a study of Jamaican bromeliad phytotelmata, ostracods were found in at least 50% of the samples, sometimes exceeding 100 specimens in a single phytotelm (Janetzky 1997). Up to now, 8 species have been identified to species level, representing the families Cypridae and Cytheridae. Tressler (1941) gave evidence of Candonopsis kingsleyi and Metacypris maracaoensis in Puerto Rican bromeliads. The latter species was also mentioned to occur in Jamaica together with Candonopsis anisitsi, Metacypris bromeliarum and M. laessli (Tressler 1956) as well as in Florida (Fish 1976). Further records of ostracods in bromeliads were given by Danielopol (1975), who described three representatives of the genus Elpidium as species A, B, and C, differing in the structure of the male's copulatory organ. The species list is far from complete, an assumption derived regarding the few detailed surveys of the phytotelmic fauna (Costa Rica: Picado 1913; Florida: Fish 1976; Jamaica: Laessle 1961, Janetzky 1997; Colombia: Robins et al. 1974; Mexico: Lucas 1975; Peru: Krügel 1993; Puerto Rico: Maguire 1970) and underlined by investigations of ostracods in Jamaican bromeliads (Little & Hebert 1996). Little & Hebert used allozyme and mitochondrial DNA analysis for species discrimination within the genera Candonopsis and Elpidium. As result, nine species of Elpidium and at least two species of Candonopsis could be distinguished. In addition, the species show morphological differences, despite the fact that they still have to be described. Except Candonopsis anisitsi, none of the species detected by Little & Hebert (1996) occur elsewhere in the Caribbean nor in Jamaican ponds investigated earlier (Little & Hebert 1994). The observation of ostracods with restricted distribution leads to the assumption that bromeliads as ecological islands foster allopatric speciation (Little & Hebert 1996).
A seed shrimp, Candona sp. (Photo: W. Janetzky)