Two New Species of Labidocera (Copepoda, Calanoida) from the Western Tropical North Atlantic Region

Résumé du livre

Two new species of Pontellidae assignable to the Labidocera jollae species group, a uniquely American radiation of coastal planktonic copepods, are described. The new species originate from Barbados (L. barbadiensis) and the Caribbean coast off Panama (L. panamae). They are most similar to the Bahamian congener, wilsoni. Of the nine confirmed species of Labidocera now known from the western tropical Atlantic wilsoni, mirabilis (southern Florida and the Florida Keys) and the two new species comprise an American east coast lineage related to and apparently derived from the American west coast lineage of the jollae group. The tropical west Atlantic lineage provides an excellent subject for intensive comparative analysis of planktonic speciation and character divergence. The species occupy a geographical region for which recent geological chronology is reasonably well established. The four species show close phylogenetic relationship, as evidenced by uniformity in morphology and habitat, and, with adequate sampling, geographical relationships may be defined with an unusually high level of precision. However, the distribution and density of this group is at present based on localized and scattered zooplankton sampling of coastal waters within the region. To utilize this promising opportunity to examine evolution in marine zooplankton widespread systematic sampling of coastal zooplankton in the Caribbean region is required and advocated.