It is widely believed that gene flow connected many shallow water populations of the Caribbean and eastern Pacific until the Panama seaway closed 3.0 to 3.5 million years ago. Measurements of biochemical and reproductive divergence for seven closely related, transisthmian pairs of snapping shrimps (Alpheus) indicate, however, that isolation was staggered rather than simultaneous. The four least...

The surface mechanical boundary conditions for most of our models are shear stress free (free slip), such that plate velocities are driven self-consistently by density contrasts within the mantle (Ricard and Vigny, 1989). The lithosphere in our models is defined rheologically as a relatively stiff layer from the surface to 100 km depth that is “broken” by weak zones of reduced viscosity, as in ...

Four new species are assigned to the genus Teretia Norman, 1888 in the family Raphitomidae Bellardi, 1875 and herein described: Teretia neocaledonica sp. nov., T. sysoevi sp. nov., T. tongaensis sp. nov. from the southeastern Pacific and Teretia tavianii sp. nov. from the Gulf of Aden. The new species represent the first Indo-Pacific record of a genus previously known in the recent molluscan fa...