Tethys Sea fragmentation and speciation of Panulirus spiny lobsters

A composite of the phylogenetic relationships of the species of Panulirus, based on morpholog ical and genetic comparisons is presented. Data on the timing of the longitudinal break up of the Tethys Sea into the separate major oceans (and the resulting ecosystem changes) allow a review of the isolating mechanisms that may have resulted in the present day species distribution. These sce narios have been supplemented by personal visits to most of the regions inhabited by the various species of Panulirus. Two major phylogenetic lineages are recognized, the first emerging earlier and exhibiting a habitat preference for clear waters associated with continents or volcanic islands, the second major lineage emerging a little later and showing a distinct preference for the turbid waters of coastal habitats. The genus originated in the broad Tethys Sea and the Panulirus stock was ini tially divided longitudinally by the collision of Africa with Eurasia, isolating the Indo-west Pacific element; the final separation of the east Pacific from the Atlantic elements occurred with the Pliocene closure of the Panama Seaway. New habitats for incipient species were formed by these geological events as well as by the emergence of oceanic islands, climatic changes, and the formation of more discrete current systems.