| Publication Type: | Journal Article |
| Year of Publication: | 1996 |
| Authors: | J. E. Duffy |
| Journal: | Biological Journal of the Linnean Society |
| Volume: | 58 |
| Pagination: | 307-324 |
| Keywords: | Animalia, animals, Arthropoda, Arthropods, Comparative and Experimental Morphology, Crustaceans, Ecology, Ecology (Environmental Sciences), Environmental Biology/Animal [07508], Environmental Biology/Oceanography [07512], Environmental Sciences), Evolution [01500], Evolution and Adaptation, General and Systematic Zoology/Arthropoda-Crustacea [63554], Invertebrata, Invertebrates, Malacostraca (Malacostraca), Malacostraca [75112], Malacostraca: Crustacea, Marine Ecology (Ecology, Physiology, Physiology and Pathology/Arthropoda-Crustacea [64054], Systematics and Taxonomy |
| Abstract: | Microevolutionary studies and natural history suggest that host-specialization has promoted the high diversity of tropical sponge-dwelling snapping shrimps (Decapoda, Alpheidae, Synalpheus). Yet the taxonomic difficulty of this genus has precluded rigorous tests of this hypothesis. S. rathbunae Coutiere is among the most abundant invertebrates inhabiting the framework of sponges and dead coral that forms the floor of Caribbean coral reefs. Even within a small area S. rathbunae exhibits the apparently wide variation in size, color, and morphology that has long frustrated efforts to identify and define species boundaries within this large ( gt 100 described species) genus. Here I show that sympatric populations of this nominal species occupying different sponge hosts display clear, concordant differences in allozyme genotypes and in multivariate morphometrics, confirming that the populations represent three distinct biological species. Moreover, careful field sampling revealed that the three S. rathbunae taxa and the closely related S. filidigitus Armstrong showed almost no overlap in the species of hosts occupied. Interestingly, while there was significant differentiation between Belizean and Panamanian populations of th eone taxon that occurred at both sites ( apprx 1500 km apart), these populations were recognizable as conspecific using both genetic and morphological characters. These results show that (1) diversity of higher than currently recognized, and (2) species of sponge-dwelling Synalpheus are highly host-specific, with related species distinctly segregated among hosts. Together with previous evidence of host race differentiation within shrimp species, these results suggest a primary role for resource specialization in the origin and/or maintenance of this group’s characteristically high diversity. |