@article {294,
	title = {Species boundaries, specialization, and the radiation of sponge-dwelling alpheid shrimp},
	journal = {Biological Journal of the Linnean Society},
	volume = {58},
	number = {3},
	year = {1996},
	note = {USA1996English},
	pages = {307-324},
	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{\textquoteright}s characteristically high diversity.},
	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},
	author = {Duffy, J. E.}
}
@inbook {298,
	title = {Sibling species in the sea},
	booktitle = {Fautin, D. G.: Ed. Annual Review of Ecology and Systematics. 24. 1993. 189-216.},
	year = {1993},
	note = {Book. Literature Review.0066-4162English},
	publisher = {Annual Reviews Inc., P.O. Box 10139, 4139 El Camino Way, Palo Alto, California 94306},
	organization = {Annual Reviews Inc., P.O. Box 10139, 4139 El Camino Way, Palo Alto, California 94306},
	abstract = {Abstract: Sibling species are common in all major marine groups and habitats. Their abundance reflects both inadequate study of morphological features of living organisms ({\textquoteright}{\textquoteright}pseudo-sibling species{\textquoteright}{\textquoteright}) and divergence in habitat, life history, and chemical recognition systems without parallel divergence in morphology. Many marine sibling species are quite distinct genetically. Others, however, exhibit slight genetic differences whose significance is only clear in sympatry and in combination with other subtle but concordant patterns of differentiation. A large number of abundant, well-studied, or economically important taxa have recently been shown to be complexes of sibling species. The broad habitat and geographic distributions characteristic of many marine species require reevaluation in this context.},
	keywords = {Animalia, animals, book chapter, Comparative and Experimental Morphology, cryptic species, Ecology, Ecology (Environmental Sciences), Environmental Biology/Animal [07508], Environmental Biology/Oceanography [07512], Environmental Sciences), Evolution [01500], Evolution and Adaptation, General Biology/Taxonomy, General Life Studies, Invertebrata, Invertebrata - Unspecified: Invertebrata, Invertebrata (Invertebrata - Unspecified), Invertebrata-Unspecified [34000], invertebrate (Invertebrata - Unspecified), Invertebrates, marine, Marine Ecology (Ecology, Nomenclature and Terminology [00504], Physiology, Physiology and Pathology/General [64001], speciation, taxonomy},
	author = {Knowlton, Nancy}
}
@article {366,
	title = {Host use patterns and demography in a guild of tropical sponge-dwelling shrimps},
	journal = {Marine Ecology-Progress Series},
	volume = {90},
	number = {2},
	year = {1992},
	note = {USA1992English},
	pages = {127-138},
	abstract = {Demographic consequences of the commensal lifestyle of shrimps Synalpheus spp. were assessed by sampling sponges and coral rubble on reefs in Caribbean Panama. Eight of 22 species were found solely or primarily within the internal canals of sponges. Among these sponge-dwellers, host specificity ranged from generation (occurrence in gtoreq 4 host species) to specialization on a single host species, and sponges used in the field were also preferreed in laboratory choice assays. Living in sponges had important consequences for shrimp populations. Parasitism by epicaridean isopods averaged 6 times higher in obligate sponge-dwellers (17\%) than in free-living species (2.5\%). Sponge species differed in the mean size and size range of habitable spaces they provide, number of potentially competing Synalpheus species they support, and vulnerability of associated shrimps to parasitism. Similarly, conspecific shrimp populations occupying different hosts differed demographically. Specifically, populations and Synalpheus brooksi in the sponge Spheciospongia vesparium were significantly less dense, less parasitized, had larger body sizes, and tended toward higher proportions of mature females than conspecifics in the co-occurring sponge Agelas clathrodes. High host specificity, regional variation in host use, and demographic and genetic differentiation among conspecific shrimps in different host species suggest that the commensal lifestyle has pervasive, and potentially evolutionarily important, consequences for the population biology of this diverse group of shrimps.},
	keywords = {Agelas clathrodes (Porifera), 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, Genetics, Genetics and Cytogenetics/Animal [03506], Genetics and Cytogenetics/Population Genetics (1972- ) [03509], Invertebrata, Invertebrates, Malacostraca: Crustacea, Marine Ecology (Ecology, Neotropical region), Panama (Central America, Physiology, Physiology and Pathology/Arthropoda-Crustacea [64054], Physiology and Pathology/Porifera [64006], Population Genetics (Population Studies), Porifera [39000], Porifera: Invertebrata, Spheciospongia vesparium (Organisms - Unspecified), sponge (Porifera), Synalpheus brooksi (Malacostraca), Synalpheus spp. (Malacostraca)},
	author = {Duffy, J. E.}
}
