ABSTRACT
The Coral Triangle is the global epicenter of marine biodiversity as well as one of the world’s most imperiled ecosystems. Conserving the biodiversity of the Coral Triangle requires understanding the mechanisms by which this hotspot has evolved. Although there are several theories to explain the origins of this biodiversity hotspot, the center of origin theory has been criticized for lacking credible speciation mechanisms within the center of the Coral Triangle. In this paper, we examine the phylogeography and evolutionary history of coral reef-associated stomatopods. Results indicate significant regional population genetic structure in all 14 species examined. Several species exhibit patterns of Indian-Pacific Ocean differentiation, suggesting vicariance during Pleistocene low sea level stands may promote lineage diversification. However, all species show a pronounced pattern of differentiation between populations east and west of the Maluku Sea, although the precise location of this phylogeographic boundary varies among species. This pattern is most likely explained by limited water flow by the Halmahera Eddy, and thus larval transport and gene flow, across the Maluku Sea, promoting lineage diversification in this region and supporting the notion of a center of origin. In contrast, Bayesian analysis of regional patterns of differentiation suggested that the most basal populations of Haptosquilla pulchella and H. glyptocercus were found in reefs in the peripheral parts of their Pacific Ocean ranges, potentially suggesting support for the center of accumulation model. However, topology constraint tests indicated that the best trees were not significantly better than alternate topologies, limiting the inferences that can be drawn from this data. Although many processes are likely contributing to the Coral Triangle biodiversity hotspot, data from stomatopods clearly shows evidence for filters to dispersal and gene flow within the center, a result consistent with a center of origin. The identification of these barriers in stomatopods and many other unrelated marine fish and invertebrates is helping define regional limits of connectivity within the Coral Triangle, supporting regional conservation planning in this threatened ecosystem.
1 CORAL TRIANGLE BIODIVERSITY
