Incongruence between morphotypes and genetically delimited species in the coral genus Stylophora: phenotypic plasticity, morphological convergence, morphological stasis or interspecific hybridization?

A genetic analysis of the coral genus Stylophora reveals that species boundaries do not align with morphological traits, challenging traditional taxonomic classifications. The study, conducted across Madagascar, Okinawa, the Philippines, and New Caledonia, identified three distinct species (A, B, and C) using mitochondrial and nuclear markers. Species A and B are endemic to Madagascar, while species C is widespread in the Indo-Pacific, including New Caledonia's lagoons. Contrary to morphological data suggesting higher diversity in the western Indian Ocean and Red Sea, genetic evidence indicates that species C also occurs in the Coral Triangle, with a distinct fourth species (D) found only in the Red Sea. The research rejects interspecific hybridization as an explanation for morphological incongruence but suggests phenotypic plasticity or morphological stasis may play roles. The findings imply the western Indian Ocean as the likely center of origin for Stylophora, influencing its biodiversity distribution.

Flot, J.-F., Blanchot, J., Charpy, L., Cruaud, C., Licuanan, W. Y., Nakano, Y., Payri, C., & Tillier, S. (2011). Incongruence between morphotypes and genetically delimited species in the coral genus Stylophora: phenotypic plasticity, morphological convergence, morphological stasis or interspecific hybridization? BMC Ecology, 11(1), 22. https://doi.org/10.1186/1472-6785-11-22