Vol. 53, 2014
Morphological and genetic evaluation of the hydrocoral Millepora species complex in the Caribbean
Dannise V Ruiz-Ramos1,2, Ernesto Weil1 and Nikolaos V Schizas1*
1Department of Marine Sciences, University of Puerto Rico, Mayagüez, Call Box 9000, Mayagüez 00681, Puerto Rico
2Current address: 208 Mueller Laboratory, Biology Department, The Pennsylvania State University, University Park, PA 16801, USA
Background: The hydrocoral Millepora
is an important framework builder that dominates shallow turbulent
environments in the Indo-Pacific and the Atlantic-Caribbean. The
Caribbean representatives of the genus are classified in four species -
Millepora alcicornis, Millepora complanata, Millepora striata, and Millepora squarrosa - but their taxonomic boundaries are not clearly defined. We used mitochondrial gene sequences to delineate the four Millepora
species and evaluated whether morphological traits and mitochondrial
sequence divergence were correlated for two most common species M. alcicornis and M. complanata.
were collected from Puerto Rico, Guadeloupe, Curaçao, Grand Cayman, and
Panama during 2006 to 2007. Diameter of dactylopores distinguished the
branching and encrusting morphotypes of M. alcicornis and M. complanata, and gastropore diameter discriminated between M. alcicornis and M. complanata. High levels of haplotypic diversity (Hd = 0.94) were observed, with the most common haplotypes shared by M. alcicornis and M. complanata. Sequence divergence ranged from 0% to 3% among M. alcicornis, M. complanata, and M. striata to 25% between these three species and M. squarrosa. Bayesian analysis of cytochrome oxidase subunit I (COI) gene indicated the presence of three Caribbean taxa: M. squarrosa, M. striata, and the ‘species complex’ encompassing the morphologies displayed by M. complanata and M. alcicornis.
Conclusions: The branched M. alcicornis and encrusted M. alcicornis and M. complanata
can be differentiated morphologically but not genetically. Phylogenetic
analysis suggests that the Caribbean milleporids include threespecies - M. squarrosa, M. striata, and the species complex of M. alcicornis-M. complanata. Millepora striata is closely related to the M. alcicornis-M. complanata species complex.
Key words: Hydrozoan; Polymorphism; Phenotypic plasticity; Cytochrome oxidase I; Puerto Rico.
*Correspondence: E-mail: firstname.lastname@example.org