A time-calibrated molecular phylogeny of the precious corals: reconciling discrepancies in the taxonomic classification and insights into their evolutionary history

• Published in: BMC Evolutionary Biology
• Main Authors: Ardila Néstor E, Giribet Gonzalo, Sánchez Juan A
• Format: Article in Journal/Newspaper
• Language: English
• Published: BMC 2012
• Subjects: Evolution; QH359-425; New Zealand; Pacific; Antarc*; Antarctica
• Online Access: https://doi.org/10.1186/1471-2148-12-246; https://doaj.org/article/5bff2dc3063e4138bea91ed77fc29c43

Abstract Background Seamount-associated faunas are often considered highly endemic but isolation and diversification processes leading to such endemism have been poorly documented at those depths. Likewise, species delimitation and phylogenetic studies in deep-sea organisms remain scarce, due to the difficulty in obtaining samples, and sometimes controversial. The phylogenetic relationships within the precious coral family Coralliidae remain largely unexplored and the monophyly of its two constituent genera, Corallium Cuvier and Paracorallium Bayer & Cairns, has not been resolved. As traditionally recognized, the diversity of colonial forms among the various species correlates with the diversity in shape of their supporting axis, but the phylogenetic significance of these characters remains to be tested. We thus used mitochondrial sequence data to evaluate the monophyly of Corallium and Paracorallium and the species boundaries for nearly all named taxa in the family. Species from across the coralliid range, including material from Antarctica, Hawaii, Japan, New Zealand, Taiwan, Tasmania, the eastern Pacific and the western Atlantic were examined. Results The concatenated analysis of five mitochondrial regions (COI, 16S rRNA, ND2, and ND3-ND6) recovered two major coralliid clades. One clade is composed of two subgroups, the first including Corallium rubrum , the type species of the genus, together with a small group of Paracorallium species ( P. japonicum and P. tortuosum ) and C. medea (clade I-A); the other subgroup includes a poorly-resolved assemblage of six Corallium species ( C. abyssale, C. ducale, C. imperiale, C. laauense, C. niobe, and C. sulcatum clade I-B). The second major clade is well resolved and includes species of Corallium and Paracorallium ( C. elatius, C. kishinouyei, C. konojoi, C. niveum, C. secundum, Corallium sp., Paracorallium nix, Paracorallium thrinax and Paracorallium spp.). A traditional taxonomic study of this clade delineated 11 morphospecies that were congruent with the ...