Mol Phylogenet Evol 2019 Jul 01;136:151-163. doi: 10.1016/j.ympev.2019.04.014.

Dark offshoot: Phylogenomic data sheds light on the evolutionary history of a new species of cave brittle star.

???displayArticle.abstract???
Caves are a useful system for testing evolutionary and biogeographic hypotheses, as they are isolated, and their environmental conditions have resulted in adaptive selection across different taxa. Although in recent years many more cave species have been discovered, cave-dwelling members of the class Ophiuroidea (brittle stars) remain scarce. Out of the more than two thousand species of brittle stars described to date, only three are regarded as true cave-dwellers. These occurrences represent rare colonising events, compared to other groups that are known to have successfully diversified in these systems. A third species from an anchihaline cave system in the Yucatan Peninsula, Mexico, has been previously identified from cytochrome oxidase I (COI) barcodes. In this study, we reassess the species boundaries of this putative cave species using a phylogenomic dataset (20 specimens in 13 species, 100 exons, 18.7 kbp). We perform species delimitation analyses using robust full-coalescent methods for discovery and validation of hypotheses on species boundaries, as well as infer its phylogenetic relationships with species distributed in adjacent marine regions, in order to investigate the origin of this cave-adapted species. We assess which hypotheses on the origin of subterranean taxa can be applied to this species by taking into account its placement within the genus Ophionereis and its demographic history. We provide a detailed description of Ophionereis commutabilis n. sp., and evaluate its morphological characters in the light of its successful adaptation to life in caves.

???displayArticle.pubmedLink??? 30981811
???displayArticle.link??? Mol Phylogenet Evol