Molecular phylogeny of the Forcipulatacea (Asteroidea: Echinodermata): systematics and biogeography

Abstract

We present a comprehensively sampled three-gene phylogeny of the monophyletic Forcipulatacea, one of three major lineages within the crown-group Asteroidea. We present substantially more Southern Hemisphere and deep-sea taxa than were sampled in previous molecular studies of this group. Morphologically distinct groups, such as the Brisingida and the Zoroasteridae, are upheld as monophyletic. Brisingida is supported as the derived sister group to the Asteriidae (restricted), rather than as a basal taxon. The Asteriidae is paraphyletic, and is broken up into the Stichasteridae and four primary asteriid clades: (1) a highly diverse boreal clade, containing members from the Arctic and sub-Arctic in the Northern Hemisphere; (2) the genus Sclerasterias; (3) and (4) two sister clades that contain asteriids from the Antarctic and pantropical regions. The Stichasteridae, which was regarded as a synonym of the Asteriidae, is resurrected by our results, and represents the most diverse Southern Hemisphere forcipulatacean clade (although two deep-sea stichasterid genera occur in the Northern Hemisphere). The Labidiasteridae is artificial, and should be synonymized into the Heliasteridae. The Pedicellasteridae is paraphyletic, with three separate clades containing pedicellasterid taxa emerging among the basal Forcipulatacea. Fossils and timing estimates from species-level phylogeographic studies are consistent with prior phylogenetic hypotheses for the Forcipulatacea, suggesting diversification of basal taxa in the early Mesozoic, with some evidence for more widely distributed ranges from Cretacous taxa. Our analysis suggests a hypothesis of an older fauna present in the Antarctic during the Eocene, which was succeeded by a modern Antarctic fauna that is represented by the recently derived Antarctic Asteriidae and other forcipulatacean lineages.

Global Diversity and Phylogeny of the Asteroidea (Echinodermata)

“…Taxon sampling from within the Velatida was incomplete [181], but monophyly for the Korethrasteridae was supported. Asthenactis , a myxasterid was upheld within the Pterasteridae, but full taxon sampling remains ongoing.…”

“…Labidiaster annulatus in the Southern Ocean is a benthopelagic predator [202], [203]. Mah and Foltz [181] recovered a sister-group relationship between Heliaster and Labidiaster , which provided the basis for synonymy of the artificial and paraphyletic Labidiasteridae within the Heliasteridae. Mah [184], Foltz et al [180], and Mah and Foltz [181] dismantled the Labidiasteridae, showing that each of its members was assignable to phylogenetically distant lineages.…”

Description of a new family, new genus, and two new species of deep-sea Forcipulatacea (Asteroidea), including the first known sea star from hydrothermal vent habitats

“…Most of the molecular data (for the mitochondrial 16S rDNA, mitochondrial 12S rDNA, and nuclear early‐stage histone H3 gene) have been previously reported and analysed by Mah & Foltz (). Mah & Foltz (, b) should be consulted for details on DNA extraction, polymerase chain reactions (PCRs), sequencing, contig assembly, GenBank accession numbers, specimen voucher numbers, alignment methods, and curation of alignments prior to phylogenetic analysis. The new sequence data for Paulasterias tyleri gen. et sp.…”

The phylogeny of extant starfish (Asteroidea: Echinodermata) including Xyloplax, based on comparative transcriptomics

“…Blake, 1987;Gale, 1987) and molecular phylogenetic studies (e.g. Knott and Wray, 2000;Foltz et al, 2007;Janies et al, 2011;Mah and Foltz, 2011a). The position of the Forcipulatacea relative to other asteroids in Fig.…”