ODONTASTERIDAE AND THE

Mah, Christopher & Foltz, David, 2011, Molecular phylogeny of the Valvatacea (Asteroidea: Echinodermata), Zoological Journal of the Linnean Society 161 (4), pp. 769-788 : 776-777

THE ODONTASTERIDAE AND THE CHAETASTERIDAE

Prior treatments (e.g. Fisher, 1911) have supported the Odontasteridae as having close affinities with the Goniasteridae . This notion has been supported by morphology-based phylogenies ( Blake, 1987; Gale, 1987b) and by our molecular data ( Fig. 1 ). The position of the monotypic Chaetasteridae in Blake’s (1987) phylogeny is also consistent with the relatively stemward position of this taxon relative to the Odontasteridae and other valvatidans in Figure 1 .

Fell (1954) described a Jurassic occurrence of Odontaster from South Auckland, New Zealand, which would be consistent with its relatively stemward phylogenetic position. The fossil shares recognizable features (e.g. Fell’s first ambulacral) with other odontasterids. Fell (1954) was confident in assigning the specimen to Odontaster but pending a full assessment of the Odontasteridae , it is unclear how reliable this character is for correct taxonomic assignment.

A single early Cretaceous member of the Chaetasteridae , Chaetasterina gracilis , was described by Hess (1970), which he postulated was intermediate between the Radiasteridae and the Ganeriidae (as represented by Hyalinothrix ). However, Chaetaster was supported as sister taxon to Odontaster and was not supported on either of the clades containing radiasterid or ganeriid taxa ( Fig. 1 ).

Figures

Figure 1. Maximum likelihood tree of valvatacean sea stars rooted against forcipulatacean + velatid sea stars. The analysis is based on 1084 bp of concatenated sequence data from two mitochondrial rDNA genes and one nuclear protein-coding gene, early-stage histone H3. As discussed in the text, solasterids are treated as part of the ingroup. The analysis was carried out in RAxML with bootstrap percentages indicated for nodes that had> 50% support. Boxed letters A–P are referred to in the text. Traditional family names are shown at the right; all families are in the Valvatida except as noted. The scale bar shows the expected number of substitutions.