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Re-evaluation of the Palasteriscidae Gregory, 1900, and the early phylogeny of the Asteroidea (Echinodermata)
Published online by Cambridge University Press: 20 May 2016
Abstract
Foliaster transversus n. gen. and sp. (Echinodermata: Asteroidea) is assigned to the Ordovician through Devonian family Palasteriscidae; the other genera included in the family are Palasteriscus and Platanaster. Platanaster is redescribed; both it and Foliaster are thought to have been suspension feeders that extended their arms into the water column. Ampullar basins in both were external; there are no podial pores. The strongly petaloid arm of Foliaster with widely separated podial basins is unique.
Two competing phylogenies have been offered for the origin of stelleroids, one treating edrioasteroids as ancestral, the other favoring crinoids. In the latter hypothesis, the Palasteriscidae is the primitive asteroid family, and Platanaster is an example of the first true asteroids. Both hypotheses are here considered to lack adequate support; stelleroid origins remain problematic.
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- Copyright © The Paleontological Society
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