Taxonomy and functional morphology of the Urasterellidae (Paleozoic Asteroidea, Echinodermata)

Abstract

AbstractFamily-level taxonomic concepts for Paleozoic Asteroidea are problematic; data availability for the family Urasterellidae, however, is judged sufficient for familial reappraisal. The survey cannot be fully comprehensive because certain available names are founded on very limited material, with specimens widely scattered among collections. Recognized urasterellid genera include Urasterella Schuchert, 1914; Anthroosasterias Blake, 2017; Meturaster Blake, Guensburg, and Lefebvre, 2016; Salteraster Stürtz, 1893; Staurasterias Blake, 2017; Ulrichaster Spencer, 1950; and Pegoasterella pompom n. gen. n. sp. Other available generic names are held in abeyance. The name Urasterella has approached form-genus status, an outcome exacerbated by incomplete understanding of the type species. Urasterella huxleyi (Billings, 1865) is reassigned to Anthroosasterias. Relatively large specimen suites for Anthroosasterias huxleyi (Billings, 1865) and Salteraster grandis (Meek, 1872) enable some interpretation of urasterellid intrataxon variation, ontogenetic change, and life mode. Morphologic changes accompanying ontogeny of A. huxleyi are argued as favoring a shift from substrate surface feeding to feeding through extension of arms into the water column in a manner comparable to that seen among extant Forcipulatida and ophiurans.UUID: http://zoobank.org/82d2eca7-55e0-42ed-a164-c666652e3972