Palaeozoic asteroids represent a stem-group to the monophyletic post-Palaeozoic Neoasteroidea, but many aspects of their anatomy are poorly known. Using serial grinding and computer reconstruction, we describe fully articulated Silurian (ca 425 Myr) specimens from the Herefordshire Lagerstätte, preserved in three dimensions complete with soft tissues. The material belongs to a species of Bdellacoma, a genus previously assigned to the ophiuroids, but has characters that suggest an asteroid affinity. These include a pyloric system in the gut, and the presence of large bivalved pedicellariae, the latter originally described under the name Bursulella from isolated valves. Ampullae are external and occur within podial basins; the radial canal is also external. Podia are elongate and lack terminal suckers. The peristome is large relative to the mouth. Aspects of the morphology are comparable to that of the extant Paxillosida, supporting phylogenetic schemes that place this order at the base of the asteroid crown group.
A diverse, upper Silurian asterozoan fauna of 16 species is described from Leintwardine, Herefordshire. The asterozoans, comprising taxa assigned to the Asteroidea and Ophiuroidea are found within the Lower Leintwardine Formation of lower Ludfordian (upper Ludlow) age, predominantly in rocks interpreted as submarine channel deposits. This paper amplifies and revises Spencer's treatment of the fauna within the broader context of British Palaeozoic Asterozoa in the early twentieth century. Owing to the rarity of asterozoan‐bearing deposits in the Palaeozoic and particularly the Silurian, the Leintwardine fauna is significant for understanding the early diversity of the group, and assessing potential diversification trends. The study is based on extensive museum collections and material collected from the Church Hill starfish beds. New observations are made on previously known taxa: the asteroids Hudsonaster? leintwardensis (Salter) (which is reassigned), Coccaster bulbiferus Spencer, Urasterella cf. ruthveni (Forbes) and Palasterina cf. antiqua, the stenurids Rhopalocoma pyrotechnica Salter, Sturtzaster marstoni (Salter), Sturtzaster colvini (Salter), Bdellacoma vermiformis Salter and Antiquaster magrumi Kesling, and the oegophiurid ophiuroids Lapworthura miltoni (Salter) and Furcaster leptosoma (Salter). The asteroids Doliaster sp. and Palasterina sp. are recognized. New species are the stenurids Bdellacoma fortispina sp. nov. and Antiquaster apertisulcus sp. nov., and the oegophiurid Loriolaster fragilicalceus sp. nov., the latter extending the range of the genus to the Ludlovian. Morphological and taxonomic diversity of this fauna is high, compared to the preceding Silurian (with the stenurids comprising a notably diverse component of the fauna), supporting potential asterozoan diversification during the Wenlockian to Ludlovian.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.