Revistes Catalanes amb Accés Obert (RACO)

A new Devonian asteroid-like ophiuroid from Spain

D.B. Blake, S. Zamora, J.L. García-Alcalde

Resum


A new Lochkovian (early Devonian) ophiuroid (Echinodermata), Ophiohispania elegans n. gen. and sp., is described based on the dorsal surface and a ventral? arm fragment of a single small, well-preserved specimen from Asturias (northwest Spain). Although readily assigned to the ophiuran family Encrinasteridae, arrangement of the robust primary ambulacral column and ambital framework ossicles of O. elegans is superficially similar to approximately coeval members of the asteroid family Xenasteridae. The ophiuroids Protaster and Encrinaster together with O. elegans and the asteroidXenaster serve to illustrate many apomorphies diagnostic of the different asterozoan clades. A second Devonian ophiuran, Strataster maciverorum, is superficially suggestive of post-Paleozoic crown-group asteroids that are very different from the Xenasteridae, demonstrating that homoplastic similarities between the two surviving asterozoan clades can transcend time and emerge in widely separated lineages.

Ophiohispania elegans n. gen. and sp. was collected from a shale-rich horizon of the Furada Formation, Asturias, Spain. Sedimentologic and palaeontologic data suggest a near-shore setting subjected to common storms.


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