A 'British' Silurian crinoid from Quinn Point, New Brunswick, eastern Canada

作者：Donovan Stephen K^*; Keighley David G

来源：Proceedings of the Geologists Association, 2015, 126(2): 226-231.

DOI：10.1016/j.pgeola.2015.01.006

• Cyclocyclicus
• Lanxocolumnus
• Systematics
• Palaeogeography
• Pseudolumen
• Iapetus Ocean

Crinoids are common fossils, yet complete specimens are rare. Diverse plates from the crinoid endoskeleton may be preserved, but the columnals from the stem are the most common. Even if not distinct enough to assign to a known group, they may be classified within columnal morphotaxa. Currently, identification of distinctive columnals is adding diversity to the Silurian biota. Lanxocolumnus (col.) chaleurensis sp. nov. is a heteromorphic crinoid column from the upper Llandovery (Telychian) of Quinn Point, Chaleur Bay, New Brunswick, eastern Canada. It has large and distinctive nodals and high-order intemodals, with smooth and discoid epifacets. The articular facets are sunken and nodals(?) have a unique feature, a circular pseudolumen into which a small intemodal lacking an epifacet may fit. The lumen/axial canal sensu stricto is narrow, central and rounded to (commonly) pentastellate. This Canadian species is closely related to Lanxocolumnus (col.) geoffnewalli (Feamhead and Donovan) comb. nov. from Shropshire, England. This is a further example of a crinoid taxon that migrated from Laurentia to Avalonia as the Iapetus Ocean closed.

• 出版日期2015-4