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17 October 2019 Asterolepis alticristata n. sp. (Antiarchi) from the Upper Devonian (Frasnian) of Nunavut, Canada, and a report on the antiarch diversity of the Fram Formation
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Abstract

A large collection of fossils from the NV2K17 locality, Upper Devonian (Frasnian) Fram Formation, Ellesmere Island, Nunavut, Canada, represents at least two species of Asterolepis. The first, Asterolepis alticristata n. sp., is diagnosed by a tall midline crest that rises sharply from the tergal angle of the anterior median dorsal plate, reaches maximum height at around the position of the lateral corners, and then drops to form a low midline crest along the posterior median dorsal plate. The second species is identified as Asterolepis cf. radiata according to an ornament of radiating rows of conjoined tubercles and ridges on the available thoracic plates (anterior median dorsal, posterior median dorsal, and mixilateral). We describe additional antiarch material from the NV2K17 locality, including an anterior median dorsal plate of Bothriolepis sp. indet., and from localities throughout the Fram Formation. The antiarch occurrences in the Fram Formation conform to a possible faunal turnover from one dominated by asterolepidoids low in the formation to one dominated by bothriolepidids high in the Fram Formation. At the NV2K17 locality, in the middle of the Fram Formation, members of the two groups appear together.

© Publications scientifiques du Muséum national d'Histoire naturelle, Paris.
Jason P. Downs, Edward B. Daeschler, Nathanael Lo, Emily N. Carey, and Neil H. Shubin "Asterolepis alticristata n. sp. (Antiarchi) from the Upper Devonian (Frasnian) of Nunavut, Canada, and a report on the antiarch diversity of the Fram Formation," Geodiversitas 41(1), 679-698, (17 October 2019). https://doi.org/10.5252/geodiversitas2019v41a19
Received: 22 August 2018; Accepted: 9 May 2019; Published: 17 October 2019
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