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1 July 2016 Multielement Conodont Apparatuses of the Ellisonidae from Japan
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The apparatuses of Triassic ellisonid conodonts: Cornudina breviramulis, Hadrodontina aequabilis, and Staeschegnathus perrii gen. et sp. nov. from the Taho Formation in Higashiuwa-gun, Ehime Prefecture, Southwest Japan and Furnishius triserratus from the Iwai Formation in Nishitama-gun, Tokyo were reconstructed on the basis of the multielement structure of natural assemblages previously reported. Ellisonia triassica was remarked on this occasion. These species well agree with the general septimembrate apparatus structure containing 15 elements: angulate or pastinate P1, angulate P2, breviform digyrate M, alate S0, extensiform digyrate S1 and S2, and bipennate S3 and S4 elements. Having compared the morphologic features of apparatus elements of the Ellisonidae, I propose herein the new subfamily Hadrodontinae within it. Among the Ellisonidae and other taxa of the Prioniodinina, a phylogenetic relationship is recognized only between E. triassica and Upper Devonian Hibbardella angulata. Other species of the Ellisonidae are more closely related to ozarkodinides with “ozarkodiniform” angulate P1 element than any previously reported prioniodininids with “oulodiniform” extensiform digyrate and carminate P1 elements.

© by the Palaeontological Society of Japan
Toshio Koike "Multielement Conodont Apparatuses of the Ellisonidae from Japan," Paleontological Research 20(3), 161-175, (1 July 2016).
Received: 9 July 2015; Accepted: 1 September 2015; Published: 1 July 2016

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