Paper No. 41-31
Presentation Time: 9:00 AM-5:30 PM
APPARATUS OF YAOXIANOGNATHUS SP., CONODONTA, FROM THE VIOLA FORMATION, FORT WORTH BASIN, UPPER ORDOVICIAN (MID MOHAWKIAN)
A drill core sample containing a high abundance, low diversity conodont fauna dominated by Yaoxianognathus sp. that also included elements of Drepanoistodus suberectus and Panderodus sp. from the Viola Formation, Fort Worth Basin, central Texas, within the Belodina compressa Zone (mid Mohawkian) enabled reconstruction of the multielement apparatus, consisting of P1, P2, M, and five S elements, including a symmetrical S0. The P1 element is carminate, differing from Y. abruptus (Branson and Mehl) by longer anterior and posterior processes, and the absence of a pronounced gap between the posteriorly inclined cusp and the nearly erect denticles of the anterior process. The P2 is a short, moderately arched angulate element. The M element is dolobrate, the S elements, for the most part fragmented and covered with apatite overgrowths, are bipennate (S4 and S3), digyrate (S2 and S1), and alate (S0). Notable on the P2, M, and S elements are longitudinal striations on the cusp and larger denticles.