Atlanticalymene Adrain & Karim 2020, n. gen.

• Main Authors: Adrain, Jonathan M., Karim, Talia S., McAdams, Neo E. B.
• Format: Other/Unknown Material
• Language: unknown
• Published: 2020
• Subjects: Biodiversity; Taxonomy; Animalia; Arthropoda; Trilobita; Phacopida; Bathycheilidae; Atlanticalymene; Canada; Lower Head; Shallow Bay; Table Cove; Newfoundland
• Online Access: https://zenodo.org/record/4537324; https://doi.org/10.5281/zenodo.4537324

Atlanticalymene n. gen. Type species. Atlanticalymene bardensis n. sp., from the Darriwilian Table Cove Formation of western Newfoundland, Canada. Other species. Atlanticalymene n. sp. A (“? Ischyrophyma sp. ind.” of Whittington [1963, p. 50, pl. 6, figs. 13-15]), Shallow Bay Formation (lower Darriwilian), Lower Head, western Newfoundland; Sthenarocalymene sp. indet. of Zhou et al. (2014, p. 114, fig. 56), Yijianfang Formation (Dapingian), Yijianfang, Bachu, northwestern Tarim, Xinjiang, China. Etymology. From the Atlantic Ocean, on the western edge of which the type locality is situated, and the genus name Calymene; gender is feminine. Diagnosis. Glabella long and parallel-sided anterior to L1; L1 well developed and nearly completely isolated; L2 and L3 scarcely developed, S2 faint and barely discernible, S3 not impressed; cranidial anterior border strongly bowed in anterior view; preglabellar area elongate (sag.; exsag.); eye ridge expressed dorsally; palpebral lobe small; sculpture of small to coarse fairly densely scattered tubercles over all skeletal parts except hypostome. Discussion. As noted above, a consensus emerged in the recent literature (Fortey, 1990; Fortey and Droser, 1999; Turvey, 2002) that Middle Ordovician Laurentian calymenoidean species should all be assigned to Protocalymene and that they are unambiguous calymenids. Revision on the basis of new photographs herein demonstrates that a calymenid affinity is true of only a handful of the occurrences (those assigned by Adrain and Fortey [1997] to Sthenarocalymene), and not necessarily true of Protocalymene mcallisteri. The various reports break down into two morphological groups: taxa related to Darriwilian material described in open nomenclature by Whittington (1965) and taxa related to P. mcallisteri. The former collectively represent Atlanticalymene n.gen., whereas the latter, while certainly calymenoidean, are considered below to be of unclear family relationships. The genus diagnosis is complicated by the fact that there is only one well ...