Pachygymnura, Adnet & Marivaux & Cappetta & Charruault & Essid & Jiquel & Ammar & Marandat & Marzougui & Merzeraud & Temani & Vianey-Liaud & Tabuce, 2020

Adnet, Sylvain, Marivaux, Laurent, Cappetta, Henri, Charruault, Anne-Lise, Essid, El Mabrouk, Jiquel, Suzanne, Ammar, Hayet Khayati, Marandat, Bernard, Marzougui, Wissem, Merzeraud, Gilles, Temani, Rim, Vianey-Liaud, Monique & Tabuce, Rodolphe, 2020, Diversity and renewal of tropical elasmobranchs around the Middle Eocene Climatic Optimum (MECO) in North Africa: New data from the lagoonal deposits of Djebel el Kébar, Central Tunisia, Palaeontologia Electronica (a 38) 23 (2), pp. 1-62 : 31

Genus PACHYGYMNURA nov. gen.

zoobank.org/ 343C7885-43ED-4D1C-A498-2F5034A8BE7D

Type species. Coupatezia attiai Cook in Murray et al. (2010) - DPC 23279, DPC 23777, DPC 23778 from the BQ-2 locality, Fayum , Egypt – Late Eocene .

Etymology. Derived from the Greek Pachy (thick) relative to the peculiar massive teeth of this gymnurid taxon.

Temporal range. Middle Eocene of West and North Africa to Latest Priabonian ( Egypt).

Diagnosis. Genus only known by minute isolated teeth, the root and crown of the teeth being as massive and similar in size. The enameloid of the crown surface is entirely smooth and free of ornamentation or keel. In occlusal view, the crown is heart-shaped with a concave labial visor and convex lingual extremity. The marginal angles are particularly rounded. The lingually directed transverse crest that separates the lingual from the labial face extends from the lateral angles to form a sharp, medially but no individualized cusp. The occlusal part of the labial face is flat, the labial visor is rounded, and the lingual face is sub-rectangular in lingual view. In profile, the lingual face is steepsided, and only slightly shorter than the labial face. Both faces are remarkably straight in this view. The bilobate root is very massive with a height equalling or surpassing the height of the crown. It is as wider than the crown width. The root lobes are particularly labiolingually elongated and extend beyond the labial margin of the crown in occlusal view. The asymmetrical root lobes are crescentshaped in basal view, and separated by a well-developed nutritive groove that bears sometimes a large median foramen and regularly many marginal foramina.