CHONDRICHTHYES Huxley, 1880 Sub

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 : 5

Class CHONDRICHTHYES Huxley, 1880 Sub Cohort NEOSELACHII Compagno, 1977 Order LAMNIFORMES Berg, 1958

Gathering the largest and most neritic species, well-preserved teeth belonging to common Eocene Lamniform taxa are very scarce in KEB, either by surface collecting during the field or in bulk samples. Several large broken cusps and roots are provisionally attributed to Macrorhizodus cf. praecursor (Leriche, 1905) , a large lamnid commonly reported in most of the middle/upper Eocene deposits of the Tethys seaway. Only a pair of complete teeth allowed a better systematic attribution. It concerns those of a fossil thresher shark Alopias sp. Until now, Alopias representatives were primarily known in tropical seas during the Late Eocene in Europe (e.g., Cappetta, 2012), and from southwestern Morocco (Adnet et al., 2011) to Egypt (Case and Cappetta, 1990; Underwood et al., 2011; Zalmout et al., 2012) with the reports of the ambiguous North American Alopias alabamensis White, 1956 (see Ebersole et al. 2019 for discussion). Only represented by a single specimen in MI (Middle Eocene), teeth of Alopias seem to be more abundant throughout all the other open marine rock units of Wadi al Hitan (Case and Cappetta, 1990; Underwood et al. 2011), GE (A-C) included. This report in KEB confirms the occurrence of genus since Bartonian in southwestern Tethys.