Pristis sp.

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 : 27-28

Pristis sp. Figures 9 G-M, 10E

2016 Pristis sp ; Merzeraud et al., p. 14-15, tab. 1.

Material. More than 200 oral teeth (including the figured specimens KEB 1-158 to 1-164; Figure 9 GM), and some fragmentary rostral denticles (e.g., KEB 1-165; Figure 10E ) from the KEB- 1 locality, Souar-Fortuna formations, Djebel el Kébar, Tunisia.

Description

Rostral denticles. These structures are badly preserved, often broken and strongly smoothed. The largest one ( Figure 10E ) probably reached 8 up to 10 cm long. They are thick, elongated and curved ventrally. Dorsal and ventral surfaces are only weakly convex. When preserved, the anterior edge is very convex. In contrast, the posterior edge bears a deep sulcus running along the length of the tooth, and there is a distinct ridge on both the dorsal and ventral margins, contrary to what is observed in rostral denticles of Anoxypristis . Most of rostral denticles exhibit clear signs of wear, with the distal half of each specimen being smooth.

Oral teeth. As rostral denticles, oral teeth of Pristis are conservative, exposing a dental pattern close to that observed in living species (e.g., Pristis pristis ). As a consequence, there is no report in the literature of oral teeth belonging strictly to Pristis lathami Galeotti, 1837 , the species commonly recovered in Eocene deposits from rostral denticles. In fact, all the oral teeth of Middle-Late Eocene Pristis are left in open nomenclature (e.g., Underwood et al., 2011; Cappetta and Case, 2016) and Case and Cappetta (1991) suggested that P. lathami possessed rather different oral teeth compared to living species. The re-examination of the material from EG (pers. observ. SA, HC.) suggests that the material attributed with uncertainty to? Rhinobatos sp. (Strougo et al., 2007, plate 2, fig. 3) belongs in fact to oral teeth of Pristis , and are besides rather comparable to those figured here.

Remarks

Pristis lathami is the common representative of Pristis that frequented the tropical Atlantic and Tethys during the Middle-Late Eocene. Numerous records of rostral denticles, sometimes still imbedded in the rostrum (e.g., Cicimuri, 2007), are reported in the literature (Cappetta, 2012) contrary to the oral teeth that seemingly did not attracted particular attention until now. Given that the largest specimens of pristid teeth from KEB-1 share similar sizes and morphologies, we can expect that they are associated with the largest rostral denticles. For the first time, the oral teeth and the rostral denticles from an Eocene sawfish are figured together, however, and for the similar reasons advocated for the previous species, we remain cautious about attributing these materials to P. lathami and preferred to leave it in open nomenclature.

Figures

FIGURE 9. A-F: Propristis cf. schweinfurti, A. Anterior oral tooth KEB 1-166, A1. Lingual view, A2. Occlusal view, A3. profile; B. Antero-lateral oral tooth KEB 1-167, B1. Occlusal view, B2. Lingual view, B3. Labial view; C. Anterior oral tooth KEB 1-168, C1. Lingual view, C2. Basal view, C3. Profile; D. lateral tooth KEB 1-169, D1. Lingual view, D2. Occlusal view, D3. Basal view, D4. Magnificence of crown-root boundary of D3; E.?male lateral tooth KEB 1-170, E1. Occlusal tooth, E2. Basal view; F.?male anterior tooth KEB 1-171, F1. Lingual view, F2. Occlusal view; G-L: Pristis sp. G. porterior tooth KEB 1-158, G1. Occlusal view, G2. Basal view; H. anterior tooth KEB 1-159, occlusal view; I. lateral tooth KEB 1-160, I1 occlusal view, I2., lingual view. J lateral tooth KEB 1-161, occlusal view; K. anterior tooth KEB 1-162, occlusal view; L. lateral tooth of?juvenile KEB 1-163, L1. Occlusal view, L2. Basal view; M. lateral tooth of juvenile KEB 1-164, M1. Occlusal view, M2. Profile.

FIGURE 10. A-D: Propristis cf. schweinfurti. A. Rostral denticle KEB 1-172, A1. Profile, A2. dorsal view; B. Rostral denticle KEB 1-173, Profile; C. Rostral denticle KEB 1-174, C1. Profile, C2. Dorsal view, C3. basal view; D. Rostral denticle KEB 1-175, D1. profile. D2. dorsal view; E: Pristis sp. Rostral denticle, KEB 1-165, dorsal view; F-G. Rhynchobatus cf. vincenti. F. anterior tooth KEB 1-176, F1. Occlusal view, F2. Basal view; G. anterior tooth KEB 1-177, occlusal view; H-I.?Torpedo sp. H. lateral tooth KEB 1-178, occlusal view, I. lateral tooth KEB 1-179, occlusal view.