Propristis cf. schweinfurthi, Dames, 1883
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publication ID |
https://doi.org/ 10.26879/1085 |
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publication LSID |
lsid:zoobank.org:pub:B6B8E985-F1CF-4C10-BB00-602E5BF36C1C |
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persistent identifier |
https://treatment.plazi.org/id/03BA87C1-FFD6-FFC1-C077-E1FACEB9B7E4 |
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treatment provided by |
Felipe |
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scientific name |
Propristis cf. schweinfurthi |
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Figures 9 View FIGURE 9 A-F, 10A-D
2016 Propristis sp. ; Merzeraud et al., p. 14-15, tab. 1. Material. More than 200 oral teeth (including the figured specimens KEB 1-166 to 1-171; Figure 9 View FIGURE 9 AF), and four badly preserved rostral denticles (KEB 1-172 to 1-175; Figure 10 View FIGURE 10 A-D) from the KEB-1 locality, Souar-Fortuna formations, Djebel el Kébar, Tunisia.
Description
Rostral denticles. The rare rostral denticles, mainly broken, are virtually as long as high, and are flattened dorso-ventrally, reaching a size up to 1.5 cm (estimated) high in the largest specimen ( Figure 10D View FIGURE 10 ). The basal edge is convex ( Figure 10A View FIGURE 10 2 View FIGURE 2 ) to straight ( Figure 10C View FIGURE 10 2, D2 View FIGURE 2 ) in dorsal or ventral view. The apical angle is wide to round in the best preserved smallest specimen ( Figure 10A View FIGURE 10 ). The two cutting edges are salient and no posterior carena is observable as in rostral denticles of Pristis . The posterior cutting edge is convex whereas the anterior one is angular due to the presence of a more or less prominent process ( Figure 10C View FIGURE 10 2, D2 View FIGURE 2 ). Without enameloid and due to functional wear, the ventral and dorsal faces of the dentine bear nearly parallel folds that fade out near the apex.
Oral teeth. These teeth are very small, reaching up to 1.5 mm maximal size. The heterodonty is not very marked with teeth more compressed mesiodistally according to files and/or ontogenetic stades ( Figure 9E, F View FIGURE 9 ). The teeth are broader than long; their crown is relatively high, always bearing a cusp, more or less erected, characterized by a sharp transversal crest and two short lateral lingual uvulae. The latter do not overlap the root in occlusal view. The median lingual uvula is well developed, prominent and rounded in profile ( Figure 9A View FIGURE 9 3, C3 View FIGURE 3 ). The labial face of the crown is short and its labial edge is sometimes truncated ( Figure 9B View FIGURE 9 3 View FIGURE 3 ). The root is thick, also compressed mesiodistally but always longer than the crown length. The margino-lingual faces are flat, regular, and form a small ( Figure 9A View FIGURE 9 2 View FIGURE 2 ) to inconspicuous ( Figure 9B View FIGURE 9 1 View FIGURE 1 , D 2 View FIGURE 2 ) lingual extension, under the median uvula of the crown. A pair of large nutritive foramina opens laterally to the medio lingual extension of the root. The basal face of the root is large and long with two root lobes separated by a deep groove. The two basal faces of the root lobes, flat ( Figure 9C View FIGURE 9 1, D1 View FIGURE 1 , B 2 View FIGURE 2 ) to convex ( Figure 9A View FIGURE 9 1, F1 View FIGURE 1 ) in lingual view, form an acute angle from 30° ( Figure 9F View FIGURE 9 1 View FIGURE 1 ) in the most anterior teeth to 90° ( Figure 9D View FIGURE 9 1 View FIGURE 1 ) in the most posterior teeth.
Remarks
Even fragmentary, rostral denticles are unequivocal representatives of Propristis , an Eocene sawfish only known by long rostrum with peculiar flat and rounded rostral denticles, without any enameloid on the dental crown surface. Firstly recovered in the Late Eocene of Fayum (Dames, 1883; Priem, 1897b, Stromer, 1905b) with Propristis schweinfurthi Dames, 1883 , the genus was subsequently recorded widely in the Middle-Late Eocene deposits from Atlantic and Tethysian coasts (see Case and Cappetta, 1990; Cappetta, 2012) including in MI, KM and BQ in Egypt (Underwood et al., 2011). Until now, oral teeth of this fossil genus were unknown or at least, have never been clearly associated to this genus in localities where unambiguous rostral denticles were found. Oral teeth are similar to those figured as? Pristis sp. from EG (Strougo et al., 2007, plate 2, figures 4-5), to those figured as? Propristis or? Pristis in KM (Adnet et al., 2012, figure 4A-B). Adnet et al. (2011) and Cappetta (2012) already considered that these peculiar pristid oral teeth might represent oral teeth of Propristis . We definitively confirm this previous hypothesis, considering that the oral tooth morphology is clearly different from that of the teeth of Anoxypristis or Pristis (e.g., Herman et al., 1997). As morphology of rostrum and rostral denticles usually differ greatly from one individual to the next among living pristids, as the rostral denticles are especially badly preserved and, as no oral teeth of P. schweinfurthi was until now reported, we remain cautious about attributing our numerous specimens to the type representative of genus.
No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.