DASYATIDAE, Jordan and Gilbert, 1879

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 : 37

publication ID

https://doi.org/ 10.26879/1085

publication LSID

lsid:zoobank.org:pub:B6B8E985-F1CF-4C10-BB00-602E5BF36C1C

persistent identifier

https://treatment.plazi.org/id/03BA87C1-FFE8-FFFF-C03F-E378C9B7B004

treatment provided by

Felipe

scientific name

DASYATIDAE
status

 

Family DASYATIDAE View in CoL incertae sedis Dasyatoid indet.

Figure 12 View FIGURE 12 N-O

2016 Dasyatis sp. 2 ; Merzeraud et al., p. 14-15, tab.

1.

Material. A dozen teeth, including those figured KEB 1-201, 1-202 ( Figure 12 View FIGURE 12 N-O) from the KEB- 1 locality, Souar-Fortuna formations, Djebel el Kébar, Tunisia.

Description

Teeth are relatively large compared to previous taxa, reaching 2.5 mm long for the largest one. Showing a typical dasyatoid design, the dentition exhibits a gradual monognathic heterodont with high-crowned teeth, which decrease in size toward the commissure. Evidence of a dignathic heterodonty was not detected, the whole teeth being non cuspidate. The crown of teeth is smooth, except along the transverse keel ( Figure 12N View FIGURE 12 1 View FIGURE 1 ) and sometimes on the labial face ( Figure 12O View FIGURE 12 ) where it bears fine alveolar enameloid crests in occlusal view. The labial visor is extremely narrow in occlusal view, and the lingual border of the lingual face is primarily straight but also punctually sinuous ( Figure 12O View FIGURE 12 ) compared to previous taxa. The lateral depression of the lingual face can be relatively large ( Figure 12N View FIGURE 12 1 View FIGURE 1 ), thereby indicating a close interlocking teeth in staggered file. The root is particularly well elongated lingually with two root lobes long, well-detached by a wide nutritive groove where a small circular foramen opens centrally in basal view ( Figure 12N View FIGURE 12 2 View FIGURE 2 ).

Remarks

Relatively scarce in the sample, teeth of these undefined taxa are different from those of previous described Dasyatidae . For instance, it is distinct from Middle-Late Eocene “D”. charlisae Case 1981 that possesses usual male teeth high crowned with strong ornamentation, conchoidal according Case (1981), covering completely the labial surface, from transversal keel to labial visor, and a narrower root compared to crown in lingual view. The presence of long and well-separated root lobes, a crown lingual face with marked articulate lateral depressions and lingual sinuous border could somewhat remind the dental traits characterizing teeth of the living Taeniurops (see Herman et al., 1998, 1999; Cappetta, 2012) or some Neogene representatives (Carrilo- Briceno et al., 2016, as cf. Taeniurops sp. ). However, the latter always have crown with labial face coarsely ornamented and none of these representatives present this peculiar fine alveolar ornamentation of the transverse keel.

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