Archaeomanta 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 : 44

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-FFE7-FFF0-C0A6-E563C9F4B40F

treatment provided by

Felipe

scientific name

Archaeomanta sp.
status

 

Archaeomanta sp.

Figure 14H View FIGURE 14

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

Material. Material consists of 11 fragmentary teeth, none with complete crown, from the KEB- 1 locality, Souar-Fortuna formations, Djebel el Kébar, Tunisia, and includes the unique figured specimen KEB 1-225 ( Figure 14H View FIGURE 14 ).

Description

Teeth of this genus are clearly distinctive in having a rather high crown, compressed mesio-distally with apex that bends strongly lingually. The cusp curves suddenly lingually at a certain distance from the ovoid base of the crown. Cusps do not bear the usual mediolabial cutting edge nor the mediolingual cutting edge on the apical region. The root is robust ( Figure 14H View FIGURE 14 1 View FIGURE 1 ), globular with a basal face longer than broad, convex, with a heart-shaped contour, and a narrow and shallow axial groove (sometimes with secondary labiolingually orientated grooves).

Remarks

This taxa is usually attributed to mobulids based on its peculiar tooth morphology reminding that of some Mobula with peg-like teeth, but the presence of a large pulp cavity extending to the tip of the cusp (Underwood et al., 2011) makes their supposed position within the mobulids very doubtful (see also Adnet et al., 2012). However, the enameloid of Archaeomanta (Enault et al., 2013) is very thin and closely resembles that of extant Mobulidae or fossil and extant Gymnuridae (e.g., Jacquhermania , Gymnura ). Three species of Archaemanta are currently known in the fossil record. It concerns the Thanetian Archaeomanta priemi Herman and Crochard, 1979 , the Ypresian Archaeomanta melenhorsti Herman and Crochard, 1979 , and the Lutetian Archaeomanta hermani Kozlov, 2001 . A morphological distinction between these chronospecies is evident, notably between the two firsts, known by numerous specimens. Indeed, teeth of A. melenhorsti have more mesiodistally compressed crowns with more elongated and distally oriented cusps and a deep, straight groove on roots compared with A. priemi that possesses a peculiar large collar at base of crowns (Herman and Crochard, 1979). In contrast, A. hermani shows an extreme long cusp strongly compressed mesiodistally compared with those observable in both older species. The morphology of the Bartonian KEB- 1 specimens is clearly different from that of these three species in having more globular and robust roots (compared to A. melenhorsti and A. hermani ), a tooth cusp without any median cutting edge (compared to A. melenhorsti , A. priemi , and? A. hermani ), and no marked collar (compared to A. priemi ). However, the bad state of preservation of specimens does not allow to provide a detailed description of this unnamed species. Often rare in Paleogene deposits, this genus is nevertheless widely distributed in the Middle-Late Eocene of the peri-Tethysian realm (Cappetta, 2012), including in EG (Strougo et al., 2007), in the Priabonian of Egypt (upper GE to QS in Underwood et al., 2011), and in Southwestern Morocco (Adnet et al., 2010), even if the species status is always left in open nomenclature.

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