Argoubia barbei Adnet & Cappetta & Guinot & Sciara 2012, SP. NOV.
Creators: name: Adnet, Sylvain
name: Cappetta, Henri
name: Guinot, Guillaume
name: Sciara, Giuseppe Notarbartolo Di
Publisher: name: Zenodo
Year: 2015
Subjects: Biodiversity
Taxonomy
Animalia
Chordata
Elasmobranchii
Myliobatiformes
Myliobatidae
Argoubia
Argoubia barbei

description: ARGOUBIA BARBEI SP. NOV. (FIG. 5)    Material: Two complete teeth and several fragments.   
 Type locality: Locality DAK3. Unit 2 level B1, close to El Argoub, south of Ad Dakhla, south-western Morocco (Adnet et al., 2010).   
 Type horizon: Samlat Formation, Gerran member (Ratschiller, 1967) – late Middle Eocene/Late Eocene.   
 Etymology: Species dedicated to Mr Gérard Barbe for his help in the field and for donation of material.   
 Holotype: DAK3-1 (Fig. 5A–E) housed at the University of Montpellier.   
 Diagnosis: Same as the genus.   
 Description: The teeth of this species are rather large, reaching between 3 and 4 mm width for anterolateral teeth. The holotype (Fig. 5A–E) is broader than high in labial view and rather thick in profile (3.2 mm wide, 2.4 mm high). The maximum width is located above the middle of the tooth and the base of the crown is practically as broad as the occlusal face. In labial view (Fig. 5C), the edges of the crown are generally convex, and distinctly and irregularly cut off above the limit of the visor. In occlusal view (Fig. 5D), the occlusal face, very slightly depressed, is less developed transversely than the rest of the crown. The enameloid of this face is completely smooth and bright. The labial margin of the face is irregular. Its lingual edge is more salient and cut off by well-developed irregular cusps with rounded extremities and separated by weak to deep notches. The labial face (Fig. 5C) of the crown bears a very strong ornamentation of more or less vertical ridges separated by deep vertical hollows. These ridges are very salient, irregular, and bear villi directed upwards. These villi have oblique directions when the tooth is observed in labial view. The basal part of this labial face is limited by a distinct crest that corresponds to a labial visor. The lower part of this visor is well developed and oblique in profile (Fig. 5B). It is smooth and, in labial view (Fig. 5C), it is higher and slightly depressed marginally on both sides.   
The lingual face is oblique in profile view (Fig. 5B), parallel to the labial face. It is restricted at its base by a distinct bulge, rounded in profile. This bulge overhangs the root in occlusal view. The lingual face is covered by vertical ridges that are shorter, less developed, and less irregular than those of the labial face. They stop above the bulge. Marginally, some ridges are oblique.  
The root is not very high, about a quarter of the tooth in profile view (Fig. 5B), and distinctly narrower than the crown. In lingual view, the width of the root itself is greater just below the crown than basally. The root is higher medially than on the margins. There are three lobes (Fig. 5E): two marginal, with a flat basal face of triangular outline, and one median that is narrow and also has a flat basal face. The lobes are separated by broad and rather deep and W- shaped furrows. Irregularly placed foramina open on the labial, lingual, and basal faces of the root.  
The paratype (Fig. 5F–J) is smaller and exhibits some differences. The occlusal face (Fig. 5I) is less distinctly separated from the labial face, with a lingual edge more strongly cut off. In profile view (Fig. 5G), the tooth is less high than the holotype, and, in occlusal (or basal) view (Fig. 5I–J), an angular labial outline can be observed medially. The lingual face of the crown is less ornamented, with only three smooth vertical ridges. The labial face bears strong vertical crests but less irregular than in the holotype. The marginal outlines of the crown are not cut off in labial view. The root shows four lobes and three furrows (Fig. 5J). It is broader just below the crown than at the level of the basal face.  
 Discussion: Despite the morphological differences observed between the holotype and paratype, one can consider that they fall within the range of intraspecific variation. It is possible that the more salient and more cut off edge of the lingual face observed on the paratype corresponds to a dental sexual dimorphism. In this case, the paratype may have belonged to a male. Several other fragmentary teeth of this species have been collected. However, they were not illustrated because of their poor state of preservation. Some teeth are more transversally developed with a distinctly polyaulacorhize root, indicating that the teeth described above would be anterior or anterolateral teeth. These more lateral teeth are also characterized by a less high crown.   
 Argoubia barbei gen. et sp. nov. can be easily separated from Oromobula dakhlaensis gen. et sp. nov. by its relatively less high and much thicker teeth. The ornamentation of the labial and lingual faces of the crown is also stronger, and the root is more massive with less high lobes in the former. It is also important to note that these taxa do not co-exist in the same level.
description: Published as part of Adnet, Sylvain, Cappetta, Henri, Guinot, Guillaume & Sciara, Giuseppe Notarbartolo Di, 2012, Evolutionary history of the devilrays (Chondrichthyes: Myliobatiformes) from fossil and morphological inference, pp. 132-159 in Zoological Journal of the Linnean Society 166 (1) on pages 143-144, DOI: 10.1111/j.1096-3642.2012.00844.x, http://zenodo.org/record/5408589