Acynodon undetermined

CF. ACYNODON SP.

Localities: Serrat del Pelleu.

Material: IPS-85800, IPS-85802, IPS-96691, IPS-96692 ( Fig. 4A–H View Figure 4 ).

Description: These teeth show bulky, low and rounded crowns. The enamel is ornamented with faint parallel basiapical ridges. Crowns are 1.8‒2.2 mm high basiapically and 1.8‒2.3 mm wide mesiodistally. Due to their progressive variation in morphology, teeth recovered from the Serrat del Pelleu site (IPS-85800, IPS-85802, IPS-96691, IPS-96692) probably correspond to different positions within the same dental series. IPS-96692 displays a slightly higher, but not wider, crown (2.9 mm) with straight lateral margins forming an isosceles triangle in outline. The basal constriction is stronger than in the others. IPS-85800 and IPS-85802 have bulky, low crowns with curved lateral margins. The basal constriction is less marked than in IPS-96692. IPS-96691 is of intermediate morphology between IPS-96692 and the other two teeth. All of them show ornamented enamel with faint and parallel ridges, running continuously from the base to the apex ( Fig. 4P–V View Figure 4 ). Mesial and distal carinae are smooth and not serrated. Carinae approximately cover the apical half of the teeth, and do not reach the base. All teeth show an apical wear facet ( Fig. 4T–U View Figure 4 ). Teeth from Serrat del Pelleu are not compressed labiolingually and show a subcircular cross-section. In spite of the shape of IPS-96692, being slightly different from the other teeth in this morphotype, it is tentatively included here because of the ornamentation, the basal constriction of the crown and the apical wear facet.

Remarks: This morphotype differs from morphotypes VI and VIII in the presence of an apical facet, the orientation of the enamel ridges, the morphology of the carinae and the degree of lateral compression. The only known crocodyliform with similar tribodont teeth in the Campanian–Maastrichtian of southwestern Europe is the eusuchian Acynodon . However, direct comparisons with maxillae and dentaries from Laño ( Spain) – the type locality of Acynodon ( Buscalioni et al., 1997, 1999; Pereda-Suberbiola et al., 2015) – revealed small differences from our sample. Whereas the anterior tooth positions in both maxillae and dentaries of Acynodon bear slightly flattened and spatulated teeth with mesial and distal carinae, the posterior tooth positions show rounded, uncompressed teeth without mesial and distal carinae, but with a well-marked apical crest. The presence of mesiodistal carinae in teeth from Serrat del Pelleu, and their degree of labiolingual compression, contrast with the morphological patterns observed in Acynodon , but they present an intermediate morphology between the anterior and posterior Acynodon mophotypes.