Acynodon undetermined

ACYNODON SP.

Localities: Els Nerets.

Material: IPS- 13360 ( Fig. 7 View Figure 7 ).

Description: The specimen IPS- 13360 preserves the anterior branch of the left dentary, the splenial and 16 dental alveoli without teeth. The lateral surface of the mandible is heavily ornamented with pits and grooves. The first 14 dental alveoli are perfectly distinguishable. However, the tooth row is partially eroded towards the posterior region, although two larger alveoli are likely present being a minimum of 16 teeth. The posterior part of the dentary is not preserved, so the presence of more alveoli cannot be safely determined. Most of the alveoli are circular and of similar size, although the first three and the last two alveoli are slightly larger. The interalveolar space is minimal, pointing to all teeth were almost confluent. The occlusal contour of the dentary is totally smooth and flat, without festooned outline. In lingual view, the anterior region of the splenial is well preserved. At its anterior margin, the splenial is limited by a large foramen intermandibularis oralis for the mandibular branch of the nerve V. No more perforations in the splenial are observed. The splenial does not participate in the mandibular symphysis but its anterior margin surpasses the foramen intermandibularis oralis and the Meckelian groove dorsally. The mandibular symphysis extends posteriorly up to the sixth dentary alveolus.

Remarks: Teeth with similar size (isodonty) along the tooth row, absence of fourth enlarged dentary tooth (caniniform) and non-festooned occlusal margin are characteristic of Acynodon ( Buscalioni et al., 1997; Martin, 2007; Delfino et al., 2008b). An almost complete lower jaw of Acynodon from Laño site shows 16 tooth positions with small packed teeth, being the last two somewhat enlarged, and with the dentary symphysis reaching the sixth alveolar position.

ALLODAPOSUCHIDAE ( NARVÁEZ, BROCHU, ESCASO, PÉREZ-GARCÍA & ORTEGA, 2015)