Megadontosuchus arduini (de Zigno, 1880 )

Piras, Paolo, Delfino, Massimo, Favero, Letizia Del & Kotsakis, Tassos, 2007, Phylogenetic position of the crocodylian Megadontosuchus arduini and tomistomine palaeobiogeography, Acta Palaeontologica Polonica 52 (2), pp. 315-328 : 316

Megadontosuchus arduini (de Zigno, 1880)

Lectotype: MGPD 1 Z, a nearly complete skull ( Figs. 1–3 ) with lower jaw (de Zigno 1880: pl. 1: 1–3 and pl. 2: 1–3).

Type locality and age: Monte Duello (Roncà, Province of Verona, NE Italy); middle Eocene.

Referred material.— MGPD 5 Z, skull lacking the anterior part of the rostrum; MGPD 4 Z, anterior part of the rostrum belonging to the specimen MGPD 5 Z; MGPD 6 Z, fragment of a right mandibular ramus, lacking retroarticular process; MGPD 8 Z, nearly complete mandibular ramus; probably these remains belong to the original type series. Two vertebrae MGPD 24 Z (cervical) and MGPD 25 Z (dorsal; de Zigno 1880: pl. 2: 6 and 4, 5, respectively).

Emended diagnosis.— Megadontosuchus arduini is a tomistomine differing from all other members of the clade because of this combination of features: the robust rostrum, the massive maxillary and dentary teeth and large supratemporal fenestrae. Approximately 14–16 maxillary teeth, and approximately 14– 17 dentary teeth. Small occipital condyle. Large narial aperture and foramen incisivum. Nasals in contact with external naris without bisecting it. Large mandibular fenestra. Elongated squamosal prongs reaching nearly the half of quadrate ramus.

Figures

Fig. 1.Tomistomine crocodile Megadontosuchus arduini (de Zigno, 1880), MGPD 1Z, lectotype from Monte Duello (Roncà, Province of Verona, NE Italy); middle Eocene. Skull in dorsal view. Photograph (A) and explanatory drawing of the same (B).

Fig. 2. Tomistomine crocodile Megadontosuchus arduini (de Zigno, 1880), MGPD 1Z, lectotype from Monte Duello (Roncà, Province of Verona, NE Italy); middle Eocene. Skull in ventral view. Photograph (A) and explanatory drawing of the same (B).

Fig. 3. Tomistomine crocodile Megadontosuchus arduini (de Zigno, 1880), MGPD 1Z, lectotype from Monte Duello (Roncà, Province of Verona, NE Italy); middle Eocene. Skull in occipital view. Photograph (A) and explanatory drawing of the same (B).