Allodaposuchus precedens, Nopcsa, 1928

Martin, Jeremy E. & Buffetaut, Eric, 2008, Crocodilus affuvelensis Matheron, 1869 from the Late Cretaceous of southern France: a reassessment, Zoological Journal of the Linnean Society 152 (3), pp. 567-580 : 578

COMPARISON WITH ALLODAPOSUCHUS PRECEDENS

Buscalioni et al. (2001) recently revised Allodaposuchus precedens . This species is considered to have a cosmopolitan distribution in Europe, being mentioned from Romania ( Nopcsa, 1928), northern Spain ( Buscalioni et al., 1986; Astibia et al., 1987, 1990) and southern France ( Buscalioni et al., 2001; Martin & Buffetaut, 2005). Martin & Buffetaut (2005), however, questioned the status of A. precedens , noting that it may have been erected on poorly diagnostic characters due to the fragmentary nature of the holotype. It is of importance to note that most of the characters used to diagnose the French and Spanish material of A. precedens are not present in the type material. Also, the taxonomic validity of A. precedens did not appear to be convincing for Salisbury et al. (2006), who noted some conflicting character scoring between descriptions (from Buscalioni et al., 2001; Hua & Jouve, 2004) and illustrations (from Buscalioni et al., 2001).

As it is considered a major component of European crocodylian faunas, it seems important to compare Allodaposuchus precedens with Massaliasuchus . A comparison with the holotype MAFI ob3131 provides limited elements, the only overlapping material being the frontal. The frontal is not as concave in Allodaposuchus precedens as in Massaliasuchus affuvelensis . Unlike A. precedens , there is no preorbital ridge in Massaliasuchus . Also, the anterior frontal process is slender and not ornamented in Massaliasuchus , unlike the condition seen in Allodaposuchus precedens . A comparison with the general description by Buscalioni et al. (2001), which may be based on material belonging to several taxa, reveals further differences with Massaliasuchus . Massaliasuchus does not show any notch behind the last premaxillary tooth, the maxillary alveoli have different organization, and the suborbital fenestra does not end at the level of the fourth maxillary tooth but more distally, at about the seventh or eighth. Also, size proportions between the proposed reconstructed skull of Allodaposuchus precedens and Massaliasuchus affuvelensis do not match. The orbits are more craniocaudally elongate in thye latter. The snout appears to be longer and more slender in Massaliasuchus . Moreover, the lateral contour of the rostrum is straight in Massaliasuchus as no premaxillary–maxillary notch is present. Therefore, it appears that Massaliasuchus and Allodaposuchus are clearly distinct taxa.

BIOGEOGRAPHY

Alligatoroids are common components of Late Cretaceous deposits in North America and Europe. However, European strata of this age have been less sampled than North America, leaving comparison between these two parts of Laurasia unbalanced. The place of origin of basal alligatoroids therefore still requires clarification. As mentioned above, although correlation of the Fuvelian is uncertain, Massaliasuchus is probably not younger than early Campanian. Thus far, the oldest described European alligatoroids, from northern Spain ( Buscalioni et al., 1997, 1999, 2001) and southern France ( Martin & Buffetaut, 2005), were Late Campanian to Early Maastrichtian in age but a possible alligatoroid has been identified on the basis of fragmentary cranial and mandibular material from the Santonian of Hungary ( Rabi, 2005). Massaliasuchus is older than the basal alligatoroid Leidyosuchus , from the Late Campanian of North America, and also seems to be more derived. The globidontan Brachychampsa is the oldest alligatoroid from North America, being recorded from the early Campanian ( Williamson, 1996). It is therefore equally likely that Alligatoroidea originated either in North America or in Europe. It is also interesting to note that the presence of the genus Acynodon in the Late Cretaceous of south-western Europe ( Delfino & Buffetaut, 2006; Martin, in press) suggests that the place of origin of more derived alligatoroids is ambiguous.