Armadillosuchus: another small herbivorous croc

Marinho and Carvalho 2009
brought us a new, small, crocodyliform from the Late Cretaceous of South America, Armadillosuchus (Fig. 1).

Oddly,
the nares are not mentioned in the text, nor labeled in the published figure (Fig. 1). Where are they?

Figure 1. Armadillosuchus skull in dorsal view and lateral view. A second specimen preserves teeth. Reconstruction below aligns the ventral maxilla with the quadrate, as in all sister taxa.

Figure 1. Armadillosuchus skull in dorsal view and lateral view. A second specimen preserves teeth. Reconstruction below aligns the ventral maxilla with the quadrate, as in all sister taxa. Where are the nares? They are not mentioned in the text.

Armadillosuchus arrudai (Marinho and Carvalho 2009; Late Cretaceous; est. 2m in length) was an herbivorous and armored crocodylomorph from South America. It nests with Mariliasuchus (above) in the LRT. Both have giant premaxillary teeth. The naris is reduced to a tiny hole facing anteriorly. The rostrum may have been more horizontal than originally reconstructed as all sister taxa line up the quadrate with the ventral maxilla (Fig. 1 bottom figure). These are members of the Ziphosuchia.

Figure 1. Mariliasuchus skull in several views. Note the premaxillaery fangs and the short blunt remainder of the teeth.

Figure 2. Mariliasuchus skull in several views. Note the premaxillaery fangs and the short blunt remainder of the teeth. The nares are very tiny and anteriorly oriented. Note the alignment of the quadrate with the ventral rim of the maxilla together with the rostrum vs. forehead angle, as in the new lateral view of Armadillosuchus (Fig. 1).

The nares of Armadillosuchus
are best found by phylogenetic bracketing based on the nares found in its sister taxon Mariliasuchus (Fig. 2).

Figure 2. Subset of the LRT focusing on Crocodylomorpha (basal Archosauria) including Armadillosuchus.

Figure 2. Subset of the LRT focusing on Crocodylomorpha (basal Archosauria) including Armadillosuchus.

Key to understanding the origin of the clade Dinosauria
is to understand the proximal outgroup taxa, the bipedal basal Crocodylomorpha, which no prior studies include (though some include Lewisuchus).

Images of complete skeletons of Armadillosuchus
are online, photographed from museum mounts. I have not found academic data for anything more than is figured above. The rest may be restored. Let me know of any citations I have missed.

References
Marinho T S and Carvalho, IS 2009. An armadillo-like sphagesaurid crocodyliform from the Late Cretaceous of Brazil. Journal of South American Earth Sciences. 27 (1): 36–41.

wiki/Mariliasuchus
wiki/Armadillosuchus

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