Calamosuchus, Sues & Schoch, 2025

Sues, Hans-Dieter & Schoch, Rainer R., 2025, Synopsis of the Triassic reptiles from Germany, Fossil Record 28 (2), pp. 411-483 : 411-483

Calamosuchus gen. nov.

Type species.

Calamosuchus arenaceus (E. Fraas, 1896) , comb. nov.

Holotype.

SMNS 80737 , partial mandible (Fig. 13 C, D ).

Type locality.

Feuerbacher Heide, Stuttgart-Feuerbach, Baden-Württemberg.

Type horizon.

Stuttgart Formation, Middle Keuper Subgroup. Age: Late Triassic (Carnian: Tuvalian).

Etymology.

Derived from Latin calamus, reed, and the Greek name for the ancient Egyptian crocodile-headed deity Sobk or Sebek, commonly used for names of reptilian genera. The word calamus alludes to the fossil coming from a formation traditionally known as Schilfsandstein (“ reed sandstone ”).

Diagnosis.

Calamosuchus arenaceus is distinguished by the following combination of features: Tooth-bearing ramus of dentary increasing in dorsoventral height posteriorly; symphyseal of region of mandible taller dorsoventrally than wide transversely; splenial long, extensively contributing to mandibular symphysis; external mandibular fenestra elongated, extending ventral to posterior dentary teeth; and dentary tooth crowns labiolingually flattened and with serrated carinae ( Hungerbühler 2001; pers. obs.).

Comments.

The holotype of “ Zanclodon ” arenaceus especially differs from that of Zanclodon laevis in the presence of distinct, serrated carinae on its tooth crowns ( Hungerbühler 2001). The two species clearly belong to different taxa, and we propose a new genus Calamosuchus for the reception of “ Zanclodon ” arenaceus . F. Huene (1902) and most later authors (e. g., Westphal 1963) have interpreted this taxon as a phytosaur. Hungerbühler (2001) argued that it could represent another group of long-snouted archosauriforms, but his phylogenetic analyses recovered it as the sister-taxon of Phytosauria. We consider Calamosuchus arenaceus a stem-phytosaur or an early-diverging phytosaur.

References.

E. Fraas (1896), F. Huene (1902), Westphal (1963), Hungerbühler (2001).

Figures

Figure 13. A, B. Archosauriform Zanclodon laevis, holotype (SMNS 6045), incomplete left maxilla with attached bone fragment in lateral (A) and medial (B) view. Scale bar: 3 cm. C, D. Phytosaur Calamosuchus arenaceus comb. nov., holotype (SMNS 80737), mandible fragment in lateral views. Scale bar: 3 cm.