Lower molars of the large morganucodontan Storchodon cingulatus from the Late Jurassic (Kimmeridgian) of Germany

Three new lower molars of Storchodon cingulatus and a fragmentary upper molar confirm its morganucodontan affinities. Cusps b and c are relatively higher than in Morganucodon, and cusp c is larger than cusp b. Cusp a is asymmetric, with slightly distally recurved tip. All known lower Storchodon molars have a pronounced furcation between the roots on the labial and lingual sides. The wear pattern of Storchodon corresponds to that observed in Morganucodon . Cusp A of the upper molar occludes into the valley between cusps a and c of the lower antagonist, causing large confluent wear facets. The smaller wear facets present on the mesiolabial flank of cusp b and the distolabial flank of cusp c were caused by cusp C of the upper antagonist that occluded into the embrasure between two lower molars. So far, the Morganucodon -like occlusal mode is restricted to the morganucodontans Morganucodon, Dinnetherium nezorum , Cifellilestes ciscoensis , and Storchodon cingulatus, whereas Megazostrodon and Erythrotherium exhibit embrasure occlusion. Although Storchodon belongs to the larger morganucodontans, it is questionable if it represents a case of island gigantism as suggested earlier.