Scelidotherium leptocephalum Owen, 1839

Miño-Boilini, AR & Zurita, AE, 2015, Dimorphism in Quaternary Scelidotheriinae (Mammalia, Xenarthra, Phyllophaga), Palaeontologia Electronica (Basel, Switzerland) 736 (1), pp. 1-16 : 5

Scelidotherium leptocephalum Owen, 1839

( Figure 2.1-2 )

Referred material. FMNH P 14274, skull, mandible, right scapula, left humerus, right and left ulnas, left and right radius, some bones from the autopod; FMNH P 14267, skull; MACN 9625, partial skull; MACN 13880, partial skull; MACN 13883, skull; MLP 3-409, partial skull, toothless; MMP 1155-M, skull and mandible; MLP 3-402, skull; MLP 3-408, skull and right hemimandible; MFCA 757, skull.

Description. In dorsal view, the parasagittal crests start in the nuchal crest and end at the postorbital process of the frontal bone, as in all Quaternary Scelidotheriinae , but no sagittal crest is observed. This morphology allows the identification of two variants. In some specimens (FMNH P 14274, FMNH P 14267, MMP 1155, MLP 3-402, MFCA 757, and MLP 3-408), the parasagittal crests are parallel along all their extension (at the level of the parietal and frontal) ( Figure 2.1 ). In other specimens (MACN 9625, MACN 13880, MACN 13883, and MLP 3-409), the parasagittal crests are parallel to each other at the level of the parietal, but have a "horseshoe" shape at the level of the fronto-parietal suture, delimiting a rhomboidal morphology; in their most anterior portion, parasagittal crests become parallel again ( Figure 2.2 ).

Figures

FIGURE 2. Scelidotherium leptocephalum. Skulls in dorsal view. 1, MMP 1155-M; 2, MACN 9625. Scale bar equals 10 mm.