Morphotype II, Bonaparte & Novas, 1985

Delcourt, Rafael, Brilhante, Natan S, Pires-Domingues, Ricardo A, Hendrickx, Christophe, Grillo, Orlando N, Augusta, Bruno G, Maciel, Bárbara S, Ghilardi, Aline M & Ricardi-Branco, Fresia, 2024, Biogeography of theropod dinosaurs during the Late Cretaceous: evidence from central South America, Zoological Journal of the Linnean Society 202 (2), pp. 1-40 : 16

Morphotype II

The second morphotype is composed of symmetrical to asymmetrical crowns with the characteristic morphology of abelisaurid mesial teeth. These teeth have a lingually curved crown with slightly to strongly convex mesial and distal profiles and are weakly to moderately compressed (CBR ranging from.6 to.9). The mesial and distal carinae are straight and often centrally positioned on their surfaces in mesial and distal views, respectively. More rarely, the mesial carina is strongly deflected lingually on the crown. There are concave surfaces adjacent to both mesial and distal carinae or restricted to the distal carina on the lingual surface, conferring a salinon to J-shaped cross-sectional outline in basal view. Both mesial and distal carinae always extend to the root. The DSDI is close to one, with mesial and distal denticles usually being asymmetrically convex or distally hooked. The enamel surface texture is irregular. Interdenticular sulci are typically present between the distal and sometimes mesial denticles. Transverse and marginal undulations can be present, typically lingually and more rarely labially. The tooth can be slightly constricted between the crown and root.

Identification: These teeth are confidently referred to the mesial dentition of young, subadult to adult abelisaurids.

Specimens from Uberaba, Minas Gerais state, Marília Formation : CPP 156 , CPP 157 ( Fig. 8 ), CPP 447 , MCT.R. 1963 ( Fig. 9 ), and MCT.R. 1965 .

Specimens from Ibirá, São Paulo state, Adamantina Formation : LPP-PV 1111 , LPP-PV 1114 , and LPP-PV 1151 .

Specimen from Álvares Machado, São Paulo state, Presidente Prudente Formation : MN 4502-V/B ( Fig. 10 ).

Specimen from Chapada dos Guimarães, Mato Grosso state, Marília Formation : MN 4566-V .

Specimen from Pirapozinho, São Paulo state, Presidente Prudente Formation : MN 5032-V .

Specimens from Prata, Minas Gerais state, Adamantina Formation : MN 6258-V and MN 6269-V .

Specimens from Tesouro, Mato Grosso state, Marília Formation : MN 6822-V and MN 6839-V .

Specimens from Monte Alto, São Paulo state, Marília Formation : MPMA 6 and MPMA 8 .

Figures

Figure 8. Abelisaurid theropod right mesial tooth of morphotype II (CPP 157) from Periópolis, Minas Gerais state, Marília Formation, in labial (A), lingual (B), mesial (C), distal (D), apical (E), and basal (F) views. Scale bar: 5 mm.

Figure 9. Abelisaurid theropod mesial tooth of morphotype II (MCT.R. 1963) from Periópolis, Minas Gerais state, Marília Formation, in labial (A), lingual (B), mesial (C), distal (D), apical (E), and basal (F) views. Scale bar: 5 mm.

Figure 10. Abelisaurid theropod left mesial tooth of morphotype II (MN 4502-V/B) from Álvares Machado, São Paulo state, Adamantina Formation, in labial (A), lingual (B), mesial (C), distal (D), apical (E), and basal (F) views.Scale bar: 5 mm.