info:eu-repo/semantics/article
Morphology of the lower deciduous premolars of South American hystricomorph rodents and age of the Octodontoidea
Fecha
2019-10Registro en:
Verzi, Diego Hector; Olivares, Adriana Itati; Morgan, Cecilia Clara; Morphology of the lower deciduous premolars of South American hystricomorph rodents and age of the Octodontoidea; Taylor & Francis; Historical Biology; 31; 9; 10-2019; 1170-1178
0891-2963
1029-2381
CONICET Digital
CONICET
Autor
Verzi, Diego Hector
Olivares, Adriana Itati
Morgan, Cecilia Clara
Resumen
We analyse the crest homologies of lower deciduous premolars (Dp4) of South American caviomorphs in a comparative context including other hystricomorphs and under a dynamic topological criterion. An hexalophodont pattern in which the three anteriormost crests are assumed to be the anterolophid, metalophulid I and metalophulid II, respectively, is proposed as ancestral morphology. Simplified pentalophodont morphologies would have resulted from loss of the metalophulid I, and distinct transformation pathways are recognised especially for Octodontoidea and Cavioidea. A basal octodontoid morphological pattern can be recognised in the fossil record from as early as the middle Eocene, supporting that an initial divergence among major clades of caviomorphs had already occurred by this time. Programs for identifying potentially useful dental characters in phylogeny and taxonomy of caviomorphs need to be revised. Interpreting lophids as dynamic components in the morpho-functional variation of molars, rather than as static landmarks, is central for understanding dental evolution in these rodents.