Evolution of the cheek teeth occlusal structures in caviomorph rodents, with special reference to octodontoids and erethizontids

Caviomorphs are representative of the oldest rodent radiation in South America, with a rich fossil record, known since the late Eocene-early Oligocene. They reached an important taxonomic diversity expressed by the existence of 12 extant families and several extinct taxa. Both in extant and fossil f...

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Autores principales:	Candela, Adriana Magdalena, Rasia, Luciano Luis
Formato:	Objeto de conferencia Resumen
Lenguaje:	Inglés
Publicado:	2010
Materias:	Ciencias Naturales Paleontología Caviomorph rodents Cheek teeth occlusal structures Evolution
Acceso en línea:	http://sedici.unlp.edu.ar/handle/10915/16672
Aporte de:	SEDICI (UNLP) de Universidad Nacional de La Plata

id	I19-R120-10915-16672
record_format	dspace
institution	Universidad Nacional de La Plata
institution_str	I-19
repository_str	R-120
collection	SEDICI (UNLP)
language	Inglés
topic	Ciencias Naturales Paleontología Caviomorph rodents Cheek teeth occlusal structures Evolution
spellingShingle	Ciencias Naturales Paleontología Caviomorph rodents Cheek teeth occlusal structures Evolution Candela, Adriana Magdalena Rasia, Luciano Luis Evolution of the cheek teeth occlusal structures in caviomorph rodents, with special reference to octodontoids and erethizontids
topic_facet	Ciencias Naturales Paleontología Caviomorph rodents Cheek teeth occlusal structures Evolution
description	Caviomorphs are representative of the oldest rodent radiation in South America, with a rich fossil record, known since the late Eocene-early Oligocene. They reached an important taxonomic diversity expressed by the existence of 12 extant families and several extinct taxa. Both in extant and fossil forms, this diversity is reflected by a significant morphological variation found in crown structures of the cheek teeth. Different hypotheses of primary homology have been proposed for these structures, which, in turn, supported diverse dental evolutionary hypotheses in caviomorphs. The identification of homologies in crown structures of the oldest fossil caviomorphs became protagonists in this context. In spite of the research generated, for most of the main clades of caviomorphs, there is not a unified nomenclature of the crown structures. In the case of octodontoids and Erethizontidae, certain fossil taxa reveal the presence of cusps, which are not so well differentiated in living species, pointing out the essential role of fossils in the identification of homologous structures. In this contribution, we examine the occlusal morphology of these rodents and evaluate alternative primary homology hypotheses for occlusal structures in the cheek teeth of caviomorphs. On this base, we explore the testing of alternative primary hypotheses of lophs / lophids correspondences in a phylogenetic context. Following a dynamic approach, we select the best primary homologies and evaluate the evolutionary transformations of the analyzed dental characters. Our results indicate that pentalophodonty is the derived condition for the lower molars in caviomorphs; the trilophodonty evolved independently at least two times during the evolutionary history of octodontoids, and pentalophodonty represents the primitive condition in erethizontids and octodontoids. Pentalophodonty emerges as the derived condition in the upper molars, from a "prepentalophodont" pattern. This study shows that the dental evolution in caviomorphs can be better understood when their occlusal structures are expressed as characters reliably comparable, and when fossils are taken into account.
format	Objeto de conferencia Resumen
author	Candela, Adriana Magdalena Rasia, Luciano Luis
author_facet	Candela, Adriana Magdalena Rasia, Luciano Luis
author_sort	Candela, Adriana Magdalena
title	Evolution of the cheek teeth occlusal structures in caviomorph rodents, with special reference to octodontoids and erethizontids
title_short	Evolution of the cheek teeth occlusal structures in caviomorph rodents, with special reference to octodontoids and erethizontids
title_full	Evolution of the cheek teeth occlusal structures in caviomorph rodents, with special reference to octodontoids and erethizontids
title_fullStr	Evolution of the cheek teeth occlusal structures in caviomorph rodents, with special reference to octodontoids and erethizontids
title_full_unstemmed	Evolution of the cheek teeth occlusal structures in caviomorph rodents, with special reference to octodontoids and erethizontids
title_sort	evolution of the cheek teeth occlusal structures in caviomorph rodents, with special reference to octodontoids and erethizontids
publishDate	2010
url	http://sedici.unlp.edu.ar/handle/10915/16672
work_keys_str_mv	AT candelaadrianamagdalena evolutionofthecheekteethocclusalstructuresincaviomorphrodentswithspecialreferencetooctodontoidsanderethizontids AT rasialucianoluis evolutionofthecheekteethocclusalstructuresincaviomorphrodentswithspecialreferencetooctodontoidsanderethizontids
bdutipo_str	Repositorios
_version_	1764820463268134915

Evolution of the cheek teeth occlusal structures in caviomorph rodents, with special reference to octodontoids and erethizontids

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