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The dental evidence on the differentiation of the ctenomyine rodents [Caviomorpha, Octodontidae, Ctenomyinae]

100%

Verzi D. H.

Acta Theriologica

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1999

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tom 44

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nr 3

Primitive species in the differentiation of the subfamily Ctenomyinae are revisited, and, on molar evidence, a new interpretation of the evolutionary pattern of these earliest members of the group is proposed. The octodontid Phtoramys is rejected as possible ancestor, whereas the genus Chasichimys (including Pattersomys), previously included in the family Echimyidae, is transferred to the Octodontidae as a primitive member of the ctenomyine radiation. During the Chasicoan and Huayquerian Ages [Late Miocene), an anagenetic event represented by an increase of hypsodonty in Chasichimys, may have led to the differentiation of the primitive euhypsodont ctenomyines of the genus Xenodontomys. Coeval cladogenetic processes, occurring during the protohypsodont evolutionary stage of the group, would have resulted in the separation of the genus Palaeoctodon from the lineage Chasichimys-Xenodontomys. These ancient representatives of the subfamily would have differentiated in central Argentine pampas. The recognition of such evolutionary events and concordant evidence from other octodontoid rodents suggest temporal differences among the outcroppings of the Cerro Azul Formation in central Argentina.

2

Phylogenetic position of Abalosia and the evolution of the extant Octodontinae [Rodentia, Caviomorpha, Octodontidae]

100%

Verzi D. H.

Acta Theriologica

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2001

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tom 46

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nr 3

South American octodontid rodents of the subfamily Octodontinae currently show low species richness but great morphological and chromosomal diversity. This diversity is interpreted alternatively as the remnant of a wider past radiation or as the result of saltational evolution. These hypotheses are discussed in relation to a phylogenetic analysis of the Late Pliocene octodontine Abalosia castellanosi. My results suggest that Abalosia, together with Tympanoctomys and Octomys, is part of a clade of desert specialist propalinal octodontids, which would have differentiated east of the Andes in the emergent semi-deserts of western Argentina. The presence of Abalosia in the coastal region of central Argentina during the Upper Marplatan Age (Late Pliocene) suggests a pulse of expansion of such arid environments, probably coeval with the global climatic deterioration detected around the transition Gauss-Matuyama magnetic ages. The phylogenetic position of A. castellanosi suggests that extinction events affected the clade of the octodontine desert specialists. Accordingly, regardless of how rough or gradual the differentiation of the octodontine's diversity has been, the living representatives seem to be remnants of a wider radiation.

3

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Late Miocene potamarchine rodents from southwestern Amazonia, Brazil - with description of new taxa

80%

Kerber L., Negri F. R., Ribeiro A. M., Vucetich M. G., De Souza-Filho J. P.

Acta Palaeontologica Polonica

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2016

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tom 61

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nr 1

The fossil rodents from the southwestern Amazonia of Brazil have been studied since the first half of the 20th century. Several caviomorph rodents were reported for the Neogene of this region, mainly neoepiblemids and dinomyids. Until recently, the record of dinomyids in the Solimões Formation (Late Miocene) was predominantly based on a few isolated teeth, which made it difficult to make more accurate taxonomic identifications due to the scarcity of diagnostic characters. Here, new remains, more complete than those previously reported, of potamarchine dinomyids from the Neogene of Brazil are described. A new species of Potamarchus and a new genus and species of a Potamarchinae are erected. In addition, new material of Potamarchus murinus and Potamarchus sp. is identified. These data suggest a higher diversity of dinomyids in in the western Amazonia than previously supposed.

4

Systematic and biostratigraphic significance of a chinchillid rodent from the Pliocene of eastern Argentina

80%

Rasia L. L., Candela A. M.

Acta Palaeontologica Polonica

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2013

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tom 58

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nr 2

Two species of chinchillid rodents, Lagostomus (Lagostomopsis) incisus and “Lagostomus (Lagostomopsis) spicatus”, have been recorded from the Monte Hermoso Formation (Montehermosan–Lower Chapadmalalan, Early Pliocene) of southern Buenos Aires Province, eastern Argentina. L. (L.) incisus is based on skull remains,while “L. (L.) spicatus” is based onmandible remains and fragmentary skulls. Detailed study of specimens recovered from the upper section of the Monte Hermoso Formation, from the Irene “Formation”, and the Chapadmalal Formation (late Early–early Late Pliocene, Buenos Aires Province), some of them represented by associated skull and mandible remains, indicates that L. (L.) incisus and “L. (L.) spicatus” are synonymous, with the valid name being L. (L.) incisus. The differences between both nominal species are here attributed to different ontogenetic states and sexual dimorphism. The stratigraphic provenance of the fossil material of L. (L.) incisus indicates a temporal distribution of this species restricted to theMontehermosan?–Chapadmalalan (Early–early Late Pliocene), instead of the Montehermosan (Early Pliocene).

Ograniczanie wyników

2 Acta Palaeontologica Polonica

2 Acta Theriologica

2 Verzi D. H.

1 Candela A. M.

1 De Souza-Filho J. P.

1 Kerber L.

1 Negri F. R.

1 Rasia L. L.

1 Ribeiro A. M.

1 Vucetich M. G.

1 2016

1 2013

1 2001

1 1999

The dental evidence on the differentiation of the ctenomyine rodents [Caviomorpha, Octodontidae, Ctenomyinae]

Phylogenetic position of Abalosia and the evolution of the extant Octodontinae [Rodentia, Caviomorpha, Octodontidae]

Late Miocene potamarchine rodents from southwestern Amazonia, Brazil - with description of new taxa

Systematic and biostratigraphic significance of a chinchillid rodent from the Pliocene of eastern Argentina