Systematics and biogeographic significance of Drytomomys typicus (Scalabrinin Ameghino, 1889) nov. comb., a Miocene Dinomyidae (Rodentia, Hystricognathi) from Northeast of Argentina

Candela, Adriana Magdalena; Nasif, Norma

doi:10.1127/njgpm/2006/2006/165

Cited by 22 publications

(22 citation statements)

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“…cf. typicus from north‐eastern Argentina (MLP 15‐250; Candela and Nasif ) is clearly different from MUSM 942 in having the anterior edge of the enamel layers crenulated, thinner and lower than the posterior edge, a deeper hypoflexid that extends towards the base of the tooth and a posterior flexid that has become a metafossettid. These traits are not observed in MUSM 942, although the latter trait might change with wear.…”

Section: Systematic Palaeontologymentioning

confidence: 93%

Life in proto‐Amazonia: Middle Miocene mammals from the Fitzcarrald Arch (Peruvian Amazonia)

et al. 2015

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The Middle Miocene has been identified as a time of great diversification in modern lineages now distributed in tropical South America, and when basic archetypal traits defining Amazonia appear, including climatic humid conditions, basic floral physiognomy and phylogenetic composition of modern rainforests. Nonetheless, Middle Miocene localities in South America are poorly known, especially at low latitudes where only one species-rich locality, La Venta in Colombia, has been extensively studied. The present contribution describes the mammal fauna of Fitzcarrald, a new Middle Miocene local fauna from western Amazonia in Peru. Fitzcarrald is correlated with the Laventan South American Land Mammal Age based on the presence of taxa defining the 'Miocochilius assemblage zone' in La Venta. The mammalian fauna of Fitzcarrald comprises 24 taxa among cingulates, folivores, astrapotheres, notoungulates, litopterns, rodents, odontocetes and a possible marsupial. At this time, tropical South America was characterized by the presence of the Pebas megawetland, a huge lacustrine complex that provided unique ecological and environmental conditions most likely isolating northern South America from southern South America. These isolating conditions might have come to an end with its disappearance in the Late Miocene and the establishment of the subsequent Acre system, the predecessor fluvial system of modern Amazonia. Results of faunistic similarity between Fitzcarrald and other Miocene faunas throughout South America support these scenarios. The Fitzcarrald mammal fauna exhibits first appearance datums and last appearance datums of various taxa, showing that tropical South America has played a crucial role in the evolutionary history and biogeography of major clades, and revealing a more complex biological history than previously proposed, based on the record from the southern cone of the continent.

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Section: Systematic Palaeontologymentioning

confidence: 93%

Life in proto‐Amazonia: Middle Miocene mammals from the Fitzcarrald Arch (Peruvian Amazonia)

et al. 2015

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“…Like the xenarthrans mentioned by Negri (2004), the rodent Drytomomys also formerly occurred in the? middle Miocene of Ecuador (Anthony 1922) (see discussion in Patterson and Wood 1982: 447 about the age of this deposit), middle Miocene of La Venta, Colombia (Fields 1957;Candela and Nasif 2006), and in the middle Miocene of the Fitzcarrald Local Fauna (Tejada-Lara et al 2015). Caviomorphs recorded from Juruá River are more problematic, because most of them have scarce stratigraphic information.…”

Section: Cf Gyriabrus Ameghino 1883mentioning

confidence: 97%

“…24.3.I-K), we assign the dentary UFAC 2742 to the generic level only. With the unresolved taxonomic problems exposed in Walton (1997), Candela and Nasif (2006), and herein, it is clear that Drytomomys plus the BOlenopsis^specimens from Colombia need to be reviewed.…”

Section: Drytomomys Anthony 1922mentioning

confidence: 97%

Tropical Fossil Caviomorph Rodents from the Southwestern Brazilian Amazonia in the Context of the South American Faunas: Systematics, Biochronology, and Paleobiogeography

et al. 2016

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The fossil-bearing stratigraphic sections of the Solimões Formation (southwestern Brazilian Amazonia) are exposed mainly along the Juruá, Purus, and Acre rivers, and in road cuts. These deposits have provided fossils of the four main lineages of Caviomorpha -Cavioidea, Erethizontoidea, Octodontoidea, and Chinchilloidea, contributing to the understanding on the evolution of tropical Neogene rodents. Herein, our knowledge about fossil rodents from this region is reviewed. New specimens are recorded, including taxa mentioned for this region for the first time, such as basal cavioids, Dolichotinae, Caviodon (Hydrochoeridae), and Drytomomys (Dinomyidae). Unfortunately, the deposits have no absolute ages, and based on palynological data and the biochronology of several taxa (mainly mammals), the encompassed fauna has been constrained to the late Miocene. However, some rodent lineages recorded here seem to be more related to older faunas, from the middle Miocene and Paleogene. Regarding the biogeographic and paleoenvironmental affinities, most of the Neogene rodents from the Acre region show more similarities to those from the Entre Rios, Argentina, and Urumaco, Venezuela, where wet environments were present during Neogene times. An increase in prospecting along southwestern Amazonian rivers looking for rodents (among other vertebrates) associated with methods to better constrain the ages of these faunal assemblages will contribute to a better understanding of the evolution of the tropical rodents as well as the stratigraphy and age of that portion of the basin.

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“…C). Both crests of enamel are crenulated, a condition similar to that of Potamarchus murinus (a protohypsodont and medium‐size dinomyid from the Late Miocene of Mesopotamic area; Argentina; see Candela & Nasif ; Nasif ).…”

Section: Resultsmentioning

confidence: 93%

“…Throughout their long evolutionary history, recorded since the Late Oligocene, dinomyids developed an important taxonomical richness, particularly in the Late Miocene (e.g. Kraglievich ; Candela & Nasif ; Nasif ). As Eumegamys paranensis , several species of dinomyids reached an extremely large size during the Late Miocene and Pliocene in South America (e.g.…”

Section: Introductionmentioning

confidence: 99%

Fractal dimension and cheek teeth crown complexity in the giant rodent Eumegamys paranensis

Candela

Cassini

Nasif

2013

LET

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In this work, we analyse cheek teeth crown complexity through the calculation of fractal dimension in the giant caviomorph rodent Eumegamys paranensis (Late Miocene of Argentina) and evaluate its functional significance. Our results indicate that, in all teeth of Eumegamys paranensis, the fractal dimension was around 1.5, similar to the Koch quadratic curve type two. The anterior portions of the molars, with the highest values of fractal dimension, are interpreted as areas that supported greater occlusal pressures. Crown complexity in E. paranensis is related to the increased mechanical capacity to process relatively demanding food items and to allow more food to be divided in each masticatory cycle. Eumegamys paranensis would have been a mixed feeder, consuming a variable diet obtained close to the ground. This feeding behaviour is compatible with the heterogeneous environment inferred for the Mesopotamic area during the Late Miocene. E. paranensis was probably a wide ranging species, being able to eat close to water bodies and in gallery forests that occurred in the surrounding of the pre‐Paraná river system.

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Systematics and biogeographic significance of Drytomomys typicus (Scalabrinin Ameghino, 1889) nov. comb., a Miocene Dinomyidae (Rodentia, Hystricognathi) from Northeast of Argentina

Cited by 22 publications

References 0 publications

Life in proto‐Amazonia: Middle Miocene mammals from the Fitzcarrald Arch (Peruvian Amazonia)

Life in proto‐Amazonia: Middle Miocene mammals from the Fitzcarrald Arch (Peruvian Amazonia)

Tropical Fossil Caviomorph Rodents from the Southwestern Brazilian Amazonia in the Context of the South American Faunas: Systematics, Biochronology, and Paleobiogeography

Fractal dimension and cheek teeth crown complexity in the giant rodent Eumegamys paranensis

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