First Confirmed Record of Incamys Bolivianus (Caviomorpha, Chinchilloidea) in the Deseadan of Patagonia (Argentina)

Busker, Felipe; Dozo, María Teresa

doi:10.5710/amgh.24.05.2017.3098

Cited by 13 publications

(5 citation statements)

References 16 publications

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“…paradoxalis in having some dP4s showing a non-taeniodont pattern characterised by a complete and high lingual protoloph in continuity to the labial protoloph (this study). Several other chinchilloid genera ( Eoincamys , Chambiramys , Incamys , Saremmys , and Scleromys/ “ Scleromys ”) [ 28 , 70 , 71 , 73 , 81 , 114 , 118 , 130 – 134 ] have a similar pattern (i.e., high-crowned teeth, homogeneous thickness of the enamel layer; taeniodonty, obliquity of loph(-id)s, no lamina and no cement). Like Microscleromys , Eoincamys , Chambiramys , Incamys and Scleromys/ “ Scleromys ” also show a great variation of the morphology of the second transverse cristid on lower molars, and third transverse crest and metaloph on upper molars in terms of presence/absence, length, orientation and connections.…”

Section: Systematic Paleontologymentioning

confidence: 99%

Late middle Miocene caviomorph rodents from Tarapoto, Peruvian Amazonia

et al. 2021

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Miocene deposits of South America have yielded several species-rich assemblages of caviomorph rodents. They are mostly situated at high and mid- latitudes of the continent, except for the exceptional Honda Group of La Venta, Colombia, the faunal composition of which allowed to describe the late middle Miocene Laventan South American Land Mammal Age (SALMA). In this paper, we describe a new caviomorph assemblage from TAR-31 locality, recently discovered near Tarapoto in Peruvian Amazonia (San Martín Department). Based on mammalian biostratigraphy, this single-phased locality is unambiguously considered to fall within the Laventan SALMA. TAR-31 yielded rodent species found in La Venta, such as the octodontoid Ricardomys longidens Walton, 1990 (nom. nud.), the chinchilloids Microscleromys paradoxalis Walton, 1990 (nom. nud.) and M. cribriphilus Walton, 1990 (nom. nud.), or closely-related taxa. Given these strong taxonomic affinities, we further seize the opportunity to review the rodent dental material from La Venta described in the Ph.D. volume of Walton in 1990 but referred to as nomina nuda. Here we validate the recognition of these former taxa and provide their formal description. TAR-31 documents nine distinct rodent species documenting the four extant superfamilies of Caviomorpha, including a new erethizontoid: Nuyuyomys chinqaska gen. et sp. nov. These fossils document the most diverse caviomorph fauna for the middle Miocene interval of Peruvian Amazonia to date. This rodent discovery from Peru extends the geographical ranges of Ricardomys longidens, Microscleromys paradoxalis, and M. cribriphilus, 1,100 km to the south. Only one postcranial element of rodent was unearthed in TAR-31 (astragalus). This tiny tarsal bone most likely documents one of the two species of Microscleromys and its morphology indicates terrestrial generalist adaptations for this minute chinchilloid.

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Section: Systematic Paleontologymentioning

confidence: 99%

Late middle Miocene caviomorph rodents from Tarapoto, Peruvian Amazonia

et al. 2021

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“…2021). Remains of I. bolivianus have been found in Bolivia (Salla; Hoffstetter & Lavocat 1970) and in Argentina (Cabeza Blanca; Busker & Dozo 2017). There are no postcrania known for the genus and its diet has never been evaluated.…”

Section: Institutional Abbreviationsmentioning

confidence: 99%

“…Crown Chinchilloidea probably originated in the late Eocene to early Oligocene and Incamys is one of several Oligocene taxa recovered as stem chinchillids (Rasia et al 2021). Remains of I. bolivianus have been found in Bolivia (Salla; Hoffstetter & Lavocat 1970) and in Argentina (Cabeza Blanca;Busker & Dozo 2017). There are no postcrania known for the genus and its diet has never been evaluated.…”

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confidence: 99%

The virtual brain endocast of Incamys bolivianus: insight from the neurosensory system into the adaptive radiation of South American rodents

Bertrand,

Lang,

Ferreira

et al. 2024

Papers in Palaeontology

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Caviomorph rodents are endemic to South America and are one of the most adaptively diverse radiations of rodents today. Although their origin and diversification have been intensively studied, questions still remain about many of the details of where, when and how the group radiated. One area of continuing debate relates to the evolution of their neurosensory system. Modern caviomorphs exhibit a rich brain shape and size diversity. So far the oldest species for which endocranial data are known is dated to the Early Miocene. Here, we describe the virtual brain endocast of the late Oligocene stem chinchillid Incamys bolivianus from Bolivia and provide new hypotheses regarding the ancestral brain of Chinchillidae and Caviomorpha more broadly. Caviomorph rodents, independent from other rodent clades, acquired an expanded neocortex and their common ancestor was probably lissencephalic or had few sulci. Incamys uniquely combines extended neocortical temporal lobes and exposed caudal colliculi, which have roles in audition and vocalization processing. We interpret this morphology as evidence for enhanced auditory acuity, vocalization processing and potentially group‐living in Incamys, which is known in modern members of the Chinchillidae family. No temporal effect was found on relative brain size in South American mammals; however, our sample is limited to available brain endocasts and as such remains small and unevenly distributed taxonomically and temporally. Incamys provides crucial insight into the evolution of the caviomorph brain and shows that we still have much to explore regarding how these small mammals achieved one the most impressive adaptive radiations of the Cenozoic.

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“…This is the case for Incamys bolivianus Hoffstetter & Lavocat, , which was described from Salla in Bolivia and Cabeza Blanca in Argentina (late Oligocene; e.g. Hoffstetter & Lavocat, ; Patterson & Wood, ; Busker & Dozo, ) and was considered a dasyproctid cavioid by Patterson & Wood (). More recently, Vucetich et al.…”

Section: Introductionmentioning

confidence: 97%

Upper molar morphology, homologies and evolutionary patterns of chinchilloid rodents (Mammalia, Caviomorpha)

Rasia

Candela

2018

Journal of Anatomy

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Chinchilloidea are a clade of caviomorph rodents that includes seven living species, the Dinomyidae Dinomys branickii, the Chinchillidae Lagostomus maximus, two species of Chinchilla and three species of Lagidium. In addition, two extinct families are traditionally considered chinchilloids -Neoepiblemidae and Cephalomyidae. The phylogeny of the Chinchilloidea has so far not been well established and is based on partial analyses. Studying the anatomy and ontogeny of extinct and extant taxa, we propose homologies for the upper molars of Chinchilloidea for which these homologies have not been previously proposed: that is the Chinchillidae Prolagostomus, Lagostomus, Lagidium and Chinchilla, and the Neoepiblemidae Neoepiblema and Phoberomys. We identify patterns of occlusal simplification within Chinchilloidea and evaluate its importance in an evolutionary context. A phylogenetic analysis recovered Dinomyidae, Chinchillidae and Neoepiblemidae as clades. 'Cephalomyidae' have not been not recovered as a monophyletic group and 'cephalomyids' are closely related to Neoepiblemidae. Branisamys is not included within the Dinomyidae and appears to be a basal chinchilloid.

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First Confirmed Record of Incamys Bolivianus (Caviomorpha, Chinchilloidea) in the Deseadan of Patagonia (Argentina)

Cited by 13 publications

References 16 publications

Late middle Miocene caviomorph rodents from Tarapoto, Peruvian Amazonia

Late middle Miocene caviomorph rodents from Tarapoto, Peruvian Amazonia

The virtual brain endocast of Incamys bolivianus: insight from the neurosensory system into the adaptive radiation of South American rodents

Upper molar morphology, homologies and evolutionary patterns of chinchilloid rodents (Mammalia, Caviomorpha)

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