Incamys

Incamys; Temporal range: Late Oligocene (Deseadan) ; ~28.0–24.0 Ma PreꞒ Ꞓ O S D C P T J K Pg N ↓
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Mammalia
Order:	Rodentia
Family:	Chinchillidae
Genus:	†Incamys; Hoffstetter and Lavocat 1970
Type species
	†Incamys bolivianus; Hoffstetter & Lavocat 1970
Species
	I. bolivianus Hoffstetter & Lavocat 1970; I. menniorum Vucetich et al. 2015;
Synonyms
	I. pretiosus Lavocat 1976;

Incamys is an extinct genus of chinchillid rodent that lived during the Late Oligocene (Deseadan) in what is now South America. Fossils of this genus have been found in the Salla Formation of Bolivia and the Agua de la Piedra^[1] and Sarmiento Formations of Argentina.^[2] Research on endocasts suggest they were group living using call communication like modern chinchillas.^[3]

Taxonomy

Incamys was first described by Hoffstetter and Lavocat, based on remains found in the Salla Formation of Bolivia, with the proposed type species being Incamys bolivianus, referring to the country it was found in. Later, in 1976, a new species was named, I. pretiosus,^[4] which was subsequently found to be a junior synonym of the type species. In 2015, Vucetich and colleagues described a new species of Incamys, I. menniorum, from the Sarmiento Formation of Chubut Province, Argentina.^[5]

The following cladogram of the Caviomorpha is based on Busker et al. 2020, showing the position of Incamys.^[6]

Baluchimyinae	Bugtimys zafarullahi

"Phiomorpha"

	Phiomys andrewsi

	Metaphiomys schaubi

Erethizontoidea

	Steiromys detentus

	Eosteiromys homogenidens

Dasyproctidae

Dasyprocta azarae

Node A

	Eoviscaccia frassinettii

	Eoviscaccia boliviana

	Garridomys curunuquem

Incamys bolivianus

Brain Endocast Research

Research on 30 million year old Incamys bolivianus virtual endocasts show they had expanded temporal lobes in the cerebrum and large caudal colliculi in the midbrain, arguing they had enhanced auditory acuity and vocalization. This is consistent with them living in social groups and using calls to communicate with each other, similar to modern chinchillas.^[3]

References

^ Candela, Adriana M.; Pérez, M. Encarnación; Rasia, Luciano L.; Cerdeño, Esperanza (2021-03-04). "New late Oligocene caviomorph rodents from Mendoza Province, central-western Argentina". Journal of Vertebrate Paleontology. 41 (2): e1929264. Bibcode:2021JVPal..41E9264C. doi:10.1080/02724634.2021.1929264. ISSN 0272-4634.
^ Patterson, B.; Wood, Albert Elmer (1982). "Rodents from the Deseadan Oligocene of Bolivia and the relationships of the caviomorpha". Bulletin of the Museum of Comparative Zoology. 149: 371–543. ISSN 0027-4100.
^ ^a ^b Bertrand, Ornella C.; Lang, Madlen M.; Ferreira, José D.; Kerber, Leonardo; Kynigopoulou, Zoi; Silcox, Mary T. (2024). "The virtual brain endocast of Incamys bolivianus : insight from the neurosensory system into the adaptive radiation of South American rodents". Papers in Palaeontology. 10 (3). Bibcode:2024PPal...10E1562B. doi:10.1002/spp2.1562. ISSN 2056-2799.
^ Lavocat, René (1976). "Rongeurs Caviomorphes de l'Oligocène de Bolivie. 2 Rongeurs du Bassin Deseadien de Salla-Luribat". Palaeovertebrata. 7: 15–90.
^ Vucetich, M.G.; Dozo, M.T.; Arnal, M.; Pérez, M.E. (2015-02-17). "New rodents (Mammalia) from the late Oligocene of Cabeza Blanca (Chubut) and the first rodent radiation in Patagonia". Historical Biology. 27 (2): 236–257. Bibcode:2015HBio...27..236V. doi:10.1080/08912963.2014.883506. hdl:11336/17958. ISSN 0891-2963.
^ Busker, Felipe; Dozo, María Teresa; Soto, Ignacio María (2020-10-01). "New remains of Cephalomys arcidens (Rodentia, Caviomorpha) and a redefinition of the enigmatic Cephalomyidae". Journal of Systematic Palaeontology. 18 (19): 1589–1629. Bibcode:2020JSPal..18.1589B. doi:10.1080/14772019.2020.1796833. ISSN 1477-2019.

[Candelaetal2021-1] Candela, Adriana M.; Pérez, M. Encarnación; Rasia, Luciano L.; Cerdeño, Esperanza (2021-03-04). "New late Oligocene caviomorph rodents from Mendoza Province, central-western Argentina". Journal of Vertebrate Paleontology. 41 (2): e1929264. Bibcode:2021JVPal..41E9264C. doi:10.1080/02724634.2021.1929264. ISSN 0272-4634.

[PattersonandWood1982-2] Patterson, B.; Wood, Albert Elmer (1982). "Rodents from the Deseadan Oligocene of Bolivia and the relationships of the caviomorpha". Bulletin of the Museum of Comparative Zoology. 149: 371–543. ISSN 0027-4100.

[o199-3] Bertrand, Ornella C.; Lang, Madlen M.; Ferreira, José D.; Kerber, Leonardo; Kynigopoulou, Zoi; Silcox, Mary T. (2024). "The virtual brain endocast of Incamys bolivianus : insight from the neurosensory system into the adaptive radiation of South American rodents". Papers in Palaeontology. 10 (3). Bibcode:2024PPal...10E1562B. doi:10.1002/spp2.1562. ISSN 2056-2799.

[Lavocat1976-4] Lavocat, René (1976). "Rongeurs Caviomorphes de l'Oligocène de Bolivie. 2 Rongeurs du Bassin Deseadien de Salla-Luribat". Palaeovertebrata. 7: 15–90.

[Vucetichetal2015-5] Vucetich, M.G.; Dozo, M.T.; Arnal, M.; Pérez, M.E. (2015-02-17). "New rodents (Mammalia) from the late Oligocene of Cabeza Blanca (Chubut) and the first rodent radiation in Patagonia". Historical Biology. 27 (2): 236–257. Bibcode:2015HBio...27..236V. doi:10.1080/08912963.2014.883506. hdl:11336/17958. ISSN 0891-2963.

[Buskeretal2020-6] Busker, Felipe; Dozo, María Teresa; Soto, Ignacio María (2020-10-01). "New remains of Cephalomys arcidens (Rodentia, Caviomorpha) and a redefinition of the enigmatic Cephalomyidae". Journal of Systematic Palaeontology. 18 (19): 1589–1629. Bibcode:2020JSPal..18.1589B. doi:10.1080/14772019.2020.1796833. ISSN 1477-2019.

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