Cyonasua Explained

Cyonasua (meaning "dog-coati" in Greek) is an extinct genus of procyonid from the Late Miocene to Middle Pleistocene of South America. Fossils of Cyonasua have been found in Argentina (Ituzaingó, Epecuén, Huayquerías, Monte Hermoso, Chapadmalal, Maimará, Ensenada, La Playa, Chiquimil, Andalhuala, and Cerro Azul Formations), Bolivia (Tariquía Formation),^[1] Uruguay (Camacho Formation),^[2] and Venezuela (San Gregorio Formation).^[3] The oldest well-dated fossils of Cyonasua are approximately 7.3 million years old.^[4] Most fossils of Cyonasua are late Miocene to early late Pliocene (Huayquerian to Chapadmalalan SALMAs, 7.3-3 million years old) in age, but a single early Pleistocene specimen (the holotype and only known specimen of Cyonasua meranii) indicates that members of this genus survived until at least 0.99 million years ago (the fossil layer where this specimen was collected dating to the Jaramillo Chron).^{[5] [6]}

Cyonasua is the oldest terrestrial carnivoran known from South America, and represents the earliest undisputed southward mammalian migrants of the Great American Interchange. Cyonasua appears in the fossil record much earlier than other North American immigrant groups, most of which did not appear until 3 million years ago, including other carnivorans, many of which did not appear in South America until the early Pleistocene (about 1.2 million years ago).^[4] The next oldest remains of carnivorans in South America are rare specimens of Lycalopex and Galictis from the Barrancalobian (~2.9 million years old), nearly 4.4 million years after the first appearance of Cyonasua in South America. The ancestors of Cyonasua are thought to have arrived from Central America by island hopping before the formation of the Isthmus of Panama.

Cyonasua arrived in South America when ecosystems there were still dominated by metatherian carnivores, namely sparassodonts and carnivorous opossums. Unlike most sparassodonts, which were hypercarnivores, Cyonasua was an omnivore and it is thought that it did not directly compete with sparassodonts for food. This is thought to be one possible reason why Cyonasua and its close relatives were able to colonize South America many millions of years before other carnivorans. Because sparassodonts and other native predators like terror birds and teratorns were hypercarnivores, and other predators such as opossums were much smaller than most procyonids, the large, omnivorous Cyonasua could occupy an otherwise unoccupied niche in South American ecosystems.

Cyonasua was much larger than any extant procyonid, weighing about 15–25 kg, about the same size as a medium-sized dog.^[7] However, it was much smaller than its later relative Chapalmalania, which was the size of a small bear.^[8] Chapalmalania is thought to have been closely related to Cyonasua, with the two genera frequently referred to as "Cyonasua-group procyonids". Chapalmalania is thought to have evolved from a species of Cyonasua in South America, with Cyonasua as traditionally defined potentially being paraphyletic.^{[3] [9]}

Limb bones of Cyonasua suggest that this genus was a generalized terrestrial mammal with some capability to dig and climb, similar to raccoons (Procyon) and coatis (Nasua).^{[10] [11]} Fossils of Cyonasua have been found inside crotovines (fossil burrows), but these are thought to have been made by the large armadillo Ringueletia and later occupied by Cyonasua.^[12] The teeth of Cyonasua suggest it was omnivorous, more carnivorous than most living procyonids, but less carnivorous than the modern ringtails (Bassariscus spp.)^{[13] [14]}

Notes and References

1. Soibelzon . Leopoldo H. . De los Reyes . Martín . Tarquini . Juliana . Tineo . David E. . Poiré . Daniel G. . González . Gloria . Vergani . Gustavo D. . First record of a fossil procyonid (Cyonasua cf. C. pascuali), Mammalia, Procyonidae) in Bolivia, Tariquía Fm., Late Miocene . Journal of South American Earth Sciences . December 2019 . 99 . 102492 . 10.1016/j.jsames.2019.102492. 213340538 .
2. Soibelzon . Leopoldo H. . Rinderknecht . Andrés . Tarquini . Juliana . Ugalde . Raúl . First record of fossil procyonid (Mammalia, Carnivora) from Uruguay . Journal of South American Earth Sciences . June 2019 . 92 . 368–373 . 10.1016/j.jsames.2019.03.024. 2019JSAES..92..368S . 135212698 .
3. Forasiepi . Analia M. . Soibelzon . Leopoldo H. . Gomez . Catalina Suarez . Sánchez . Rodolfo . Quiroz . Luis I. . Jaramillo . Carlos . Sánchez-Villagra . Marcelo R. . Carnivorans at the Great American Biotic Interchange: new discoveries from the northern neotropics . Naturwissenschaften . 17 September 2014 . 101 . 11 . 965–974 . 10.1007/s00114-014-1237-4. 25228347 . 2014NW....101..965F . 11336/32009 . 253635703 .
4. Woodburne. M. O.. The Great American Biotic Interchange: Dispersals, Tectonics, Climate, Sea Level and Holding Pens. Journal of Mammalian Evolution. 17. 4. 2010-07-14. 245–264. 10.1007/s10914-010-9144-8. 21125025. 2987556.
5. Book: Berta . A. . Marshall . L. G. . Fossilium catalogus, I: Animalia. South American Carnivora . 1978 . Westphal. F.. Dr. W Junk Publishers. The Hague . 125. 1–48.
6. Soibelzon . E. . Gasparini . G. M. . Zurita . A. E. . Soibelzon . L. H. . Análisis faunístico de vertebrados de las toscas del Río de La Plata (Buenos Aires, Argentina): un yacimiento paleontológico en desaparición . Revista del Museo Argentino de Ciencias Naturales . 2008 . 10 . 2 . 291–308. 10.22179/REVMACN.10.284 . free .
7. Tarquini . Juliana . Toledo . Néstor . Soibelzon . Leopoldo H. . Morgan . Cecilia C. . Body mass estimation for †Cyonasua (Procyonidae, Carnivora) and related taxa based on postcranial skeleton . Historical Biology . March 2017 . 30 . 4 . 496–506 . 10.1080/08912963.2017.1295042. 90408657 . 11336/49670 . free .
8. Book: Forasiepi . Analía M. . Prevosti . Francisco J. . Evolution of South American mammalian predators during the Cenozoic : paleobiogeographic and paleoenvironmental contingencies . 2018 . Springer . Cham . 978-3-319-03701-1 . 124–125.
9. Kraglievich. J.L.. de Olazabal. A.G.. Los prociónidos extinguidos del género Chapalmalania Amegh.. Revista del Museo Argentino de Ciencias Naturales, Ciencias Zoologícas. 6. 1–59 .
10. Tarquini . Juliana . Morgan . Cecilia C. . Toledo . Néstor . Soibelzon . Leopoldo H. . Comparative osteology and functional morphology of the forelimb of Cyonasua (Mammalia, Procyonidae), the first South American carnivoran . Journal of Morphology . March 2019 . 280 . 3 . 446–470 . 10.1002/jmor.20956. 30747454 . 73435251 .
11. Tarquini . J. . Toledo . N. . Morgan . C. C. . Soibelzon . L. H. . The forelimb of †Cyonasua sp. (Procyonidae, Carnivora): ecomorphological interpretation in the context of carnivorans . Earth and Environmental Science Transactions of the Royal Society of Edinburgh . 16 January 2017 . 106 . 4 . 325–335 . 10.1017/S1755691016000207. free . 11336/49712 . free .
12. Cenizo . Marcos . Soibelzon . Esteban . Magnussen Saffer . Mariano . Mammalian predator–prey relationships and reoccupation of burrows in the Pliocene of the Pampean Region (Argentina): new ichnological and taphonomic evidence . Historical Biology . 28 September 2015 . 28 . 8 . 1026–1040 . 10.1080/08912963.2015.1089868. 83862150 .
13. Engelman . Russell K. . Croft . Darin A. . Strangers in a strange land: Ecological dissimilarity to metatherian carnivores may partly explain early colonization of South America by Cyonasua-group procyonids . Paleobiology . 12 September 2019 . 45 . 4 . 598–611 . 10.1017/pab.2019.29. 2019Pbio...45..598E . free .
14. Soibelzon . Leopoldo H. . First description of milk teeth of fossil South American procyonid from the lower Chapadmalalan (Late Miocene–Early Pliocene) of "Farola Monte Hermoso," Argentina: paleoecological considerations . Paläontologische Zeitschrift . 17 June 2010 . 85 . 1 . 83–89 . 10.1007/s12542-010-0073-x. 129068918 . 11336/104244 . free .