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A New Extinct Species of the Genus Microcavia (Rodentia, Caviidae) from the Upper Pleistocene of the Northern Basin of Uruguay, with Paleobiogeographic and Paleoenvironmental Comments

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Abstract

A new species, Microcavia criolloensis (Rodentia, Caviidae), from the Upper Pleistocene (Sopas Formation) of the northern basin of Uruguay (South America) is described. This species is characterised by an exclusive association of skull and dental state characters. An analysis of similarity including other species of the genus and the related genera of Caviidae was performed. The new species of Microcavia behaved in the phenogram obtained as a discrete unit closely associated to Microcavia chapalmalensis and Microcavia niata . A mosaic of habitats, ranging from open and arid or semiarid microhabitats to fluvial and riparian forests, is suggested here, mainly based on the current adaptations of the genus Microcavia and the records of several taxa of mammals in the Sopas Formation. The geographic area occupied by Microcavia in the Pleistocene was different, with fossil records located more than 500 km eastward with respect to its present distribution. This variation could have occurred as a response to environmental changes in the last interglacial and glacial cycles.
... The genus Microcavia H. Gervais and Ameghino 1880 is together with Cavia and Galea part of the subfamily Caviinae of caviid rodents. Microcavia includes six species of terrestrial, medium-sized, living cavies, which are distributed from southern Peru, northern Chile, and western Bolivia to southern Argentina and Chile (Dunnum 2015;Teta et al. 2017Teta et al. , 2021, and four fossil species from the Pliocene and Pleistocene of Argentina and Uruguay (Quintana 1996;Ubilla et al. 1999). Species of Microcavia, including the two recently described species Microcavia jayat Teta et al. 2017 and Microcavia sorojchi Teta, Jayat and Ortiz 2022, were delimited using only morphological characters (Quintana 1996). ...
... mm vs. 12-18 mm in fossil species; cf. Quintana 1996;Ubilla et al. 1999) and a less robust cranium. ...
Article
The genus Microcavia includes six species of terrestrial, medium-sized, living cavies that occupy arid to semiarid environments at both high and low elevations in western and southern South America. Among these, Microcavia shiptoni is one of the least known species, being recorded only at two isolated localities from northwestern Argentina. Genetic information and a detailed morphological characterization are lacking for this elusive species. In this work, we start filling these gaps by including M. shiptoni in a phylogenetic analysis based on mitochondrial DNA sequences that includes five of the six currently recognized species and place M. shiptoni as sister to M. niata in a clade of highland species. In addition, using both qualitative and quantitative morphological traits, we provided an emended diagnosis for this taxon and a key for the living species of the genus. Finally, we present, the first notes on the natural history of this species.
... The genus Microcavia H. Gervais and Ameghino, 1880 includes three living and at least four fossil species of small (< 400 g), semifossorial and herbivorous caviomorph rodents endemic to southern South America (Quintana 1996;Ubilla et al. 1999;Dunnum 2015). Among the living forms, M. niata (Thomas, 1898) and M. shiptoni (Thomas, 1925) are restricted to highland areas of northwestern Argentina, southwestern Bolivia and northern Chile, while M. australis (I. ...
... M. jayat n. sp. differs from the fossil species M. chapadmalensis, M. criollensis, M. reigi, and M. robusta by its much smaller size (length of tootrow ca.11 mm vs. 12-18 mm in fossil species; q.v., Ubilla et al. 1999) and less robust cranium. ...
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We analyzed the geographic variation in cranial morphology of the Southern Mountain Cavy, Microcavia australis, throughout of its distributional range. Our analysis allows us to recognize three geographically allopatric morphotypes. These morphotypes differ in the general size and shape of the skull and discrete morphological traits of the zygomatic arch, palate and mesopterygoid fossa. Based on these results, we restrict the name australis to populations distributed in southern Argentina and west-central Andes and the name maenas to the morphotype of northwestern and central Argentina. The third morphotype occurs in the Dry Chaco ecoregion and is described here as a new species.
... e., M. chapadmalensis, M. criolloensis, M. reigi y M. robusta) por su tamaño mucho menor (serie molar superior < 11.9 mm, vs. 12-18 mm en las formas fósiles; cf. Ubilla et al. 1999;véase también Quintana 1996) y su cráneo menos robusto. ...
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Based on qualitative and quantitative morphological evidence, we describe a new species of Microcavia (Rodentia, Caviidae). The new species is characterized by a unique combination of morphological traits, that distinguished it from all others within the genus (i. e., upper incisors moderately proodont; palatal crest low, narrow anteriorly and expanded posteriorly; paraorbital process of the jugal small; sphenopalatine vacuities small, with their anterior border located behind the anterior half of the mesopterygoid fossa). The new species seems to be endemic from northwestern Argentina, where it occurs in open shrublands and grasslands >3,100 masl. With the description of this taxon, there are already four species of Microcavia that are distributed in the central Andes. Sobre la base de evidencias morfológicas cualitativas y cuantitativas, describimos una nueva especie de Microcavia (Rodentia, Caviidae). La nueva especie se caracteriza por una combinación única de rasgos morfológicos, que la distinguen de todas las otras dentro del género (i. e., incisivos superiores moderadamente proodontes; cresta palatal baja, angosta anteriormente y expandida hacia atrás; proceso paraorbitario del yugal pequeño; vacuidades esfenopalatinas pequeñas, con el borde anterior ubicado por detrás de la mitad anterior de la fosa mesopteri-goidea). La nueva especie parece ser endémica del noroeste de Argentina, donde ocupa matorrales abiertos y pastizales > 3.100 msnm. Con la descripción de este taxón, ya son cuatro las especies de Microcavia que se distribuyen en los Andes Centrales.
... As known before, this kind of generalist diet is considered one of the main factors contributing to the success of the group (McManus, 1974;Cantor et al., 2010). In this context, Galea sp., Microcavia criolloensis Ubilla et al. (1999), Reithrodon sp. and Lundomys molitor (Winge, 1887) (4 small rodents) are recorded in the Sopas Formation (Prevosti et al., 2009 and references therein;Ubilla and Martínez, 2016), so the possibility that these species could have been potential prey of Didelphis species during the Late Pleistocene in the territory of current Uruguay cannot be ruled out. ...
... chapalmal- ensis, M. reigi, M. robusta, and M. criolloensis) and it is abundant since the Pliocene. Isolated molars found in the Aconquija Formation (Catamarca Province), assigned to the late Miocene-early Pliocene, possibly represent the oldest record of this genus (Quintana 1996;Ubilla et al. 1999;Nasif et al. 2007). The oldest record of Cavia (C. ...
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Caviidae is one of the groups of rodents with the greatest ecomorphological disparity, and with currently three known lineages: Caviinae (cuises), Dolichotinae (maras), and Hydrochoerinae (capybaras). Caviinae include small caviids represented by three extant genera (Microcavia, Cavia, and Galea) and three fossils forms (Dolicavia, Palaeocavia, and Neocavia). In Argentina, the fossil record of Caviinae is continuous and abundant since the late Miocene. Neocavia, specifically, is represented by different species recorded in the late Miocene–Pliocene. Here, we describe a new species of Neocavia from the late Miocene–early Pliocene of the Cerro Azul Formation (La Pampa Province, Argentina), and provide a re-description of already known species (Neocavia lozanoi and “Neocavia depressidens”). Also, we perform a more comprehensive review of the genus and include the Neocavia species in a phylogenetic context within Caviinae. We analyze the main patterns of the evolution of the tympanic bullae within Caviidae, and infer about a possible occasional fossorial habit of Neocavia. The morphological and phylogenetic analyses indicate that Neocavia is more closely related to Dolicavia and Microcavia than to the other Caviinae, and confirm the monophyly of the genus, with at least two clearly differentiable species. Since this study cannot confirm the systematic position and validity of “N. depressidens”, we suggest not to use this taxon as a biostratigraphic indicator.
... In addition, this fauna presents also "pampean" taxa, like Ctenomys, recorded in the Pleistocene of Argentina, Uruguay, Bolivia, and Chile (Mones & Castiglioni, 1979;Marshall et al., 1984;Reig et al., 1990), and Cavia magna (Ximenez, 1980). The similarity between the Quaternary mastofauna from southern Brazil and that from Argentina and Uruguay, which has already been suggested (e.g., Bombin, 1975;Cartelle, 1999), became established for the Late Pleistocene through the megafauna and caviomorph rodents like Microcavia and Dolichotinae (Tonni, 1981;Ubilla et al., 1999). Consequently, the Rio Grande do Sul fauna was a mixture of "pampean" and brazilian taxa; it is possible that one or other faunal elements were predominant in the composition of the fauna at different times. ...
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The Serra da Capivara National Park, in the southeast of State of Piauí, is widely recognized for its important archeological sites. However, in the areas surrounding the park there are also paleontological sites, especially limestone caves, where fossils of small mammals have been found. This material was recovered from deposits attributed to the Late Pleistocene and Early Holocene. Previous works have listed the occurrence of eight species of bats in two caves, Toca do Gordo do Garrincho and Toca da Janela da Barra do Antonião. The present study reports new data on the Chiroptera from Serra da Capivara, based on cranio-mandibular fragments from three caves. From Toca do Barrigudo we identified Tonatia sp., Phyllostomus discolor and Artibeus planirostris. The latter two species have also been identified from Toca do Serrote do Artur, in addition to Lophostoma sp. and Eptesicus fuscus. From Toca do Gordo do Garrincho, the record of Desmodus rotundus is confirmed, along with the identification of Lophostoma sp. Thus, the following taxa are recorded for the first time for the Quaternary of the Serra da Capivara region: Lophostoma sp., Phyllostomus discolor and Eptesicus fuscus. All taxa currently occur in the area, except Eptesicus fuscus, which has previously been recorded for the Quaternary of Brazil, in the states of Rio Grande do Sul and Bahia, suggesting a much wider geographical distribution at least until the beginning of the Holocene, which is corroborated by the Serra da Capivara findings.
... La anatomía dental del espécimen estudiado se comparó con las siguientes especies del género Microcavia: Microcavia australis, M. robusta, M. niata, M. chapalmalensis, M. shiptoni, M. reigi y M. criolloensis, de las cuales las más próximas morfológicamente fueron, M. chapalmalensis Ameghino, 1908, de edad Chapadmalalense y M. robusta Gervais & Ameghino, 1880, de edad Ensenadense-Lujanense. Sin embargo, hay una diferencia de talla entre ambas y, teniendo en cuenta las mediciones realizadas por Quintana (1996) y Ubilla et al. (1999) para las especies extintas M. chapalmalensis, M. reigi, M. robusta y M. criolloensis en el p4, m1 y m2, el material de La Cruz estaría más relacionado con la primera especie mencionada. Familia OCTODONTIDAE Waterhouse, 1839 Subfamilia CTENOMYINAE Tate, 1935Eucelophorus Ameghino, 1908 Eucelophorus chapalmalensis Ameghino, 1908 ( Figura , procedente del sector Río de los Sauces, (RS 4, NF 6) (32°31'54,07"S, 64°34'40,82"O; 724 m s.n.m.). ...
Article
We describe Pseudoseisuropsis cuelloi, a new fossil furnariid from the upper Pleistocene of Uruguay, and investigate its phylogenetic relationships. Results of a cladistic analysis using 52 osteological characters from 29 taxa, including the extinct Pseudoseisuropsis nehuen, were consistent with placing the new species in the genus Pseudoseisuropsis. We conclude that the skull of Pseudoseisuropsis was prokinetic, although the shape of the nostrils was like a typical schizorhinal and rhynchokinetic furnariid. This observation reveals the inadequacy of the traditional categories of nasal types in characterizing the diversity of morphologies found in skulls of the Furnariidae. Finally, the analysis did not support a close relationship between Pseudoseisuropsis and Pseudoseisura, as previously thought, but suggests that Pseudoseisuropsis either belongs to the Dendrocolaptinae, or represents a more basal lineage within the Furnariidae. Un Nuevo Furnárido Fósil del Pleistoceno de Uruguay, con Observaciones sobre Tipos Nasales, Quinesis Craneal y Relaciones Filogenéticas del Género Extinto Pseudoseisuropsis Resumen. En el presente estudio se describe a Pseudoseisuropsis cuelloi, una nueva especie fósil de Furnariidae del Pleistoceno superior de Uruguay, y se investigan sus relaciones filogenéticas. El resultado de un análisis cladístico con 52 caracteres osteológicos y 29 taxa, incluyendo el ejemplar tipo de Pseudoseisuropsis nehuen es consistente con la inclusión de la nueva especie en el género Pseudoseisuropsis. Se concluye que el movimiento craneal de Pseudoseisuropsis era proquinético, a pesar de que la forma de las aberturas nasales es similar al de un típico furnárido esquizorrino/rincoquinético. Esta aparente contradicción pone en evidencia que las categorías tradicionales de tipos nasales son poco adecuadas para caracterizar la diversidad morfológica del cráneo en los Furnariidae. Por último, el análisis filogenético revela que Pseudoseisuropsis no esta estrechamente emparentado con Pseudoseisura, como fuera propuesto originalmente, sino que sugiere su inclusión en Dendrocolaptinae o en un linaje más basal dentro de la familia Furnariidae.
Chapter
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The behavior and ecology of a population of individually marked Microcavia australis was studied in a xerophytic thornbush habitat in Buenos Aires Province, Argentina, from April 1966 to October 1967. Another cavy, Galea musteloides, occurred in smaller numbers on the study area. Interactions between the two genera were amicable. Microcavia births occurred from August to April with most litters born in the September-December period. Gestation was 54 days. One female gave birth to four litters during the breeding season. Adult males have home ranges of approximately 3/4 hectare, about twice the size of female home ranges. Microcavia is diurnal and may be active at any time of day. Most social interactions occur in the bare areas surrounding thornbush associations. Communal rolling sites are loci for olfactory communication. Interactions between adult males are agonistic and organized by a straight-line dominance hierarchy. Males congregate around the home bush of a female near term; a conspicuous mating chase occurs at the post-partum estrus. Juveniles may suckle from lactating females other than the mother. Adult males associate with juveniles and respond sexually to them. Females maintain amicable relations with their daughters until the birth of the next litter. Many behavioral similarities between Microcavia and sciurid ecological equivalents, such as Citellus and Cynomys, are convergently evolved adaptations to open habitats. Microcavia social organization is more similar to that of rabbits (which also have a high reproductive potential and high mortality rate) than to sciurid ecological equivalents.