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Fossils of amphibians and squamates are relatively common in Pliocene–Pleistocene sediments in the southeastern Atlantic coast of Buenos Aires Province (Argentina), particularly in the southern slope of the Tandilia mountain system. These taxa are less known in the northern slope, which in the county of Mar Chiquita are solely represented by one anuran record. Here, new herpetofaunal material is described from Mar Chiquita county in the northern slope of the Tandilia mountain system. These specimens, while few, present an interesting taxonomical and morphological diversity. From the Ensenadan outcrops, amphibians are represented by cf. Rhinella. On the other hand, Stenocercus, an indeterminate tropidurid, Colubroides, and an indeterminate snake account for the Ensenadan squamates. In the Bonaerian outcrops, squamates are represented by the viperid Bothrops and an indeterminate Pleurodont. These latter taxa are also present in the Lujanian with an indeterminate snake. These are the first fossil records of squamates from Mar Chiquita and together with the new and previous amphibian records constitute a herpetological assemblage (Ceratophrys ornata, cf. Rhinella, Stenocercus, and Bothrops) that suggests that the paleoclimatic conditions during the Pleistocene of the Pampean region would have been similar to those of the present day. This inference should be considered with caution, since it contradicts those suggested by the mammalian record, which is richer and presents taxonomic identifications that are more precise. Mammalian fossil records indicate a cold and dry glacial Pleistocene interspersed with short, warmer, and more humid periods.

Middle and Late Pleistocene large and mega-mammal records of the Argentine Pampas, belonging to the Bonaerian and Lujanian Stages/Ages, have not yet been adequately dated by standard numerical radiometric methods. Reference timescales for Argentina and other South American fossil sites are mainly based on the mammalian faunal content (biostratigraphic units or biozones). We have recently dated three Middle and Late Pleistocene faunal sites located in the Buenos Aires Province using Electron Spin Resonance (ESR), U-series, Optically Stimulated Luminescence (OSL) and radiocarbon dating. The geographically distant sites (Salto de Piedra, Campo Spósito and Cascada de Paleolama) have yielded fossil assemblages representative of the Lujanian and Bonaerian Stages/Ages. Salto de Piedra, systematically excavated, records one of the most complete fossil sequences and our results indicate that it deposited between at least 127.4 ka (minimum age; Late Pleistocene, MIS 5) and 4.8–4.3 cal ka BP (Middle Holocene, MIS 1). Campo Spósito lower level (corresponding to 'El Tala' unit) was dated to >188 ka via ESR/U-series dating of teeth. Finally, Cascada de Paleolama Unit D, towards the base of the sequence, produced an age of 143 ± 20 ka (Late Pleistocene, MIS 5/6). The new dating results provide a crucial additional age control for the Bonaerian and Lujanian Stages/Ages, and allowed us to better identify and calibrate the limits of Equus neogeus, Megatherium americanum biozones, as well as to better constrain other index taxa that are used to construct local biostratigraphical frameworks. Our results indicate the need for a revision of the biozone schemes established for the Quaternary of Pampean region. • Three Pampean sites have been dated and fossil assemblages taxonomically revised. • Our dating results yielded a robust framework for Pleistocene Pampean sites. • Our revision confirmed index fossils from different biozones overlapped. • Our results advise strong revision of the biozones of the Pampean Quaternary. [ABSTRACT FROM AUTHOR]

En este trabajo se da a conocer un premaxilar izquierdo referible al género Jenynsia recuperado en facies lacustres correspondientes al Piso-Edad Bonaerense (Pleistoceno Medio tardío) de la localidad de Centinela del Mar, provincia de Buenos Aires, Argentina. Dicho material constituye el primer registro fósil para este género y uno de los escasos antecedentes para la familia Anablepidae. El hallazgo aquí comunicado brinda nuevas evidencias para la comprensión de las ictiofaunas cuaternarias de América del Sur.In this article, we described a left premaxilla assigned to Jenynsia, recovered in lacustrine facies corresponding to the Bonaerian Stage-Age (Late Middle Pleistocene) from Centinela del Mar, Buenos Aires Province, Argentina. This material constitutes the first fossil record of the genus and one among the few antecedents of the Anablepidae family. The finding communicated here offers new evidence towards the understanding of the Quaternary South American ichthyofaunas.

Tayassu pecariis widely distributed across the Neotropical region, from northern Argentina to south-eastern Mexico. However, its fossil record is scarce; it is recorded since the middle Pleistocene to Holocene in Argentina, Brazil and Uruguay. This paper aims to: (1) update the systematic synonymy of this species; (2) review and update its geographic chronologic distribution and provide a new Lujanian record ofTayassu pecariin Buenos Aires Province and (3) discuss the paleoenvironmental and paleobiogeographical implications of this record. Considering the quantitative analysis performed, the fossil here recorded clearly integrates the group ofTayassu pecari.This specimen corresponds to the first record ofTayassu pecariin the central-northern region of the Buenos Aires Province. During Late Pleistocene,Tayassu pecariwas distributed southern to its recent range, probably evidencing different paleoenvironment conditions. This species is the better adapted peccary to tropical and subtropical rainforests, but may also be present in arid environments. Consequently,Tayassuby itself is insufficient to infer the prevailing environmental conditions. However, according to the fauna associated with the specimen described here, it is possible to infer an open or semi-open and arid or semi-arid environment for the central-northern Buenos Aires region by Late Pleistocene times. [ABSTRACT FROM AUTHOR]

Abstract: Using species of the genus Sclerocalyptus, found in Argentina and considered valid, the authors recognize: (1) four species for the Ensenadan stage (Late Pliocene–Middle Pleistocene): S. pseudornatus (Ameghino), restricted to Buenos Aires province; S. ornatus (Owen), recorded at Buenos Aires, Córdoba, and Santa Fe provinces; S. perfectus (Gervais and Ameghino) in Buenos Aires and Santiago del Estero provinces; and S. cordubensis (Ameghino), endemic to west-central Córdoba province; (2) a single species for the Bonaerian stage (Middle–Late Pleistocene), S. migoyanus, restricted to the Buenos Aires province; and (3) Lujanian taxa (Late Pleistocene–Early Holocene) represented by Sclerocalyptus cf. S. heusseri (Ameghino), distributed in Buenos Aires, Córdoba, Tucumán, Corrientes, and Santa Fe provinces, and S. evidens (Ameghino) in Salta province. From a paleoenvironmental standpoint, the Sclerocalyptus species show adaptations to arid–semiarid and cold environments, such as strong development of the fronto-nasal sinuses, a characteristic that probably appeared during the Sanadresian–Ensenadan. Sclerocalyptus is not frequent in those areas in which relatively more humid and warm climates than those inferred for the Pampean region and central northern Argentina (e.g. Mesopotamia, west of Uruguay, south of Brazil) prevailed during the Quaternary. [Copyright &y& Elsevier]