The subfamily Glyptodontinae (Xenarthra, Cingulata) comprises one of the most frequently recorded... more The subfamily Glyptodontinae (Xenarthra, Cingulata) comprises one of the most frequently recorded glyptodontids in South America. Recently, the North American genus Glyptotherium was recorded in South America, in addition to the genus Glyptodon. It has been shown that both genera shared the same geographic distribution in central-north and eastern areas of South America (Venezuela and Brazil, respectively). Although some characters allow differentiation between adult specimens of both genera, the morphological distinction between these two genera is rather difficult in juvenile specimens. In this contribution, a detailed morphological, morphometric and histological survey of a juvenile specimen of Glyptodontinae recovered from the Late Pleistocene of northern Brazil is performed. The relative lower osteoderms thickness, the particular morphology of the annular and radial sulci and the distal osseous projections of the caudal osteoderms suggest that the specimen belongs to the genus Glyptotherium. In addition, the validity of some statistical tools to distinguish between different ontogenetic stages and in some cases between genera is verified. The osteoderm microstructure of this juvenile individual is characterized by being composed of a cancellous internal core surrounded by a compact bone cortex. Primary bone tissue mostly consists of highly vascularized, woven-fibered bone tissue. Unlike that observed in adult Glyptodontinae, both the Sharpey fibers and the fibrous and laminar parallel bone tissue as secondary bone are absent. This study enhances our knowledge about those morphological and histological changes that occur through the ontogeny in glyptodonts.
Neues Jahrbuch für Geologie und Paläontologie - Abhandlungen
The most northern fossil record of Panthera onca (Linnaeus, 1758) from Argentina is here reported... more The most northern fossil record of Panthera onca (Linnaeus, 1758) from Argentina is here reported. The specimen, PVE-F 130, represented by an articulated and well preserved cranium and mandible, atlas and a fragment of left humerus, was exhumed from levels assigned to the Río Bermejo Formation (late Pleistocene-early Holocene; ca. 12.0-9.7 ka), near Villa Escolar, Formosa Province. The associated paleofauna, comprised mostly of large and megafaunal mammals, has a clear taxonomic similarity to that of the Pampean region of Argentina, and suggests open arid to semiarid environments. Indeed, previous analyses of plant remains associated with these vertebrates support the predominance of mega/mesothermal grasslands characterized by C 3 /C 4 grass species.
Resumen. En el extremo sur de Sudamérica se han postulado varias áreas que podrían haber actuado ... more Resumen. En el extremo sur de Sudamérica se han postulado varias áreas que podrían haber actuado como reservorio de taxones supérstites, especialmente en el lapso Mioceno-Pleistoceno tardío ("Araucanense"-Lujanense). Así, en el Pleistoceno tardío (ca. 58-28 ka) de la provincia de Corrientes, Argentina, se ha reconocido la persistencia de ciertos taxones ya desaparecidos en la región pampeana de Argentina, particularmente entre los Xenarthra Glyptodontidae, Artiodactyla Cervidae y Notoungulata "Haplodontheriinae". Aquí se efectua una revisión con criterios taxonómicos modernos de los materiales (3 restos dentarios) asignados a Toxodontidae Haplodontheriinae, cuyos registros últimos en la región pampeana provienen del Montehermosense (Plioceno). El estudio comparado indica que los 2 "caniniformes" superiores derechos (CTES-PZ 1608, 1609) corresponden en realidad a un Xenarthra Phyllophaga (Lestodon), en tanto que el tercero (CTES-PZ 1610) debe ser asignado a un Notoungulata (Toxodon), ambos géneros típicos del Pleistoceno de América del Sur. Por último, las revisiones sistemáticas que se llevan a cabo son claves para refinar el registro paleontológico regional, y brindar un aporte fundamental al esquema bioestratigráfico en áreas extra-pampeanas.
Paleogene records of Cingulata Glyptodontidae are scarce. The only well described comes from the ... more Paleogene records of Cingulata Glyptodontidae are scarce. The only well described comes from the Paleogene of Argentine Patagonia. Two subfamilies have been reported for that period: Glyptatelinae and Propalaehoplophorinae. Until this contribution, the latter taxon was geographically restricted to the locality of El Pajarito (Late Oligocene, Deseadan SALMA), Chubut province, Argentina. Here we present and describe the northernmost record of a Paleogene Propalaehoplophorinae. The material is represented by three associated osteoderms of the dorsal carapace from the Fray Bentos Formation (Late Oligocene, Deseadan SALMA) in the locality of Cueva del Tigre, Chajarí, Entre Ríos province, Argentina. Morphologically, these remains are almost identical to those reported from the late Oligocene of the Patagonian region, showing that during the Paleogene the Propalaehoplophorinae had a larger latitudinal distribution than previously known.
Se lleva a cabo un estudio sistemático de los Glyptodontidae Hoplophorinae Hoplophorini (=Scleroc... more Se lleva a cabo un estudio sistemático de los Glyptodontidae Hoplophorinae Hoplophorini (=Sclerocalyptini) y se evalúa su importancia como indicadores paleoambientales, paleobiogeográficos y bioestratigráficos. De este modo, se ha elaborado un moderno esquema nomenclatural, sistemático, paleobiogeográfico y bioestratigráfico de las diferentes especies reconocidas como válidas. Desde una perspectiva nomenclatural, este estudio ha conducido, siguiendo las disposiciones del Código Internacional de Nomenclatura Zoológica vigente, al reemplazo de los nombres de la subfamilia Sclerocalyptinae, de la tribu Sclerocalyptini y del género Sclerocalyptus por Hoplophorinae, Hoplophorini y Neosclerocalyptus, respectivamente. De igual modo, el uso prolongado de Glyptodontidae por sobre Hoplophoridae justifica su mantenimiento en carácter de nomen protectum. Previamente a esta contribución, era posible reconocer en la bibliografía ocho géneros y 26 especies de Glyptodontidae Hoplophorini. Eonaucum ...
The Cingulata Glyptodontidae (Xenarthra) are one of the most conspicuous Cenozoic herbivore clade... more The Cingulata Glyptodontidae (Xenarthra) are one of the most conspicuous Cenozoic herbivore clades in South America reaching North America during the Great American Biotic Interchange. The evidence of predation on these large armoured mammals is very scarce and limited to a Pliocene skull (Glyptotherium) in North America and some latest Pleistocene-early Holocene specimens in South America, with signals of human consumption. In this contribution, we present the first case of scavenging on a glyptodont belonging to cf. Eosclerocalyptus lineatus (Hoplophorini) from the Pliocene of the Pampean region (Argentina). In addition, we analyze the potential scavengers and the paleoenvironmental context in which this occurred. The evidence suggests that: a) the carcass was covered by a shallow water body, probably an abandoned channel; b) the carcass was completely covered during a brief lapse of time, probably less than a year; c) the morphology of the bite marks clearly coincide with the dentition of the procyonid Chapalmalania (Mammalia, Procyonidae), thus corroborating some presumptions about the paleoautoecological trends of this taxon.
The contributions concerning possible cases of sexual dimorphisms in fossil and living sloths are... more The contributions concerning possible cases of sexual dimorphisms in fossil and living sloths are scarce. Until now, studies in fossil ground sloth sexual dimorphism have been limited to the subfamilies Megatheriinae (Eremotherium) and Mylodontinae (Paramylodon) from the Pliocene and Pleistocene of South America and North America. Scelidotheriinae constitutes an endemic lineage of ground sloths from South American, with a biochron age ranging the lapse "Friasian"-Lujanian SALMAs (middle Miocene-early Holocene). An integral phylogenetic and taxonomic revision of the Quaternary Scelidotheriinae shows that it is possible to recognize three genera and six species: Scelidotherium Owen (Scelidotherium leptocephalum and S. bravardi), Valgipes Gervais (Valgipes bucklandi), and Catonyx Ameghino (Catonyx cuvieri, C. tarijensis, and C. chiliensis). One of the most noticeable aspects in some specimens analyzed (n= 47) was the presence of two morphtypes in each species at the level of the dorsal crests of the skull (parasagittal crests and sagittal crest) and at the level of the distal-most region of the mandible (only in C. tarijensis). In all but two species (S. leptocephalum and S. bravardi) the two types involve the absence and presence of a sagittal crest. We suggest that specimens with sagittal crest are males, and specimens lacking sagittal crest are females. This represents the third reported ground sloth clade with evidence of sexual dimorphism of the skull and mandible.
Anais da Academia Brasileira de Ciencias, Jan 16, 2018
The Mylodontidae Scelidotheriinae (Mammalia, Xenarthra, Tardigrada) are a diversified clade of So... more The Mylodontidae Scelidotheriinae (Mammalia, Xenarthra, Tardigrada) are a diversified clade of South American fossil ground sloths, with a wide geographic distribution, especially in high and middle latitudes. According to the last revision, the Quaternary diversity includes the genera Scelidotherium, Catonyx, and Valgipes. The clade Scelidotheriinae is well represented in the Pleistocene of the Tarija-Padcaya basin, and the first mention of these ground sloths correspond to the middle of the XIX Century. Since then, several species (i.e., Scelidotherium tarijensis, Scelidodon tarijensis, Scelidotherium capellini) have been reported as inhabiting the Tarija-Padcaya basin during the Pleistocene. Despite the abundance of fossil records of Scelidotheriinae in this area, no modern taxonomic revisions are available. In consequence, in this contribution a revision of the remains assigned to Scelidotheriinae from the Tarija-Padcaya basin is accomplished, and some biostratigraphic and geogr...
Synbranchus marmoratus es la espe-cie más austral del genero y la única presente actualmente en A... more Synbranchus marmoratus es la espe-cie más austral del genero y la única presente actualmente en Argentina (López et al., 2003), donde se distribuye desde el norte del país hasta los arroyos de pendiente atlántica del sureste de la provincia de Buenos Aires (cione & Barla, 1997; Liotta, 2005). Esta especie se caracteriza por presentar un cuerpo alargado, anguiliforme y carente de aletas pares. Presenta hábitos fosoriales y anfibios (rosen & rumney, 1972). Se alimenta básicamente de moluscos, insectos y pequeños peces (casciotta et al., 2005) y presenta una sorprendente adaptación a la sequía. En épocas de bajo régimen pluvial puede mantenerse con vida enterrada bajo el suelo reseco de lagunas y charcas efímeras (ringuelet, 1975). Esta adaptación,
Revision of the genus Nopachtus Ameghino and Phlyctaenopyga Cabrera (Xenarthra, Glyptodontidae, H... more Revision of the genus Nopachtus Ameghino and Phlyctaenopyga Cabrera (Xenarthra, Glyptodontidae, Hoplophorinae) from the late Miocene and Pliocene of Argentina. This work presents the first formal diagnosis for two genera of Hoplophorinae glyptodons, Nopachtus and Phlyctaenopyga, as well as for the species they incluye. In addition, a new species of Nopachtus is recognized for the Montehermosan, and a new combination is proposed: Phlyctaenopyga trouessarti. Precise geographical and stratigraphic provenance is provided for all the analyzed taxa. The most significant differences between Phlyctaenopyga and Nopachtus lie in the osteoderms, especially in the degree of convexity of the central figures and the number of peripheral figures that surround them. Although the central figure is convex in both genera, it is more "bulbous"/ "bubble-shaped" in Phlyctaenopyga compared to Nopachtus. Lastly, in Phlyctaenopyga the peripheral figures are arranged in two or three rows, with 18 to 23 figures in the first row. In the genus Nopachtus there are never more than two rows peripheral figures, and the first one comprises 12 figures.
The most complete record of a Hoplophorini (Xenarthra: Glyptodontidae) for the Chapadmalalan-Marp... more The most complete record of a Hoplophorini (Xenarthra: Glyptodontidae) for the Chapadmalalan-Marplatan Stages (Late Pliocene-Early Pleistocene). The late Neogene (Chapadmalalan-Marplatan Stages; ca. 3.9-1.8 Ma) Glyptodontidae from southern South America are poorly known since most of the record are limited to remains of the dorsal and/or caudal armour. In this sense, the exceptions are represented by Paraglyptodon chapadmalensis (Ameghino in Rovereto), a fossil guide of the Upper Chapadmalalan Stage, and the Plohophorini Plohophorus figuratus Ameghino. On the other hand, the "Hoplophorinae" Hoplophorini are glyptodonts that have its first records during the Huayquerian (late Miocene) and "Araucanian" Stages (late Miocene-early Pliocene), but they are almost absents during the Chapadmalalan-Marplatan Stages (Pliocene-early Pleistocene). Later, the Hoplophorini (Neosclerocalyptus Paula Couto) are, together with Glyptodon Owen, the most common South American Pleistocene Glyptodontidae. In this contribution we report the first record of a Chapadmalalan Hoplophorini, assigned to the genus Eosclerocalyptus C. Ameghino (Eosclerocalyptus cf. E. lineatus), coming from the Mar del Plata locality, Buenos Aires province (Argentina). This new material, represented by a complete dorsal carapace, was exhumed from the upper section of the Chapadmalalan Formation. From a morphological perspective, this dorsal carapace shows an intermediate size between E. tapinocephalus Cabrera, E. proximus (Moreno & Mercerat) and Neosclerocalyptus Paula Couto. Together with cf. Paraglyptodon chapadmalensis and Plohophorus figuratus Ameghino those records represents the most entire Pliocene Glyptodontidae known and, in addition, it partially complete the stratigraphical distribution of the Glyptodontidae Hoplophorini.
During the mid-19th century, the German naturalist Hermann Karsten conducted a 12-year exploratio... more During the mid-19th century, the German naturalist Hermann Karsten conducted a 12-year exploration (1844–1856) in the territories of Ecuador, New Granada (now Colombia) and Venezuela, allowing him to produce important botanic, geographic and geologic descriptions with valuable information that permits us to refer to him as a pioneer in many of these topics. With his return to Europe, abundant geological, paleontological and living plant specimens were brought and housed in European museums and botanical gardens. The Karsten collection included an important invertebrate collection from the Cretaceous of the Andes of Colombia and Venezuela, which was studied and published by himself and the renowned German paleontologist Leopold von Buch, filling a large void in the knowledge about ancients faunas. H. Karsten's vertebrate collection was never illustrated or subjected to a detailed taxonomic study, being mentioned in scientific publications in a repetitive manner and with incorrect...
Revista del Museo Argentino de Ciencias Naturales, 2008
Faunistic analisys of vertebrates from las toscas del Río de La Plata (Buenos Aires, Argentina): ... more Faunistic analisys of vertebrates from las toscas del Río de La Plata (Buenos Aires, Argentina): a palaeontological site in disappearance. At the coast of the río de la Plata in the Buenos Aires city lies a classic paleontological site, known as toscas del Río de La Plata or simple as las toscas. It has been studied for over 120 years and, although it has been widely spread, today is only possible to observe it during low tide. For this reason, most of the available materials are those collected during the first half of the XX th century, and that so far have only been incorporated into scarce taxonomic reviews. Among the fossils collected in las toscas highlights Glyptodon munizi Ameghino, Neosclerocalyptus pseudornatus Ameghino, Mesotherium cristatum Serrés, Arctotherium angustidens Gervais y Ameghino and Theriodictis platensis (Mercerat); all are exclusive species from the Ensenadan Stage (early to-middle Pleistocene). The sediments of las toscas were deposited during times of normal polarity, more precisely during the Jaramillo event (Chron C1r1n, ca. de 1 Ma). Faunistic evidences (e.g. Tolypeutes, Catagonus) allow to interpret las toscas as an open environment with dry conditions and probably colder than the present.
Within the Late Neogene Glyptodontidae of the Pampean region of Argentina, “Urotheriumantiquum” w... more Within the Late Neogene Glyptodontidae of the Pampean region of Argentina, “Urotheriumantiquum” was described on the basis of some associated osteoderms of the dorsal carapace,which in addition include a partial skull and left hemimandible. The diagnostic charac-ters are located on the exposed surface of the osteoderms of the dorsal carapace whichsomewhat resembles those of the Pleistocene genus Neuryurus. Although the relation-ship of “U. antiquum” to the remaining Glyptodontidae has never been clarified, somecladistic analyses suggest a close phylogenetic affinity with the clade composed of Plohopho-rus + (Glyptodon + Doedicurus). A careful comparison of “U. antiquum” to well-characterizedtaxa with similar stratigraphic and geographic provenance reveals that no significant skulldifferences are observed from Plohophorus figuratus Ameghino. It seems likely that thealleged ornamentation pattern that characterizes this species was produced by a tapho-nomic alteration of the exposed surface of the osteoderms, a process broadly distributedin glyptodonts having a “rosette” ornamentation pattern. Finally, some characters presentin the osteoderms of the type specimen of “U. antiquum” suggest that it may be a juvenilespecimen. In summary, “U. antiquum” should be considered a junior synonym of P. figuratus.
A large diversity of Glyptodontidae has been proposed as characterizing the Chapadmalalan Age (Pl... more A large diversity of Glyptodontidae has been proposed as characterizing the Chapadmalalan Age (Pliocene). Most of these taxa were recognized on the basis of partial dorsal carapaces and/or caudal tubes, whereas the main diagnostic characteristic is a particular morphology of the exposed surface of the osteoderms. From a biostratigraphic point of view some species are biostratigraphically important. The Upper Chapadmalalan is based on the Paraglyptodon chapadmalensis biozone. Both the re-evaluation of the type and referred materials and new significant findings from the Chapadmalal and El Polvorín Formations indicate that the diversity of Pliocene Glyptodontidae is more limited than previously supposed. The particular morphology of the exposed surface of the osteoderms that characterizes some of the species actually corresponds to a taphonomic alteration, which results in a non-real ornamentation pattern. Thus, the Glyptodontinae P. chapadmalensis must be replaced as a fossil guide b...
The subfamily Glyptodontinae (Xenarthra, Cingulata) comprises one of the most frequently recorded... more The subfamily Glyptodontinae (Xenarthra, Cingulata) comprises one of the most frequently recorded glyptodontids in South America. Recently, the North American genus Glyptotherium was recorded in South America, in addition to the genus Glyptodon. It has been shown that both genera shared the same geographic distribution in central-north and eastern areas of South America (Venezuela and Brazil, respectively). Although some characters allow differentiation between adult specimens of both genera, the morphological distinction between these two genera is rather difficult in juvenile specimens. In this contribution, a detailed morphological, morphometric and histological survey of a juvenile specimen of Glyptodontinae recovered from the Late Pleistocene of northern Brazil is performed. The relative lower osteoderms thickness, the particular morphology of the annular and radial sulci and the distal osseous projections of the caudal osteoderms suggest that the specimen belongs to the genus Glyptotherium. In addition, the validity of some statistical tools to distinguish between different ontogenetic stages and in some cases between genera is verified. The osteoderm microstructure of this juvenile individual is characterized by being composed of a cancellous internal core surrounded by a compact bone cortex. Primary bone tissue mostly consists of highly vascularized, woven-fibered bone tissue. Unlike that observed in adult Glyptodontinae, both the Sharpey fibers and the fibrous and laminar parallel bone tissue as secondary bone are absent. This study enhances our knowledge about those morphological and histological changes that occur through the ontogeny in glyptodonts.
Neues Jahrbuch für Geologie und Paläontologie - Abhandlungen
The most northern fossil record of Panthera onca (Linnaeus, 1758) from Argentina is here reported... more The most northern fossil record of Panthera onca (Linnaeus, 1758) from Argentina is here reported. The specimen, PVE-F 130, represented by an articulated and well preserved cranium and mandible, atlas and a fragment of left humerus, was exhumed from levels assigned to the Río Bermejo Formation (late Pleistocene-early Holocene; ca. 12.0-9.7 ka), near Villa Escolar, Formosa Province. The associated paleofauna, comprised mostly of large and megafaunal mammals, has a clear taxonomic similarity to that of the Pampean region of Argentina, and suggests open arid to semiarid environments. Indeed, previous analyses of plant remains associated with these vertebrates support the predominance of mega/mesothermal grasslands characterized by C 3 /C 4 grass species.
Resumen. En el extremo sur de Sudamérica se han postulado varias áreas que podrían haber actuado ... more Resumen. En el extremo sur de Sudamérica se han postulado varias áreas que podrían haber actuado como reservorio de taxones supérstites, especialmente en el lapso Mioceno-Pleistoceno tardío ("Araucanense"-Lujanense). Así, en el Pleistoceno tardío (ca. 58-28 ka) de la provincia de Corrientes, Argentina, se ha reconocido la persistencia de ciertos taxones ya desaparecidos en la región pampeana de Argentina, particularmente entre los Xenarthra Glyptodontidae, Artiodactyla Cervidae y Notoungulata "Haplodontheriinae". Aquí se efectua una revisión con criterios taxonómicos modernos de los materiales (3 restos dentarios) asignados a Toxodontidae Haplodontheriinae, cuyos registros últimos en la región pampeana provienen del Montehermosense (Plioceno). El estudio comparado indica que los 2 "caniniformes" superiores derechos (CTES-PZ 1608, 1609) corresponden en realidad a un Xenarthra Phyllophaga (Lestodon), en tanto que el tercero (CTES-PZ 1610) debe ser asignado a un Notoungulata (Toxodon), ambos géneros típicos del Pleistoceno de América del Sur. Por último, las revisiones sistemáticas que se llevan a cabo son claves para refinar el registro paleontológico regional, y brindar un aporte fundamental al esquema bioestratigráfico en áreas extra-pampeanas.
Paleogene records of Cingulata Glyptodontidae are scarce. The only well described comes from the ... more Paleogene records of Cingulata Glyptodontidae are scarce. The only well described comes from the Paleogene of Argentine Patagonia. Two subfamilies have been reported for that period: Glyptatelinae and Propalaehoplophorinae. Until this contribution, the latter taxon was geographically restricted to the locality of El Pajarito (Late Oligocene, Deseadan SALMA), Chubut province, Argentina. Here we present and describe the northernmost record of a Paleogene Propalaehoplophorinae. The material is represented by three associated osteoderms of the dorsal carapace from the Fray Bentos Formation (Late Oligocene, Deseadan SALMA) in the locality of Cueva del Tigre, Chajarí, Entre Ríos province, Argentina. Morphologically, these remains are almost identical to those reported from the late Oligocene of the Patagonian region, showing that during the Paleogene the Propalaehoplophorinae had a larger latitudinal distribution than previously known.
Se lleva a cabo un estudio sistemático de los Glyptodontidae Hoplophorinae Hoplophorini (=Scleroc... more Se lleva a cabo un estudio sistemático de los Glyptodontidae Hoplophorinae Hoplophorini (=Sclerocalyptini) y se evalúa su importancia como indicadores paleoambientales, paleobiogeográficos y bioestratigráficos. De este modo, se ha elaborado un moderno esquema nomenclatural, sistemático, paleobiogeográfico y bioestratigráfico de las diferentes especies reconocidas como válidas. Desde una perspectiva nomenclatural, este estudio ha conducido, siguiendo las disposiciones del Código Internacional de Nomenclatura Zoológica vigente, al reemplazo de los nombres de la subfamilia Sclerocalyptinae, de la tribu Sclerocalyptini y del género Sclerocalyptus por Hoplophorinae, Hoplophorini y Neosclerocalyptus, respectivamente. De igual modo, el uso prolongado de Glyptodontidae por sobre Hoplophoridae justifica su mantenimiento en carácter de nomen protectum. Previamente a esta contribución, era posible reconocer en la bibliografía ocho géneros y 26 especies de Glyptodontidae Hoplophorini. Eonaucum ...
The Cingulata Glyptodontidae (Xenarthra) are one of the most conspicuous Cenozoic herbivore clade... more The Cingulata Glyptodontidae (Xenarthra) are one of the most conspicuous Cenozoic herbivore clades in South America reaching North America during the Great American Biotic Interchange. The evidence of predation on these large armoured mammals is very scarce and limited to a Pliocene skull (Glyptotherium) in North America and some latest Pleistocene-early Holocene specimens in South America, with signals of human consumption. In this contribution, we present the first case of scavenging on a glyptodont belonging to cf. Eosclerocalyptus lineatus (Hoplophorini) from the Pliocene of the Pampean region (Argentina). In addition, we analyze the potential scavengers and the paleoenvironmental context in which this occurred. The evidence suggests that: a) the carcass was covered by a shallow water body, probably an abandoned channel; b) the carcass was completely covered during a brief lapse of time, probably less than a year; c) the morphology of the bite marks clearly coincide with the dentition of the procyonid Chapalmalania (Mammalia, Procyonidae), thus corroborating some presumptions about the paleoautoecological trends of this taxon.
The contributions concerning possible cases of sexual dimorphisms in fossil and living sloths are... more The contributions concerning possible cases of sexual dimorphisms in fossil and living sloths are scarce. Until now, studies in fossil ground sloth sexual dimorphism have been limited to the subfamilies Megatheriinae (Eremotherium) and Mylodontinae (Paramylodon) from the Pliocene and Pleistocene of South America and North America. Scelidotheriinae constitutes an endemic lineage of ground sloths from South American, with a biochron age ranging the lapse "Friasian"-Lujanian SALMAs (middle Miocene-early Holocene). An integral phylogenetic and taxonomic revision of the Quaternary Scelidotheriinae shows that it is possible to recognize three genera and six species: Scelidotherium Owen (Scelidotherium leptocephalum and S. bravardi), Valgipes Gervais (Valgipes bucklandi), and Catonyx Ameghino (Catonyx cuvieri, C. tarijensis, and C. chiliensis). One of the most noticeable aspects in some specimens analyzed (n= 47) was the presence of two morphtypes in each species at the level of the dorsal crests of the skull (parasagittal crests and sagittal crest) and at the level of the distal-most region of the mandible (only in C. tarijensis). In all but two species (S. leptocephalum and S. bravardi) the two types involve the absence and presence of a sagittal crest. We suggest that specimens with sagittal crest are males, and specimens lacking sagittal crest are females. This represents the third reported ground sloth clade with evidence of sexual dimorphism of the skull and mandible.
Anais da Academia Brasileira de Ciencias, Jan 16, 2018
The Mylodontidae Scelidotheriinae (Mammalia, Xenarthra, Tardigrada) are a diversified clade of So... more The Mylodontidae Scelidotheriinae (Mammalia, Xenarthra, Tardigrada) are a diversified clade of South American fossil ground sloths, with a wide geographic distribution, especially in high and middle latitudes. According to the last revision, the Quaternary diversity includes the genera Scelidotherium, Catonyx, and Valgipes. The clade Scelidotheriinae is well represented in the Pleistocene of the Tarija-Padcaya basin, and the first mention of these ground sloths correspond to the middle of the XIX Century. Since then, several species (i.e., Scelidotherium tarijensis, Scelidodon tarijensis, Scelidotherium capellini) have been reported as inhabiting the Tarija-Padcaya basin during the Pleistocene. Despite the abundance of fossil records of Scelidotheriinae in this area, no modern taxonomic revisions are available. In consequence, in this contribution a revision of the remains assigned to Scelidotheriinae from the Tarija-Padcaya basin is accomplished, and some biostratigraphic and geogr...
Synbranchus marmoratus es la espe-cie más austral del genero y la única presente actualmente en A... more Synbranchus marmoratus es la espe-cie más austral del genero y la única presente actualmente en Argentina (López et al., 2003), donde se distribuye desde el norte del país hasta los arroyos de pendiente atlántica del sureste de la provincia de Buenos Aires (cione & Barla, 1997; Liotta, 2005). Esta especie se caracteriza por presentar un cuerpo alargado, anguiliforme y carente de aletas pares. Presenta hábitos fosoriales y anfibios (rosen & rumney, 1972). Se alimenta básicamente de moluscos, insectos y pequeños peces (casciotta et al., 2005) y presenta una sorprendente adaptación a la sequía. En épocas de bajo régimen pluvial puede mantenerse con vida enterrada bajo el suelo reseco de lagunas y charcas efímeras (ringuelet, 1975). Esta adaptación,
Revision of the genus Nopachtus Ameghino and Phlyctaenopyga Cabrera (Xenarthra, Glyptodontidae, H... more Revision of the genus Nopachtus Ameghino and Phlyctaenopyga Cabrera (Xenarthra, Glyptodontidae, Hoplophorinae) from the late Miocene and Pliocene of Argentina. This work presents the first formal diagnosis for two genera of Hoplophorinae glyptodons, Nopachtus and Phlyctaenopyga, as well as for the species they incluye. In addition, a new species of Nopachtus is recognized for the Montehermosan, and a new combination is proposed: Phlyctaenopyga trouessarti. Precise geographical and stratigraphic provenance is provided for all the analyzed taxa. The most significant differences between Phlyctaenopyga and Nopachtus lie in the osteoderms, especially in the degree of convexity of the central figures and the number of peripheral figures that surround them. Although the central figure is convex in both genera, it is more "bulbous"/ "bubble-shaped" in Phlyctaenopyga compared to Nopachtus. Lastly, in Phlyctaenopyga the peripheral figures are arranged in two or three rows, with 18 to 23 figures in the first row. In the genus Nopachtus there are never more than two rows peripheral figures, and the first one comprises 12 figures.
The most complete record of a Hoplophorini (Xenarthra: Glyptodontidae) for the Chapadmalalan-Marp... more The most complete record of a Hoplophorini (Xenarthra: Glyptodontidae) for the Chapadmalalan-Marplatan Stages (Late Pliocene-Early Pleistocene). The late Neogene (Chapadmalalan-Marplatan Stages; ca. 3.9-1.8 Ma) Glyptodontidae from southern South America are poorly known since most of the record are limited to remains of the dorsal and/or caudal armour. In this sense, the exceptions are represented by Paraglyptodon chapadmalensis (Ameghino in Rovereto), a fossil guide of the Upper Chapadmalalan Stage, and the Plohophorini Plohophorus figuratus Ameghino. On the other hand, the "Hoplophorinae" Hoplophorini are glyptodonts that have its first records during the Huayquerian (late Miocene) and "Araucanian" Stages (late Miocene-early Pliocene), but they are almost absents during the Chapadmalalan-Marplatan Stages (Pliocene-early Pleistocene). Later, the Hoplophorini (Neosclerocalyptus Paula Couto) are, together with Glyptodon Owen, the most common South American Pleistocene Glyptodontidae. In this contribution we report the first record of a Chapadmalalan Hoplophorini, assigned to the genus Eosclerocalyptus C. Ameghino (Eosclerocalyptus cf. E. lineatus), coming from the Mar del Plata locality, Buenos Aires province (Argentina). This new material, represented by a complete dorsal carapace, was exhumed from the upper section of the Chapadmalalan Formation. From a morphological perspective, this dorsal carapace shows an intermediate size between E. tapinocephalus Cabrera, E. proximus (Moreno & Mercerat) and Neosclerocalyptus Paula Couto. Together with cf. Paraglyptodon chapadmalensis and Plohophorus figuratus Ameghino those records represents the most entire Pliocene Glyptodontidae known and, in addition, it partially complete the stratigraphical distribution of the Glyptodontidae Hoplophorini.
During the mid-19th century, the German naturalist Hermann Karsten conducted a 12-year exploratio... more During the mid-19th century, the German naturalist Hermann Karsten conducted a 12-year exploration (1844–1856) in the territories of Ecuador, New Granada (now Colombia) and Venezuela, allowing him to produce important botanic, geographic and geologic descriptions with valuable information that permits us to refer to him as a pioneer in many of these topics. With his return to Europe, abundant geological, paleontological and living plant specimens were brought and housed in European museums and botanical gardens. The Karsten collection included an important invertebrate collection from the Cretaceous of the Andes of Colombia and Venezuela, which was studied and published by himself and the renowned German paleontologist Leopold von Buch, filling a large void in the knowledge about ancients faunas. H. Karsten's vertebrate collection was never illustrated or subjected to a detailed taxonomic study, being mentioned in scientific publications in a repetitive manner and with incorrect...
Revista del Museo Argentino de Ciencias Naturales, 2008
Faunistic analisys of vertebrates from las toscas del Río de La Plata (Buenos Aires, Argentina): ... more Faunistic analisys of vertebrates from las toscas del Río de La Plata (Buenos Aires, Argentina): a palaeontological site in disappearance. At the coast of the río de la Plata in the Buenos Aires city lies a classic paleontological site, known as toscas del Río de La Plata or simple as las toscas. It has been studied for over 120 years and, although it has been widely spread, today is only possible to observe it during low tide. For this reason, most of the available materials are those collected during the first half of the XX th century, and that so far have only been incorporated into scarce taxonomic reviews. Among the fossils collected in las toscas highlights Glyptodon munizi Ameghino, Neosclerocalyptus pseudornatus Ameghino, Mesotherium cristatum Serrés, Arctotherium angustidens Gervais y Ameghino and Theriodictis platensis (Mercerat); all are exclusive species from the Ensenadan Stage (early to-middle Pleistocene). The sediments of las toscas were deposited during times of normal polarity, more precisely during the Jaramillo event (Chron C1r1n, ca. de 1 Ma). Faunistic evidences (e.g. Tolypeutes, Catagonus) allow to interpret las toscas as an open environment with dry conditions and probably colder than the present.
Within the Late Neogene Glyptodontidae of the Pampean region of Argentina, “Urotheriumantiquum” w... more Within the Late Neogene Glyptodontidae of the Pampean region of Argentina, “Urotheriumantiquum” was described on the basis of some associated osteoderms of the dorsal carapace,which in addition include a partial skull and left hemimandible. The diagnostic charac-ters are located on the exposed surface of the osteoderms of the dorsal carapace whichsomewhat resembles those of the Pleistocene genus Neuryurus. Although the relation-ship of “U. antiquum” to the remaining Glyptodontidae has never been clarified, somecladistic analyses suggest a close phylogenetic affinity with the clade composed of Plohopho-rus + (Glyptodon + Doedicurus). A careful comparison of “U. antiquum” to well-characterizedtaxa with similar stratigraphic and geographic provenance reveals that no significant skulldifferences are observed from Plohophorus figuratus Ameghino. It seems likely that thealleged ornamentation pattern that characterizes this species was produced by a tapho-nomic alteration of the exposed surface of the osteoderms, a process broadly distributedin glyptodonts having a “rosette” ornamentation pattern. Finally, some characters presentin the osteoderms of the type specimen of “U. antiquum” suggest that it may be a juvenilespecimen. In summary, “U. antiquum” should be considered a junior synonym of P. figuratus.
A large diversity of Glyptodontidae has been proposed as characterizing the Chapadmalalan Age (Pl... more A large diversity of Glyptodontidae has been proposed as characterizing the Chapadmalalan Age (Pliocene). Most of these taxa were recognized on the basis of partial dorsal carapaces and/or caudal tubes, whereas the main diagnostic characteristic is a particular morphology of the exposed surface of the osteoderms. From a biostratigraphic point of view some species are biostratigraphically important. The Upper Chapadmalalan is based on the Paraglyptodon chapadmalensis biozone. Both the re-evaluation of the type and referred materials and new significant findings from the Chapadmalal and El Polvorín Formations indicate that the diversity of Pliocene Glyptodontidae is more limited than previously supposed. The particular morphology of the exposed surface of the osteoderms that characterizes some of the species actually corresponds to a taphonomic alteration, which results in a non-real ornamentation pattern. Thus, the Glyptodontinae P. chapadmalensis must be replaced as a fossil guide b...
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