A reassessment of the taxonomic status of Paraglyptodon Castellanos, 1932 (Mammalia, Cingulata, Glyptodontia)

Castellanos described and published about new genera of glyptodonts, according to a phylogenetic scheme mainly based on the evolution of the external surface of the dorsal carapace. Among these new genera, Castellanos proposed Paraglyptodon as the predecessor of Glyptodon, and included within Paraglyptodon all known species of Glyptodontinae recovered from “horizontes pre-Ensenadenses”, and within Glyptodon all known species from “Horizontes pampeanos”, restricting the latter to the Quaternary. All the species that belong to Paraglyptodon, that is Paraglyptodon chapalmalensis, Paraglyptodon uquiensis, Paraglyptodon dubius, and Paraglyptodon paranensis were established based on one, two or few osteoderms, mostly from the dorsal carapace. Regarding P. paranensis and P. dubius, Oliva and collaborators consider the first as a nomen vanum, representing an indeterminate Glyptodontinae, and the second as a synonym of P. chapalmalensis. Upon re-examination of the holotypes of P. chapalmalensis and P. uquiensis together with their comparison with other well-known specimens of glyptodonts, mainly with Glyptodon (of both juvenile and adult stages), we found the same ornamentation in different sections of the dorsal carapaces, particularly in P. chapalmalensis and in juvenile stages of Glyptodon spp.We could not identify features that would allow us to make a distinction between the holotype of P. uquiensis and Glyptodon spp. Therefore, we consider that a new taxon guide for naming the Upper Chapadmalalan biozone is necessary. The biostratigraphic range of Glyptodon could possibly be extended to the late Pliocene. However, new records and studies are needed to verify the existence of this taxon in the Chapadmalalan Stage/Age in its type locality.Facultad de Ciencias Naturales y Muse

Regarding the real diversity of Glyptodontidae (Mammalia, Xenarthra) in the late Pliocene (Chapadmalalan Age/Stage) of Argentina

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 because neither this species nor the species included in the genera Urotherium, Trachycalyptus and Lomaphorus are well characterized. Taking into account the diversity of Glyptodontidae for this lapse, the Glyptodontinae are very scarce (a situation that contrasts with its records in the Pleistocene), whereas Eosclerocalyptus, “Plohophorini” (Plohophorus) and Doedicurinae (cf. Eleutherocercus antiquus) are among the most recorded taxa.Facultad de Ciencias Naturales y MuseoCentro de Investigaciones Geológica

Regarding the real diversity of Glyptodontidae (Mammalia, Xenarthra) in the late Pliocene (Chapadmalalan Age/Stage) of Argentina

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 because neither this species nor the species included in the genera Urotherium, Trachycalyptus and Lomaphorus are well characterized. Taking into account the diversity of Glyptodontidae for this lapse, the Glyptodontinae are very scarce (a situation that contrasts with its records in the Pleistocene), whereas Eosclerocalyptus, “Plohophorini” (Plohophorus) and Doedicurinae (cf. Eleutherocercus antiquus) are among the most recorded taxa.Facultad de Ciencias Naturales y MuseoCentro de Investigaciones Geológica

A mitogenomic timetree for Darwin’s enigmatic South American mammal Macrauchenia patachonica

The unusual mix of morphological traits displayed by extinct South American native ungulates (SANUs) confounded both Charles Darwin, who first discovered them, and Richard Owen, who tried to resolve their relationships. Here we report an almost complete mitochondrial genome for the litoptern Macrauchenia. Our dated phylogenetic tree places Macrauchenia as sister to Perissodactyla, but close to the radiation of major lineages within Laurasiatheria. This position is consistent with a divergence estimate of B66Ma (95% credibility interval, 56.64–77.83 Ma) obtained for the split between Macrauchenia and other Panperissodactyla. Combined with their morphological distinctiveness, this evidence supports the positioning of Litopterna (possibly in company with other SANU groups) as a separate order within Laurasiatheria. We also show that, when using strict criteria, extinct taxa marked by deep divergence times and a lack of close living relatives may still be amenable to palaeogenomic analysis through iterative mapping against more distant relatives.Facultad de Ciencias Naturales y Muse

Palaeoproteomics resolves sloth relationships

The living tree sloths Choloepus and Bradypus are the only remaining members of Folivora, a major xenarthran radiation that occupied a wide range of habitats in many parts of the western hemisphere during the Cenozoic, including both continents and the West Indies. Ancient DNA evidence has played only a minor role in folivoran systematics, as most sloths lived in places not conducive to genomic preservation. Here we utilize collagen sequence information, both separately and in combination with published mitochondrial DNA evidence, to assess the relationships of tree sloths and their extinct relatives. Results from phylogenetic analysis of these datasets differ substantially from morphology-based concepts: Choloepus groups with Mylodontidae, not Megalonychidae; Bradypus and Megalonyx pair together as megatherioids, while monophyletic Antillean sloths may be sister to all other folivorans. Divergence estimates are consistent with fossil evidence for mid-Cenozoic presence of sloths in the West Indies and an early Miocene radiation in South America

A mitogenomic timetree for Darwin’s enigmatic South American mammal Macrauchenia patachonica

The unusual mix of morphological traits displayed by extinct South American native ungulates (SANUs) confounded both Charles Darwin, who first discovered them, and Richard Owen, who tried to resolve their relationships. Here we report an almost complete mitochondrial genome for the litoptern Macrauchenia. Our dated phylogenetic tree places Macrauchenia as sister to Perissodactyla, but close to the radiation of major lineages within Laurasiatheria. This position is consistent with a divergence estimate of B66Ma (95% credibility interval, 56.64–77.83 Ma) obtained for the split between Macrauchenia and other Panperissodactyla. Combined with their morphological distinctiveness, this evidence supports the positioning of Litopterna (possibly in company with other SANU groups) as a separate order within Laurasiatheria. We also show that, when using strict criteria, extinct taxa marked by deep divergence times and a lack of close living relatives may still be amenable to palaeogenomic analysis through iterative mapping against more distant relatives.Facultad de Ciencias Naturales y Muse

First fossil record of the South American frog genus <i>Odontophrynus</i> Reinhardt and Lütken, 1862 (Anura, Neobatrachia)

<p>The frog genus <i>Odontophrynus</i> comprises 10 species arranged in three species groups that inhabit southeastern South America. In Argentina, it is represented by the <i>O. americanus</i> and <i>O. occidentalis</i> species groups and, despite being a fairly common taxon of the extant herpetofauna, it has no known fossil record. Here we report on the first fossil record of the genus, based on an almost complete right ilium from the lower levels of the Buenos Aires Formation (OIS 11, Bonaerian age, middle Pleistocene) in the Bonaerian Pampas of Argentina. The taxonomic allocation is derived from a thorough survey of anuran ilia and is grounded in a set of distinct ilial characters that, in combination, do not occur in any other anuran. These include: ilium not fused to ischium; well-developed dorsal acetabular expansion; broad preacetabular zone with a shallow preacetabular fossa; straight ilial shaft lacking dorsal ridge; and spike-like dorsal prominence bearing a distinct dorsal protuberance. Additionally, after comparing with a large sample of specimens representing most species of <i>Odontophrynus</i>, we propose two main characters (high spike-like dorsal prominence, absence of a lateral knob on the dorsal prominence) that allow referral to <i>Odontophrynus</i> aff. <i>O. americanus</i> or <i>O. cordobae</i>.</p> <p>SUPPLEMENTAL DATA—Supplemental materials are available for this article for free at <a href="http://www.tandfonline.com/UJVP" target="_blank">www.tandfonline.com/UJVP</a></p> <p>Citation for this article: Turazzini, G. F., M. L. Taglioretti, and R. O. Gómez. 2016. First fossil record of the South American frog genus <i>Odontophrynus</i> Reinhardt and Lütken, <a href="#cit0031" target="_blank">1862</a> (Anura, Neobatrachia). Journal of Vertebrate Paleontology. DOI: 10.1080/02724634.2017.1228657.</p

Regarding the real diversity of Glyptodontidae (Mammalia, Xenarthra) in the late Pliocene (Chapadmalalan Age/Stage) of Argentina

ABSTRACT 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 because neither this species nor the species included in the genera Urotherium, Trachycalyptus and Lomaphorus are well characterized. Taking into account the diversity of Glyptodontidae for this lapse, the Glyptodontinae are very scarce (a situation that contrasts with its records in the Pleistocene), whereas Eosclerocalyptus, "Plohophorini" (Plohophorus) and Doedicurinae (cf. Eleutherocercus antiquus) are among the most recorded taxa

New radiometric ⁴⁰Ar–³⁹Ar dates and faunistic analyses refine evolutionary dynamics of Neogene vertebrate assemblages in southern South America

The vertebrate fossil record of the Pampean Region of Argentina occupies an important place in South American vertebrate paleontology. An abundance of localities has long been the main basis for constructing the chronostratigraphical/geochronological scale for the late Neogene-Quaternary of South America, as well as for understanding major patterns of vertebrate evolution, including the Great American Biotic Interchange. However, few independently-derived dates are available for constraining this record. In this contribution, we present new ⁴⁰Ar/³⁹ dates on escorias (likely the product of meteoric impacts) from the Argentinean Atlantic coast and statistically-based biochronological analyses that help to calibrate Late Miocene-Pliocene Pampean faunal successions. For the type areas of the Montehermosan and Chapadmalalan Ages/Stages, our results delimit their age ranges to 4.7-3.7 Ma and ca. 3.74-3.04 Ma, respectively. Additionally, from Buenos Aires Province, dates of 5.17 Ma and 4.33 Ma were recovered for "Huayquerian" and Montehermosan faunas. This information helps to better calibrate important first appearances of allochthonous taxa in South America, including one of the oldest records for procyonids (7.24-5.95 Ma), cricetids (6.95-5.46 Ma), and tayassuids (> 3.74 Ma, oldest high-confidence record). These results also constrain to ca. 3 Ma the last appearances of the autochthonous sparassodonts, as well as terror birds of large/middle body size in South America. South American faunal turnover during the late Neogene, including Late Pliocene extinctions, is interpreted as a consequence of knock-on effects from global climatic changes and initiation of the icehouse climate regime.Facultad de Ciencias Naturales y Muse

First fossil record of the South American frog genus Odontophrynus Reinhardt and Lütken, 1862 (Anura, Neobatrachia)

The frog genus Odontophrynus comprises 10 species arranged in three species groups that inhabit southeastern South America. In Argentina, it is represented by the O. americanus and O. occidentalis species groups and, despite being a fairly common taxon of the extant herpetofauna, it has no known fossil record. Here we report on the first fossil record of the genus, based on an almost complete right ilium from the lower levels of the Buenos Aires Formation (OIS 11, Bonaerian age, middle Pleistocene) in the Bonaerian Pampas of Argentina. The taxonomic allocation is derived from a thorough survey of anuran ilia and is grounded in a set of distinct ilial characters that, in combination, do not occur in any other anuran. These include: ilium not fused to ischium; well-developed dorsal acetabular expansion; broad preacetabular zone with a shallow preacetabular fossa; straight ilial shaft lacking dorsal ridge; and spike-like dorsal prominence bearing a distinct dorsal protuberance. Additionally, after comparing with a large sample of specimens representing most species of Odontophrynus, we propose two main characters (high spike-like dorsal prominence, absence of a lateral knob on the dorsal prominence) that allow referral to Odontophrynus aff. O. americanus or O. cordobae. SUPPLEMENTAL DATA—Supplemental materials are available for this article for free at www.tandfonline.com/UJVP Citation for this article: Turazzini, G. F., M. L. Taglioretti, and R. O. Gómez. 2016. First fossil record of the South American frog genus Odontophrynus Reinhardt and Lütken, 1862 (Anura, Neobatrachia). Journal of Vertebrate Paleontology. DOI: 10.1080/02724634.2017.1228657.Fil: Turazzini, Guillermo Fidel. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Geología; ArgentinaFil: Taglioretti, Matias Luciano. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Geología de Costas y del Cuaternario. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Instituto de Geología de Costas y del Cuaternario; ArgentinaFil: Gomez, Raul Orencio. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Geología; Argentin