Laureano Raúl González Ruiz

The most complete known Neogene Glyptodontidae (Mammalia, Xenarthra, Cingulata) from northern South America: taxonomic, paleobiogeographic, and phylogenetic implications

ABSTRACT The knowledge of northern South American Glyptodontidae (Mammalia, Xenarthra, Cingulata) is very scarce compared with that of southern South American taxa, which have been systematically studied since the 19th century. Recently, the northern taxa (originally assigned to the Glyptodontidae Propalaehoplophorinae Asterostemma and Propalaehoplophorus) have been reinterpreted as basal Glyptodontinae, belonging to the new genus Boreostemma. In this contribution, we present and describe the most complete Neogene Glyptodontidae from northern South America (middle Miocene of the Honda Group, La Venta, Colombia), and its main taxonomic, paleobiogeographic, and phylogenetic implications. This new material expands the morphological characterization of B. acostae and corroborates differences compared with Glyptodontidae from Miocene southern South America. A cladistic analysis corroborates the monophyly of the Glyptodontinae, that B. acostae and B. venezolensis being the sister group of the remaining taxa of Glyptodontinae. The traditionally recognized genera (e.g., Glyptodon and Glyptotherium) constitute natural groups. Whereas the Miocene seems to represent a diversification period for Glyptodontidae in southern South America, the recorded taxa in northern South America are restricted with certainty only to the Glyptodontinae Boreostemma.

A Peculiar New Pampatheriidae (Mammalia: Xenarthra: Cingulata) from the Pleistocene of Argentina and Comments on Pampatheriidae Diversity

Pampatheriidae are a group of cingulates native to South American that are known from the middle Miocene to the lower Holocene. Two genera have been recognized between the lower Pleistocene and the lower Holocene: Pampatherium Gervais and Ameghino (Ensenadan, Bonaerian and Lujanian, lower Pleistocene–lower Holocene) and Holmesina Simpson (Blancan, Irvingtonian, upper Pliocene–lower Holocene). They have been mainly differentiated by their osteoderm morphology and cranio-dental characters. These taxa had a wide latitudinal distribution, extending from the southern part of South America (Península Valdés, Argentina) to North America (Florida, USA). In this contribution, we describe a new genus and species of Pampatheriidae for the lower and middle Pleistocene of Buenos Aires Province and for the upper Pleistocene of Santa Fe Province (Argentina).The new taxon is represented by disarticulated osteoderms, one skull element, two thoracic vertebrae and a right femur and patella. It has extremely complex osteoderm ornamentations and particular morphological characters of the cranial element and femur that are not found in any other species of the family. This new taxon, recorded in the lower–middle Pleistocene (Ensenadan Stage/Age) and in the upper Pleistocene–early Holocene (Lujanian Stage/Age), is incorporated to the Pleistocene mammal assemblage of South America. Finally, the Pampatheriidae diversity is greater during the Lujanian Stage/Age than the Ensenadan Stage/Age.

The Interatheriinae (Mammalia, Notoungulata) of the Friasian sensu stricto and Mayoan (middle to late Miocene), and the fossils from Cerro Zeballos, Patagonia, Argentina

The middle to late Miocene Friasian sensu stricto, Colloncuran and Mayoan South American Land Mammal Ages (SALMAs) were established based on the mammals recovered from the Río Frías, Collón Curá and Río Mayo formations, respectively (southern Argentina and Chile). Records of Interatheriinae (Notoungulata) from these sediments have been known since the first contributions of Ameghino and Roth, but most of this material has only been superficially revised or is almost unstudied. Based on these old collections and new interatheriine records from Cerro Zeballos (Chubut Province), we improve the diagnosis of Caenophilus tripartitus, describe new and peculiar characters for this taxon, consider Epipatriarchus bifidens as Protypotherium cf. colloncurensis, and propose Epipatriarchus as a junior synonym of Protypotherium. In turn, the holotype of Epipatriarchus innexus is here identified as the mesotheriid Trachytypotherium sp. Therefore, only two genera of Interatheriinae, Protypotherium and Caenophilus, are recognized in the Friasian sensu stricto and Mayoan. We identify Protypotherium cf. endiadys and a probable new species of Protypotherium for the Friasian sensu stricto, P. cf. colloncurensis and Caenophilus tripartitus for the Mayoan, and C. tripartitus, P. colloncurensis and P. cf. endiadys for Cerro Zeballos. An extended phylogenetic analysis is performed, including species from low latitudes and new data for P. colloncurensis and Caenophilus tripartitus, with the latter recovered as a sister taxon to Miocochilius federicoi. Both Protypotherium and Miocochilius are recovered as paraphyletic. The updated information we present provides a better knowledge of Interatheriinae for the middle to late Miocene of southern South America.

Morphology of the Mid-Sized Tortoises (Testudines: Testudinidae) from the Middle Miocene of Northwestern Chubut (Argentina)

Abstract. In this paper, new remains of the extinct mid-sized testudinid Chelonoidis gringorum (Simpson) from northwestern Chubut (Argentina) are described in detail. The specimens were collected in outcrops of the Collón Curá Formation (middle Miocene) and are represented by postcranial remains, mainly carapaces and plastrons. The taxonomic assignation of these specimens was based on their anatomical comparison with other extant and extinct mid-sized testudinids from South America. Their high intraspecific variation, and the lack of a detailed diagnosis of C. gringorum and detailed descriptions of extinct mid-sized testudinids from South America in general, rendered the study of this group problematic. The geographic distribution of mid-sized testudinids in Argentina during the Miocene shows that there was a displacement towards lower latitudes, which is consistent with the climatic deterioration at the end of the Miocene and in turn had a big impact on Patagonia. Last but not least, the assignation of these specimens to C. gringorum expands the stratigraphic distribution of this species to the middle Miocene because, before, it was only known from the early Miocene.

Erratum to: Megatherioidea (Mammalia, Xenarthra, Tardigrada) from the Pinturas Formation (Early Miocene), Santa Cruz Province (Argentina) and their chronological implications

Kurzfassung An verschiedenen Fundstellen im oberen Tal des Pinturas Flusses sowie seinen Nebenflüssen, im Nordwesten der Provinz Santa Cruz in Argentinien, treten pyroklastische und epiklastische Kontinentalsedimente zu Tage, welche die ,,Astrapothericulense Fauna‘‘ der Pinturas-Formation von Ameghino enthalten. Diese kontinentalen Sedimente werden stratigraphisch dem Burdigalium zugeordnet und bilden die erkennbare Basis der Pinturas-Formation. Die in dieser Formation enthaltene Fauna besteht größtenteils aus Mammaliern, v. a. Rodentiern, einheimischen Ungulaten, Xenarthren und Primaten. Hier beschreiben wir erstmalig die Vergesellschaftung von Megalotherioidea (Mammalia, Xenarthra, Tardigrada) unterschiedlicher Lokalitäten der Pinturas-Formation mit genauen geographischen und stratigraphischen Angaben. Die dabei nachgewiesenen Megatherioidea sind (1) Schismotherium cf. binum; (2) Hapalops sp.; und (3) ein Exemplar Megatherioidea indet. Darüber hinaus stammen die Holotypen von Schismotherium binum (MACN A 11750), Hapalops curvus (MACN A 11140) und Pelecydon arcuatus aus der ,,Astrapothericulense Fauna‘‘ von Ameghino; unglücklicherweise ist es jedoch weiterhin unklar, ob diese tatsächlich aus der Pinturas-Formation stammen. Diese sind zwar Teil der Ameghino-Sammlung (MACN), wurden jedoch zu einer Zeit aufgesammelt, als die Pinturas-Formation noch nicht offiziell aufgestellt war. Das Vorhandensein von jeweils einer Art der Gattungen Schismotherium und Hapalops innerhalb der PinturasThe online version of the original article can be found under doi:10.1007/s12542-016-0306-8.