François Pujos

Late Oligocene Megatherioidea fauna (Mammalia: Xenarthra) from Salla-Luribay (Bolivia): new data on basal sloth radiation and Cingulata-Tardigrada split

Abstract The origins of the distinct sloth lineages are not well documented. The Deseadan SALMA site of Salla-Luribay presents four Tardigrada and constitutes one of the two oldest sloth assemblages. The peculiar glypto-sloth Pseudoglyptodon sallaensis is found together with two orophodontoid taxa and a Megalonychidae. The study of the P. sallaensis remains confirms that is effectively a sloth with various glyptodontoid convergences easily explicable by a grazing way of life. The orophodontids exhibit a common dental pattern with Octodontotherium from Patagonia. Except for the presence of Pseudoglyptodon, the Salla-Luribay Xenarthra assemblage closely resembles the La Flecha site from Santa Cruz province, Argentina. The Megalonychidae are also recorded, which increases the paleogeographic distribution of this clade in the late Oligocene. The phylogenetic status of Pseudoglyptodon remains doubtful and additional material is necessary to resolve it. Two species of Peltephilinae, a Glyptodontidae closely related to Eocoleophorus and Glyptatelus complete the xenarthran assemblage. All of the Bolivian specimens are considerably smaller than the Patagonian forms, a difference that may reflect distinct diets, latitudinal cline, and environments during the end of the Oligocene. The existence of Pseudoglyptodon, four Orophodontidae and two Megalonychidae at the end of the Oligocene (25.65 and 29.4 Ma) in South America is surprising and implies an early diversification of sloths and a Cingulata/Tardigrada split, probably before the Casamayoran, which would be in agreement with predictions based on molecular evidence.

Recent Advances on Variability, Morpho-Functional Adaptations, Dental Terminology, and Evolution of Sloths

The occasion of the Xenarthra Symposium during the ICVM 9 meeting allowed us to reflect on the considerable advances in the knowledge of sloths made by the “X-community” over the past two decades, particularly in such aspects as locomotion, mastication, diet, dental terminology, intraspecific variation, sexual dimorphism, and phylogenetic relationships. These advancements have largely been made possible by the application of cladistic methodology (including DNA analyses) and the discovery of peculiar forms such as Diabolotherium, Thalassocnus, and Pseudoglyptodon in traditionally neglected areas such as the Chilean Andes and the Peruvian Pacific desert coast. Modern tree sloths exhibit an upside-down posture and suspensory locomotion, but the habits of fossil sloths are considerably more diverse and include locomotory modes such as inferred bipedality, quadrupedality, arboreality or semiarboreality, climbing, and an aquatic or semi-aquatic lifestyle in saltwater. Modern tree sloths are generalist browsers, but fossil sloths had browsing, grazing, or mixed feeding dietary habits. Discovery of two important sloth faunas in Brazil (Jacobina) and southern North America (Daytona Beach and Rancho La Brea) have permitted evaluation of the ontogenetic variation in Eremotherium laurillardi and the existence of possible sexual dimorphism in this sloth and in Paramylodon harlani. A new dental terminology applicable to a majority of clades has been developed, facilitating comparisons among taxa. An analysis wherein functional traits were plotted onto a phylogeny of sloths was used to determine patterns of evolutionary change across the clade. These analyses suggest that megatherioid sloths were primitively semiarboreal or possessed climbing adaptations, a feature retained in some members of the family Megalonychidae. Pedolateral stance in the hindfoot is shown to be convergently acquired in Mylodontidae and Megatheria (Nothrotheriidae + Megatheriidae), this feature serving as a synapomorphy of the latter clade. Digging adaptations can only be securely ascribed to scelidotheriine and mylodontine sloths, and the latter are also the only group of grazing sloths, the remainder being general browsers.

A Miocene Relative of the Ganges River Dolphin (Odontoceti, Platanistidae) from the Amazonian Basin

A Miocene relative of the Ganges River dolphin (Odontoceti, Platanistidae) from the Amazonian Basin Giovanni Bianucci a , Olivier Lambert b , Rodolfo Salas-Gismondi c , Julia Tejada c d , Francois Pujos d e , Mario Urbina c & Pierre-Olivier Antoine f a Dipartimento di Scienze della Terra , Universita di Pisa, via S. Maria, 53 , I-56126 , Pisa , Italy b Institut royal des Sciences naturelles de Belgique , Departement de Paleontologie , Rue Vautier, 29, B-1000 , Brussels , Belgium c Departamento de Paleontologia de Vertebrados , Museo de Historia Natural-UNMSM , Av. Arenales 1256, Lima 14 , Peru d Institut Francais d’Etudes Andines (IFEA) , Casilla 18-1217, Av. Arequipa 4595, Lima 18 , Peru e Departamento de Paleontologia , Instituto Argentino de Nivologia, Glaciologia y Ciencias Ambientales (IANIGLA), CCT-CONICET-Mendoza , Avda. Ruiz Leal s/n, Parque Gral. San Martin, 5500 , Mendoza , Argentina f Institut des Sciences de l’Evolution (CNRS-UMR 5554), CC064, Universite Montpellier 2 , Place Eugene Bataillon , F-34095 Montpellier Cedex 05, France Published online: 07 May 2013.

PRESENCE OF THE EXTINCT LIZARD PARADRACAENA (TEIIDAE) IN THE MIDDLE MIOCENE OF THE PERUVIAN AMAZON

FRANÇOIS PUJOS, ADRIANA M. ALBINO, PATRICE BABY, and JEAN-LOUP GUYOT; Dpto de Geologı́a y Paleontologı́a, Instituto Argentino de Nivologı́a Glaciologı́a y Ciencias Ambientales (IANIGLA), CCT-CONICET-Mendoza, Avda.Ruiz Leal s/n, Parque Gral. San Martı́n, 5500 Mendoza, Argentina and Institut Français d’Etudes Andines (IFEA), Casilla 18-1217, Avenida Arequipa 4595, Lima 18, Peru (fpujos@yahoo.fr and fpujos@lab.cricyt.edu.ar); CONICET, Departamento de Biologı́a, Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Mar del Plata, Funes 3250, 7600 Mar del Plata, Argentina, aalbino@mdp.edu.ar; Laboratoire des Mécanismes et Transferts en Géologie, Université de Toulouse, CNRS, IRD. OMP, 14 Av. E. Belin, F-31400 Toulouse, France, patrice.baby@ird.fr; IRD – LMTG, CP 7091 Lago Sul, 71619-970 Brasilia DF, Brazil, jean-loup.guyot@ird.fr.

Hiskatherium saintandrei, gen. et sp. nov.: an unusual sloth from the Santacrucian of Quebrada Honda (Bolivia) and an overview of middle Miocene, small megatherioids

ABSTRACT A dentary from the Laventan SALMA (middle Miocene) of Quebrada Honda, Bolivia, recognized as a new, small member of Megatherioidea (Hiskatherium saintandrei, gen. et sp. nov.), is reported. This taxon is clearly distinct from Nothrotheriidae and Megalonychidae and has affinities with Hapalops and Xyophorus. It is characterized by m1–m4 without diastema; strong hypsodonty (HI = 0.93); m1–m3 constituted by two transverse lophids separated by a deep, transverse, and labially open valley; m4 round with distal lophid mesiolingually-distolabially extended and without vertical groove; m2–m3 with lingual and labial vertical grooves; and the posteroventral margin of symphysis located anteriorly to m1. Although Hiskatherium and Diabolotherium have a similar dental formula, the ‘megatheriine-shaped’ teeth of Diabolotherium do not support a close phylogenetic relationship between Hiskatherium and Diabolotherium. Their dental formulae suggest that both genera were selective feeders, capable of consuming tough items. Hiskatherium, like most other sloths, has lower molariform teeth that have a mesial and a distal lophid; the former has a mesial cuspid ‘A,’ located at the center of the mesial lophid, and the latter has distolingual (‘B,’ or lingual) and distolabial (‘C’) cuspids at each end. This terminology permits a straightforward nomenclature based on cusp/cuspid position and facilitates comparisons among Tardigrada.

Implication of the presence of Megathericulus (Xenarthra: Tardigrada: Megatheriidae) in the Laventan of Peruvian Amazonia

Middle Miocene remains of giant megatheriine ground sloths (Tardigrada: Megatherioidea) are scarce and generally located in southern South America. The discovery of a well-preserved edentulous dentary of Megathericulus sp. from the Middle Miocene (Laventan South American Land Mammal Age - SALMA; 13.5–11.8 Ma) of the Amazonian Peru increases our knowledge of this genus, which had previously been recognized in Argentina. A preliminary revision of the earliest Megatheriinae allowed clustering the four middle Miocene species within the genus Megathericulus Ameghino: M. patagonicus Ameghino, M. primaevus Cabrera, M. andinum (Kraglievich), and M. cabrerai (Kraglievich). This small-sized genus is mainly characterized by a lateral depression that borders m1, a posterior external opening of the mandibular canal anterior to the base of the ascending ramus that opens anteriorly or anterodorsally, the base of the symphysis located anteriorly to the m1, important anteroposterior compression of the teeth, elongation of the region of the maxilla anterior to the M1, humerus elongated and gracile, patellar trochlea of femur contiguous with medial and lateral articular facets for tibia, strongly developed odontoid tuberosity, and astragalus with prominent odontoid process. The genus Eomegatherium Kraglievich is therefore restricted to the Huayquerian SALMA of Argentina and represented by a single species, E. nanum Burmeister. Megatheriinae constitute the first clade of Tardigrada in which the caniniform tooth has been secondarily modified into a molariform tooth. Three molariform patterns can be observed during megatheriine evolution in relation to tooth compression and loph or lophid orientation. Middle Miocene Megatheriinae occur only in the westernmost part of South America. These giant ground sloths might have dispersed latitudinally from Colombia/Patagonian Argentina before colonizing eastern areas of Andean South America (Bolivia, Venezuela, north, and east of Argentina) during the late Miocene and early Pliocene.

Systematic and Taxonomic Revision of the Pleistocene Ground Sloth Megatherium (Pseudomegatherium) Tarijense (Xenarthra: Megatheriidae)

ABSTRACT Our understanding of South American megatheriine ground sloths was traditionally based largely on abundant material from Brazil and Argentina, mainly because megatheriine remains from elsewhere in South America were scant and poorly preserved. In recent years, however, the recovery and description of remains from northwestern South America has led to the recognition of several new taxa and the validation of species originally based on sparse remains. Falling in the latter group is Megatherium (Pseudomegatherium) tarijense Gervais and Ameghino, 1880, which is based on a complete but eroded calcaneum from Pleistocene deposits of the Tanja Valley of southern Bolivia. Most authors of the past century viewed this species as poorly defined and probably synonymous with Megatherium (Megatherium) americanum. This uncertainty is attributable to both the poor nature of the remains of M. (P.) tarijense and the presence of M. (M.) americanum in the Bolivian Pleistocene. Well preserved and nearly complete remains of several individuals indicate that M. (P.) tarijense is indeed valid. This material includes abundant remains from the Tarija Basin (Bolivia) housed in the Field Museum of Natural History (USA) and the Museo Nacional de Paleontología y Arqueología de Tarija (Bolivia) and also from the Peruvian Andes (Yantac), housed in the Universidad Nacional de Ingeniería de Lima. M. (P.) tarijense differs from M. (M.) americanum mainly in its smaller size; shorter, less robust premaxillae; shallower mandibular ramus; reduced size of the humeral deltopectoral crest; less torsion of the femoral diaphysis; unreduced patellar trochlea; and relatively shorter, stockier calcaneum.

Evolution of body size in anteaters and sloths (Xenarthra, Pilosa): phylogeny, metabolism, diet and substrate preferences

Pilosa include anteaters (Vermilingua) and sloths (Folivora). Modern tree sloths are represented by two genera, Bradypus and Choloepus (both around 4–6 kg), whereas the fossil record is very diverse, with approximately 90 genera ranging in age from the Oligocene to the early Holocene. Fossil sloths include four main clades, Megalonychidae, Megatheriidae, Nothrotheriidae, and Mylodontidae, ranging in size from tens of kilograms to several tons. Modern Vermilingua are represented by three genera, Cyclopes , Tamandua and Myrmecophaga , with a size range from 0.25 kg to about 30 kg, and their fossil record is scarce and fragmentary. The dependence of the body size on phylogenetic pattern of Pilosa is analysed here, according to current cladistic hypotheses. Orthonormal decomposition analysis and Abouheif C-mean were performed. Statistics were significantly different from the null-hypothesis, supporting the hypothesis that body size variation correlates with the phylogenetic pattern. Most of the correlation is concentrated within Vermilingua, and less within Mylodontidae, Megatheriidae, Nothrotheriidae and Megalonychidae. Influence of basal metabolic rate (BMR), dietary habits and substrate preference is discussed. In anteaters, specialised insectivory is proposed as the primary constraint on body size evolution. In the case of sloths, mylodontids, megatheriids and nothrotheriids show increasing body size through time; whereas megalonychids retain a wider diversity of sizes. Interplay between BMR and dietary habits appears to be the main factor in shaping evolution of sloth body size.

Form and Function in the Xenarthra–an Introduction to the Symposium Proceedings Volume

This special issue of the Journal of Mammalian Evolution represents the proceedings from a symposium held in conjunction with the 9th International Congress of Vertebrate Morphology (ICVM IX, Punta del Este, Uruguay, July 29, 2010), and entitled “Form and Function in the Xenarthra.” This symposium was the third on xenarthran biology to be presented in association with the ICVM meetings. In this brief introduction to the symposium proceedings, we plan to discuss the justification for the symposium, to provide a brief history of previous symposia and their results, and to introduce the contents of the present volume.

All About Current and Fossil Neotropical Mammals: 100 Million Years of Evolution Under the Tropics

The novel title of this book corresponds to the Proceedings oftwo symposia that took place in 2010 during the 10thInternational Mammalogical Congress in Mendoza, Argentina.These symposia, on settings and patterns of the historical bio-geography of Neotropical mammals, were organized by twointernational experts in mammals, who are also the editors ofthis book, Bruce Patterson and Leonora Costa. The editorsbenefited from the contribution of numerous specialists onrecent and fossil mammals, allowing them to compile an over-view of our present knowledge on the origin, evolution, anddiversity of the fascinating Neotropical mammals in the WestIndies and in Central and South America.The book is divided in two sections, preceded by an intro-ductory chapter (Chapter 1) authored by the editors.Thefirstsection,titledTheGeologicalSetting,includessixcontributions made primarily by paleontologists and biolo-gists from Argentina (FJ Goin, FJ Prevosti, SF Vizcaino, andcolleagues from CONICET), the United States (D Croft, JJFlynn, and colleagues), and Brazil (E Eizirik). This first partfocuses on the origin, evolution, systematics, paleobiology,radiation, and distribution of mammals, with each specialist(and their colleagues) dealing with a favored theme. Thecontribution of Darin Croft (Chapter 2) treats the origin anddiversityofextinctSouthAmericanmammals.Croftschapteris an introduction to the geological section of the book. InChapter 3, Francisco Goin and his co-authors trace the fasci-nating history of South American mammals. This chapter isextremely detailed, well illustrated, and supported with ex-tended selected references. The chapter covers a time periodextending from the early Gondwanan period, through the riseoftheAndes,totheformationofthePanamanianisthmus,anddescribes the five (hypothetical) phases of mammalian evolu-tion in South America in relation to biotic and abiotic eventssuch as climate changes and tectonic stages. The history ofSouthAmericanmammalsismainlybasedonresearchdevel-oped over the course of more than two centuries in ArgentinePatagonia; however, new discoveries made during the pastseveraldecadesinothersareasofthecontinenthavehelpedtocomplete the puzzle of South American mammalian history.In this context, the research of John Flynn and his colleagues(Chapter 4) has contributed enormously to the more recentdiscoveries in the Andes, mainly in Chile, Bolivia, andColombia. The overarching work of these researchers coversthe evolution of mammals in South America from the lateMesozoic La Amarga Formation (Argentina, Rougier et al.,2009), through the Paleocene of Tiupampa, the “RosettaStone” for South American mammalian evolution,preservingnearly complete skeletons of early mammals such as themarsupials Pucadelphys and Mayulestes (Muizon andCifelli 1997), to the incredible Tinguirirican fauna of Chile,which helps fill an important gap during the Eocene/Oligocene transition (Flynn et al.2003), and withoutneglecting Branisella boliviana (Hoffstetter 1969), generallyconsidered an early African primate immigrant from the lateOligocene Bolivian locality of Salla, or the monotremeMonotrematum sudamericanum from the early Paleocene ofPunta Peligro in Argentine Patagonia (Pascual et al. 1992).Some of these faunas, located in western and central South