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Martin Ciancio

Universidad Nacional de La Plata, División Paleontología de Vertebrados, Investigador Asistente CONICET (Assistant Researcher)

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Supervisors: Dr. Prof. A. A. Carlini and Dr. Prof. G. J. Scillato-Yane

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Carlini Alfredo

Universidad Nacional de La Plata

Claudio Barbeito

Universidad Nacional de La Plata

Matías E. Medina

National Scientific and Technical Research Council

Esteban Soibelzon

Universidad Nacional de La Plata

Universidad Nacional de Rosario

diego catriel leon

Universidad Nacional de Santiago del Estero, Argentina

Claudia Marcela Herrera

claudio barbeito

Universidad Nacional de La Plata

Rodrigo Tomassini

Universidad Nacional del Sur

Eduardo Pedro Pedro

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Papers by Martin Ciancio

Comparative histology and ontogenetic change in the carapace of armadillos (Mammalia: Dasypodidae)

Zoomorphology, 2015

Among extant mammals, the presence of osteoderms is limited to armadillos (Xenarthra, Dasypodidae... more Among extant mammals, the presence of osteoderms is limited to armadillos (Xenarthra, Dasypodidae), being one of its distinctive features. The osteoderms are articulated to form a carapace that covers their body dorsally. In this paper we study the integumentary structures of the armadillos Chaetophractus vellerosus, Chaetophractus villosus, Euphractus sexcinctus, and Zaedyus pichiy (Euphractinae), Dasypus hybridus, and Dasypus novemcinctus (Dasypodinae) within a comparative framework, aiming to identify patterns common to the family and to the subfamilies Dasypodinae and Euphractinae, as well as peculiarities of each species. Differences between the two subfamilies were observed in the dorsal integument, related to the production of blood cells and the mobility of the carapace. The Euphractinae present more numerous and larger cavities filled with adipose tissue in the osteoderms, as well as more marginal follicles than the Dasypodinae. These provide thermal insulation that could be related to their distribution in cooler climates. The sebaceous glands associated with surface follicles are also more developed in the Euphractinae and could be related to preventing the desiccation of the cornified scales in arid climates. Keywords Armadillo Á Osteoderm Á Cornified scales Á Histology Á Dasypodinae Á Euphractinae Communicated by A. Schmidt-Rhaesa.

The late Oligocene xenarthran fauna of Quebrada Fiera (Mendoza, Argentina) and its implications for sloth origins and the diversity of Palaeogene cingulates

Papers in Palaeontology

The late Oligocene mammalian fauna of Quebrada Fiera is one of the most diverse of the Deseadan S... more The late Oligocene mammalian fauna of Quebrada Fiera is one of the most diverse of the Deseadan SALMA (South American Land Mammal Age). We describe its endemic xenarthran assemblage, represented by 13 species, consisting of 2 stem sloths and 11 armoured cingulates. The rare folivoran material confirms the presence of Octodontotherium, one of the early known mylodontids, and suggests the existence of a new, small, non‐megalonychid megatherioid, Similhapalops nivis. The lumbar vertebrae of Octodontotherium sp. provide the oldest evidence of xenarthry for the order. The presence at the knee joint of an ossified meniscus and cyamo‐fabella strongly suggests a plantigrade ancestral condition in Mylodontidae. Armoured xenarthrans are represented by the armadillos Eutatini (Meteutatus sp., M. lagenaformis, and Stenotatus ornatus), an undetermined Euphractinii, the ‘horned’ peltephilids Peltephilus sp. and P. undulatus, and the palaeopeltid Palaeopeltis inornatus; an undetermined Glyptodontidae, the glyptatelines Glyptatelus cf. tatusinus and Clypeotherium sp., and an undetermined propalaehoplophorine. The xenarthrans represent one‐third of the mammals of the Quebrada Fiera fauna, one of the most varied at the end of the Palaeogene in South America. This vertebrate fauna is represented by a mix of endemic taxa and other species of high latitude (Patagonian) origin, but few from low latitude faunas. A detailed study of this mammalian assemblage, complemented by detailed geological and petrographical studies, suggests the existence of strong volcanic activity, and the presence of braided rivers and lagoonal environments in open habitats under a temperate or hot climate, with savannas and/or grasslands and isolated forests during the late Oligocene at the foot of the proto‐Andes.

Primer registro de Chaetophractus villosus (Mammalia, Dasypodidae) en el Pleistoceno tardío de la provincia de Corrientes (Argentina)

Chaetophractus villosus is recorded from the Chapadmalalian (middle Pliocene) to present. This sp... more Chaetophractus villosus is recorded from the Chapadmalalian (middle Pliocene) to present. This species shows one of the widest distributions of living dasypodids, but its current and past ranges do not include the provinces of the argentinean Mesopotamia (Entre Ríos, Corrientes and Misiones Provinces). We report the first record of Chaetophractus villosus in the Quaternary of Corrientes Province. These Quaternary deposits are exposed along the banks of the Paraná River and are represented by two successive upper Pleistocene formations: the Toropí Formation and Yupoí Formation. During the Pleistocene the southern end of South America has experienced climatic fluctuations, with alternations of short humid and warm periods and arid/semiarid and cold periods, leading to contraction or expansion of the biota from neighboring areas. The presence of Chaetophractus villosus in the late Pleistocene of argentinean Mesopotamia provides new evidence of periods with more arid and colder climatic...

The late Oligocene Xenarthran fauna of Quebrada Fiera (Mendoza, Argentina) and its implications for sloth origins and the diversity of Paleogene Cingulates

The late Oligocene mammalian fauna of Quebrada Fiera is one of the most diverse of the Deseadan S... more The late Oligocene mammalian fauna of Quebrada Fiera is one of the most diverse of the Deseadan SALMA. We describe its endemic xenarthran assemblage, represented by 13 species, including two stem sloths and 11 armored cingulates. The rare folivoran remains complete the knowledge of Octodontotherium, one of the early known mylodontids, and suggest the existence of a new small non-megalonychid megatherioid Similhapalops nivis gen. et sp. nov. The lumbar vertebrae of Octodontotherium sp. provide the oldest evidence of xenarthry for the order. The presence at the knee joint of an ossified meniscus and cyamo-fabella strongly suggests a plantigrade ancestral condition in Mylodontidae. Armored xenarthrans are represented by armadillos Eutatini (Meteutatus sp., M. lagenaformis, and Stenotatus ornatus), an undetermined Euphractinii, the "horned" peltephilids Peltephilus sp. and P. undulatus, and the palaeopeltid Palaeopeltis inornatus; an undetermined Glyptodontidae, the glyptateli...

Caminando sobre gliptodontes y tigres dientes de sable

Los fósiles despertaron admiración y curiosidad en los naturalistas durante siglos, conﬁriendo al... more Los fósiles despertaron admiración y curiosidad en los naturalistas durante siglos, conﬁriendo al estudio de la vida del pasado uno de los temas más apasionantes de las Ciencias Naturales. Reconstruir ese pasado se ha convertido en la meta de numerosos cientíﬁcos, quienes se ocupan de descubrir y rescatar evidencias, aportando pequeñas piezas a un gran rompecabezas y cada nueva pieza ofrece nuevas respuestas, aunque también nuevos interrogantes... Caminando… invita a despertar el interés por las Ciencias Naturales, a través de la paleontología y la evolución faunística en la región Pampeana. La guía está organizada en cuatro módulos, incluyendo actividades, que nos introducen en el mundo de la paleontología y su historia en Argentina. Recorremos los millones de años de historia de la vida en la Tierra. Conocemos la megafauna pleistocena pampeana y las hipótesis sobre su extinción. Finalmente, discutimos la relación e importancia de los museos y las comunidades locales y el valor pat...

Descubrimos nuestro subsuelo: paleontología y patrimonio en el aula

Fil: Rodriguez, Sergio G.. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Mus... more

Dental enamel structure in long-nosed armadillos (Xenarthra: Dasypus) and its evolutionary implications

Zoological Journal of the Linnean Society, 2020

Most xenarthrans have a reduced and simplified dentition that lacks enamel. However, the presence... more Most xenarthrans have a reduced and simplified dentition that lacks enamel. However, the presence of prismatic enamel has been recorded in the Eocene armadillos Utaetus buccatus (Euphractinae) and Astegotherium dichotomus (Astegotheriini). Among extant xenarthrans, the occurrence of enamel has been recognized only in the long-nosed armadillo, Dasypus novemcinctus (Dasypodinae), but its microstructure has never been described. In this contribution, we analyse the enamel microstructure in deciduous and permanent teeth of four Dasypus species. In deciduous molariform teeth of some species, we identify an apical cap of vestigial enamel (without crystalline structure), interpreted as an amorphous ameloblastic secretion. In permanent teeth, a thin layer of true enamel is found in the apical portion of unworn molariforms. The enamel is prismatic in D. novemcinctus, but in Dasypus hybridus, Dasypus sabanicola and Dasypus punctatus it is prismless. Taking into account the Eocene species of a...

Internal Morphology of Osteoderms of Extinct Armadillos and Its Relationship with Environmental Conditions

Journal of Mammalian Evolution, 2017

The most complete and continuous fossil record of armadillos is composed mostly by isolated osteo... more The most complete and continuous fossil record of armadillos is composed mostly by isolated osteoderms, frequently found in paleontological and archaeological sites that bear continental South American mammals. Their external morphology has been used to define several species. In the last decade, many authors have focused on the internal structure of vertebrate osteoderms using histological and paleohistological studies. These studies allowed identification of useful features in systematic and phylogenetic contexts. In armadillos, osteoderms are constituted by compact bone tissue (primary and secondary osteons, and concentric layers or lamellae) that delimits cavities, which could contain different soft tissues (adipose tissue, hair follicles, bone marrow, and sweat and sebaceous glands). Traditional paleohistological techniques have allowed the recognition of homologous cavities to those found in osteoderms of current species and from comparison deduce which kind of tissue could had occupied them. We have recently utilized 3D reconstructions in osteoderms of extant species of armadillos to analyze the micromorphology, disposition, and the relationship of different cavities and understand them in depth. Here, we present the results of the application of paleohistology and microtomography in osteoderms of representatives of diferent taxa of extinct Dasypodidae (Astegotheriini, Stegotheriini, BUtaetini,^Euphractini, Eutatini), which allowed us to compare homologous structures based on their three-dimensional reconstruction. The results, added to the previous external morphology studies, have allowed us to define morphological patterns (consistent within each linage). The variation of the volume and extension of cavities associated with different tissues could be strongly associated with changes in the climate and environmental conditions of the species distribution areas.

New mammal faunal data from Cerdas, Bolivia, a middle-latitude Neotropical site that chronicles the end of the Middle Miocene Climatic Optimum in South America

Journal of Vertebrate Paleontology, 2016

ABSTRACT We provide new and revised identifications of mammals from the early middle Miocene (Lan... more ABSTRACT We provide new and revised identifications of mammals from the early middle Miocene (Langhian age, Colloncuran South American Land Mammal Age [SALMA]) of Cerdas, Bolivia. We also formally name a new typothere notoungulate, Hegetotherium cerdasensis, sp. nov., that can be distinguished by the absence of an external talonid sulcus on m3 and its small size (15–25% smaller than Hegetotherium mirabile). We refer several typothere specimens from Nazareno, Bolivia, to H. cerdasensis, which suggests that the two sites are of similar age. We report the first sparassodont and astrapothere remains from Cerdas. Sparassodont remains include an associated basicranium and mostly complete mandible; the species appears to represent a new, small-bodied borhyaenoid. Astrapothere remains consist of many tooth fragments from a new species of the subfamily Uruguaytheriinae. A partial sloth dentary from Cerdas likely pertains to the subfamily Megatheriinae and is the first report of the family Megatheriidae from the site. A newly discovered peltephilid armadillo specimen includes a partial articulated carapace that supports recognition of the Cerdas taxon as a new species. The two dasypodids of Cerdas (one Euphractini, one Eutatini) represent two new species closely related to undescribed species from the late middle Miocene (Serravallian age, Laventan SALMA) of Quebrada Honda, Bolivia. The mammals of Cerdas indicate that (1) the middle latitudes (southern tropics) contributed significantly to the diversity of Miocene mammal communities in South America; and (2) the Middle Miocene Climatic Optimum was a key factor in the differentiation of South American mammal assemblages.

Diversity of cingulates (Mammalia, Xenarthra) in the middle-late Eocene of Northwestern Argentina

Acta Palaeontologica Polonica, 2016

The study of Paleogene mammals of intermediate and low latitudes has increased in the last decade... more The study of Paleogene mammals of intermediate and low latitudes has increased in the last decades and has been clearly demonstrated their importance in the comprehension of the evolution and faunistic changes outside Patagonia. The study of these faunas permits establishing new comparisons among contemporaneous faunistic associations, completing the distributional patterns, and evaluating evolutionary changes in the lineages in relation to climatic conditions prevailing in each of the different regions. In this work we study the diversity of Dasypodidae recovered from the Geste Formation (Northwestern Argentina). Bearing levels of Geste Formation were referred alternatively to a Barrancan subage of Casamayoran SALMA (middle Eocene, Lutetian-Bartonian) or a Mustersan SALMA (middle-late Eocene, Bartonian-Priabonian) on faunistic comparations with their equivalent in Patagonia, although absolute isotopic data indicates ca. 37-35 Ma (late Eocene, Priabonian). We described the following taxa of Dasypodidae: (i) Dasypodinae Astegotheriini: cf. Astegotherium sp., ?Prostegotherium sp., Parastegosimpsonia cf. P. peruana; (ii) Dasypodinae indet.; (iii) Euphractinae Euphractini: Parutaetus punaensis sp. nov.; (iv) Dasypodidae incertae sedis: Pucatherium parvum, Punatherium catamarcensis gen. et sp. nov. In comparison with other beds bearing Eocene cingulate faunas from Northwestern Argentina, Geste Formation presents the greatest diversity of dasypodids. This association is consistent with a late Eocene age and shows a taxonomic and biogeographic relevant features given by a unique specific composition: (i) it differs from that known for contemporaneous faunas from Southern latitudes and younger associations from more tropical areas; (ii) it includes genera with close affinities to those distant areas; (iii) it presents unique taxa typical from Eocene units exposed at Northwestern Argentina. This highlights the evolutionary and biogeographic meaning of the cingulate of the Geste Formation and supports the idea that the faunistic regionalization probably obeyed to latitudinal than to temporal factors.

<strong>Reassessment of the hairy long-nosed armadillo “Dasypus” pilosus (Xenarthra, Dasypodidae) and revalidation of the genus <em>Cryptophractus</em> Fitzinger, 1856</strong>

Zootaxa, 2015

Reassessment of the hairy long-nosed armadillo "Dasypus" pilosus (Xenarthra, Dasypodidae) and rev... more

Los Xenarthra De Gran Barranca: Mas De 20 Ma De Historia

When xenarthrans had enamel: Insights on the evolution of their hypsodonty and paleontological support for independent evolution in armadillos

All xenarthrans known to date are characterized by having permanent teeth that are both high crow... more All xenarthrans known to date are characterized by having permanent teeth that are both high crowned and open rooted, i.e., euhypsodont, and with a type of hypsodonty different from that of the rest of Placentalia: dentine hypsodonty. Also, most xenarthrans lack enamel; however, its presence has been reported in the fossil armadillo Utaetus buccatus and in living Dasypus. Considering the divergence of Xenarthra from other eutherians that possessed enameled teeth, the absence of enamel is a derived character. Diverse specializations are known in the dentition of xenarthrans, but the primitive pattern of their teeth and dentitions is still unknown. Here, we describe the mandible and teeth of a fossil armadillo, Astegotherium dichotomus (Astegotheriini, Dasypodidae), from the early Middle Eocene of Argentine Patagonia, with teeth showing both true enamel and closed roots. It is the oldest xenarthran with mandibular remains exhibiting protohypsodonty and is therefore likely representative of ancestral cingulates and xenarthrans generally. Astegotherium supports a recent hypothesis based on molecular data that enamel loss occurred independently not only within xenarthrans but also within dasypodid armadillos.

Los Peltephilidae (Mammalia, Xenarthra) de la Formación Collón Curá (Colloncurense, Mioceno médio), Argentina

Revista Brasileira de Paleontologia, 2013

THE PELTEPHILIDAE (MAMMALIA, XENARTHRA) FROM THE COLLÓN CURÁ FORMATION (COLLONCURAN, MIDDLE MIOCE... more THE PELTEPHILIDAE (MAMMALIA, XENARTHRA) FROM THE COLLÓN CURÁ FORMATION (COLLONCURAN, MIDDLE MIOCENE), ARGENTINA. The Peltephilidae (early Eocene-late Miocene) are a group of extinct armadillos exclusive from South America, known for having horn-like osteoderms on the nasals and maxillaries. This paper discusses a nomenclatorial proposal for anatomical description of these cingulate osteoderms and describes for the fi rst time specimens of Peltephilidae (Xenarthra, Cingulata) from the Collón Curá Formation (Colloncuran, middle Miocene) of Patagonia (Argentina). The major change in the nomenclature of the osteoderms in Peltephilidae here proposed is to replace the term "central or main fi gure" by "central longitudinal elevation". Finally, by analogy with the living species of Dasypodidae and the extinct Pampatheriidae, some considerations are presented about the relationships between the osteoderm and the overlying epidermal scale in Peltephilidae. The new specimens are assigned to Peltephilidae gen. et sp. indet., Peltephilus pumilus Ameghino and P. nanus Ameghino. The latter two species represent their youngest record and indicate a closer taxonomic affi nity of the Colloncuran age with the previous Santacrucian, instead of the subsequent Laventan and Mayoan.

La Presencia Del Xenartro Palaeopeltis Inornatus Ameghino, 1894, en La Formación Fray Bentos (Oligoceno Tardío), Uruguay

Ameghiniana, 2014

Armadillos: antiguos mamíferos acorazados habitantes de las Américas

Desde hace varios millones de años, un peculiar grupo de mamíferos habita nuestro continente, los... more Desde hace varios millones de años, un peculiar grupo de mamíferos habita nuestro continente, los armadillos, cuyo nombre alude a la "armadura" que recubre su cuerpo dorsalmente. Actualmente están representados por las mulitas, los peludos, el armadillo de tres bandas, el tatú carreta, los armadillos de cola desnuda y los pichiciegos. Pero esta diversidad es solo una pequeña muestra de lo que fueron en el pasado.

Short Communication First Recordof Supernumerary Teeth in Glyptodontidae (Mammalia, Xenarthra, Cingulata)

LAUREANO R. GONZ ALEZ-RUIZ,* MARTIN R. CIANCIO, GABRIEL M. MARTIN, and ALFREDO E. ZURITA; Laborat... more LAUREANO R. GONZ ALEZ-RUIZ,* MARTIN R. CIANCIO, GABRIEL M. MARTIN, and ALFREDO E. ZURITA; Laboratorio de Investigaciones en Evoluci on y Biodiversidad (LIEB), Universidad Nacional de la Patagonia ‘San Juan Bosco’ sede Esquel (UNPSJB), Ruta Nacional 259, km 16.5, 9200, Esquel, Chubut, Argentina, [email protected]; [email protected]; Divisi on Paleontolog ıa de Vertebrados, Museo de La Plata, Universidad Nacional de La Plata (UNLP), Paseo del Bosque s/n, B1900FWA La Plata, Buenos Aires, Argentina, [email protected]; Centro de Ecolog ıa Aplicada del Litoral (CECOAL-CONICET), Ruta 5, km. 2.5, 3400, CC128, Corrientes, Argentina, [email protected]

First record of Chaetophractus villosus (Mammalia, Dasypodidae) in the late Pleistocene of Corrientes Province (Argentina)

Fil: Francia, Analia. Universidad Nacional de la Plata. Facultad de Ciencias Naturales y Museo. D... more

Evolutionary Implications of Dental Eruption in Dasypus (Xenarthra)

Journal of Mammalian …, 2011

Late eruption of the permanent dentition was recently proposed as a shared anatomical feature of ... more Late eruption of the permanent dentition was recently proposed as a shared anatomical feature of endemic African mammals (Afrotheria), with anecdotal reports indicating that it is also present in dasypodids (armadillos). In order to clarify this question, and address the possiblity that late eruption is shared by afrotherians and dasypodids, we quantified the eruption of permanent teeth in Dasypus, focusing on growth series of D. hybridus and D. novemcinctus. This genus is the only known xenarthran that retains two functional generations of teeth. Its adult dentition typically consists of eight upper and eight lower ever-growing (or euhypsodont) molariforms, with no premaxillary teeth. All but the posterior-most tooth are replaced, consistent with the identification of a single molar locus in each series. Comparison of dental replacement and skull metrics reveals that most specimens reach adult size with none or few erupted permanent teeth. This pattern of growth occurring prior to the full eruption of the dentition is similar to that observed in most afrotherians. The condition observed in Dasypus and many afrotherians differs from that of most other mammals, in which the permanent dentition erupts during (not after) growth, and is complete at or near the attainment of sexual maturity and adult body size. The suture closure sequence of basicranial and postcranial epiphyses does not correlate well with dental eruption. The basal phylogenetic position of the taxon within dasypodids suggests that diphyodonty and late dental replacement represent the condition of early xenarthrans. Additionally, the inferred reduction in the number of molars to a single locus and the multiplication of premolars represent rare features for any living mammal, but may represent apomorphic characters for Dasypus.

Micromorphology of osteoderms in Dasypodidae (Cingulata, Mammalia): Characterization and 3D‐reconstructions

Journal of Morphology

Comparative histology and ontogenetic change in the carapace of armadillos (Mammalia: Dasypodidae)

Zoomorphology, 2015

Among extant mammals, the presence of osteoderms is limited to armadillos (Xenarthra, Dasypodidae... more Among extant mammals, the presence of osteoderms is limited to armadillos (Xenarthra, Dasypodidae), being one of its distinctive features. The osteoderms are articulated to form a carapace that covers their body dorsally. In this paper we study the integumentary structures of the armadillos Chaetophractus vellerosus, Chaetophractus villosus, Euphractus sexcinctus, and Zaedyus pichiy (Euphractinae), Dasypus hybridus, and Dasypus novemcinctus (Dasypodinae) within a comparative framework, aiming to identify patterns common to the family and to the subfamilies Dasypodinae and Euphractinae, as well as peculiarities of each species. Differences between the two subfamilies were observed in the dorsal integument, related to the production of blood cells and the mobility of the carapace. The Euphractinae present more numerous and larger cavities filled with adipose tissue in the osteoderms, as well as more marginal follicles than the Dasypodinae. These provide thermal insulation that could be related to their distribution in cooler climates. The sebaceous glands associated with surface follicles are also more developed in the Euphractinae and could be related to preventing the desiccation of the cornified scales in arid climates. Keywords Armadillo Á Osteoderm Á Cornified scales Á Histology Á Dasypodinae Á Euphractinae Communicated by A. Schmidt-Rhaesa.

The late Oligocene xenarthran fauna of Quebrada Fiera (Mendoza, Argentina) and its implications for sloth origins and the diversity of Palaeogene cingulates

Papers in Palaeontology

The late Oligocene mammalian fauna of Quebrada Fiera is one of the most diverse of the Deseadan S... more The late Oligocene mammalian fauna of Quebrada Fiera is one of the most diverse of the Deseadan SALMA (South American Land Mammal Age). We describe its endemic xenarthran assemblage, represented by 13 species, consisting of 2 stem sloths and 11 armoured cingulates. The rare folivoran material confirms the presence of Octodontotherium, one of the early known mylodontids, and suggests the existence of a new, small, non‐megalonychid megatherioid, Similhapalops nivis. The lumbar vertebrae of Octodontotherium sp. provide the oldest evidence of xenarthry for the order. The presence at the knee joint of an ossified meniscus and cyamo‐fabella strongly suggests a plantigrade ancestral condition in Mylodontidae. Armoured xenarthrans are represented by the armadillos Eutatini (Meteutatus sp., M. lagenaformis, and Stenotatus ornatus), an undetermined Euphractinii, the ‘horned’ peltephilids Peltephilus sp. and P. undulatus, and the palaeopeltid Palaeopeltis inornatus; an undetermined Glyptodontidae, the glyptatelines Glyptatelus cf. tatusinus and Clypeotherium sp., and an undetermined propalaehoplophorine. The xenarthrans represent one‐third of the mammals of the Quebrada Fiera fauna, one of the most varied at the end of the Palaeogene in South America. This vertebrate fauna is represented by a mix of endemic taxa and other species of high latitude (Patagonian) origin, but few from low latitude faunas. A detailed study of this mammalian assemblage, complemented by detailed geological and petrographical studies, suggests the existence of strong volcanic activity, and the presence of braided rivers and lagoonal environments in open habitats under a temperate or hot climate, with savannas and/or grasslands and isolated forests during the late Oligocene at the foot of the proto‐Andes.

Primer registro de Chaetophractus villosus (Mammalia, Dasypodidae) en el Pleistoceno tardío de la provincia de Corrientes (Argentina)

Chaetophractus villosus is recorded from the Chapadmalalian (middle Pliocene) to present. This sp... more Chaetophractus villosus is recorded from the Chapadmalalian (middle Pliocene) to present. This species shows one of the widest distributions of living dasypodids, but its current and past ranges do not include the provinces of the argentinean Mesopotamia (Entre Ríos, Corrientes and Misiones Provinces). We report the first record of Chaetophractus villosus in the Quaternary of Corrientes Province. These Quaternary deposits are exposed along the banks of the Paraná River and are represented by two successive upper Pleistocene formations: the Toropí Formation and Yupoí Formation. During the Pleistocene the southern end of South America has experienced climatic fluctuations, with alternations of short humid and warm periods and arid/semiarid and cold periods, leading to contraction or expansion of the biota from neighboring areas. The presence of Chaetophractus villosus in the late Pleistocene of argentinean Mesopotamia provides new evidence of periods with more arid and colder climatic...

The late Oligocene Xenarthran fauna of Quebrada Fiera (Mendoza, Argentina) and its implications for sloth origins and the diversity of Paleogene Cingulates

The late Oligocene mammalian fauna of Quebrada Fiera is one of the most diverse of the Deseadan S... more The late Oligocene mammalian fauna of Quebrada Fiera is one of the most diverse of the Deseadan SALMA. We describe its endemic xenarthran assemblage, represented by 13 species, including two stem sloths and 11 armored cingulates. The rare folivoran remains complete the knowledge of Octodontotherium, one of the early known mylodontids, and suggest the existence of a new small non-megalonychid megatherioid Similhapalops nivis gen. et sp. nov. The lumbar vertebrae of Octodontotherium sp. provide the oldest evidence of xenarthry for the order. The presence at the knee joint of an ossified meniscus and cyamo-fabella strongly suggests a plantigrade ancestral condition in Mylodontidae. Armored xenarthrans are represented by armadillos Eutatini (Meteutatus sp., M. lagenaformis, and Stenotatus ornatus), an undetermined Euphractinii, the "horned" peltephilids Peltephilus sp. and P. undulatus, and the palaeopeltid Palaeopeltis inornatus; an undetermined Glyptodontidae, the glyptateli...

Caminando sobre gliptodontes y tigres dientes de sable

Los fósiles despertaron admiración y curiosidad en los naturalistas durante siglos, conﬁriendo al... more Los fósiles despertaron admiración y curiosidad en los naturalistas durante siglos, conﬁriendo al estudio de la vida del pasado uno de los temas más apasionantes de las Ciencias Naturales. Reconstruir ese pasado se ha convertido en la meta de numerosos cientíﬁcos, quienes se ocupan de descubrir y rescatar evidencias, aportando pequeñas piezas a un gran rompecabezas y cada nueva pieza ofrece nuevas respuestas, aunque también nuevos interrogantes... Caminando… invita a despertar el interés por las Ciencias Naturales, a través de la paleontología y la evolución faunística en la región Pampeana. La guía está organizada en cuatro módulos, incluyendo actividades, que nos introducen en el mundo de la paleontología y su historia en Argentina. Recorremos los millones de años de historia de la vida en la Tierra. Conocemos la megafauna pleistocena pampeana y las hipótesis sobre su extinción. Finalmente, discutimos la relación e importancia de los museos y las comunidades locales y el valor pat...

Descubrimos nuestro subsuelo: paleontología y patrimonio en el aula

Fil: Rodriguez, Sergio G.. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Mus... more

Dental enamel structure in long-nosed armadillos (Xenarthra: Dasypus) and its evolutionary implications

Zoological Journal of the Linnean Society, 2020

Most xenarthrans have a reduced and simplified dentition that lacks enamel. However, the presence... more Most xenarthrans have a reduced and simplified dentition that lacks enamel. However, the presence of prismatic enamel has been recorded in the Eocene armadillos Utaetus buccatus (Euphractinae) and Astegotherium dichotomus (Astegotheriini). Among extant xenarthrans, the occurrence of enamel has been recognized only in the long-nosed armadillo, Dasypus novemcinctus (Dasypodinae), but its microstructure has never been described. In this contribution, we analyse the enamel microstructure in deciduous and permanent teeth of four Dasypus species. In deciduous molariform teeth of some species, we identify an apical cap of vestigial enamel (without crystalline structure), interpreted as an amorphous ameloblastic secretion. In permanent teeth, a thin layer of true enamel is found in the apical portion of unworn molariforms. The enamel is prismatic in D. novemcinctus, but in Dasypus hybridus, Dasypus sabanicola and Dasypus punctatus it is prismless. Taking into account the Eocene species of a...

Internal Morphology of Osteoderms of Extinct Armadillos and Its Relationship with Environmental Conditions

Journal of Mammalian Evolution, 2017

The most complete and continuous fossil record of armadillos is composed mostly by isolated osteo... more The most complete and continuous fossil record of armadillos is composed mostly by isolated osteoderms, frequently found in paleontological and archaeological sites that bear continental South American mammals. Their external morphology has been used to define several species. In the last decade, many authors have focused on the internal structure of vertebrate osteoderms using histological and paleohistological studies. These studies allowed identification of useful features in systematic and phylogenetic contexts. In armadillos, osteoderms are constituted by compact bone tissue (primary and secondary osteons, and concentric layers or lamellae) that delimits cavities, which could contain different soft tissues (adipose tissue, hair follicles, bone marrow, and sweat and sebaceous glands). Traditional paleohistological techniques have allowed the recognition of homologous cavities to those found in osteoderms of current species and from comparison deduce which kind of tissue could had occupied them. We have recently utilized 3D reconstructions in osteoderms of extant species of armadillos to analyze the micromorphology, disposition, and the relationship of different cavities and understand them in depth. Here, we present the results of the application of paleohistology and microtomography in osteoderms of representatives of diferent taxa of extinct Dasypodidae (Astegotheriini, Stegotheriini, BUtaetini,^Euphractini, Eutatini), which allowed us to compare homologous structures based on their three-dimensional reconstruction. The results, added to the previous external morphology studies, have allowed us to define morphological patterns (consistent within each linage). The variation of the volume and extension of cavities associated with different tissues could be strongly associated with changes in the climate and environmental conditions of the species distribution areas.

New mammal faunal data from Cerdas, Bolivia, a middle-latitude Neotropical site that chronicles the end of the Middle Miocene Climatic Optimum in South America

Journal of Vertebrate Paleontology, 2016

ABSTRACT We provide new and revised identifications of mammals from the early middle Miocene (Lan... more ABSTRACT We provide new and revised identifications of mammals from the early middle Miocene (Langhian age, Colloncuran South American Land Mammal Age [SALMA]) of Cerdas, Bolivia. We also formally name a new typothere notoungulate, Hegetotherium cerdasensis, sp. nov., that can be distinguished by the absence of an external talonid sulcus on m3 and its small size (15–25% smaller than Hegetotherium mirabile). We refer several typothere specimens from Nazareno, Bolivia, to H. cerdasensis, which suggests that the two sites are of similar age. We report the first sparassodont and astrapothere remains from Cerdas. Sparassodont remains include an associated basicranium and mostly complete mandible; the species appears to represent a new, small-bodied borhyaenoid. Astrapothere remains consist of many tooth fragments from a new species of the subfamily Uruguaytheriinae. A partial sloth dentary from Cerdas likely pertains to the subfamily Megatheriinae and is the first report of the family Megatheriidae from the site. A newly discovered peltephilid armadillo specimen includes a partial articulated carapace that supports recognition of the Cerdas taxon as a new species. The two dasypodids of Cerdas (one Euphractini, one Eutatini) represent two new species closely related to undescribed species from the late middle Miocene (Serravallian age, Laventan SALMA) of Quebrada Honda, Bolivia. The mammals of Cerdas indicate that (1) the middle latitudes (southern tropics) contributed significantly to the diversity of Miocene mammal communities in South America; and (2) the Middle Miocene Climatic Optimum was a key factor in the differentiation of South American mammal assemblages.

Diversity of cingulates (Mammalia, Xenarthra) in the middle-late Eocene of Northwestern Argentina

Acta Palaeontologica Polonica, 2016

The study of Paleogene mammals of intermediate and low latitudes has increased in the last decade... more The study of Paleogene mammals of intermediate and low latitudes has increased in the last decades and has been clearly demonstrated their importance in the comprehension of the evolution and faunistic changes outside Patagonia. The study of these faunas permits establishing new comparisons among contemporaneous faunistic associations, completing the distributional patterns, and evaluating evolutionary changes in the lineages in relation to climatic conditions prevailing in each of the different regions. In this work we study the diversity of Dasypodidae recovered from the Geste Formation (Northwestern Argentina). Bearing levels of Geste Formation were referred alternatively to a Barrancan subage of Casamayoran SALMA (middle Eocene, Lutetian-Bartonian) or a Mustersan SALMA (middle-late Eocene, Bartonian-Priabonian) on faunistic comparations with their equivalent in Patagonia, although absolute isotopic data indicates ca. 37-35 Ma (late Eocene, Priabonian). We described the following taxa of Dasypodidae: (i) Dasypodinae Astegotheriini: cf. Astegotherium sp., ?Prostegotherium sp., Parastegosimpsonia cf. P. peruana; (ii) Dasypodinae indet.; (iii) Euphractinae Euphractini: Parutaetus punaensis sp. nov.; (iv) Dasypodidae incertae sedis: Pucatherium parvum, Punatherium catamarcensis gen. et sp. nov. In comparison with other beds bearing Eocene cingulate faunas from Northwestern Argentina, Geste Formation presents the greatest diversity of dasypodids. This association is consistent with a late Eocene age and shows a taxonomic and biogeographic relevant features given by a unique specific composition: (i) it differs from that known for contemporaneous faunas from Southern latitudes and younger associations from more tropical areas; (ii) it includes genera with close affinities to those distant areas; (iii) it presents unique taxa typical from Eocene units exposed at Northwestern Argentina. This highlights the evolutionary and biogeographic meaning of the cingulate of the Geste Formation and supports the idea that the faunistic regionalization probably obeyed to latitudinal than to temporal factors.

<strong>Reassessment of the hairy long-nosed armadillo “Dasypus” pilosus (Xenarthra, Dasypodidae) and revalidation of the genus <em>Cryptophractus</em> Fitzinger, 1856</strong>

Zootaxa, 2015

Reassessment of the hairy long-nosed armadillo "Dasypus" pilosus (Xenarthra, Dasypodidae) and rev... more

Los Xenarthra De Gran Barranca: Mas De 20 Ma De Historia

When xenarthrans had enamel: Insights on the evolution of their hypsodonty and paleontological support for independent evolution in armadillos

All xenarthrans known to date are characterized by having permanent teeth that are both high crow... more All xenarthrans known to date are characterized by having permanent teeth that are both high crowned and open rooted, i.e., euhypsodont, and with a type of hypsodonty different from that of the rest of Placentalia: dentine hypsodonty. Also, most xenarthrans lack enamel; however, its presence has been reported in the fossil armadillo Utaetus buccatus and in living Dasypus. Considering the divergence of Xenarthra from other eutherians that possessed enameled teeth, the absence of enamel is a derived character. Diverse specializations are known in the dentition of xenarthrans, but the primitive pattern of their teeth and dentitions is still unknown. Here, we describe the mandible and teeth of a fossil armadillo, Astegotherium dichotomus (Astegotheriini, Dasypodidae), from the early Middle Eocene of Argentine Patagonia, with teeth showing both true enamel and closed roots. It is the oldest xenarthran with mandibular remains exhibiting protohypsodonty and is therefore likely representative of ancestral cingulates and xenarthrans generally. Astegotherium supports a recent hypothesis based on molecular data that enamel loss occurred independently not only within xenarthrans but also within dasypodid armadillos.

Los Peltephilidae (Mammalia, Xenarthra) de la Formación Collón Curá (Colloncurense, Mioceno médio), Argentina

Revista Brasileira de Paleontologia, 2013

THE PELTEPHILIDAE (MAMMALIA, XENARTHRA) FROM THE COLLÓN CURÁ FORMATION (COLLONCURAN, MIDDLE MIOCE... more THE PELTEPHILIDAE (MAMMALIA, XENARTHRA) FROM THE COLLÓN CURÁ FORMATION (COLLONCURAN, MIDDLE MIOCENE), ARGENTINA. The Peltephilidae (early Eocene-late Miocene) are a group of extinct armadillos exclusive from South America, known for having horn-like osteoderms on the nasals and maxillaries. This paper discusses a nomenclatorial proposal for anatomical description of these cingulate osteoderms and describes for the fi rst time specimens of Peltephilidae (Xenarthra, Cingulata) from the Collón Curá Formation (Colloncuran, middle Miocene) of Patagonia (Argentina). The major change in the nomenclature of the osteoderms in Peltephilidae here proposed is to replace the term "central or main fi gure" by "central longitudinal elevation". Finally, by analogy with the living species of Dasypodidae and the extinct Pampatheriidae, some considerations are presented about the relationships between the osteoderm and the overlying epidermal scale in Peltephilidae. The new specimens are assigned to Peltephilidae gen. et sp. indet., Peltephilus pumilus Ameghino and P. nanus Ameghino. The latter two species represent their youngest record and indicate a closer taxonomic affi nity of the Colloncuran age with the previous Santacrucian, instead of the subsequent Laventan and Mayoan.

La Presencia Del Xenartro Palaeopeltis Inornatus Ameghino, 1894, en La Formación Fray Bentos (Oligoceno Tardío), Uruguay

Ameghiniana, 2014

Armadillos: antiguos mamíferos acorazados habitantes de las Américas

Desde hace varios millones de años, un peculiar grupo de mamíferos habita nuestro continente, los... more Desde hace varios millones de años, un peculiar grupo de mamíferos habita nuestro continente, los armadillos, cuyo nombre alude a la "armadura" que recubre su cuerpo dorsalmente. Actualmente están representados por las mulitas, los peludos, el armadillo de tres bandas, el tatú carreta, los armadillos de cola desnuda y los pichiciegos. Pero esta diversidad es solo una pequeña muestra de lo que fueron en el pasado.

Short Communication First Recordof Supernumerary Teeth in Glyptodontidae (Mammalia, Xenarthra, Cingulata)

LAUREANO R. GONZ ALEZ-RUIZ,* MARTIN R. CIANCIO, GABRIEL M. MARTIN, and ALFREDO E. ZURITA; Laborat... more LAUREANO R. GONZ ALEZ-RUIZ,* MARTIN R. CIANCIO, GABRIEL M. MARTIN, and ALFREDO E. ZURITA; Laboratorio de Investigaciones en Evoluci on y Biodiversidad (LIEB), Universidad Nacional de la Patagonia ‘San Juan Bosco’ sede Esquel (UNPSJB), Ruta Nacional 259, km 16.5, 9200, Esquel, Chubut, Argentina, [email protected]; [email protected]; Divisi on Paleontolog ıa de Vertebrados, Museo de La Plata, Universidad Nacional de La Plata (UNLP), Paseo del Bosque s/n, B1900FWA La Plata, Buenos Aires, Argentina, [email protected]; Centro de Ecolog ıa Aplicada del Litoral (CECOAL-CONICET), Ruta 5, km. 2.5, 3400, CC128, Corrientes, Argentina, [email protected]

First record of Chaetophractus villosus (Mammalia, Dasypodidae) in the late Pleistocene of Corrientes Province (Argentina)

Fil: Francia, Analia. Universidad Nacional de la Plata. Facultad de Ciencias Naturales y Museo. D... more

Evolutionary Implications of Dental Eruption in Dasypus (Xenarthra)

Journal of Mammalian …, 2011

Late eruption of the permanent dentition was recently proposed as a shared anatomical feature of ... more Late eruption of the permanent dentition was recently proposed as a shared anatomical feature of endemic African mammals (Afrotheria), with anecdotal reports indicating that it is also present in dasypodids (armadillos). In order to clarify this question, and address the possiblity that late eruption is shared by afrotherians and dasypodids, we quantified the eruption of permanent teeth in Dasypus, focusing on growth series of D. hybridus and D. novemcinctus. This genus is the only known xenarthran that retains two functional generations of teeth. Its adult dentition typically consists of eight upper and eight lower ever-growing (or euhypsodont) molariforms, with no premaxillary teeth. All but the posterior-most tooth are replaced, consistent with the identification of a single molar locus in each series. Comparison of dental replacement and skull metrics reveals that most specimens reach adult size with none or few erupted permanent teeth. This pattern of growth occurring prior to the full eruption of the dentition is similar to that observed in most afrotherians. The condition observed in Dasypus and many afrotherians differs from that of most other mammals, in which the permanent dentition erupts during (not after) growth, and is complete at or near the attainment of sexual maturity and adult body size. The suture closure sequence of basicranial and postcranial epiphyses does not correlate well with dental eruption. The basal phylogenetic position of the taxon within dasypodids suggests that diphyodonty and late dental replacement represent the condition of early xenarthrans. Additionally, the inferred reduction in the number of molars to a single locus and the multiplication of premolars represent rare features for any living mammal, but may represent apomorphic characters for Dasypus.

Micromorphology of osteoderms in Dasypodidae (Cingulata, Mammalia): Characterization and 3D‐reconstructions

Journal of Morphology

Internal Morphology of Osteoderms of Extinct Armadillos and Its Relationship with Environmental Conditions

Journal of Mammalian Evolution, 2019

The most complete and continuous fossil record of armadillos is composed mostly by isolated osteo... more The most complete and continuous fossil record of armadillos is composed mostly by isolated osteoderms, frequently found in paleontological and archaeological sites that bear continental South American mammals. Their external morphology has been used to define several species. In the last decade, many authors have focused on the internal structure of vertebrate osteoderms using histological and paleohistological studies. These studies allowed identification of useful features in systematic and phylogenetic contexts. In armadillos,
osteoderms are constituted by compact bone tissue (primary and secondary osteons, and concentric layers or lamellae) that delimits cavities, which could contain different soft tissues (adipose tissue, hair follicles, bone marrow, and sweat and sebaceous glands). Traditional paleohistological techniques have allowed the recognition of homologous cavities to those found in osteoderms of current species and from comparison deduce which kind of tissue could had occupied them.We have recently utilized 3D reconstructions in osteoderms of extant species of armadillos to analyze the micromorphology, disposition, and the relationship of different cavities and understand them in depth. Here, we present the results of the application of
paleohistology and microtomography in osteoderms of representatives of diferent taxa of extinct Dasypodidae (Astegotheriini, Stegotheriini, Utaetini, Euphractini, Eutatini), which allowed us to compare homologous structures based on their three-dimensional reconstruction. The results,
added to the previous external morphology studies, have allowed us to define morphological patterns (consistent within each linage). The variation of the volume and extension of cavities associated with different tissues could be strongly associated with changes in the climate and environmental conditions of the species distribution areas.

New mammal faunal data from Cerdas, Bolivia, a middle-latitude Neotropical site that chronicles the end of the Middle Miocene Climatic Optimum in South America

by Darin A Croft, Martin Ciancio, and Nicholas Drew

We provide new and revised identifications of mammals from the early middle Miocene (Langhian age... more We provide new and revised identifications of mammals from the early middle Miocene (Langhian age, Colloncuran South American Land Mammal Age [SALMA]) of Cerdas, Bolivia. We also formally name a new typothere notoungulate, Hegetotherium cerdasensis, sp. nov., that can be distinguished by the absence of an external talonid sulcus on m3 and its small size (15–25% smaller than Hegetotherium mirabile). We refer several typothere specimens from Nazareno, Bolivia, to H. cerdasensis, which suggests that the two sites are of similar age. We report the first sparassodont and astrapothere remains from Cerdas. Sparassodont remains include an associated basicranium and mostly complete mandible; the species appears to represent a new, small-bodied borhyaenoid. Astrapothere remains consist of many tooth fragments from a new species of the subfamily Uruguaytheriinae. A partial sloth dentary from Cerdas likely pertains to the subfamily Megatheriinae and is the first report of the family Megatheriidae from the site. A newly discovered peltephilid armadillo specimen includes a partial articulated carapace that supports recognition of the Cerdas taxon as a new species. The two dasypodids of Cerdas (one Euphractini, one Eutatini) represent two new species closely related to undescribed species from the late middle Miocene (Serravallian age, Laventan SALMA) of Quebrada Honda, Bolivia. The mammals of Cerdas indicate that (1) the middle latitudes (southern tropics) contributed significantly to the diversity of Miocene mammal communities in South America; and (2) the Middle Miocene Climatic Optimum was a key factor in the differentiation of South American mammal assemblages.