A new didolodontid mammal from the late Paleocene–earliest Eocene of Laguna Umayo, Peru

A previously undescribed tooth from the Muani Formation at the Laguna Umayo locality, Peru, represents the new didolodontid Umayodus raimondi gen. et sp. nov., here diagnosed by the presence of a well developed metastylid and ectostylid, and a twinned hypoconulid. This taxon is closely related to the middle Paleocene genera Escribania and Raulvaccia from the locality of Punta Peligro in Patagonia, Argentina. Phylogenetic analysis here performed indicates that they constitute a monophyletic group within Didolodontidae, supported by five derived characters: the hypocone well developed and close to the protocone; the strongly concave precingulum; the contact between the postcristid and the entoconid; the contact of the crista pre-paraconular, precingulum and parastyle; and the mesiodistal enlargement of the m3 talonid. Their paleogeographic distribution fit with those of the actual Andean Region of the Austral Kingdom. The previously assumed ThanetianYpresian age assignment for the Laguna Umayo LU3 fauna is here reinforced by faunistic comparisons with the earliest Eocene Murgon fauna, in Australia, and the Itaboraian South American Land Mammal Age, represented from faunas of Patagonia, Argentina and So Jos de Itabora, Brazil.Facultad de Ciencias Naturales y Muse

The alleged astragalar remains of Didolodus Ameghino, 1897 (Mammalia, Panameriungulata) and a critic of isolated bone association models

Postcranial characters of South American native ungulates are important in order to analyze their relationships in the actual therian taxonomy, particularly to test their alleged afrotherian affinities. In this sense, the most primitive and oldest South American eutherians are represented by two endemic groups of "condylarths", the Kollpaniinae and Didolodontidae. These forms, characterized by lower crowned bunodont dentition, have never been found in direct association with their postcranial remains. Even though, several skeletal elements have been assigned to some of forms, following different assumptions and criteria. Two distinct astragalar remains (MACN-CA 10737 and AMNH 117457) have been referred to the genus Didolodus, one of the most common didolodontids from early and middle Eocene Patagonian outcrops. Here we describe in detail and illustrate these materials. A critical analysis is made of several regression equation models which have been used in other cases to associate by size isolated postcranial elements to taxa defined by teeth. A new model was formulated based on 19 modern bunodont mammals with directly associated skeletons in order to test the accuracy of the regression equations. Although the results of the equation models failed to accuratly assigned the isolated astragali to any of the Didolodus species, they can be used as a good tool to disprove the association hypothesis. A broad comparison with astragalar remains of South American native ungulates indicates that MACN-CA 10737 has notoungulate affinities, in contrast AMNH 117457 resembles the astragali assigned to didolodontids from São José de Itaboraí, Brazil, according to the models criticized here. The similitude is particularly due to the broad development of the cotylar fossa, a character proposed as an afrotherian synapomorphy, but probably developed independently in different groups. Improvement in knowledge regarding postcranial characters of the earliest South American native ungulates is necessary not only due to its importance in improving accuracy of phylogenetic relationships, but also for the inferences made on paleobiological features.Facultad de Ciencias Naturales y Muse

The alleged astragalar remains of Didolodus Ameghino, 1897 (Mammalia, Panameriungulata) and a critic of isolated bone association models

Postcranial characters of South American native ungulates are important in order to analyze their relationships in the actual therian taxonomy, particularly to test their alleged afrotherian affinities. In this sense, the most primitive and oldest South American eutherians are represented by two endemic groups of "condylarths", the Kollpaniinae and Didolodontidae. These forms, characterized by lower crowned bunodont dentition, have never been found in direct association with their postcranial remains. Even though, several skeletal elements have been assigned to some of forms, following different assumptions and criteria. Two distinct astragalar remains (MACN-CA 10737 and AMNH 117457) have been referred to the genus Didolodus, one of the most common didolodontids from early and middle Eocene Patagonian outcrops. Here we describe in detail and illustrate these materials. A critical analysis is made of several regression equation models which have been used in other cases to associate by size isolated postcranial elements to taxa defined by teeth. A new model was formulated based on 19 modern bunodont mammals with directly associated skeletons in order to test the accuracy of the regression equations. Although the results of the equation models failed to accuratly assigned the isolated astragali to any of the Didolodus species, they can be used as a good tool to disprove the association hypothesis. A broad comparison with astragalar remains of South American native ungulates indicates that MACN-CA 10737 has notoungulate affinities, in contrast AMNH 117457 resembles the astragali assigned to didolodontids from São José de Itaboraí, Brazil, according to the models criticized here. The similitude is particularly due to the broad development of the cotylar fossa, a character proposed as an afrotherian synapomorphy, but probably developed independently in different groups. Improvement in knowledge regarding postcranial characters of the earliest South American native ungulates is necessary not only due to its importance in improving accuracy of phylogenetic relationships, but also for the inferences made on paleobiological features.Facultad de Ciencias Naturales y Muse

Horned Armadillos and Rafting Monkeys. The Fascinating Fossil Mammals of South America. : Darin Croft. Ilustrated by Velizar Simeonovski. 2016, Format: cloth 320 pages, 197 color illus. Series: Life of the Past, Indiana University Press. ISBN: 978-0-253-02084-0

The paleobiological history of South America has long captivated amateurs and researchers. The book titled “Horned armadillos and rafting monkeys. The fascinating fossil mammals of South America” is not only a well-written volume on mammal paleontology, but a geographical and temporal journey to ancient South America. It is available in electronic and hardcover formats; indeed, those who also value books as objects should consider the plus of the nice Chinese manufacture of the printed edition. Its 320 pages are fully illustrated with photographs of paleontological localities and fossil specimens, as well as interesting reconstructions of extinct mammals by Velizar Simenovski. Reconstructions of mammals in paleontology are not always as daring as those of dinosaurs, so re-creations such as the two male Trigodon notoungulates engaged in fighting behavior during the mating season are very welcome.Facultad de Ciencias Naturales y Muse

Los Didolodontidae [Mammalia: Ungulatomporpha] del Terciario Sudamericano : Sistemática, origen y evolución

Tesis presentada para optar al Grado de Doctor en Ciencias NaturalesFil: Gelfo, Javier Nicolás. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo; Argentin

Ancient proteins resolve the evolutionary history of Darwin’s South American ungulates

No large group of recently extinct placental mammals remains as evolutionarily cryptic as the approximately 280 genera grouped as 'South American native ungulates'. To Charles Darwin, who first collected their remains, they included perhaps the 'strangest animal[s] ever discovered'. Today, much like 180 years ago, it is no clearer whether they had one origin or several, arose before or after the Cretaceous/Palaeogene transition 66.2 million years ago, or are more likely to belong with the elephants and sirenians of superorder Afrotheria than with the euungulates (cattle, horses, and allies) of superorder Laurasiatheria. Morphology-based analyses have proved unconvincing because convergences are pervasive among unrelated ungulate-like placentals. Approaches using ancient DNA have also been unsuccessful, probably because of rapid DNA degradation in semitropical and temperate deposits. Here we apply proteomic analysis to screen bone samples of the Late Quaternary South American native ungulate taxa Toxodon (Notoungulata) and Macrauchenia (Litopterna) for phylogenetically informative protein sequences. For each ungulate, we obtain approximately 90% direct sequence coverage of type I collagen α1- and α2-chains, representing approximately 900 of 1,140 amino-acid residues for each subunit. A phylogeny is estimated from an alignment of these fossil sequences with collagen (I) gene transcripts from available mammalian genomes or mass spectrometrically derived sequence data obtained for this study. The resulting consensus tree agrees well with recent higher-level mammalian phylogenies. Toxodon and Macrauchenia form a monophyletic group whose sister taxon is not Afrotheria or any of its constituent clades as recently claimed, but instead crown Perissodactyla (horses, tapirs, and rhinoceroses). These results are consistent with the origin of at least some South American native ungulates from 'condylarths', a paraphyletic assembly of archaic placentals. With ongoing improvements in instrumentation and analytical procedures, proteomics may produce a revolution in systematics such as that achieved by genomics, but with the possibility of reaching much further back in time.La lista completa de autores puede consultarse en el documento o en la página web de la revista.Facultad de Ciencias Naturales y Muse

Early steps in the radiation of notoungulate mammals in southern South America: A new henricosborniid from the Eocene of Patagonia

Here we describe a new notoungulate mammal from the early Eocene (Itaboraian SALMA) of Chubut, Argentinian Patagonia, from the localities of Las Flores and Las Violetas Farm, represented by fragments of maxilla and isolated teeth. The specimens were found in the Las Flores Formation, Río Chico Group, and assigned to the Henricosborniidae, a primitive family within the order Notoungulata. Orome deepi gen. et. sp. nov. differs from other henricosborniids in a less developed metacone column in the upper molars, a larger metaloph in the third upper molar and a larger mean size. The morphometric analysis does not show any difference between the individuals of the two studied localities. The new addition to the henricosborniid diversity in Patagonia allows to provide a better understanding of the early radiation of notoungulates in South America.Fil: Bauzá, Nicolás. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Departamento Científico de Paleontología de Vertebrados; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; ArgentinaFil: Gelfo, Javier Nicolás. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Departamento Científico de Paleontología de Vertebrados; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; ArgentinaFil: López, Guillermo Marcos. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Departamento Científico de Paleontología de Vertebrados; Argentin

A new didolodontid mammal from the late Paleocene–earliest Eocene of Laguna Umayo, Peru

A previously undescribed tooth from the Muani Formation at the Laguna Umayo locality, Peru, represents the new didolodontid Umayodus raimondi gen. et sp. nov., here diagnosed by the presence of a well developed metastylid and ectostylid, and a twinned hypoconulid. This taxon is closely related to the middle Paleocene genera Escribania and Raulvaccia from the locality of Punta Peligro in Patagonia, Argentina. Phylogenetic analysis here performed indicates that they constitute a monophyletic group within Didolodontidae, supported by five derived characters: the hypocone well developed and close to the protocone; the strongly concave precingulum; the contact between the postcristid and the entoconid; the contact of the crista pre-paraconular, precingulum and parastyle; and the mesiodistal enlargement of the m3 talonid. Their paleogeographic distribution fit with those of the actual Andean Region of the Austral Kingdom. The previously assumed ThanetianYpresian age assignment for the Laguna Umayo LU3 fauna is here reinforced by faunistic comparisons with the earliest Eocene Murgon fauna, in Australia, and the Itaboraian South American Land Mammal Age, represented from faunas of Patagonia, Argentina and So Jos de Itabora, Brazil.Facultad de Ciencias Naturales y Muse

Postcranial remains associations in paleogene native ungulates

Los ungulados nativos del Cenozoico de América del Sur se encuentran conformados por diversos grupos extintos, correspondientes según los autores a los ordenes Litopterna (incluyendo a los Notopterna), Notoungulata, Xenungulata, Astrapotheria (incluyendo a los Trigonostylop oidea) y Pyrotheria. A estos se suma la temprana radiación de “condilartros” representados p or los Mioclaenidae Kollpaniinae y los Didolodontidae, usualmente vinculados con el origen de estos grupos. Los d idolod óntidos (Paleoceno medio – Oligoceno?) han sido descriptos exclusivamente por restos dentales, no conociéndose postcráneo en asociación directa. Esto restringe el planteo de hipótesis filogenéticas al estudio de los caracteres dentales. Sin embargo, d iversos restos p ostcraneanos han sido asociados a los didolod óntidos. En el presente trabajo se realiza un análisis preliminar sobre (1) la morfología y la asignación de dos astrágalos izquierdos al género Didolodus (Eoceno de Patagonia), correspondientes a AMNH 117457 y MACN-CA 10737; y (2) se evalúa la utilidad de las herramientas utilizadas hasta el presente en el planteo de hipótesis de asociación de elementos postcraneales y dentarios.The native ungulates of the Cenozoic of South America included several extinct groups, that according to different authors belong to the orders Litopterna (including Noptoterna), Notoungulata, Xenungulata (including Trigonostylopoidea), Astrapotheria and Pyrotheria. To them is added an early radiation of “condylarths”, represented by the Mioclaenidae Kollpaniinae and the Didolodontidae, usually linked to the origin of these groups. The didolodontids (mid Pale ocene- Oligocene?) have been described exclusively by dental remains, without any postcranial elements directly associated. This constrains the phylogenetic hypothesis to the use of dental characters. However, postcranial remains have been referred to didolod ontids. In the present paper, we perform a prelim inary analysis of (1) the morphology and the assignation of two left astragali to the genus Didolodus (Patagonia E ocene) without any explicit criteria for association, corresponding to AMNH 117457 and MACN-CA 10737; and (2) we evaluated the utility of the tools used to make association hypothesis within dental and postcranial remains until the present.Sociedad de Ciencias Morfológicas de La Plat

Postcranial remains associations in paleogene native ungulates

Los ungulados nativos del Cenozoico de América del Sur se encuentran conformados por diversos grupos extintos, correspondientes según los autores a los ordenes Litopterna (incluyendo a los Notopterna), Notoungulata, Xenungulata, Astrapotheria (incluyendo a los Trigonostylop oidea) y Pyrotheria. A estos se suma la temprana radiación de “condilartros” representados p or los Mioclaenidae Kollpaniinae y los Didolodontidae, usualmente vinculados con el origen de estos grupos. Los d idolod óntidos (Paleoceno medio – Oligoceno?) han sido descriptos exclusivamente por restos dentales, no conociéndose postcráneo en asociación directa. Esto restringe el planteo de hipótesis filogenéticas al estudio de los caracteres dentales. Sin embargo, d iversos restos p ostcraneanos han sido asociados a los didolod óntidos. En el presente trabajo se realiza un análisis preliminar sobre (1) la morfología y la asignación de dos astrágalos izquierdos al género Didolodus (Eoceno de Patagonia), correspondientes a AMNH 117457 y MACN-CA 10737; y (2) se evalúa la utilidad de las herramientas utilizadas hasta el presente en el planteo de hipótesis de asociación de elementos postcraneales y dentarios.The native ungulates of the Cenozoic of South America included several extinct groups, that according to different authors belong to the orders Litopterna (including Noptoterna), Notoungulata, Xenungulata (including Trigonostylopoidea), Astrapotheria and Pyrotheria. To them is added an early radiation of “condylarths”, represented by the Mioclaenidae Kollpaniinae and the Didolodontidae, usually linked to the origin of these groups. The didolodontids (mid Pale ocene- Oligocene?) have been described exclusively by dental remains, without any postcranial elements directly associated. This constrains the phylogenetic hypothesis to the use of dental characters. However, postcranial remains have been referred to didolod ontids. In the present paper, we perform a prelim inary analysis of (1) the morphology and the assignation of two left astragali to the genus Didolodus (Patagonia E ocene) without any explicit criteria for association, corresponding to AMNH 117457 and MACN-CA 10737; and (2) we evaluated the utility of the tools used to make association hypothesis within dental and postcranial remains until the present.Sociedad de Ciencias Morfológicas de La Plat