Fossil Mammals Research Papers - Academia.edu (original) (raw)

2009 In L. B. Albright III (ed.), Papers on Geology, Vertebrate Paleontology, and Biostratigraphy in Honor of Michael O. Woodburne. Museum of Northern Arizona Bulletin 65, pp. 569-594. Flagstaff, Arizona. The mammalian faunal succession... more

2009
In L. B. Albright III (ed.), Papers on Geology, Vertebrate Paleontology, and Biostratigraphy in Honor of Michael O. Woodburne. Museum of Northern Arizona Bulletin 65, pp. 569-594. Flagstaff, Arizona.
The mammalian faunal succession in South America is well documented throughout the Eocene from about 47 to 37 Ma. Most Eocene land mammal-bearing deposits occur in Patagonia and in basins of the Antarctic Peninsula, and these have been studied intensely over the last 20 years. The geology of the San Jorge (eastern Patagonia), “Volcanic-Pyroclastic Complex” (western Patagonia), and James Ross (Antarctic Peninsula) basins are here reviewed and their faunal content analyzed. The geochronology of Itaboraian and Riochican South American Land Mammals Ages (SALMAs), usually regarded as late Paleocene, is also discussed. In order to evaluate the similarity between Eocene faunas, a cluster analysis applying the Simpson coefficient was performed using a data matrix with 13 faunas and 228 taxa. The faunas represent both classic and new localities from Antarctica, Patagonia, Mendoza, and central Chile, and we analyzed three taxonomic categories (genus, family, and order) so that faunas lacking common genera could be compared. The analysis supports at least three major clusters. The first, which consists of faunas from western Patagonia (the Paso del Sapo localities) plus Antarctica, seems to fall biochronologically between the Riochican and Casamayoran SALMAs. The second cluster is divided between faunas related to the Casamayoran and those related to the younger Mustersan SALMA. The latest Eocene-earliest Oligocene faunas also group together and are represented by three Tinguirirican faunas plus a fourth younger fauna which seems to be pre-Deseadan (Oligocene).

The Late Miocene continental successions of the Baccinello-Cinigiano basin (Grosseto), one of the longest and most continuous vertebrate-bearing continental successions in the Neogene Italian record, yielded at least four superimposed... more

The Late Miocene continental successions of the Baccinello-Cinigiano basin (Grosseto), one of the longest and most continuous vertebrate-bearing continental successions in the Neogene Italian record, yielded at least four superimposed vertebrate assemblages bracketed in the time span 8.3-6.4 Ma. The Baccinello-Cinigiano basin is famous for recording endemic vertebrate assemblages that include the youngest European Miocene hominoid, Oreopithecus bambolii. The late Miocene endemic vertebrate fauna known as the Baccinello V0 assemblage is the oldest vertebrate fauna within the Baccinello-Cinigiano basin succession, being correlated to the European mammal Neogene unit MN11. Recent field surveys along the Trasubbie river allowed studying in detail the basal Baccinello-Cinigiano sedimentary succession, and sampling fossiliferous level bearing microvertebrates along the small creek Fosso della Fittaia. The sample " Fosso della Fittaia 2013 " yielded about 170 fossil remains improving our documentation of the oldest vertebrate assemblages from the Baccinello-Cinigiano basin. As far as rodents are concerned, in addition to the already recognized murid Huerzelerimys and glirid Anthracoglis, a few dental remains are assigned to a new genus and species of giant dormouse. It is further worth noting the occurrence in the sample of shrew remains (the first described from the Baccinello-Cinigiano basin) identified as cf. Lartetium. The latter attests the presence of a crocidosoricine in the Fosso della Fittaia 2013 assemblage, postdating the youngest known occurrences of the subfamily by at least 1 my. The vertebrate assemblage is completed by a diverse herpetofauna and the first fish remains reported from the basin.

El Gran Intercambio Biótico Americano (GIBA) (Marshall et al., 1984; Stehli y Webb, 1985) es uno de los mayores eventos biogeográficos que han modelado la composición de la fauna moderna en las Américas. Este término se refiere al proceso... more

El Gran Intercambio Biótico Americano (GIBA) (Marshall et al., 1984; Stehli y Webb, 1985) es uno de los mayores eventos biogeográficos que han modelado la composición de la fauna moderna en las Américas. Este término se refiere al proceso de migración de faunas continentales entre Norte y Sudamérica, particularmente durante el Neógeno tardío y Cuaternario. Originalmente considerado como un evento relativamente rápido ocurrido a inicios del Pleistoceno, actualmente se considera como un proceso complejo que involucró múltiples oleadas de migraciones en ambas direcciones iniciadas durante el Mioceno (Cione et al., 2007). Este proceso se aceleró significativamente tras la formación del Istmo de Panamá hacia fines del Plioceno, creando una conexión permanente entre ambos continentes y terminando con el aislamiento Sudamericano. Este capítulo tiene por finalidad ofrecer una breve introducción actualizada a los procesos biogeográficos que modelaron la fauna Sudamericana, con énfasis en el origen de las fauna que habitaba el continente previo al GIBA. Dada la naturaleza sintética del presente texto, solo se ofrecen referencias esenciales y en lo posible recientes a modo de ejemplo, y no deben considerarse como una revisión exhaustiva en la temática.

Los hallazgos realizados en las dos y media últimas décadas de numerosas localidades a lo largo del territorio chileno con abundantes y variados restos fósiles de mamíferos terrestres cenozoicos, pre-pelistocénicos, han constituido una... more

Los hallazgos realizados en las dos y media últimas décadas de numerosas localidades a lo largo del territorio chileno con abundantes y variados restos fósiles de mamíferos terrestres cenozoicos, pre-pelistocénicos, han constituido una revolución para el conocimiento de la fauna sudamericana en esta región andina. La fauna recuperada cubre un rango de edad de, al menos, 30 millones de años (entre ~40 y ~10 millones de años atrás) y un rango latitudinal cercano a 30º (entre el Altiplano y la Patagonia) y constituye uno de los más completos e importantes archivos de la evolución de los mamíferos en el continente. Estos hallazgos han tenido importantes implicancias para establecer con bastante precisión comprender la historia evolutiva de los mamíferos sudamericanos y la evolución geológica (tectónica América del Sur y la escasez de estudios anteriores en territorio chileno, la mayor parte de las formas fósiles encontradas corresponden a especies nuevas para la ciencia. La importancia que revisten estos hallazgos se hace más palpable aún si se considera que hasta mediados del siglo pasado sólo se tenía conocimiento en el país de un solo sitio con mamíferos fósiles terciarios, cual es el río Frías (río Cisnes), en Aysén. Las regiones fosilíferas corresponden, de Norte a Sur, a: 1. Precordillera de Arica-Iquique (localidad de Caragua), 2. Cordillera Occidental de Arica-Iquique (localidad de Chucal), 3. Franja costera de la región de Caldera, 4. Cordillera Principal de Chile central (entre las hoyas superiores de los ríos Maipo y Bio-Bío), 5. Sector del río Cisnes (o Frías), Región de Aysén, 6. Meseta Guadal-Cosmelli, Región de Aysén, y 7. Región de Magallanes, en diversos sectores. Los estratos fosilíferos de cada una de estas regiones y localidades, a excepción de Bahía Inglesa, que corresponde a un ambiente litoral, se depositaron en cuencas formadas en ambientes terrestres, localmente con desarrollo de lagos y asociadas con actividad volcánica. Estas cuencas estuvieron controladas por la actividad de fallas (en en ambientes geológicos tectónicamente activos, pero de naturaleza diferente. En este estudio se hace especial énfasis en las regiones 1, 2 y 4, mencionadas, donde las investigaciones interdisciplinarias estos ambientes. Se enumeran las formas fósiles recolectadas y se destaca sus implicancias geológicas, evolutivas y paleoambientales.

Se ofrece una extensa revisión bibliográfica y hemerográfica de los trabajos paleontológicos realizados en el Valle de Puebla desde principios del siglo xx hasta la actualidad. Se hace especial énfasis en los estudios efectuados por el... more

Se ofrece una extensa revisión bibliográfica y hemerográfica de los trabajos paleontológicos realizados en el Valle de Puebla desde principios del siglo xx hasta la actualidad. Se hace especial énfasis en los estudios efectuados por el Proyecto Valsequillo y la Fundación Alemana para la Investigación Científica, dado que estos aportaron las mayores contribuciones al conocimiento de la paleontología del Valle de Puebla. Además, se proporcionan datos inéditos sobre las exploraciones que dieron origen a la colección paleontológica del extinto Museo de Historia Natural de Puebla y se comenta sobre el inicio de las investigaciones actuales y su perspectiva hacia el futuro.

MAMMALS AND STRATIGRAPHY FROM THE NEOGENE OF URUGUAY. Knowledge on the Uruguayan Neogene deposits is updated. These deposits are distributed along the southern coast of the country, and outcrop mainly in the departmentos of Colonia and... more

MAMMALS AND STRATIGRAPHY FROM THE NEOGENE OF URUGUAY. Knowledge on the Uruguayan Neogene deposits is updated. These deposits are distributed along the southern coast of the country, and outcrop mainly in the departmentos of Colonia and San José. An updated list of the mammals is given including new records and some stratigraphic reallocations. The Camacho Formation, of clearly marine and marginal origins, is at least in part correlated with the Paraná Formation of Argentina, and contains important mastofaunistic representatives that are in common with the “Conglomerado osífero” of the Ituzaingó Formation and other beds of the Huayquerian Stage (Late Miocene). The Raigón Formation, of fluvial and in part marginal origins, overlies the former, and contains a mammal assemblage representing a wide temporal range, from Pliocene to middle Pleistocene. Both units represent a sequence beginning with the entrance of the “Mar Entrerriense”, its later retraction and associated phenomena: rivers, deltas, and origins of the estuary today named “Río de la Plata”.

Until recently, few well-described rodent faunae from the Whitneyan North American Land Mammal Age [NALMA] were known, hindering studies of rodent diversity, biogeography, and evolutionary patterns during the Oligocene. This study... more

Until recently, few well-described rodent faunae from the Whitneyan North American Land Mammal Age [NALMA] were known, hindering studies of rodent diversity, biogeography, and evolutionary patterns during the Oligocene. This study describes a new Whitneyan rodent assemblage from the Obritsch Ranch paleontological locality in the Little Badlands region of North Dakota. Specimens were collected from three stratigraphi-cally restricted sampling intervals within the middle to upper Brule Formation, resulting in the recognition of fourteen rodent species, five of which are elsewhere known to first appear in Whitneyan faunae. Described is one new species, the eomyid Paradjidaumo obritschorum, and the first cranial material of the heteromyid rodent Proharrymys Korth and Branciforte, 2007. The rodent fauna from the upper two sampling intervals at Obritsch Ranch and the uppermost fauna recently described from the nearby Fitterer Ranch paleontological locality share four taxa in common with the late Whitneyan Blue Ash local fauna from southwestern South Dakota, indicating these two North Dakota rodent faunae are also from the late Whitneyan. Increasing knowledge of Whitneyan rodent faunae in North America reveals unusually high survivorship of rodent species from the older Orellan NALMA into the Whitneyan NALMA and much geographic variation in the diversity, distribution, and relative abundance of different rodent families between individual Whitneyan rodent faunae. Those factors help explain prior difficulties in differentiating Orellan and Whitneyan rodent faunae and in identifying biostratigraphically useful rodent taxa for the Whitneyan. Overall, Whitneyan rodent faunae from North America display an increase in the diversity of aplodontiids, cricetids, and sciurids and a decrease in eomyid and ischyromyid diversity relative to the Orellan.

For most of the past 200 years, knowledge of South American fossil mammals was derived largely from Argentine lowland, high-latitude sites. The continent’s mammalian record, therefore, was not only highly skewed geographically, but it... more

For most of the past 200 years, knowledge of South American fossil mammals was derived largely from Argentine lowland, high-latitude sites. The continent’s mammalian record, therefore, was not only highly skewed geographically, but it also contained several impor- tant temporal gaps. A few dramatic faunal changes were traditionally seen as punctuating an otherwise steady series of evolutionary and environmental transitions (G. G. Simpson’s “Three-Stratum” concept). There is growing evidence, however, that the actual pattern is far more complex, with Cenozoic mammal faunas responding to biogeographic, climatic, tectonic, sea level, ecologic, and environmental changes. Data from previously unsampled regions have clari ed regional and continental patterns of faunal change. Notable Tertiary mammal faunas uncovered in the Andes in recent decades include: Tiupampa (early Paleo- cene, Bolivia); several from central Chile (Eocene-middle Miocene); Salla and Moquegua (early Oligocene, Bolivia); others from diverse sites in Bolivia (Miocene-Pliocene); two from Chilean Patagonia and Altiplano (early Miocene); and La Venta (middle Miocene, Colom- bia). In contrast to many lowland temperate sequences, Andean faunas are often precisely dated because of associated volcanics. Here we review the late Mesozoic to middle Cenozoic mammal record, including: (1) new Andean faunas (and other key assemblages); (2) major taxonomic groups of South American mammals (early nontribosphenic and nontherian forms, as well as Cenozoic monotremes, marsupials, xenarthrans, the endemic “ungulates” [basal forms plus Xenungulata, Astrapotheria, Pyrotheria, Litopterna, and Notoungulata], platyrrhine primates, and caviomorph rodents); and (3) their broad continental paleoen- vironmental context. In addition we discuss biogeographic, paleoenvironmental, and tec- tonic implications of early to middle Cenozoic Andean mammal faunas, emphasizing new assemblages across the length of Chile, including a series of midlatitude sites spanning considerable time (Eocene to mid-Miocene) and space (more than 5° of latitude). For ex- ample, the ∼31.5 Ma Tinguiririca Fauna, representing a new South American Land Mam- mal Age, contains the oldest known caviomorph rodents and provides the earliest global evidence of open grassland habitats. Evidence from the Tinguirirican caviomorphs and the 20.1 Ma platyrrhine primate Chilecebus support African origins for these immigrant clades.

The South American porcupines (Erethizontidae) are included in two genera: Chaetomys and Coendou. The latter is a very speciose taxon, with about 13 living species. During at least the late Plioceneeearly Pleistocene, erethizontids... more

The South American porcupines (Erethizontidae) are included in two genera: Chaetomys and Coendou. The latter is a very speciose taxon, with about 13 living species. During at least the late Plioceneeearly Pleistocene, erethizontids immigrated to Central and North America during the Great American Biotic Interchange. Although some Pleistocene fossils have been reported, the Quaternary history of this clade is still understudied. The only known extinct species is Coendou magnus. In this work, a fossil of a porcupine is reported from an Upper Pleistocene fluvial sedimentary sequence cropping out in the Northern Pampa geomorphological region, Santa Fe Province, Argentina. Despite this group having different living forms widely distributed in South American Neotropical woodland habitats, the Pleistocene occurrences of Erethizontidae are scarce and limited to Upper Pleistocene deposits from Bolivia, Brazil, and Uruguay. Currently, the specimen here reported represents the only Pleistocene porcupine from Argentina with a stratigraphical context. The morphological characters as well as the dimensions indicate that it is close to the Pleistocene erethizontid Coendou magnus. In this context, the presence of this erethizontid in such a southern locality, together with other taxa recorded from this site and the associated geological and paleoenvironmental evidence, indicates subtropical conditions, compared with the current conditions, which may have allowed a southern displacement of taxa more related to woodlands and xeric subtropical environments.

A succession of marine and continental strata on the southern flank of Cerro Cono in the Sierra Baguales, northeast of Torres del Paine, can be correlated with stratigraphic units exposed along the southern border of the Lago Argentino... more

A succession of marine and continental strata on the southern flank of Cerro Cono in the Sierra Baguales, northeast of Torres del Paine, can be correlated with stratigraphic units exposed along the southern border of the Lago Argentino region in Santa Cruz Province, Argentina. These include the Estancia 25 de Mayo Formation and the basal part of the Santa Cruz Formation. The lithological correlation is also confirmed by detrital zircon ages (maximum age of 18.23±0.26 Ma) and a rich assemblage of terrestrial vertebrate fossils, biostratigraphically equivalent to a post-Colhuehuapian, pre-Santacrucian South American Land Mammal Age (SALMA) fauna, suggesting a range of 19 to 17.8 Ma. Similar ages have been obtained from the basal part of the Santa Cruz Formation at Estancia Quién Sabe in southwestern Argentina, supporting the assumption of a regional continuity between these deposits. A measured lithostratigraphic column is presented and the depositional environment is interpreted as a coastal plain with small, meandering rivers and ephemeral floodplain lakes. The sedimentation coincides with intensified uplift of the Patagonian Andes during the ‘Quechua Phase’ of Andean tectonism, which is reflected by a change in paleocurrent directions from northwest to east-northeast.

The Neogene ichnofauna from San Juan de los Lagos, Jalisco State, north-central Mexico, is one of the most interesting episodes of the history of vertebrate paleoichnology in Mexico, since its first mention at the end of the XIX Century.... more

The Neogene ichnofauna from San Juan de los Lagos, Jalisco State, north-central Mexico, is one of the most interesting
episodes of the history of vertebrate paleoichnology in Mexico, since its first mention at the end of the XIX Century. It includes
four avian morphotypes, a camelid (Lamaichnum macropodum), a proboscidian (Orden Proboscidipedida), and the tracks of
a felid that constitute a new ichnotaxon named Mitsupes dugesii ichnogen. et ichnosp. nov. These felid tracks are medium to
large in size; these bear a conspicuous interdigital pad, it is asymmetrical in outline, being sub-triangular to reniform. Hands
are stronger impressed in the sediment than the feet impressions, this condition suggests a heavier anterior portion of the
felid body; in this way it is assumed that the track producer was a member of the Subfamily Machairodontinae, probably
a member of the Tribe Homotherinii. The ichnotaxonomical diversity of this track-site is moderate and in accordance with
other late Cenozoic ichnofaunas in North America, that preserve abundant bird and mammal tracks.

We describe Galadi speciosus, gen. et sp nov., the second peramelemorphian (Yarala burchfieldi being the first) to be described from Oligo-Miocene deposits of Riversleigh World Heritage Property, northwestern Queensland. G. speciosus is... more

We describe Galadi speciosus, gen. et sp nov., the second peramelemorphian (Yarala burchfieldi being the
first) to be described from Oligo-Miocene deposits of Riversleigh World Heritage Property, northwestern Queensland. G.
speciosus is represented by relatively complete craniodental material, including an exceptionally well-preserved skull. This
taxon exhibits several apomorphies that clearly place it in the order Peramelemorphia, but it appears to be more plesiomorphic
than any modern bandicoot. We present the first morphological phylogenetic analyses of Peramelemorphia, using 51
craniodental characters. Our analyses recover Yarala and Galadi speciosus outside crown group Peramelemorphia, with G.
speciosus weakly supported as the sister taxon of the crown group. The craniodental morphology of G. speciosus, particularly
its robust skull and proportionately short and broad snout, suggests that it filled a different ecological niche to extant bandicoots.
We hypothesize that G. speciosus occupied a predominantly faunivorous, dasyurid-like niche in the Oligo-Miocene
rainforests of Riversleigh, at a time when dasyurids appear to have been relatively rare.

The Chaco Region is the third biogeographic and morpho-structural territory of South America after the Amazon and Cerrado savannahs. This region is one of the few areas in the world where the transition from the tropics to temperate zones... more

The Chaco Region is the third biogeographic and morpho-structural territory of South America after the Amazon and Cerrado savannahs. This region is one of the few areas in the world where the transition from the tropics to temperate zones does not consist of a desert but of semi-arid woodlands and savannahs. The modern biodiversity patterns of the region were severely affected by the climatic and environmental changes that occurred during the Quaternary. Remains of an extinct megamammal Neosclerocalyptus sp. (Upper Pleistocene) and charred fossil woods inside of sedimentary nodules, was recently discovered in Chaco Argentina. The aim of paper is the paleoenvironmental reconstruction of quaternary sedimentation in the western Chaco through the taxonomic identification of charred woods and siliceous microfossils analysis. Twenty-three charcoal fragments related to Anacardiaceae, Apocynaceae, Fabaceae, Rhamnaceae and Malvaceae were identified. The phytolith analysis showed that Poaceae elements were the most abundant compared to the other herbaceous and non-herbaceous elements, along with algae and sponge microfossils. Eco-anatomic features of the charcoals and the microfossil remains suggest that environment and climate conditions existed in the area during the Upper Pleistocene were similar to the current one. Finally, the results reveal the presence of natural wildfires during the Quaternary in the region.

Examined was a larger block of fossil bones containing marlstone found near Zidani Most in Zasavje area, central Slovenia. After examination of fossil remains it was found that bones and teeth are parts of skeleton of a smaller-sized... more

Examined was a larger block of fossil bones containing marlstone found near Zidani Most in Zasavje area, central
Slovenia. After examination of fossil remains it was found
that bones and teeth are parts of skeleton of a smaller-sized
aquatic mammal, of a toothed whale. The shape and size of
bones and teeth are indicative of a smaller dolphin, most
probably of species ?Champsodelphis karreri Brandt, 1873.

La región austral de Sudamérica ha experimentado importantes cambios geobióticos a lo largo del Cenozoico. El registro de mamíferos fósiles ha sido clave para inferir parte de estos cambios, a partir de las investigaciones desarrolladas... more

La región austral de Sudamérica ha experimentado importantes cambios geobióticos a lo largo del Cenozoico. El registro de mamíferos fósiles ha sido clave para inferir parte de estos cambios, a partir de las investigaciones desarrolladas en Argentina desde finales del siglo XIX. En Chile los reportes han sido esporádicos y de carácter casual, limitando el conocimiento de los ecosistemas patagónicos nacionales. Investigaciones realizadas por nuestro equipo y otras expediciones asociadas durante los últimos 5 años, han permitido descubrir nuevos afloramientos, reestudiar localidades históricas, caracterizar cientos de fósiles y generar un marco geocronológico robusto. Un único registro Paleógeno incluye restos fragmentarios de Isotemnidae indet., colectados en paleosuelos del Eoceno medio en el Río Oscuro, Aysén. Durante el Mioceno temprano, producto del alzamiento de los Andes australes, se genera la deposición masiva de unidades sedimentarias de origen fluvial, altamente fosilíferas. Cientos de restos colectados entre los 19 y 17 Ma., en las zonas de Puerto Guadal y Chile Chico, Aysén, y en diversas localidades de Magallanes, muestran una riqueza específica intermedia, asociada a ambientes cálidos y forestados. Durante el Mioceno medio (14.8 Ma) la fauna del Alto Río Cisnes confirma la persistencia en Patagonia de linajes mayormente tropicales/subtropicales, como los primates, eretizóntidos, equíimidos y dasipróctidos. La flora contemporánea sin embargo está dominada por elementos comunes a los bosques de Nothofagus del centro-sur de Chile. Las unidades fosilíferas más tardías incluyen estratos de la Edad Mamífero Mayoense (Mioceno medio tardío, 12.3 Ma) ubicados al sur de Balmaceda, donde la reactivación de los depósitos sedimentarios post-alzamiento Andino evidencian nuevos cambios ambientales. A partir del análisis taxonómico y ecomorfológico de las distintas especies se comienza a delinear un nuevo escenario biogeográfico, caracterizado por un marcado provincialismo en la fauna patagónica neógena, con algunos quiebres latitudinales y longitudinales aún insuficientemente caracterizados y/o delimitados.

The holotype of the nothrotherid Nothropus carcaranensis Bordas, 1942 is a partial dentary from the Pleistocene of Santa Fe Province (Argentina) associated with other isolated bones (see Bordas, 1942; Brandoni & McDonald, 2015), including... more

The holotype of the nothrotherid Nothropus carcaranensis Bordas, 1942 is a partial dentary from the Pleistocene of Santa Fe Province (Argentina) associated with other isolated bones (see Bordas, 1942; Brandoni & McDonald, 2015), including an isolated braincase and has been considered the cotype of N. carcaranensis in the original publication
of Bordas (1942, 174–175). This contribution provides, for the first time, a detailed anatomical description of the braincase assigned to Nothropus carcaranensis, as well as a discussion about its original assignment.

1. Observed patterns in the fossil record reflect not just macroevolutionary dynamics, but preservation patterns. Sampling rates themselves vary not simply over time or among major taxonomic groups, but within time intervals over... more

1. Observed patterns in the fossil record reflect not just macroevolutionary dynamics, but preservation patterns. Sampling rates themselves vary not simply over time or among major taxonomic groups, but within time intervals over geography and environment, and among species within clades. Large databases of presences of taxa in fossil-bearing collections allow us to quantify variation in per-collection sampling rates among species within a clade. We do this separately not just for different time/stratigraphic intervals, but also for different geographic or ecologic units within time/stratigraphic intervals. We then re-assess per-million-year sampling rates given the distributions of per-collection sampling rates
2. We use simple distribution models (geometric and lognormal) to assess general models of per-locality sampling rate distributions given occurrences among appropriate fossiliferous localities. We break these down not simply by time period, but by general biogeographic units in order to accommodate variation over space as well as among species.
3. We apply these methods to occurrence data for Meso-Cenozoic mammals drawn from the Paleobiology Database and the New and Old Worlds fossil mammal database. We find that all models of distributed rates do vastly better than the best uniform sampling rates and that the lognormal in particular does an excellent job of summarizing sampling rates. We also show that the lognormal distributions vary fairly substantially among biogeographic units of the same age.
4. As an example of the utility of these rates, we assess the most likely divergence times for basal (Eocene–Oligocene) carnivoramorphan mammals from North America and Eurasia using both stratigraphic and morphological data. The results allow for unsampled taxa or unsampled portions of sampled lineages to be in either continent and also allow for the variation in sampling rates among species. We contrast five models using stratigraphic likelihoods in different ways to summarize how they might affect macroevolutionary inferences.

The docodontan mammal Docodonhas been found to be relatively common in the Morrison Formation of the Black Hills. This genus has now been found at seven quarries in the Morrison Formation, and it is often the most abundant single genus at... more

The docodontan mammal Docodonhas been found to be relatively common in the Morrison Formation of the Black Hills. This genus has now been found at seven quarries in the Morrison Formation, and it is often the most abundant single genus at sites from which it is known; it is also the most abundant single genus of mammal known from the Morrison Formation overall and is the largest in terms of body mass. The apparent restriction of Docodon
to sites in the eastern halves of Wyoming and Colorado may reflect a real paleobiogeographic pattern resulting from habitat preference.

Recent (2006–2009) excavations at the Palaeolithic site from La Adam Cave (central Dobrogea, south-eastern Romania) yielded numerous fossil remains, that were analysed in order to obtain more information on the Late Pleistocene faunal... more

Recent (2006–2009) excavations at the Palaeolithic site from La Adam Cave (central Dobrogea, south-eastern Romania) yielded numerous fossil remains, that were analysed in order to obtain more information on the Late Pleistocene faunal assemblage from the area of the cave, on the animal and anthropic contributions to bone accumulation in the cave, and on the taphonomic processes present at the site. The faunal remains analysed were highly fragmented, which prevented the precise taxonomic assessment for most of them. However, numerous specimens bear signs of chemical corrosion and carnivore bite marks, only a few showing signs of anthropic activity. The cave seems to have functioned as shelter for the carnivores, with cave bear remains dominating numerically. Other large carnivores, such as cave hyenas, most probably also contributed to bone accumulation, with large and middle-sized ruminants being their most common prey.

Remains of Bison (Eobison) sp. from Salcia and Ursoaia, and Bison cf. menneri from Cimichioi-III and Hadjimus are briefly described and discussed. The paper also proposes an overview of most important Early Pleistocene bison findings from... more

Remains of Bison (Eobison) sp. from Salcia and Ursoaia, and Bison cf. menneri from Cimichioi-III and Hadjimus are briefly described and discussed. The paper also proposes an overview of most important Early Pleistocene bison findings from Eastern and Southern Europe and a discussion of their taxonomy and paleobiogeography.

Described are bone remains of a smaller sized dolphin found end of 2014 in younger Middle Miocene – Sarmatian siltstones in excavation for the hydroelectric station Brežice. Recognized were remains of anterior extremities, vertebral... more

Described are bone remains of a smaller sized dolphin
found end of 2014 in younger Middle Miocene – Sarmatian
siltstones in excavation for the hydroelectric station Brežice.
Recognized were remains of anterior extremities, vertebral
column and thorax. All bones belong to the same individual
of Champsodelphis fuchsii Brandt, 1873.

The description of an I3 assigned to Arctotherium sp. obtained from the Baño Nuevo-1 site (Central Patagonia, Chile) is presented. The finding was recovered from Layer 5 and it is associated to Macrauchenia sp., Lama guanicoe, Felidae,... more

The description of an I3 assigned to Arctotherium sp. obtained from the Baño Nuevo-1 site (Central Patagonia, Chile) is presented. The finding was recovered from Layer 5 and it is associated to Macrauchenia sp., Lama guanicoe, Felidae, Camelidae, Equidae and Mylodontidae, within a sterile deposit of cultural material, dated between ca. 13.500 and 11.200 BP. Despite the fact that it is only a single specimen, such finding extends the known distribution for the genus in Chile.

"Haitian species of the extinct ground sloth genus Neocnus (Mammalia: Pilosa: Megalonychidae) have previously been hypothesized to have a much reduced jugal bone and a correspondingly reduced masseter musculature but a paucity of... more

"Haitian species of the extinct ground sloth genus Neocnus (Mammalia: Pilosa: Megalonychidae) have previously been hypothesized to have a much reduced jugal bone and a correspondingly reduced masseter musculature but a paucity of specimens has prevented further investigation of this hypothesis. Recent discovery of jugal bones belonging to Haitian specimens of Neocnus within the University of Florida Museum
collections enables the element to be more accurately described. The discovery also makes it possible to explore mastication in these sloths. Osteological characters related to feeding were examined, along with comparative estimations of bite force with the extant tree sloths, Bradypus and Choloepus, and their known dietary habits as a means to infer aspects of the paleodiet of Neocnus. There is a significant difference in moment arm calculations for m. masseter between predicted and actual jugals, but the overall significance for bite force is lost
and hampered by small sample size. Neocnus demonstrates a variety of characters that are similar to those of Bradypus and not to Choloepus, which is a close phylogenetic relative. The masticatory musculature of Neocnus enabled a chewing cycle emphasizing a grinding combination of mesiodistal and linguobuccal movements of the molariform dentition. The orientations of m. masseter and m. temporalis are estimated to produce relatively high bite force ratios that imply a masticatory system with stronger versus faster components. Because of the
similarity of bite forces and jaw mechanics to those of Bradypus, in addition to a number of osteological adaptations indicative of herbivorous grazers (elevated mandibular condyle, large and complex masseter, and robust angular process), the Haitian forms of Neocnus are considered to have been selective feeders with a folivorous
diet."

The past geographic distribution of the genus Theropithecus Primates: Cercopithecidae) is mainly restricted to Africa. Outside that continent, the earliest reported records of this genus consist of a calcaneus of cf. Theropithecus sp.... more

The past geographic distribution of the genus Theropithecus Primates: Cercopithecidae) is mainly restricted to Africa. Outside that continent, the earliest reported records of this genus consist of a calcaneus of cf. Theropithecus sp. from ‘Ubeidiya (Israel, 1.6e1.2 Ma [millions of years ago]), as well as three associated cervical vertebrae from Pirro Nord (Italy, 1.7-1.3 Ma) attributed to Theropithecus sp. The attribution of the Pirro Nord vertebrae to this genus has been disputed on morphometric grounds, although their assignment to a large-bodied cercopithecid has remained undisputed. Here we report unpublished cervical vertebral specimens with a similar morphology and, given their significance for the paleobiogeography of Theropithecus (purportedly representing its earliest European record), we reevaluate their taxonomic attribution. In particular, we reconsider the possibility that they belong to another non-primate mammal recorded at this site. Based on both qualitative and metric morphological comparisons, we strongly favor an alternative attribution of the cervical vertebrae from Pirro Nord to the large porcupine Hystrix refossa, which is widely documented at the site by both dentognathic and other postcranial remains. We therefore conclude that the dispersal of Theropithecus out of Africa before ca. 1 Ma (when it is recorded by dental remains from Cueva Victoria, Spain) is currently based only on the calcaneus from ‘Ubeidiya tentatively attributed to this genus.

"Understanding the paleoecology of extinct xenarthrans, such as ground sloths, is complicated because they lack living analogues. Previous studies have applied functional morphology and biomechanical analyses to reconstruct the diet and... more

"Understanding the paleoecology of extinct xenarthrans, such as ground sloths, is complicated because they lack living analogues. Previous studies have applied functional morphology and biomechanical analyses to reconstruct the diet and lifestyle of ground sloths, yet the application of dental microwear as a proxy for feeding ecology in extinct xenarthrans remains understudied.
Here, we hypothesize that dental microwear patterns are statistically different among extinct ground sloths, thereby providing new evidence of feeding ecology in these animals. In a blind study, the dental microwear patterns in three extinct taxa representing two clades [Megalonyx wheatleyi and Acratocnus odontrigonus in Megalonychidae, Thinobadistes segnis in Mylodontidae] were quantitatively analyzed using scanning electron microscopy at 5003 magnification. Two independent observers recovered similar relative trends in microwear patterns between M. wheatleyi, A. odontrigonus, and T. segnis, with mean number of scratches and feature width being the most informative variables among taxa. Microwear patterns in M. wheatleyi correspond most closely with living selective xenarthran herbivores (i.e., Bradypus), with a low number of scratches but a high feature width. T. segnis, in contrast, has an unusually high number of scratches but low feature width, which is unlike any patterns exhibited by living xenarthrans and indicates possible grazing habits. A. odontrigonus falls between these two extremes, which we interpret as a more generalized browser, similar to Choloepus. Microwear patterns among living and extinct sloths sampled to date seem to fall along a continuum of herbivorous feeding strategies, with grazing and selective browsing representing the two extremes. Although we only examine three taxa, our results (stemming from a blind analysis that accounts for observer error) support the feasibility of using high-magnification dental microwear to examine feeding ecology in extinct ground sloths."

The Physeteridae family is one of the basal branches in odontocete cetaceans. At the present, it is only represented by three species belonging to the genus Physeter and Kogia, although it includes numerous extinct genera as Scaldicetus.... more

The Physeteridae family is one of the basal branches in odontocete cetaceans. At the present, it is only represented by three species belonging to the genus Physeter and Kogia, although it includes numerous extinct genera as Scaldicetus. From a systematic point of view, Scaldicetus is one of the most common and problematic group of the extinct subfamily Hoplocetinae during the Neogene. It is considered a polyphyletic genus and its taxonomic use has been relegated to the identification of isolated teeth. Two dental pieces identified as Scaldicetus found in two late Miocene units of the western sector of the Guadalquivir Basin (south of Spain) have been analyzed in this work. The sedimentological and palaeontological analysis of the facies indicates littoral to open marine environments with profuse potential preys for Scaldicetus. The morphological characteristics and the heterogeneous palaeobiogeographic and ecological distribution

Paleontological and archaeological sites have frequently been found in open locations of the Intermediate Depression of south-central Chile. This paper presents the results of two field sampling seasons carried out at the Pilauco Site... more

Paleontological and archaeological sites have frequently been found in open locations of the Intermediate Depression of south-central Chile. This paper presents the results of two field sampling seasons carried out at the Pilauco Site (ca. 39°S) and compares them with those of three well known sites in Chile: Quereo, Tagua-Tagua and Monte Verde, ca. 32°, 34° and 41°S, respectively. Stratigraphic data collected at Pilauco and the resulting radiocarbon age model suggest that before 12,540 ± 90 BP the old Damas River eroded an older volcaniclastic hill, which was followed by a bog formation in an ox-bow lake. The site was developing up to 11,004 ± 186 BP, the date of the youngest vertebrate fossil. Two younger peat beds seal the site. As in Tagua-Tagua and Monte Verde, Gomphotheres are the most represented megafauna. Fossils of Equidae, Camelidae, Cervidae, Mephitidae, Muridae, Myocastoridae and Xenarthra are also found in Pilauco. As a whole, 718 bones, 30 teeth and 11 coprolites represent the extinct and extant vertebrates. Preliminary taphonomic results suggest action of various agents in the bones, i.e. trampling, root etching, abrasion, and carnivore gnawing. The spatial analysis suggests the transfer of smaller anatomical units (e.g. bones of camelids and horses) and the rearrangement of some pieces comparatively large (e.g. gomphothere bones). Similar to the present day north Patagonian landscape, the area where Pilauco site is located had a variety of animal resources, plants and stones in an ecotone between hills, floodplains and wetlands. A total of 101 lithics were recorded: basalt and quartzite were collected from nearby fluvial deposits and dacitic obsidian from the local volcaniclastic deposits. Debitage is the most represented lithic item (75%); cores and marginal edge-trimmed artifacts represented 12 and 13%, respectively. Artifacts and flakes are spatially and temporality associated in the same PB-7 bed with high bone concentrations in some specific areas, between 361 and 424 cm of local altitude. This industry is characterized by a recurrent lithic expedite technology with production of flakes and chips which mastered marginal retouches over the bifacial trimming. This seems to be connected to strategic conditions of high resource diversity, especially of human groups with a high or medium mobility across land. Pilauco represents a site contemporaneous to Monte Verde related as well to the first human occupation in the southern cone of South America, but with higher mammal diversity.

This paper reports the newly collected fossil of the brown bear (Ursus arctos) found from the Fuji-do cave, Ueno Village, Tano County, Gunma Prefecture. The cave is known as one of the largest caves for tourism in the Kanto region. The... more

This paper reports the newly collected fossil of the brown bear (Ursus arctos) found from the Fuji-do cave, Ueno Village, Tano County, Gunma Prefecture. The cave is known as one of the largest caves for tourism in the Kanto region. The fossil was collected during the earth removal work of a newly found pathway of the southeastern part of the cave in 1992. The specimen (Fuji-do cave specimen) is a portion of left scapula buried in the cave deposit. The deposit is composed of limestone rubbles that are cemented by calcareous sinter (travertine) with porous structure. The age of the specimen is presumably Late Pleistocene. Based on some morphological characteristics (spine of scapula with linear outline, acromion with proximal expansion, arrangement between lateral margin of glenoid cavity and the spine, and the size), the specimen is identified into Ursus arctos. The living brown bear do not naturally inhabit the Japanese archipelago except on the Island of Hokkaido. Brown bear fossil...

We present the first reported occurrence of canid coprolites from the late Pleistocene of central Mexico. The sample consists of five associated coprolites recovered from Quaternary deposits that crop out in southeastern Hidalgo, central... more

We present the first reported occurrence of canid coprolites from the late Pleistocene of central Mexico. The sample consists of five associated coprolites recovered from Quaternary deposits that crop out in southeastern Hidalgo, central Mexico. The material shows several of the typical features of canid feces, including elongated cylindrical shape, uncommon and nondistinct constrictions, and one tapered end. The coprolites are similar in size to feces of North American foxes, such as Vulpes macrotis, V. lagopus, V. vulpes, and Urocyon cinereoargenteus; likewise, their size might be comparable to those of the Pleistocene canid Canis cedazoensis. The content of the studied coprolites consists of numerous teeth and bone fragments referable to the pocket gophers Pappogeomys or Cratogeomys. The coprolite content is related to a mostly carnivorous diet comparable to that of C. cedazoensis, wolves (Canis lupus, C. rufus, and C. dirus), and some foxes (V. macrotis and V. velox). As a result, it is proposed that the potential trace maker of the coprolites could be a form similar to a carnivorous fox or a small dog. These trace fossils represent the first indirect evidence of canids in the late Pleistocene of Hidalgo and provide additional information regarding the geographic distribution of the Canidae in temperate areas of North America that now are part of central Mexico during the second half of the Pleistocene.

We describe Galadi speciosus, gen. et sp nov., the second peramelemorphian (Yarala burchfieldi being the first) to be described from Oligo-Miocene deposits of Riversleigh World Heritage Property, northwestern Queensland. G. speciosus is... more

We describe Galadi speciosus, gen. et sp nov., the second peramelemorphian (Yarala burchfieldi being the first) to be described from Oligo-Miocene deposits of Riversleigh World Heritage Property, northwestern Queensland. G. speciosus is represented by relatively complete craniodental material, including an exceptionally well-preserved skull. This taxon exhibits several apomorphies that clearly place it in the order Peramelemorphia, but it appears to be more plesiomorphic than any modern bandicoot. We present the first morphological phylogenetic analyses of Peramelemorphia, using 51 craniodental characters. Our analyses recover Yarala and Galadi speciosus outside crown group Peramelemorphia, with G. speciosus weakly supported as the sister taxon of the crown group. The craniodental morphology of G. speciosus, particularly its robust skull and proportionately short and broad snout, suggests that it filled a different ecological niche to extant bandicoots. We hypothesize that G. speciosus occupied a predominantly faunivorous, dasyurid-like niche in the Oligo-Miocene rainforests of Riversleigh, at a time when dasyurids appear to have been relatively rare.

Se da a conocer un nuevo representante de la familia Oldfieldthomasiidae del Noroeste Argentino, Dolichostylodon saltensis gen. et sp. nov. Sus restos provienen de afloramientos de la Formación Lumbrera, situados por encima la “Faja Verde... more

Se da a conocer un nuevo representante de la familia Oldfieldthomasiidae del Noroeste Argentino,
Dolichostylodon saltensis gen. et sp. nov. Sus restos provienen de afloramientos de la Formación Lumbrera, situados
por encima la “Faja Verde II”, en El Simbolar, Departamento Guachipas, provincia de Salta.
Dolichostylodon saltensis está definido por una serie de caracteres tales como: dentición superior decidua y permanente
similar a Ultrapithecus rutilans Ameghino, 1901, pero dP más triangulares, con paracono más prominente,
sin foseta mesiolabial y metalofo del dP3 bien desarrollado. Molares superiores con parastilo y metastilo
prominentes. Columna del metacono más amplia que en Colbertia lumbrerense Bond, 1981. Foseta mesiolabial
ausente, foseta distolabial relativamente amplia y somera. Crochet bien desarrollado y curvado, rodeando
a la foseta distolabial. Cíngulo distal amplio. Hipocono pequeño en relación al protocono. Surco labial
poco marcado. Molares inferiores con entocónido expandido y poco diferenciado del hipoconúlido, y con un
surco reducido entre ambos. Valle del talónido más profundo que en C. lumbrerense. Este hallazgo constituye
la segunda especie de Oldfieldthomasiidae para esta formación y la tercera para el Noroeste Argentino. Otros
restos asignados a Oldfieldthomasiidae han sido reportados para Antofagasta de la Sierra pero fueron referidos
al género Colbertia Paula Couto, 1952. La especie muestra afinidades morfológicas con Ultrapithecus rutilans,
del “Barranquense” (Casamayorense) de Patagonia. Dolichostylodon saltensis parece tener mayor relación
con las formas patagónicas que con las especies extrapatagónicas de Oldfieldthomasiidae, a pesar de su grado
de braquiodoncia relativamente mayor.

Fossils of the raccoon dog (genus Nyctereutes) are particularly rare in the African Plio-Pleistocene record, whilst the sole living representative, Nyctereutes procyonoides, is found in eastern Asia and parts of Europe. In southern... more

Fossils of the raccoon dog (genus Nyctereutes) are particularly rare in the African Plio-Pleistocene record, whilst the sole living representative, Nyctereutes procyonoides, is found in eastern Asia and parts of Europe. In southern Africa, only one fossil species of raccoon dog has been identified – Nyctereutes terblanchei. N. terblanchei is recognised from a handful of Plio-Pleistocene sites in South Africa: Kromdraai, Kromdraai–Coopers and Sterkfontein in Gauteng, as well as Elandsfontein in the Western Cape Province. The validity of this species identification was questioned on the basis of the rarity of southern African fossils assigned to Nyctereutes, that is, fewer than 10 specimens have been identified as Nyctereutes. This study examined this fossil sample of the raccoon dog from the Gauteng sites and compared dental and cranial metrics of the fossil with samples of modern canids and published data. Morphological traits used to distinguish Nyctereutes, such as the pronounced subangular lobe on the mandible and the relatively large size of the lower molars, were observed to be variable in all samples. Analysis showed that the size of the dentition of the southern African fossil samples was larger than that of living raccoon dogs, but fell well within the range of that of African jackals. These results suggest that fossil Nyctereutes cannot be distinguished from other canid species based on metric data alone, and may only be diagnosable using combinations of non-metric traits of the dentition and skull. However, based on the degree of morphological variability of the traits used to diagnose Nyctereutes, as well as the rarity of this genus in the African fossil record, these fossils are more likely to belong to a species of jackal or fox.

How Mammals Grew in Size Mammals diversified greatly after the end-Cretaceous extinction, which eliminated the dominant land animals (dinosaurs). Smith et al. (p. 1216 ) examined how the maximum size of mammals increased during their... more

How Mammals Grew in Size Mammals diversified greatly after the end-Cretaceous extinction, which eliminated the dominant land animals (dinosaurs). Smith et al. (p. 1216 ) examined how the maximum size of mammals increased during their radiation in each continent. Overall, mammal size increased rapidly, then leveled off after about 25 million years. This pattern holds true on most of the continents—even though data are sparse for South America—and implies that mammals grew to fill available niches before other environmental and biological limits took hold.