Mammals

A higher-level MRP supertree of placental mammals

by Andy Purvis

Latent extinction risk and the future battlegrounds of mammal conservation

by Andy Purvis

Multiple Causes of High Extinction Risk in Large Mammal Species

by Andy Purvis

Nonrandom Extinction and the Loss of Evolutionary History

by Andy Purvis

Predicting extinction risk in declining species

by Andy Purvis

The even darker side of the eastern gray squirrel (Sciurus carolinensis): a review of global introductions, invasion biology, and pest management strategies

by Cody Thompson

Karyotype designation and habitat description of the northern short-tailed shrew (Blarina brevicauda, Say) from the type locality

by Cody Thompson

RBP3 IN GEOMYID RODENTS: REDUCED RATE OF MOLECULAR EVOLUTION OR EVIDENCE FOR SELECTION?

by Cody Thompson

Identification and characterization of the contact zone between short-tailed shrews (Blarina) in Iowa and Missouri

by Cody Thompson

Blarina hylophaga (Soricomorpha: Soricidae)

by Cody Thompson

Mitochondrial genomes reveal an explosive radiation of extinct and extant bears near the Miocene-Pliocene boundary.

by Sergios-Orestis Kolokotronis

BMC Evolutionary Biology

A new stratigraphic profile of Punta Hermengo (Buenos Aires Province, Argentina). Magnetostratigraphy and biostratigraphy

by Esteban Soibelzon

Soibelzon E., Tonni, E.P., Bidegain, JC.

Small mammal carbon isotope ecology across the Miocene–Pliocene boundary, northwestern Argentina

by José Luis Prado

Hynek S.A., B.H. Passey, J.L. Prado, F.H. Brown, T.E. Cerling & J. Quade. 2012. Small mammal carbon isotope ecology across the Miocene-Pliocene boundary, northwestern Argentina. Earth and Planetary Science Letters (321-322) 177–188.

The late Miocene expansion of plants using the C4 photosynthetic pathway in South America has been documented
by... more The late Miocene expansion of plants using the C4 photosynthetic pathway in South America has been documented
by tooth enamel carbon isotope ratios (δ13Cen). However, a more detailed understanding of this ecological event is hampered by poor chronological control on the widespread fossil localities from which isotopic data are derived. This study develops a δ13Cen record from a single 2500 m-thick stratigraphic section in subtropical South America. Strata at Puerta de Corral Quemado (PCQ), northwestern Argentina, span 9 to 3.5 Ma in age, and existing paleosol carbonate data (δ13Cpc) document C4 expansion across the Miocene–Pliocene
boundary. Comparison of δ13Cen data with δ13Cpc data at high stratigraphic resolution refines understanding of this ecological event in South America. Small mammal δ13Cen data in particular are complementary to that of large mammal and paleosol δ13C data. Small mammal teeth integrate isotopic data over much shorter temporal and spatial scales than large mammal teeth, providing a sensitive measure of local vegetation and placing constraints on the landscape distribution of C3 and C4 plants. Explicit consideration of the distinctive carbon isotope enrichment factor between enamel and diet for rodents (ε*en–
diet=11‰, as opposed to 14‰ for large mammals) allows for unequivocal inference of C4 vegetation ~1 Ma prior to that inferred from large mammal δ13Cen data, and ~2 Ma prior to δ13Cpc data. This multiproxy record demonstrates that C4 plants were a stable component of the ecosystem hundreds of thousands of years prior to their major ecological expansion, and that the expansion of C4 plants was pulsed at PCQ. Two periods of ecological change are demonstrated by δ13C and δ18O data at ~7 Ma and 5.3 Ma (coincident with the Miocene–Pliocene boundary). Development of small mammal δ13Cen records on other continents may provide similar insight into the early stages of the global C4 event.

The extinction of Equidae and Proboscidea in South America. A test using Carbon isotope data.

by José Luis Prado

Prado J.L., M.T. Alberdi, B. Sánchez & G. Gómez. 2011. The extinction of Equidae and Proboscidea in South America. A test using Carbon isotope data. Estudios Geológicos [online], doi: 10.3989/egeol.40422

Carbon isotopes, preserved in 166 samples of fossil teeth and bone, provide key data for understanding the ecology of... more Carbon isotopes, preserved in 166 samples of fossil teeth and bone, provide key data for understanding the ecology of extinct horses and gomphotheres during the Plio-Pleistocene in South America. To analyze the patterns of dietary partitioning throughout this time we divided the samples into 19 groups,
taking into account the genus and the age of the corresponding localities. In this study, the diets of both groups are assessed to test extinction hypotheses. The strong resource partitioning among herbivores assumed under Co-evolutionary disequilibrium hypothesis is supported by isotopic data of horses from latest Pleistocene. Hippidon and Equus had very different diets. In contrast, species of gomphotheres from late Pleistocene in South America seem to have had less specialized diets containing a broad mix of both C3 and C4 plants, which is in line with the dietary assumptions of the mosaic-nutrient hypothesis, but does not support the assumptions of Co-evolutionary disequilibrium hypothesis.

Cerro Bombero: registro de Hippidion saldiasi Roth, 1899 (Equidae, Perissodactyla) en el Holoceno temprano de Patagonia (Santa Cruz, Argentina).

by José Luis Prado

Paunero, R.S.; Rosales, G.; Prado, J.L.; Alberdi, M.T. 2008. Cerro Bombero: registro de Hippidion saldiasi Roth, 1899 (Equidae, Perissodactyla) en el Holoceno temprano de Patagonia (Santa Cruz, Argentina). Estudios Geológicos, 64 (1): 89-98.

A new record of Hippidion saldiasi with new radiocarbon data referred to early Holocene (8,850 ± 80 year C-14 B.P) of... more A new record of Hippidion saldiasi with new radiocarbon data referred to early Holocene (8,850 ± 80 year C-14 B.P) of Patagonia is reported. Both its peculiar geographic location in a scarcely prospected zone and its radiocarbon age, provide new elements to discuss the previous hypotheses about the
extinction of the horses and its relations with the human beings that inhabited the different environments of South America.

Stegomastodon platensis (Proboscidea, Gomphotheriidae) en el Pleistoceno de Santiago del Estero, Argentina

by José Luis Prado

Alberdi, M.T., E. Cerdeño y J.L. Prado. 2008. Stegomastodon platensis (Proboscidea, Gomphotheriidae) en el Pleistoceno de Santiago del Estero, Argentina. Ameghiniana, 45 (2): 257-271.

Mammal fossil remains from Santiago del Estero Province (Argentina) are very poorly known. In this paper, best... more Mammal fossil remains from Santiago del Estero Province (Argentina) are very poorly known. In this paper, best preserved specimens of Gomphotheriidae (Mammalia, Proboscidea) are
presented. They come from Quaternary beds outcropping along the Río Dulce, near of the city of Santiago del Estero. The comparative study with other South American gomphotheres remains, mainly from Argentina and Brazil, allow their identification as Stegomastodon platensis, being among the largest forms of this species. Previous studies referred this locality to the late Pleistocene. Enamel tooth sample was dated
to 19.900 ± 120 BP by AMS 14C, supporting that age for this fauna. Carbon and oxygen isotopic composition of the tooth enamel has been analyzed to get new data on the paleodiet and habitat preference of South American gomphotheres. Carbon isotopic values indicate an adaptation to an exclusively C4 diet.
The oxygen isotopic analysis indicates cooler climatic conditions than present.

Stegomastodon waringi (Mammalia, Proboscidea) from the Late Pleistocene of northeastern Uruguay

by José Luis Prado

Alberdi, M.T., J.L. Prado, D. Perea and M. Ubilla. 2007. Stegomastodon waringi (Mammalia, Proboscidea) from the late Pleistocene of Northeastern Uruguay. Neues Jahrbuch für Geologie und Paläontologie. Abh. 243 (2) 179-189.

Fossil remains belonging to Proboscidea from the Cerro Largo Department (northeastern Uruguay), are described and... more Fossil remains belonging to Proboscidea from the Cerro Largo Department (northeastern Uruguay), are described and taxonomically identified in this work. We compared these remains with those of Stegomastodon warring and Stegomastodon platensis from several localíties in Brazil and Argentina using Discriminant Analysis. Based on general morphology and the resuIts of muItivariate analyses we considered this specimen as Stegomastodon waringi (HOLLAND, 1920), which along with previous reports significantly expand the southem geographic distribution of this gomphothere species in South America.

Mamíferos continentales del Mioceno tardío a la actualidad en la Argentina: cincuenta años de estudios.

by José Luis Prado

Cione, A.; E. Tonni; S. Bargo; M. Bond; A. Candela; A. Carlini; C. Deschamps; M. Dozo; G, Esteban; F. Goin; C. Montalvo; N. Nasif; J. Noriega; E. Ortiz Jaureguizar; R. Pascual; J. Prado; M. Reguero; G. Scillato-Yane; L. Soibelson; D. Verzi; E. Vieytes; S. Vizcaino y M. Vucetich. 2007. Mamíferos continentales del Mioceno tardío a la actualidad en la Argentina: cincuenta años de estudios. Asociación Paleontológica Argentina. Publicación Especial 11, Ameghiniana 50º aniversario: 257-278.

Ameghiniana was created 50 years ago. During this lapse, the late Cenozoic paleomastozoology developed exponentially... more Ameghiniana was created 50 years ago. During this lapse, the late Cenozoic paleomastozoology developed exponentially in Argentina. Many of the papers dealed with systematics. However, fossil mammals were also used for establish the chronological scale based on a biostratigraphic sequence of faunas mainly from the Pampean area. This scale proved valid for other South American areas. Besides, mammals were used
as proxies for understanding the continental climatic evolution and, at the same time, biogeographic studies flourished. In recent years, many paleoecological and morphofunctional studies were carried out. Certainly, the last 50 years were the most productive time in Argentina since the pioneering work of
Florentino Ameghino.

Ancient feeding, ecology and extinction of Pleistocene horses from the Pampean Region, Argentina

by José Luis Prado

Sánchez, B., J.L. Prado and M.T. Alberdi. 2006. Ancient feeding, ecology and extinction of Pleistocene horses from the Pampean Region, Argentina. Ameghiniana, 43 (2): 427-436.

To reconstruct the diet and habitat preference of fossil horses, we measured the carbon and oxygen isotope composition... more To reconstruct the diet and habitat preference of fossil horses, we measured the carbon and oxygen isotope composition of 35 bone and tooth samples of Equus (Amerhippus) neogeus Lund, Hippidion principale (Lund), and Hippidion devillei (Gervais) from 10 different Pleistocene localities in the Pampean region (Argentina). To compare the three species by stratigraphic age, we divided the samples into three groups: lower Pleistocene, middle-late Pleistocene and latest Pleistocene. Samples of Hippidion devillei from the lower Pleistocene were more homogeneous, with δ13C values ranging between -11.73 to -9.79‰. These data indicate a diet exclusively dominated by C3 plants. In contrast, Hippidion principale and Equus (Amerhippus) neogeus from middle-late Pleistocene showed a wide range of feeding adaptations (with a range of δ13C values between -12.05 to -8.08 ‰ in Hippidion and δ13C values between -11.46 to -7.21 ‰ in Equus (Amerhippus)). These data seem to indicate a mixed C3 - C4 diet, while data from the latest Pleistocene suggest a tendency toward an exclusively C3 diet for both species. Furthermore, the results of δ18O indicate an increase of approximately 4ºC from the early to latest Pleistocene in this area. Several nutritional hypotheses explaining latest Pleistocene extinctions are based on the assumption that extinct taxa had specialized diets. The resource partitioning preference of these species from latest Pleistocene in the Pampean region supports these hypotheses.

Late Pleistocene Stegomastodon (Mammalia, Proboscidea) from Uruguay

by José Luis Prado

Gutiérrez G., M. T. Alberdi, J.P. Prado and D. Perea. 2005. Late Pleistocene Stegomastodon (Mammalia, Proboscidea) from Uruguay. Neues Jahrbuch für Geologie und Paläontologie, Mh. (11) 641-662

Fossil Proboscidea remains from the Dolores Formation, Montevideo, Uruguay, are described and taxonomically... more Fossil Proboscidea remains from the Dolores Formation, Montevideo, Uruguay, are described and taxonomically identified. We compared these remains with those of
Stegomastodon waringi and Stegomastodon platensis from several localities in Brazil and Argentina using multivariate analysis. The results indicate that Stegomastodon waringi
(HOLLAND, 1920) is represented in the quarry. Enamel tooth sample of gomphothere wasdated to 17,620 :!: 100 BP by AMS 14C so we confirm the late Pleistocene age for this fauna. To reconstruct the paleodiet and habitat preference we measured the carbon and oxygen isotope composition of the teeth dentine. Of the two different adaptations attributed to Stegomastodon waringi, we found that at this latitude they were mixed-C3 feeders, closely related with the Brazil population.