Mammalian Record Research Articles

The Miocene mammal record of the Vallès-Penedès Basin (Catalonia)

The land mammal record of the Vallès-Penedès Basin (Catalonia, NE Spain) ranges from the early Miocene (Ramblian) to the late Miocene (Turolian), that is from about 20 to 7Ma. Here we present an updated review of the mammal succession focusing on biochronology as well as on environmental and faunal changes. Based on faunal similarities with central Europe, we interpret this basin as a transitional zone between the forested environments of northern regions and the more arid landscapes of the inner Iberian Peninsula. The quality of the Vallès-Penedès record and its chronostratigraphic control is clearly better for the late Aragonian and the Vallesian (between 12.6–9.0Ma), especially for small mammals. Therefore, we analyze small mammal diversity dynamics during this interval. Contrary to previous analyses, which found an abrupt extinction event coinciding with the early/late Vallesian boundary (the Vallesian Crisis), our results show that this pattern is due to uneven sampling. Instead, taxonomic richness slowly decreased since the late Vallesian as a result of a series of extinctions that mostly affected forest-dwelling taxa.

Cold-climate rodent indicators for the Late Pleistocene of Central Iberia: New data from the Buena Pinta Cave (Pinilla del Valle, Madrid Region, Spain)

In the Iberian Peninsula, the Late Pleistocene record of small mammal indicators of cold climates is largely restricted to two sets of sites at the eastern and western ends of the Pyrenees. Some assemblages from other sites at the Peninsular centre have, however, recently yielded such taxa. This work describes the remains of three such rodent species from the Buena Pinta Cave, a site in the Sierra de Guadarrama mountains in the Spanish Central System. Excavation campaigns in the cave have taken place every summer since 2003. Thermoluminescence analyses of sediments from levels 2–5 of the site suggest an age corresponding to the middle of the Late Pleistocene, within Marine Isotope Stage 4 or the beginning of Marine Isotope Stage 3. Sieve-washing and picking out of the small fossils contained in the sediments of levels 2–5 yielded several thousand small mammal teeth and other remains, dominated by Microtus arvalis. Smaller numbers of remains belonging to other rodents typical of cold climates were also identified, such as Microtus oeconomus, Microtus gregalis and Chionomys nivalis. Thus, the small mammal record of the Buena Pinta Cave shows that rodent indicators of cold climates reached the centre of the Iberian Peninsula during the mid-Late Pleistocene, i.e., well before the Last Glacial Maximum. These findings represent one of the southernmost Pleistocene records for M. oeconomus in Europe, and the most southerly for M. gregalis.

Continuous evolutionary change in Plio-Pleistocene mammals of eastern Africa

Much debate has revolved around the question of whether the mode of evolutionary and ecological turnover in the fossil record of African mammals was continuous or pulsed, and the degree to which faunal turnover tracked changes in global climate. Here, we assembled and analyzed large specimen databases of the fossil record of eastern African Bovidae (antelopes) and Turkana Basin large mammals. Our results indicate that speciation and extinction proceeded continuously throughout the Pliocene and Pleistocene, as did increases in the relative abundance of arid-adapted bovids, and in bovid body mass. Species durations were similar among clades with different ecological attributes. Occupancy patterns were unimodal, with long and nearly symmetrical origination and extinction phases. A single origination pulse may be present at 2.0-1.75 Ma, but besides this, there is no evidence that evolutionary or ecological changes in the eastern African record tracked rapid, 100,000-y-scale changes in global climate. Rather, eastern African large mammal evolution tracked global or regional climatic trends at long (million year) time scales, while local, basin-scale changes (e.g., tectonic or hydrographic) and biotic interactions ruled at shorter timescales.

New data on Early Pleistocene vertebrates from Monte Argentario (Central Italy). Paleoecological and biochronological implications

A first record of non-mammalian remains and small mammals from the Early Pleistocene of Monte Argentario (Central Italy) is reported herein, together with paleoecological and biochronological remarks based on the whole fossil assemblage. This site is known since the 1950s mostly for large mammal remains. So far, the known taxa collected from this site comprise mainly large mammals with few birds and reptiles. Recent fieldworks in this locality led to the recognition of a small mammal assemblage that consists of twelve taxa, including Talpa cf. T. fossilis, Sorex cf. S. minutus, Petenyia hungarica, Asoriculus gibberodon, Oryctolagus cf. O. valdarnensis, Eliomys cf. E. intermedius, Glis sackdillingensis, Microtus (Allophaiomys) cf. M. (A.) ruffoi, Victoriamys chalinei, Apodemus (Sylvaemus) sylvaticus, Apodemus (S.) flavicollis, Apodemus (S.) gr. sylvaticus-flavicollis, and Apodemus (Karstomys) gr. mystacinus-epimelas. An updated description of amphibians, squamates and birds is also provided. Following the chronological data derived from the large and small mammals, the vertebrate assemblage of Monte Argentario can be referred to the Early Pleistocene, Early Biharian, corresponding to the Farneta and Pirro Faunal Units of the Italian biochronological scheme. In addition, the data presented herein support the hypothesis of a biochronological equivalence of these two Italian Faunal Units.

Revised timing of the South American early Paleogene land mammal ages

A new Ar/Ar date on the Las Flores Tuff (Río Chico Group, Las Flores Fm., central Patagonia, Argentina) yielded an age of 49.512 ± 0.019 Ma. This tuff, which stratigraphically overlies the mammal-bearing deposits that produced the Las Flores fauna, helps constrain the age of the Itaboraian SALMA [South American Land Mammal Age] to which that fauna is referred. The new data also have implications for the age of succeeding mammal biochrons, such as the Riochican and “Sapoan” which are revised to being somewhat younger than previously interpreted. Although closer in age than formerly interpreted, they still are biotically distinct. Concomitant evaluations suggest that the Itaboraian SALMA is perhaps more contemporary with the EECO (Early Eocene Climatic Optimum) than previously considered. The Riochican may be interpreted as post-EECO, with its cooler climate consistent in that regard. A recent reconsideration of the chronology of elements of the Salamanca Formation resulted in the downward revision of the ages of the Peligran SALMA and the Carodnia Zone biochrons. These operations, together with our results, reflect a 9 m.y. gap in the late Paleocene and early Eocene land mammal record in South America.

Molecular Genetic Evidence for the Place of Origin of the Pacific Rat, Rattus exulans

Commensal plants and animals have long been used to track human migrations, with Rattus exulans (the Pacific rat) a common organism for reconstructing Polynesian dispersal in the Pacific. However, with no knowledge of the homeland of R. exulans, the place of origin of this human-commensal relationship is unknown. We conducted a mitochondrial DNA phylogeographic survey of R. exulans diversity across the potential natural range in mainland and Island Southeast Asia in order to establish the origin of this human-commensal dyad. We also conducted allozyme electrophoresis on samples from ISEA to obtain a perspective on patterns of genetic diversity in this critical region. Finally, we compared molecular genetic evidence with knowledge of prehistoric rodent faunas in mainland and ISEA. We find that ISEA populations of R. exulans contain the highest mtDNA lineage diversity including significant haplotype diversity not represented elsewhere in the species range. Within ISEA, the island of Flores in the Lesser Sunda group contains the highest diversity in ISEA (across all loci) and also has a deep fossil record of small mammals that appears to include R. exulans. Therefore, in addition to Flores harboring unusual diversity in the form of Homo floresiensis, dwarfed stegodons and giant rats, this island appears to be the homeland of R. exulans.

Palaeocene-Eocene evolution of beta diversity among ungulate mammals in North America

Aim The Palaeocene–late Eocene transition in North America marks a critical interval in the evolution and diversification of land mammals, including adaptive radiation in the Palaeocene, and repeated waves of immigration over habitat bridges at the Palaeocene–Eocene boundary. We investigate the fossil record of ungulate mammals over this period to understand the effects of immigration and faunal exchange on local (alpha), regional (gamma) and between-site (beta) diversity. Location North America. Methods We use Palaeocene and Eocene records of North American ungulate mammals taken from the Paleobiology Database (PBDB), and calculate beta diversity among families and genera within the seven stages of the Cenozoic. We reconstruct geographic ranges sizes for studied taxa, and test trends in these ranges against null models used to control for sampling biases. Finally, we use Mantel tests to quantify the relationship between geographic distance and faunal dissimilarity within each time slice, in order to visualize changes in the spatial complexity of mammal communities. Results Gamma diversity increases over the studied interval, with varying contributions from alpha and beta diversity. Beta diversity increases from the Palaeocene to Eocene, reflected in decreasing range size and increased correlation between reconstructed distance and faunal similarity. Increase in beta diversity over the Palaeocene–Eocene transition is driven by smaller geographic ranges among putatively invasive ‘immigrant’ and secondarily endemic taxa; range contraction among these groups in the middle–late Eocene leads to a Bartonian peak in beta diversity. Main conclusions High gamma diversity in the Eocene was driven by high beta diversity rather than alpha diversity, indicating that range contraction in both immigrant and secondarily endemic taxa restructured the spatial organization of mammal communities. These parallel trends suggest that factors such as tectonic uplift or climate change were responsible, as opposed to ecological differences. Increase in beta diversity over the Palaeocene–Eocene boundary suggests that over longer time-scales, mass immigration events can lead to greater overall richness and greater heterogeneity, rather than homogeneity, within regional assemblages.

New Records of Eutherian Mammals from the Goler Formation (Tiffanian, Paleocene) of California and Their Biostratigraphic and Paleobiogeographic Implications

ABSTRACT The Goler Formation is the only rock unit on the West Coast of North America that has yielded a diverse assemblage of Paleocene vertebrates. Intense prospecting of strata representing member 4 of the formation over the past two decades has resulted in recovery of over 70 specimens of eutherian mammals, representing 18 species. All specimens were recovered from member 4a and the lower part of member 4b, except an isolated tooth referred to Phenacodus cf. P. vortmani from member 4d in the uppermost part of the formation. Three taxa are new, the plesiadapid, Nannodectes lynasi, and two hyopsodontid condylarths, Promioclaenus walshi and Protoselene ashtoni. Also present are four species of Phenacodus, two species of Protictis, and single species representing Goleroconus, Mimotricentes, Lambertocyon, Ignacius, Paromomys, Bessoecetor, Thryptacodon, Dissacus, and a taeniodont. The mammalian fauna from member 4a and the lower part of member 4b is collectively referred to as the Goler Assemblage because t...

The fossil record and macroevolutionary history of North American ungulate mammals: standardizing variation in intensity and geography of sampling

The record of the taxonomic evolution of North American ungulates is critical to our understanding of mammalian evolution and environmental change throughout the Cenozoic. The distribution of sampling in the ungulate fossil record over time and geographic space and the degree to which this biases the observed patterns of taxonomic evolution is poorly understood. To address these issues, I placed fossil collections and occurrences drawn from the Paleobiology Database into 2-Myr time intervals between 55 and 1 Ma. I determined the variation in numbers of fossil collections and occurrences, using three metrics to measure geographic variation: first, the area of the convex hull containing all collections in an interval, to determine the areal coverage of sampling; second, the mean pairwise geographic distance among collections as a measurement of the dispersion of collections within that area; and third, the interval-to-interval migration of the geographic centroid of all collections, to calculate changes in the geographic location of sampling. Each of these showed considerable variation over the Cenozoic, and both the area of the convex hull (ACH) encompassing all collections in an interval, and mean pairwise distance (MPWD) among them showed increasing trends over time.To minimize the effect of variation in numbers of fossil samples over time, I used standard sample-standardization procedures. To minimize the effect of geographic variation in sampling over time, I standardized the area of sampling among intervals. I also employed both standardizations sequentially. Each standardization procedure had surprisingly little effect on observed patterns of taxonomic richness and rates. This indicates that, for North American ungulates, neither variation in number nor geographic distribution of fossil samples exerts an overwhelming influence on perceived macroevolutionary patterns. These results confirm the ungulate fossil record as a critical and faithful record for our understanding of Cenozoic environmental change and the mammalian evolutionary response.

THE EARLY DIVERSIFICATION HISTORY OF DIDELPHID MARSUPIALS: A WINDOW INTO SOUTH AMERICA'S “SPLENDID ISOLATION”

The geological record of South American mammals is spatially biased because productive fossil sites are concentrated at high latitudes. As a result, the history of mammalian diversification in Amazonia and other tropical biomes is largely unknown. Here we report diversification analyses based on a time-calibrated molecular phylogeny of opossums (Didelphidae), a species-rich clade of mostly tropical marsupials descended from a Late Oligocene common ancestor. Optimizations of habitat and geography on this phylogeny suggest that (1) basal didelphid lineages inhabited South American moist forests; (2) didelphids did not diversify in dry-forest habitats until the Late Miocene; and (3) most didelphid lineages did not enter North America until the Pliocene. We also summarize evidence for an Early- to Middle-Miocene mass extinction event, for which alternative causal explanations are discussed. To the best of our knowledge, this study provides the first published molecular-phylogenetic evidence for mass extinction in any animal clade, and it is the first time that evidence for such an event (in any plant or animal taxon) has been tested for statistical significance. Potentially falsifying observations that could help discriminate between the proposed alternative explanations for didelphid mass extinction may be obtainable from diversification analyses of other sympatric mammalian groups.

New eutherian mammals from the Late Cretaceous of Aix-en-Provence Basin, south-eastern France

In Europe, the fossil record of Late Cretaceous eutherian mammals is very poor, being limited to only three genera (Labes, Lainodon, and Valentinella). Labes and Lainodon are well-supported members of Zhelestidae, a stem eutherian clade, whereas Valentinella is more problematic, being recently considered as a nomen dubium. Based on X-ray computed microtomography scan analysis of the holotype and thanks to the discovery of new specimens from the type locality (Vitrolles-La Plaine, south-eastern France, late Maastrichtian), we reassessed Valentinella. This genus is unique by the association of an enlarged and rounded jaw angle with an assumed relatively elevated angular process, a bulbous protoconid and an unbasined heel on p4, a p5 with a wide molariform talonid and a hypoflexid, a robust molar morphology with a potential specialized crushing-grinding function (bulbously constructed cusps, large talonid, and horizontal apical wear facet of the hypocone), a somewhat reduced m3 relative to m2, a premolariform ?P3 or ?P4 lacking a metacone, and a relatively large hypocone on upper molars. These characters reinstate Valentinella as a valid genus. We also describe Mistralestes arcensis gen. et sp. nov. from a newly discovered locality (La Cairanne-Highway, south-eastern France, late Campanian). Mistralestes is defined by a robust premolariform p5 with no cingulid, paraconid, or metaconid; molars with a transverse protocristid, a gradual compression of the trigonid from m1 to m3, and paracristid and protocristid probably confluent on m3. Based on comparisons and phylogenetic analyses, Valentinella and Mistralestes may belong to Zhelestidae but this systematic attribution remains poorly supported. © 2013 The Linnean Society of London

Species composition of the Late Cretaceous eutherian mammalParanyctoidesFox

Although the known record of Mesozoic eutherian mammals has been significantly enriched in recent years, early eutherian evolution is still not well understood. Among the more controversial of Mesozoic eutherians is Paranyctoides Fox, which was described in 1979 from the Judithian Dinosaur Park Formation, Alberta, Canada. It is a rare taxon and therefore has been identified in only a few other North American Late Cretaceous local faunas since. Within the past decade, dental and gnathic remains discovered in Central Asia have also been referred to Paranyctoides, thereby expanding the geographic range of the genus substantially and making it the only Late Cretaceous eutherian ostensibly occurring in both continents. As a result of our detailed study of Paranyctoides, however, we find that the Central Asian species lack the diagnostic characters of Paranyctoides and must be referred to other taxa. We conclude that this genus was limited to North America, ranging from Aquilan to Lancian time, and accordingly we recognize as valid only the following species: Paranyctoides sternbergi (Judithian, Alberta), P. maleficus (Aquilan, Alberta), Paranyctoides Wahweap sp. A and sp. B (Judithian, Utah), Paranyctoides Kaiparowits sp. A and sp. B (Judithian, Utah). Another purported species of Paranyctoides, P. megakeros, from the Lancian of Wyoming, is a junior synonym of Alostera saskatchewanensis.

Environmental conditions vs. landscape. Assessment of the factors that influence small mammal fauna distribution in Southern Iberia during the latest Messinian by mean of stable isotopes

Tropical conditions during the late Miocene in southwestern Europe influenced the continental environments. Although there are previous qualitative environmental interpretations of these continental landscapes during the late Miocene, quantitative environmental and paleohydrological data are scarce. A very long sequence of small mammals allowed to date the different continental drainage stages of the Granada Basin from latest Tortonian to the Holocene and to reconstruct qualitatively its environmental evolution. The study of the isotopic record of these fossil small mammals and sediments in the stratigraphic sequence of a latest Messinian paleo-lake in the Granada Basin has provided quantitative environmental and paleohydrological data, in order to know if the fluctuations in the faunal distribution were mainly influenced by the paleogeographic configuration, such as changes in the landscape of the basin, or by the climatic conditions. Open habitats with C3 plants predominated. Estimated quantitative data suggest an oxygen isotopic composition of meteoric waters ranging from −4.9 to −3.9‰, past temperatures from ~2.5°C to 4.7°C higher than the current ones, and summer relative paleohumidity from ~60% to ~70%. In this context, changes in the landscape, such as the reduction of the lacustrine system caused by tectonic activity, would affect taxa with high dependence on humid conditions.

Origin of an Assemblage Massively Dominated by Carnivorans from the Miocene of Spain

Carnivoran-dominated fossil sites provide precious insights into the diversity and ecology of species rarely recovered in the fossil record. The lower level assemblage of Batallones-1 fossil site (Late Miocene; Madrid Basin, Spain) has yielded one of the most abundant and diversified carnivoran assemblage ever known from the Cenozoic record of mammals. A comprehensive taphonomic study is carried out here in order to constrain the concentration mode of this remarkable assemblage. Another distinctive feature of Batallones-1 is that the accumulation of carnivoran remains took place in the context of a geomorphological landform (cavity formation through a piping process) practically unknown in the generation of fossil sites. Two characteristics of the assemblage highly restrict the probable causes for the accumulation of the remains: (1) the overwhelming number of carnivorans individuals; and (2) the mortality profiles estimated for the four most abundant taxa do not correspond to the classic mortality types but rather were the consequence of the behavior of the taxa. This evidence together with other taphonomic data supports the hypothesis that carnivoran individuals actively entered the cavity searching for resources (food or water) and were unable to exit. The scarcity of herbivores implies that the shaft was well visible and avoided by these taxa. Fossil bones exhibit a very good preservation state as a consequence of their deposition in the restricted and protective environment of the chamber. Batallones-1 had another assemblage (upper level assemblage) that was dominated by herbivore remains and that potentially corresponded to the final stages of the cavity filling.

Palynostratigraphy and depositional environment of Vastan Lignite Mine (Early Eocene), Gujarat, western India

Early Eocene sedimentary successions of south Asia, are marked by the development of extensive fossil-bearing, lignite-rich sediments prior to the collision of India with Asia and provide data on contemporary equatorial faunal and vegetational assemblages. One such productive locality in western India is the Vastan Lignite Mine representing approximately a 54–52 Ma sequence dated by the presence of benthic zone marker species, Nummulites burdigalensis burdigalensis. The present study on Vastan Lignite Mine succession is based on the spore-pollen and dinoflagellate cyst assemblages and documents contemporary vegetational changes. 86 genera and 105 species belonging to algal remains (including dinoflagellate cysts), fungal remains, pteridophytic spores and angiospermous pollen grains have been recorded. On the basis of first appearance, acme and decline of palynotaxa, three cenozones have been recognized and broadly reflect changing palaeodepositional environments. These are in ascending stratigraphic order (i) Proxapertites Spp. Cenozone, (ii) Operculodinium centrocarpum Cenozone and (iii) Spinizonocolpites Spp. Cenozone. The basal sequence is lagoonal, palm-dominated and overlain by more open marine conditions with dinoflagellate cysts and at the top, mangrove elements are dominant. The succession has also provided a unique record of fish, lizards, snakes, and mammals.

First mammals from the Paleocene Porcupine Hills Formation of southwestern Alberta, Canada

Although mammals of Paleocene age are well known from Alberta, their record is largely restricted to one lithological unit, the Paskapoo Formation (a record that includes mammals from the Cochrane area erroneously attributed to the Porcupine Hills Formation). We report here the first occurrence of Paleocene mammals from the Porcupine Hills Formation at exposures near the western edge of the city of Calgary. The assemblage, termed the Bearspaw local fauna, documents a diversity of multituberculate and eutherian mammals, including new species of the pentacodontid Aphronorus bearspawensis sp. nov., the mixodectid Eudaemonema bohachae sp. nov., the hyopsodontid Promioclaenus thnetus sp. nov., and a new genus and species of multituberculate (Alopocosmodon hadrus gen. et sp. nov.) tentatively referred to the Microcosmodontidae. The Bearspaw local fauna also details the first Canadian occurrences of several taxa, including Ptilodus wyomingensis, Aphronorus fraudator, Bryanictis microlestes, Elpidophorus minor, and possibly Goniacodon. Preliminary biostratigraphic analyses suggest that the Bearspaw local fauna is middle Torrejonian (To2) in age, correlating most closely with near-coeval Gidley Quarry of Montana and Rock Bench Quarry of Wyoming. In addition to improving the depauperate record of Torrejonian mammals in western Canada, the new fauna is important in documenting a mammal assemblage from a lithological unit that is thought to have been deposited in semi-arid conditions, rather than the wetter and more humid conditions of the Paskapoo Formation. Further, the Bearspaw localities, along with several other recently discovered localities in the Calgary and Cochrane areas, closely bracket the 27n–26r chron boundary and as such will be important in detailing the Torrejonian–Tiffanian transition in western Canada.

The Plio-Pleistocene fluvio-lacustrine Upper Valdarno Basin (central Italy): stratigraphy and Basin fill evolution

The Upper Valdarno Basin stands out from the Neogene-Quaternary basins of the Northern Apennines given its outstanding fossil mammal record, good quality of natural and artificial outcrops and remarkable chronological control on the basin-fill succession. The present paper aims to summarize the stratigraphic and sedimentological studies focused on the Upper Valdarno Basin during the past decades, and integrate them with recent investigations. The Upper Valdarno Basin is located about 35 km SE of Florence between the Chianti Mountains and the Pratomagno Ridge. It consists of a main asymmetric tectonic depression filled with 550 m of Plio-Pleistocene fluvio-lacustrine deposits (Upper Valdarno Basin s.s.) and a minor basin known as the Palazzolo sub-basin. The Upper Valdarno Basinfill is made of three unconformity-bounded units, named Castelnuovo dei Sabbioni (CSB), Montevarchi (VRC), Torrente Ciuffenna (UFF) synthems, whereas the Palazzolo sub-basin fill consists of the Fosso Salceto (OLC) and Torrente Ciuffenna (UFF) synthems. The Upper Valdarno Basin formed during Late Pliocene because of the tectonic damming of a northeastward flowing drainage. The early phase of basin development is recorded by the accumulation of fluvial gravels in vallive settings, whereas the definitive of these streams damming caused the development of lacustrine conditions at about 3.1 Ma. The accumulation of deltaic sand fed from the SW margin caused the lake filling and stopped the deposition of the CSB Synthem.Before 2.58 Ma, a tectonic phase caused uplift of the basin and partial erosion of the CSB deposits. Deposition of the lower part of the VRC Synthem occurred during a marked basin broadening and accumulation of alluvial fan successions, which were capped by aeolian-reworked alluvial sand deposited at about 2.5 Ma. At about 2.3 Ma, a new deformative phase caused further basin widening, erosion along the SW margin and development of a small lake inthe central areas. Deposition of the upper part of the Montevarchi Synthem started just after this tectonic phase and was characterized by development of axial fluvial drainage and marginal alluvial fans.During the Early Pleistocene (Olduvai Subchron, 1.95-1.78 Ma) a subsidence pulse promoted development of floodplain lakes and swamps in the axial part of the basin, where thick organic-rich mud were accumulated. During late Early Pleistocene the capture of the paleo-Arno River, which started to flow into the basin, caused the development of a marked unconformity. This unconformity was covered by fluvial and alluvial fan deposit in the axial part and along the margin respectively.

Dispersal of African mammals in Eurasia during the Cenozoic: Ways and whys

Several groups of mammals originated in Africa and then immigrated to Eurasia during some intervals of the Cenozoic, thus greatly contributing to the mammalian biodiversity in Eurasia. Nevertheless, the African components of Eurasian mammalian faunas have had variable success in their diversification and survival. The Afro-Arabian plate remained separated from Eurasia by the Tethyan seaway, which was definitely closed in the Burdigalian, some 20myr ago. Before its closure, the marine barrier between the Afro-Arabian and Eurasian plates did not totally prevent mammalian exchanges between these landmasses, as documented by the arrival of rodents and primates in Africa in the late Paleocene-early Eocene, the dispersal of embrithopods on both sides of the Tethyan seaway during the Eocene, and the immigration of elephantoids from Africa to Asia in late Oligocene. These events seem to be restricted to some groups of mammals, which apparently had abilities to use sweepstake dispersal routes. The massive mammalian dispersal from Africa to Eurasia started sometimes in the early Miocene, involving several groups of African mammals, in particular proboscideans, hyracoids, tubulidentates, and anthropoids. This contribution discusses the timing of these events under the light of recent discoveries of Africa-originated mammals in Eurasia. The impact of the evolving paleogeography of the area situated between the Afro-Arabian and Eurasian plates on the mammalian dispersal is reconsidered. The dispersal of land mammals from Africa to Eurasia is controlled not only by the paleogeographic changes (sea level changes, dispersal routes, terrestrial bridges, etc.), but also by climatic factors that modified the environments of terrestrial mammals, favoring or not the occurrence of dispersal routes and/or the enlargement or restriction of climatic belts and biogeographic provinces to which these mammals were adapted. These questions are discussed taking into account the present knowledge of the record of the Africa-originated mammals in Eurasia during the Cenozoic times.

Paleoenvironmental reconstruction of the early Neolithic to middle Bronze Age Peña Larga rock shelter (Álava, Spain) from the small mammal record

The Peña Larga site, a rock shelter on the southern slopes of the Cantabrian cordillera (north Spain), is an archeological deposit covering nearly 4000years, from the early Neolithic to the middle Bronze Age (Atlantic/Subboreal chronozones). It was used both as a household and as a stable, with a hiatus in the Chalcolithic when it was used as a collective sepulcher. Nearly twenty-eight thousand small vertebrate elements were recovered from its seven stratigraphic units, of which 2553 items were identified to the genus and/or species levels. The assemblage is composed of mammals, birds, reptiles, and amphibians. Of these, small mammals were used for paleoenvironmental reconstruction since they are very sensitive to climatic conditions, the sample sizes are large, and their preservation is good. Their distributions over time, measured in terms of relative abundance, serve as reliable proxies of habitat and climate change. The reconstruction of Peña Larga's past environments based on small mammals roughly coincides with the pollen and the amphibian/reptile records on the local scale, and with that of an ice core from Central Greenland on the global scale. This makes it a valuable tool for comparative purposes both in the regional and continental scales.

First extinct genus of a flea (Siphonaptera: Pulicidae) in Miocene amber from the Dominican Republic

A new, extinct genus of flea is described and figured in the tribe Spilopsyllini (Siphonaptera: Pulicidae) from a male preserved in Early Miocene Dominican amber. Eospilopsyllus kobberti Beaucournu & Perrichot, n. gen. and n. sp., is characterized by the absence of ctenidia, very small eyes, lanceolate terminal segment of the maxillary palpus, enlarged second abdominal sternite, legs with six notches on dorsal margin of tibiae, five pairs of lateral plantar bristles on distitarsomeres, and ungues with a reduced space between the basal lobe and the tarsal claw. Most of the extant spilopsyllines parasitize lagomorphs and squirrels, but these taxa were seemingly absent from the Greater Antilles until very recently. Instead, the Tertiary record and biogeographical history of land mammals on these islands suggests that early spilopsyllines may have parasitized the endemic solenodon insectivores or echimyid rats.