Evolution of bird communities in the Neogene of Central Asia,with a review of the Neogene fossil record of Asian birds

A complete taxonomic review of Neogene birds of continental Asia is provided. To date, avifauna from the latter half of the Miocene and Pliocene of Central Asia (Mongolia and adjacent regions of Inner Asia) are most thoroughly investigated. Available data enable a reconstruction of successive replacement of Early and Middle Miocene avifaunas by communities of the Recent type. Middle Miocene avifaunas of Mongolia include a great number of extinct genera and species, many of which were widespread in Eurasia. Extant genera became dominant in the Late Miocene and taxa close to living species appear in the Late Pliocene fossil record. Late Pliocene communities of birds of Central Asia were complex in genesis, composed of Miocene relicts (Struthio), immigrants from the European regions of the Palearctic (phasianid Plioperdix), North American immigrants (Calcarius), and also autochthonous elements, the origin of which is apparently connected with the arid belt of Central Asia (diverse passerines).     

On the origin of northern and southern hemisphere grasslands

The origin of the grassy habit during the Eocene and the development of C4 grasses during the Miocene/Pliocene boundary are discussed before the origin of primary and secondary grassland in Eurasia and North America are discussed. A comparison shows that both Northern and Southern hemisphere primary grassland originated due to climatic changes to drier conditions during the end of the Eocene, and that modern grassland vegetation types can be traced back to the Oligocene. The Eurasian steppes becomes more fragmented towards the west and south and relicts of primary grassland exists only in the most xerothermic localised habitats in central and western Europe. Secondary grassland clearly due to manmade deforestation, started with the spread of Neolithic husbandry. Southern African grasslands were however not only determined by droughty conditions, but cooler conditions at high altitudes are one of the major driving forces that prevent colonisation by trees of a generally tropical origin.     

Tropical forests and the genus Homo

Tropical forests constitute some of the most diverse and complex terrestrial ecosystems on the planet. From the Miocene onward, they have acted as a backdrop to the ongoing evolution of our closest living relatives, the great apes, and provided the cradle for the emergence of early hominins, who retained arboreal physiological adaptations at least into the Late Pliocene. There also now exists growing evidence, from the Late Pleistocene onward, for tool‐assisted intensification of tropical forest occupation and resource extraction by our own species, Homo sapiens. However, between the Late Pliocene and Late Pleistocene there is an apparent gap in clear and convincing evidence for the use of tropical forests by hominins, including early members of our own genus. In discussions of Late Pliocene and Early Pleistocene hominin evolution, including the emergence and later expansion of Homo species across the globe, tropical forest adaptations tend to be eclipsed by open, savanna environments. Thus far, it is not clear whether this Early‐Middle Pleistocene lacuna in Homo‐rainforest interaction is real and representative of an adaptive shift with the emergence of our species or if it is simply reflective of preservation bias.     

Evidence for a vicariant origin of Macaronesian–Eritreo/Arabian disjunctions in Campylanthus Roth (Plantaginaceae)

The numerous disjunct plant distributions between Macaronesia and eastern Africa–Arabia suggest that these could be the relicts of a once continuous vegetation belt along the southern Tethys, which has been fragmented by Upper Miocene–Pliocene aridification. We tested this vicariance hypothesis with a phylogenetic analysis of Campylanthus (Plantaginaceae), based on nuclear and plastid DNA sequence data. Our results indicate a basal split within Campylanthus giving rise to Macaronesian and Eritreo–Arabian lineages in the Pliocene/Upper Miocene. This is consistent with the vicariance hypothesis, thus obviating the need to postulate trans-Saharan long-distance dispersal. The biogeography of Campylanthus may parallel patterns in other plant groups and the implications for our understanding of the biogeography of northern and eastern Africa, and Arabia are discussed.     

Age and historical biogeography of the pantropically distributed Spathelioideae (Rutaceae,Sapindales)

Aim The family Rutaceae (rue family) is the largest within the eudicot order Sapindales and is distributed mainly in the tropical and subtropical regions of both the New World and the Old World, with a few genera in temperate zones. The main objective of this study is to present molecular dating and biogeographical analyses of the subfamily Spathelioideae, the earliest branching clade (which includes eight extant genera), to interpret the temporal and spatial origins of this group, ascertaining possible vicariant patterns and dispersal routes and inferring diversification rates through time. Location Pantropics. Methods A dataset comprising a complete taxon sampling at generic level (83.3% at species level) of Spathelioideae was used for a Bayesian molecular dating analysis (beast ). Four fossil calibration points and an age constraint for Sapindales were applied. An ancestral area reconstruction analysis utilizing the dispersal–extinction–cladogenesis model and diversification rate analyses was conducted. Results Dating analyses indicate that Rutaceae and Spathelioideae are probably of Late Cretaceous origin, after which Spathelioideae split into a Neotropical and a Palaeotropical lineage. The Palaeotropical taxa have their origin inferred in Africa, with postulated dispersal events to the Mediterranean, the Canary Islands, Madagascar and Southeast Asia. The lineages within Spathelioideae evolved at a relatively constant diversification rate. However, abrupt changes in diversification rates are inferred from the beginning of the Miocene and during the Pliocene/Pleistocene. Main conclusions The geographical origin of Spathelioideae probably lies in Africa. The existence of a Neotropical lineage may be the result of a dispersal event at a time in the Late Cretaceous when South America and Africa were still quite close to each other (assuming that our age estimates are close to the actual ages), or by Gondwanan vicariance (assuming that our age estimates provide minimal ages only). Separation of land masses caused by sea level changes during the Pliocene and Pleistocene may have been triggers for speciation in the Caribbean genus Spathelia.     

Small mammal (rodents and lagomorphs) European biogeography from the Late Oligocene to the mid Pliocene

Aim To analyse the fossil species assemblages of rodents and lagomorphs from the European Neogene in order to assess what factors control small mammal biogeography at a deep‐time evolutionary time‐scale. Location Western Europe: 626 fossil‐bearing localities located within 31 regions and distributed among 18 successive biochronological units ranging from c. 27 Ma (million years ago; Late Oligocene) to c. 3 Ma (mid Pliocene). Methods Taxonomically homogenized pooled regional assemblages are compared using the Raup and Crick index of faunal similarity; then, the inferred similarity matrices are visualized as neighbour‐joining trees and by projecting the statistically significant interregional similarities and dissimilarities onto palaeogeographical maps. The inferred biogeographical patterns are analysed and discussed in the light of known palaeogeographical and palaeoclimatic events. Results Successive time intervals with distinct biogeographical contexts are identified. Prior to c. 18 Ma (Late Oligocene and Early Miocene), a relative faunal homogeneity (high interregional connectivity) is observed all over Europe, a time when major geographical barriers and a weak climatic gradient are known. Then, from the beginning of the Middle Miocene onwards, the biogeography is marked by a significant decrease in interregional faunal affinities which matches a drastic global climatic degradation and leads, in the Late Miocene (c. 11 Ma), to a marked latitudinal pattern of small mammal distribution. In spite of a short rehomogenization around the Miocene/Pliocene boundary (6–4 Ma), the biogeography of small mammals in the mid Pliocene (c. 3 Ma) finally closely reflects the extant situation. Main conclusions The resulting biogeographical evolutionary scheme indicates that the extant endemic situation has deep historical roots corresponding to global tectonic and climatic events acting as primary drivers of long‐term changes. The correlation of biogeographical events with climatic changes emphasizes the prevalent role of the climate over geography in generating heterogeneous biogeographical patterns at the continental scale.     

Climate‐driven rampant speciation of the Cape flora

Aim To test whether the radiation of the extremely rich Cape flora is correlated with marine‐driven climate change. Location Middle to Late Miocene in the south‐east Atlantic and the Benguela Upwelling System (BUS) off the west coast of South Africa. Methods We studied the palynology of the thoroughly dated Middle to Late Miocene sediments of Ocean Drilling Program (ODP) Site 1085 retrieved from the Atlantic off the mouth of the Orange River. Both marine upwelling and terrestrial input are recorded at this site, which allows a direct correlation between changes in the terrestrial flora and the marine BUS in the south‐east Atlantic. Results Pollen types from plants of tropical affinity disappeared, and those from the Cape flora gradually increased, between 10 and 6 Ma. Our data corroborate the inferred dating of the diversification in Aizoaceae c. 8 Ma. Main conclusions Inferred vegetation changes for the Late Miocene south‐western African coast are the disappearance of Podocarpus‐dominated Afromontane forests, and a change in the vegetation of the coastal plain from tropical grassland and thicket to semi‐arid succulent vegetation. These changes are indicative of an increased summer drought, and are in step with the development of the southern BUS. They pre‐date the Pliocene uplift of the East African escarpment, suggesting that this did not play a role in stimulating vegetation change. Some Fynbos elements were present throughout the recorded period (from 11 Ma), suggesting that at least some elements of this vegetation were already in place during the onset of the BUS. This is consistent with a marine‐driven climate change in south‐western Africa triggering substantial radiation in the terrestrial flora, especially in the Aizoaceae.     

Fossil pollen grains of Asteraceae from the Miocene of Patagonia: Nassauviinae affinity

Fossil pollen grains with morphological features unique in the subtribe Nassauviinae (tribe Mutisieae, Asteraceae) occur in Miocene marine deposits of eastern Patagonia, southern South America. A new morphogenus and two morphospecies are proposed to assemble fossil pollen grains characterized by having a complex bilayered exine structure with delicate columellae, separated by an internal tectum. Subprolate specimens with Trixis exine type (ectosexine thinner than endosexine, straight internal tectum) are referred to Huanilipollis cabrerae. This species is similar to pollen of recent Holocheilus, Jungia, and Proustia. Suboblate specimens with Oxyphyllum exine type (ectosexine and endosexine equally thick, zigzag internal tectum) are referred to Huanilipollis criscii. This species is similar to pollen of recent Triptilion. The spore/pollen sequences in which Nassauviinae pollen types occur suggest a wide range of vegetation types varying from forest dominated during the Early Miocene (Chenque Formation) to virtually xerophytic ones during the Late Miocene (Puerto Madryn Formation). The subtribe Nassauviinae comprises 25 genera and ca. 320 species of vines, shrubs and low trees endemic to America with a wide range of ecological preferences; the nearest living relatives of the fossil types being mostly confined to humid landscapes. The unusual occurrence of these groups during the arid characterized Late Miocene time could be attributed to the complex interplay of the mountain uplift and global circulation patterns. These forcing factors would have created a mosaic of different habitats with both patches of forest and dry-adapted species developing in relatively small regions. This is the first fossil record of Nassauviinae and confirms that this subtribe of Asteraceae was already differentiated in the Miocene.     

Biogeography of cedrela (meliaceae, sapindales) in central and South america

Dated phylogenies have helped clarify the complex history of many plant families that today are restricted to the world's tropical forests, but that have Eocene, Oligocene, and Miocene fossils from the northern hemisphere. One such family is the Meliaceae. Here we infer the history of the neotropical Meliaceae genus Cedrela (17 species), the sister clade of which today is restricted to tropical Asia. Sequences from the nuclear ribosomal spacer region and five plastid loci obtained for all ingroup species and relevant outgroups were used to infer species relationships and for molecular-clock dating under two Bayesian relaxed clock models. The clock models differed in their handling of rate autocorrelation and sets of fossil constraints. Results suggest that (1) crown group diversification in Cedrela started in the Oligocene/Early Miocene and intensified in the Late Miocene and Early Pliocene, and (2) Central American Cedrela species do not form a clade, implying reentry into Central America after the closure of the Panamanian Isthmus. At present, Cedrela is distributed in both dry and humid habitats, but morphological features suggest an origin in dry forest under seasonal climates, fitting with Miocene and Pliocene Cedrela fossils from deciduous forests.     

The Cenozoic vegetation of the Iberian Peninsula: A synthesis

The aim of this work is to provide a first approach to the evolution of Iberia's vegetation during the Cenozoic (with the exclusion of the Quaternary). The Palaeogene was floristically defined by Palaeotropical elements forming tropical/subtropical rainforests, mangrove swamps, edaphically-mediated laurophyllous forests and leguminous-sclerophyllous communities. During the Miocene, Iberian landscapes were drastically modified due to geographic and climatic changes (mainly cooling and aridification) changes. Open, steppe-like environments developed towards the interior of the peninsula and Arctotertiary elements invaded mountainous and riparian ecosystems, coexisting with or becoming part of evergreen, broadleaved forests of Palaeotropical species. From the Late Miocene onwards these forests suffered changes due to the extinction of taxa, the impact of environmental change on the survivors, and the perturbations caused by the arrival of further Arctotertiary elements. However, several Palaeotropical taxa overcame the environmental and climatic changes of the Miocene and Pliocene to form a part of the modern flora of the Iberian Peninsula.     

Age and implications of the Forest Bed, Falkland Islands, southwest Atlantic Ocean: Evidence from fossil pollen and spores

Diverse pollen and spore assemblages (microfloras) are preserved in organic clays and lignites associated with fossil tree remains in the Forest Bed. At present, these microfloras provide the only reliable basis for determining the age, composition, structure and affinity of the Forest Bed community. The Bed is suggested to be Middle? Miocene to Early Pliocene (age range Oligocene–Early Pliocene) based on the time distribution of a number of rare pollen types and the present-day ecology of their nearest living relatives in central–southern America and the southwest Pacific. The wet forest community whose remains form the Forest Bed was a form of broadleaf-gymnosperm temperate rainforest in which Dacrydium, Lagarostrobos and Podocarpus are likely to have formed an overstorey above a closed canopy dominated by Nothofagus (Nothofagus) spp. The latter subgenus is now endemic to ±uniformly wet regions in southern South America whilst two of the tall gymnosperms (Dacrydium, Lagarostrobos) are now endemic to the southwest Pacific region. An extinct, probable shrub-sized, conifer (Podosporites microsaccatus) appears to have formed the ground cover. Ferns and fern allies were very rare, in contrast to most living Nothofagus-gymnosperm communities. Fossil pollen and spore types produced by uncommon subcanopy tree, shrub and fern species potentially provide a means for more accurately dating the deposit once their time of first occurrence and extinction at subantarctic latitudes in the southwest Atlantic region is established (nearest living equivalents given in parentheses) — Clavatipollenites cf glarius (Hedyosmum), Thymelaepollis sp. (Ovidia-type) and Cyatheacidites annulatus (Lophosoria). This will require palynostratigraphic analysis of Late Palaeogene–Neogene sediments recovered from basins surrounding the Falkland Islands, for example from DSDP Site 329 drilled on the Maurice Ewing Bank at the eastern margin of the Falkland Plateau.     

Oceanographic significance of Pacific late miocene calcareous nannoplankton

An analysis of the variability in the composition and distribution of Pacific Late Miocene calcareous nannoplankton about their average biogeography shows that there are primarily two environmental factors causing that variability, climate and dissolution. Climate produces a latitudinal, biogeographic differentiation of the Late Miocene nannoflora, while selective dissolution superimposes a bathymetric differentiation of the nannoflora on that due to climate. Together, these two factors produce three distinct Late Miocene nannofloral assemblages, a high-latitude, temperate assemblage characterized by Reticulofenestra pseudoumbilica and Coccolithus pelagicus, and two tropical assemblages, their differences in composition depending on water depth and surface-water productivity: (1) in shallower water and beneath areas of higher organic production and sedimentation of calcite there is an undissolved assemblage characterized by sphenoliths, small elliptical placoliths and Coccolithus pataecus; (2) in deeper water and areas of lower productivity there is a dissolved assemblage dominated by discoasters.Selective dissolution produces most of the apparent biogeographic variation in Pacific Late Miocene nannoplankton compositions, the variation in compositions observed between the seventeen sites studied. Dissolution preferentially removes the more soluble constituents of the tropical nannoflora so that increasing dissolution tends to give tropical nannoflora a cooler, more temperate aspect. At the same time, selective dissolution shifts the composition of the warmer, tropical component towards its more resistant taxa.Nannoplankton records show a period of greatly decreased calcite dissolution in deep tropical and temperate South Pacific sites between about 8 and 10 m.y. ago. This decrease is strongly correlated with a temporary increase in the ¹³C composition of Pacific deep waters. Calcite dissolution increased during this same period in the deep North Pacific.Nannoplankton records of Late Miocene climate in the tropics are distinctly different from those at higher, south temperate latitudes. Tropical records show a sharp warming in the earliest Late Miocene after a generally cool late Middle Miocene. This was followed by a temporary cooling, nearly to Middle Miocene levels, about 7 m.y. ago. Toward the end of the Late Miocene, the tropical Pacific warmed again and remained warm into the Pliocene. Warming of temperate climates occurred much later. Not until latest Miocene did the southern the Pliocene. Warming of temperate climates occurred much later. Not until latest Miocene did the southern temperate latitudes warm appreciably. Southern subpolar climate cooled continuously through the Late Miocene. We attribute the resulting increases in the latitudinal climatic contrast across the southern Pacific Ocean to the development and migration of a strong subtropical convergence.On the basis of the nannoplankton oceanographic records we postulate that beginning about 10.5 m.y. ago Pacific surface circulation became primarily zonal and the production of deep and bottom waters in the Southern Ocean increased sharply. This produced a northward decrease in calcite preservation, an increase in benthic ¹³C, and a strong climatic gradient across southern latitudes. The period of most vigorous deep Pacific circulation ended 7 m.y. ago in response, we speculate, to the reduced ocean salinities during the Messinian.     

临夏盆地的新生代地层及其哺乳动物化石证据

临夏盆地的新生代地层相当发育 ,保存了从渐新世至全新世的连续沉积序列。更为重要的是 ,这些沉积物中含有丰富的哺乳动物化石 ,为划分和对比临夏盆地的新生代地层提供了可靠的证据。然而 ,此前关于这个盆地地层层序和时代的认识有许多矛盾之处 ,地层命名繁复 ,化石证据混乱。近年来我们对临夏盆地的野外考察已理清了沉积序列 ,并在充分的哺乳动物化石证据的基础上重新厘定了各个岩石地层单位所对应的地质时代。临夏盆地的新生代哺乳动物化石以晚渐新世的巨犀动物群、中中新世的铲齿象动物群、晚中新世的三趾马动物群和早更新世的真马动物群最为丰富。     

西欧地中海地区中新世以来的植被演化和现代地中海植被的形成

从距今2500万年的中新世初到更新世,欧洲地中海沿岸地区的植被是从东亚型的热带——亚热带常绿阔叶林逐渐过渡为旱生性的蒿——藜草原。古热带和亚洲、北美成份从晚中新世起逐渐消失,少数一直延续到中更新世。孢粉分析表明,地中海成分从中上新世起有明显增加,地中海常绿硬叶林的发展与北极冰盖的形成密切相关。     

Palynoflora at Late Miocene?aEarly Pliocene from Leijiahe of Lingtai,Gansu Province,China

Vegetation and climate changes of Late Miocene-Early Pliocene have been deduced based on pollen research from Wenwanggou and Xiaoshigou sections near Leijiahe village (ca 35°04′15″N,107°43′30″E). The two sections are quite famous of rich micromammalian fossils. Before ca. 6.5 Ma, open forest-grassland was distributed in the studied area indicating a temperate and humid condition at that time. In the period between ca.6.5 and 5.8 Ma BP (Late Miocene) predominance of Chenopodiaceae and Artemisia implies that desert or desert-grassland was developed in the area and the climate should be cold and dry. During the time interval from ca.5.8 to 3.4 Ma BP mixed conifer and broad leaved deciduous forest with a few subtropical tree taxa had replaced the arid desert vegetation indicating a warm and humid climate. The climate aridity event of Late Miocene can be correlated with the global climatic event.     

A temporally dynamic approach for cladistic biogeography and the processes underlying the biogeographic patterns of North American deserts

We implemented a temporally dynamic approach to the cladistic biogeographic analysis of 13 areas of North American deserts and several plant and animal taxa. We undertook a parsimony analysis of paralogy‐free subtrees based on 43 phylogenetic hypotheses of arthropod, vertebrate and plant taxa, assigning their nodes to three different time slices based on their estimated minimum ages: Early‐Mid‐Miocene (23?7 Ma), Late Miocene/Pliocene (6.9?2.5 Ma) and Pleistocene (2.4?0.011 Ma). The analyses resulted in three general area cladograms, one for each time slice, showing different area relationships. They allowed us to detect influences of different geological and palaeoclimatological events of the Early‐Mid‐Miocene, Late Miocene/Pliocene and Pleistocene that might have affected the diversification of the desert biota. Several diversification events in the deserts of North America might have been driven by Neogene uplift, marine incursion and the opening of the California Gulf during the Miocene–Pliocene, whereas climatic fluctuations had the highest impact during the Pleistocene.     

Late neogene biostratigraphy and stable isotope stratigraphy of a drilled core from the Gulf of Mexico

Late Neogene stable isotope stratigraphy and planktonic foraminiferal biostratigraphy have been examined in a high sedimentation rate core (E67-135, Shell Oil Co.) drilled at 725 m water depth in the De Soto Canyon, Gulf of Mexico. The 305 m core contains sections that are Late Miocene, Early Pliocene, Late Pliocene, and Quaternary in age, and is rich in well-preserved assemblages of planktonic foraminifera.A biostratigraphy has been established based on the ranges of 34 selected species of foraminifera. The core 3orrelates with sections from the Gulf of Mexico, the Caribbean Sea, and the subtropical North and South Atlantic Oceans using, as datums, the evolutionary appearances of Globorotalia miocenica Palmer and Globorotalia margaritae evoluta Cita, the extinction of Globorotalia miocenica and the first appearance of Globorotalia truncatulinoides (d'Orbigny).Oxygen and carbon isotope stratigraphy is based on analysis of the benthonic foraminifer, Uvigerina d'Orbigny. Isotopic trends are similar to those observed in the Pacific and Atlantic Oceans. From Early Pliocene to Late Pleistocene time, average δ¹⁸O values increase (2.42‰ to 3.36‰) and exhibit a wider range of values (0.71‰ in Early Pliocene compared to 1.65‰ in Late Pleistocene sediments), probably reflecting Late Neogene climatic deterioration. The ratio ${}^{13}\text{C}{}^{12}\text{C}$ decreases significantly by ?0.21‰ from the Late Miocene to the Early Pliocene. A decrease in δ¹³C is observed in other cores and is probably related to changing oceanic circulation patterns in Late Miocene time.     

Phylogeny and adaptive diversity of rodents of the family Ctenomyidae (Caviomorpha): delimiting lineages and genera in the fossil record

Differentiation of genera of the modern (Late Miocene to Recent) South American rodent family Ctenomyidae would have been linked to the acquisition of disparate adaptations to digging and life underground. In accordance with this hypothesis, the delimitation of lineages and genera in the ctenomyid fossil record is evaluated here following an adaptation-rooted criterion that involves both an assessment of the monophyly and of the adaptive profiles of recognized clades. The application of such a criterion, including morphofunctional information, delimited four cohesive lineages among crown ctenomyids (i.e. euhypsodont species of the Late Miocene to Recent): Eucelophorus (Early Pliocene–Middle Pleistocene), Xenodontomys-Actenomys (Late Miocene–Pliocene), Praectenomys (Pliocene) and Ctenomys (including Paractenomys ; Pliocene–Recent); in addition, the results supported the status of Xenodontomys as a paraphyletic ancestor of Actenomys . The cladogenesis that gave rise to the crown group would have occurred immediately after the acquisition of euhypsodonty in a Xenodontomys simpsoni -like ancestor during the Late Miocene. This putative ancestor would have had fossorial habits and moderate digging specializations, an adaptive profile maintained in Xenodontomys-Actenomys . Eucelophorus and Ctenomys would have independently evolved subterranean habits at least since the Pliocene. Although the earliest history of the only living representative, Ctenomys , is known only fragmentarily, remains from Esquina Blanca (Uquía Formation), in north-western Argentina, suggest a minimum age of around 3.5 Ma (Early–Late Pliocene) for the differentiation of the genus. This date agrees with recent molecular estimates.     

New observations on the Late Miocene–Early Pliocene Lutrinae (Mustelidae: Carnivora,Mammalia) from the Middle Awash,Afar Rift,Ethiopia

New observations on the Late Miocene and Earliest Pliocene mustelids from the Middle Awash of Ethiopia are presented. The Middle Awash study area samples the last six million years of African vertebrate evolutionary history. Its Latest Miocene (Asa Koma Member of the Adu-Asa Formation, 5.54–5.77 Ma) and Earliest Pliocene (Kuseralee and Gawto Members of the Sagantole Formation, 5.2 and 4.85 Ma, respectively) deposits sample a number of large and small carnivore taxa among which mustelids are numerically abundant. Among the known Late Miocene and Early Pliocene mustelid genera, the Middle Awash Late Miocene documents the earliest Mellivora in eastern Africa and its likely first appearance in Africa, a new species of Plesiogulo, and a species of Vishnuonyx. The latter possibly represents the last appearance of this genus in Africa. Torolutra ougandensis is known from both the Late Miocene and Early Pliocene deposits of the Middle Awash. The genus Sivaonyx is represented by at least two species: S. ekecaman and S. aff. S. soriae. Most of the lutrine genera documented in the Middle Awash Late Miocene/Early Pliocene are also documented in contemporaneous sites of eastern Africa. The new observations presented here show that mustelids were more diverse in the Middle Awash Late Miocene and Early Pliocene than previously documented.     

Extent and timing of floristic exchange between Australian and Asian rain forests

Aim We tested an entrenched concept – that the Australian rain forest flora is essentially a Gondwanan relict. We also assessed the role of regional‐level source–sink dynamics in the assembly of this flora. Location Eastern Australia. Methods To avoid potential biases inherent in selective studies undertaken to date, we used an analytical, whole‐of‐flora approach integrated with the fossil record. We identified disjunctions between woody Australian rain forest plant taxa and relatives on other land masses. To test the strength of the fossil evidence for the regional antiquity of this flora, we evaluated the proportion of these disjunct clades represented in the Australian fossil record, and to minimize the effects of biases in this record, we compared late Quaternary (i.e. late Pleistocene and Holocene, 126–0 ka), Pliocene and late Oligocene–early Miocene Australian pollen records interpreted as tropical rain forest. Using within‐species disjunctions as a proxy, we assessed the role of recent immigration from Asia into Australia. To assess the role of source–sink dynamics, we performed comparative analyses of disjunctions in major rain forest categories representing a north–south/climatic gradient. Results Southern Australian, cool temperate (microthermal) rain forests contain many floristic disjunctions with Gondwanan fragments and most of these clades have Gondwanan fossils. Disjunct clades in Australian mesothermal rain forest mostly occur in Asia/Malesia and a low proportion of these clades show pre‐Neogene records. Many clades in lowland tropical and ‘dry’ rain forest show disjunctions with Asia/Malesia and few have Australian fossil records. Rates of recent immigration from Asia/Malesia are high in these northern forests, and outweigh rates of recent emigration approximately nine‐fold. The late Quaternary fossil record has many more rain forest angiosperms than Oligocene–Miocene and Pliocene floras, consistent with extensive late Cenozoic immigration. Main conclusions The microthermal rain forests are largely Gondwanan relicts, but there is progressively greater, and more recent contribution from Asia/Malesia into more northern, and more lowland tropical rain forests. This variation reflects a strong gradient in geographic and ecological proximity between these forests and source floras in Asia/Malesia, and is consistent with a source–sink size model of immigration driven by late Cenozoic contractions and expansions of Australian rain forest.