Faunal Migration Research Articles

Timing of intercontinental faunal migrations: Anguimorph lizards from the earliest Eocene (MP 7) of Dormaal, Belgium

Abstract Here we report on anguimorph lizards from the earliest Eocene (MP 7) of the Dormaal locality in Belgium, from the time of the warmest global climate of the past 66 million years. Several clades can be identified in this site: Glyptosauridae, Varanidae, and Palaeovaranidae. Our study focuses on glyptosaurid specimens previously reported from the site, some of which had been provisionally described as a new species,?Placosaurus ragei, and some assigned to an unnamed Placosauriops-like ‘melanosaurine’. Our study presents data on new material, including an almost complete glyptosaurine frontal that has enabled us to assign much of the previously described material to a single genus and species. The specimens that had been assigned to both ?P ragei and the ‘melanosaurine’ share apomorphies (flat osteoderms and chevron-shaped osteoderms) with Gaultia, a glyptosaurid previously known from the earliest Eocene of Wyoming, USA. The Dormaal material represents the first record of this genus outside North America. In fact, the only potential evidence of the occurrence of ‘Melanosaurinae’ in Dormaal might be a single isolated vertebra described here. Here we also describe previously unfigured material of Saniwa and palaeovaranids from Dormaal. The presence of previously reported helodermatids cannot be supported in this Belgian site.

Ecological control of the Pelsonian colonisation event (Anisian, Triassic) leading to the first settlement of Tetractinella-beds (Brachiopoda) in the Iberian palaeomargins. Palaeobiogeographical and biostratigraphical significance

Marine benthic biota recovery after the Permian/Triassic extinction is still a challenging topic in several fossil clades such as brachiopods. In fact, available data from the Early-Middle Triassic are scarce worldwide and their global record derives from limited localities throughout the Tethys Ocean. This work presents the first record of the Anisian Tetractinella-beds (Brachiopoda, Athyridida) in the peri-Iberian epicontinental platforms established in the westernmost Tethys margins. Their utility as a reliable biohorizon marker is emphasised as they provide an effective tool for age calibration and correlation in the middle Anisian (Pelsonian) successions, also supported by the co-occurring fossil assemblage. In the South-Iberian Palaeomargin, Tetractinella-beds occur in an intensively-burrowed shallow-marine succession. The rich ichnological content has been exhaustively evaluated in order to assess the ecological factors controlling the development of the brachiopod fauna. Three ichnoassemblages are documented dominated by Oravaichnium, Balanoglossites and Thalassinoides, respectively. The gathered faunal, ichnological, taphonomical, and sedimentological data reveal an alternation of sea-level changes influencing the composition of the Anisian marine communities. The first stage consists of near-shore restricted environments sporadically disturbed by short-term shallow-marine interludes, characterised by the presence of Oravaichnium and its associated fauna. Subsequently, the Pelsonian transgression event is recorded (MID-2), documented by a firm-ground surface pointed out by the development of a Balanoglossites surface, followed by the highstand, when shallow epicontinental environments developed in connection with open-marine areas. This phase involved the spreading of Tetractinella and deep-water bivalves. Finally, near-shore restricted conditions were re-established typified by Oravaichnium and the last occurrences of Tetractinella, with the disappearance of the open sea-water fauna. The maximum flooding reached after the Pelsonian transgression facilitated new palaeobiogeographical migration routes, allowing for an Alpine-Germanic dispersion of taxa throughout the North-South epicontinental Tethyan seaway as well as the earliest first faunal migration event from the Sephardic Bioprovince northwards to the South-Iberian palaeomargin.

Crystallographic Study of Vertebrate Fossils from The Central Narmada Valley, India.

The Narmada River originates in eastern Madhya Pradesh near Amarkantak (200 40' N, 81 46' E), travels through Madhya Pradesh, Maharashtra, and Gujarat before emptying into the Gulf of Cambay in the Arabian Sea, close to Baruch in Gujarat. Numerous fossil discoveries in the region include various mammals, reptiles, fishes, amphibians, and molluscan shells. In addition to being a rare mid-continental location in the Old World, the Narmada Valley has traditionally served as a line delineating Northern and Southern India. This valley has produced countless animal fossils as well as a few human fossils. This has been a crucial route for the movement of both faunal migrations from the north to the south and the transmission of the monsoons from the southeast to the northwest. The present work examines the crystallization index of the faunal fossils from three (Barmanghat ,Talayyaghat ,Devakachar) localities in the Central Narmada valley falling within the region of Madhya Pradesh. Fossil samples were subjected to X-Ray diffraction in order to calculate the Crystallization index as a direct indicator of the degree of fossilization. The materials of Narmada river valley have been studied extensively by previous scholars; however, this study is first attempt to study the fossils using scientific technique such as XRD.

First record of Anisian deposits in the Betic External Zone of southern Spain and its paleogeographical implications

In the External Zone of the Betic Cordillera (S Spain), upper Muschelkalk (Ladinian) facies have been known for decades; however, so far there is no stratigraphic record of Anisian deposits. In the present study, new biostratigraphic data from a carbonate succession in the easternmost Subbetic domain reveal a Pelsonian-Illyrian (Anisian) age. The nautiloids Germanonautilus salinarius and Germanonautilus saharonicus are documented for the first time in the Iberian Peninsula, and together with the brachiopod Tetractinella trigonella and the bivalves Neoschizodus orbicularis and Myophoria vulgaris they represent marker fossils of Anisian deposits previously described from many other basins, both in the Germanic and Alpine realms. The co-occurrence of the nautiloid G. saharonicus and the bivalve Gervillia joleaudi at the top of the studied succession serves as correlation tool for the first faunal migration event from the Sephardic towards the Subbetic domain. The palynomorph assemblage, including the monosaccate pollen grain Cristianisporites triangulatus, provides further evidence of a late Anisian age. An integrated study of fossil assemblages and sedimentary facies reveals tidal and very shallow-marine environments that characterize an extensive epicontinental platform in the western Tethys along the paleo-margin of the Iberian Massif. Two thin shale intervals represent two distinct transgressive phases, correlative to the Pelsonian maximum-flooding zone recorded in other European basins. The new findings contribute to the ongoing paleogeographic reconstruction of epicontinental platform settings which developed during the Middle Triassic in the Peri-Tethyan realm.

The Rare Trilobites Exallaspis (Odontopleuridae) and Kosovoproetus? (Tropidocoryphidae) in the Homerian (Silurian) Of The Prague Basin, Bohemian Massif

Abstract The deep-water Aulacopleura koninckii Assemblage in the lower Homerian (T. testis Sub-Biozone) “Aulacopleura shales“ strata at the classical ‘Barrande’s pits’ locality on the Černidla hillside at Loděnice in the Prague Basin is supplemented by the addition of two new trilobite taxa, viz. Exallaspis? perunicana sp. n. and Kosovoproetus? aff. praecursor (Přibyl & Vaněk 1987). The palaeogeographic distribution of Exallapis Ramsköld & Chatterton, 1991 is extended by the occurrence of Exallaspis? perunicana sp. n. and the younger Exallaspis sp. in the upper Homerian (the P. parvus – G. nassa Biozone) of the Prague Basin, reflecting the faunal migration between the southern shelf of the Baltica palaeocontinent and the Perunica microcontinent accross the Rheic Ocean. The small dimensions of the K.? aff. praecursor exoskeletons compared to those of K.? praecursor in the bordering shallow-water Liolalax–Sphaerexochus– Cheirurus Assemblage represent another example of adaptive nanism in trilobites of the Aulacopleura-Raphiophorus Biofacies.

Cambrian (Stage 4 to Wuliuan) brachiopods from Sonora, Mexico

AbstractThe Cambrian successions at the Chihuarruita Hill outcrop, Sonora, Mexico, have yielded two successive linguliform brachiopod assemblages that are transitional between Cambrian Stage 4 and the newly recognized global Wuliuan Stage. The lowermost assemblage includesDictyoninasp.,Paterinasp.,Eothelesp.,Hadrotreta rara? (Cooper), andLinnarssonia arellanoi? (Cooper), coming from the upper part of the Buelna Formation. The younger, recently named El Gavilán Formation contains a more diverse linguliform brachiopod assemblage, includingAcrothele concavaCooper,Batenevotreta?mexicanan. sp.,Dictyonina minutipunctaCooper,Eothelesp.,Eoobolussp.,Hadrotreta rara? (Cooper),Linnarssonia arellanoi? (Cooper),Micromitrasp.,Paterinasp., andPrototretasp. The El Gavilán Formation contains a diverse trilobite fauna suggesting Delamaran age in terms of the Laurentian regional stratigraphical scheme. The base of the global Wuliuan Stage and Miaolingian Series is defined by the first occurrence ofOryctocephalus indicus; in the absence of the index species, the base should be provisionally placed at the base of the El Gavilán Formation. The Wuliuan age of the brachiopod assemblage recovered from the El Gavilán Formation is supported by the occurrence ofAcrothelein the Cambrian biostratigraphical succession of Himalaya, where the genus makes its first appearance in theKaotaia prachinaZone. In addition, the co-occurrences ofAcrotheleandEothelecan be taken as an indication of the Wuliuan age of the fauna. A new biogeographic analysis confirms that theEotheleFauna first appeared at the end of Cambrian Stage 4, as a result of increased faunal migration within the southern tropical latitudes directed from Australasian Gondwana to Laurentia.UUID:http://zoobank.org/6598f51f-cb07-4df3-bd1f-025a13e64edf

Diversity of Crinozoa (Echinodermata: Eocrinoidea, Blastoidea, Crinoidea) from the Paleozoic of MexicoDiversity of Crinozoa (Echinodermata: Eocrinoidea, Blastoidea, Crinoidea) from the Paleozoic of Mexico

Paleozoic outcrops in Mexico containing echinoderms are located to the north, center and south of the country, mainly in the states of Baja California, Sonora, Chihuahua, Tamaulipas, Coahuila, Hidalgo, Puebla, Guerrero, Oaxaca, and Chiapas. These rocks correspond to marine carbonates deposited in warm shallow environments, with an approximate age of 541 to 251 Ma. Also containing a varied and diverse biota made up of phylloid algae, foraminifera (fusulinids), coralline sponges, corals, bryozoans, brachiopods, mollusks, trilobites and echinoderms. In order to know the diversity of Crinozoa from the Paleozoic of Mexico, an analysis of the species documented for the country was carried out, with the objective of contributing to the knowledge of the biostratigraphy and paleogeography of Mexico. The methodology consisted of a detailed analysis of bibliographic sources with information on echinoderms from the Paleozoic of Mexico. Cambrian eocrinoids (Gogia, and Ubaghsicystis) are distributed mainly in Sonora. Crinoid plates from the Carboniferous and Permian, particularly morphospecies of the genera Cyclocaudex, Cyclocrista, Heterostelechus, Lamprosterigma, Mooreanteris, Pentagonopternix, Preptopremnum, and Pentaridica, are widely distributed throughout the country. Analysis of the Mississippian-Permian biota indicates that the cosmopolitan distribution of the fauna studied in this work is due to the connections between the seas of western North America and eastern Asia. The Late Permian benthic fauna of Sonora was widely dispersed in the Tethyan realm, which stretched from western North America to North Africa and Asia. The comprehensive study of Paleozoic marine stratigraphic successions and their biotic content provided information on faunal migrations regarding the Paleozoic carbonate facies. It also contributed to reconstructing the geographical, climatological, and ecological characteristics of the Paleozoic of Mexico.

First discovery of Stegodon (Proboscidea) in Malaysia

A cheek tooth of Stegodon, an extinct genus of Proboscidea, had been discovered in a cave in Gopeng, Perak. The discovery represents the first fossil of Stegodon ever found in Malaysia. Embedded in lithified cave infillings are the associated dental remains from at least three or four other different taxa of fossil mammals commonly found among Southeast Asian Pleistocene-Holocene faunas. The finding provides a unique chance for investigations into the evolution dynamics of Stegodon in this part of Southeast Asia and the species diversity of Proboscidea in prehistoric Peninsular Malaysia. Fossil mammal assemblages from different phases of Pleistocene-Holocene period collected from karstic caves in Peninsular Malaysia, when considered with similar assemblages from other parts of Southeast Asia, have the potential to contribute to our understanding of prehistoric faunal migrations and species compositional changes among the biogeographic (sub)divisions in Southeast Asia. This may ultimately lead to a better knowledge of the possible paleoenvironmental and paleoclimatic fluctuations that influenced patterns of migration and adaptive responses of mammalian faunas in Quaternary Southeast Asia.

First records of Somalinautilus (Cephalopoda: Nautiloidea) from the Jurassic of Southern Germany – inferences for trans-provincial migrations

The Late Jurassic nautiloid Somalinautilus antiquus (Dacqué, 1910), previously only known by the holotype from Lower Kimmeridgian strata of Ethiopia, is reported from the Lower Kimmeridgian (Platynota Zone) of Southern Germany. This unexpected record largely expands the known geographic distribution of this species. Another species of Somalinautilus, S. clavifer Tintant , 1994, is recorded for the first time from the Middle Jurassic (Lower Bathonian, Zigzag Zone) of Southern Germany. A short stratigraphic and palaeogeographic review of Somalinautilus occurrences is provided. Faunal migrations of nautiloids over large distances were probably triggered by sea- level highstands and/or palaeocurrents.

Paleomagnetic insights into the Cambrian biogeographic conundrum: Did the North China craton link Laurentia and East Gondwana?

Abstract Redlichiid trilobite and small shelly fossils indicate strong ties of the North China craton (NCC) to Gondwana during the early Cambrian, while recent discoveries of the characteristic fossils of Laurentia in Wuliuan shales in the eastern NCC imply its possible connection with Laurentia during the middle Cambrian. Here we report a new paleomagnetic pole at 31.8°S, 140.4°E (radius of 95% confidence cone of paleomagnetic pole, A95, = 5.3°), obtained from the Wuliuan (ca. 505 Ma) Hsuchuang Formation, by averaging our new data and existing virtual geomagnetic poles acquired from different parts of the NCC. A positive regional tilt test and the presence of geomagnetic reversals demonstrate that the remanence was primary. The paleomagnetic data permit placing the NCC near 20°N between Laurentia and Australia at ca. 505 Ma, suggesting that the NCC may have played the role of biogeographic link between East Gondwana and Laurentia in the middle Cambrian. Low-latitudinal westward ocean currents may have facilitated faunal migrations from Laurentia to East Gondwanan blocks via the NCC as well as the newly formed tectono-paleogeographic archipelago, which likely further enhanced biological exchange in the late Cambrian.

Faunal mediated carbon export from mangroves in an arid area

The outwelling paradigm argues that mangrove and saltmarsh wetlands export much excess production to downstream marine systems. However, outwelling is difficult to quantify and currently 40–50% of fixed carbon is unaccounted for. Some carbon is thought outwelled through mobile fauna, including fish, which visit and feed on mangrove produce during tidal inundation or early life stages before moving offshore, yet this pathway for carbon outwelling has never been quantified. We studied faunal carbon outwelling in three arid mangroves, where sharp isotopic gradients across the boundary between mangroves and down-stream systems permitted spatial differentiation of source of carbon in animal tissue. Stable isotope analysis (C, N, S) revealed 22–56% of the tissue of tidally migrating fauna was mangrove derived. Estimated consumption rates showed that 1.4% (38 kg C ha−1 yr−1) of annual mangrove litter production was directly consumed by migratory fauna, with <1% potentially exported. We predict that the amount of faunally-outwelled carbon is likely to be highly correlated with biomass of migratory fauna. While this may vary globally, the measured migratory fauna biomass in these arid mangroves was within the range of observations for mangroves across diverse biogeographic ranges and environmental settings. Hence, this study provides a generalized prediction of the relatively weak contribution of faunal migration to carbon outwelling from mangroves and the current proposition, that the unaccounted-for 40–50% of mangrove C is exported as dissolved inorganic carbon, remains plausible.

Bivalves from the Innviertel Group of Allerding in the North Alpine Foreland Basin (lower Miocene, Upper Austria)

During the Ottnangian (Burdigalian, early Miocene), the North Alpine Foreland Basin operated as a sea-way connecting the Central Paratethys Sea with the Rhône Basin in the Western Mediterranean. Within this short time window, an intensive faunal exchange between the two paleo-biogeographic units occurred, which is reflected in macrofossil assemblages. The extraordinarily rich fossil record of the study site, Allerding, located in the westernmost Central Paratethys, provides valuable insights into the composition and origins of the bivalve fauna colonizing the marine gateway. The site documents the early Ottnangian marine transgression over deeply weathered crystalline basement, grading from fossil bearing shallow water clay and sand into the open marine "Schlier" facies of the Ottnang Formation. Despite considerable taphonomic overprint including aragonite leaching and mechanical abrasion of bivalve shells under turbulent shallow-water conditions, a total of 46 species are recorded, including two new species (Lima allerdingensis n. sp. and Astarte danningeri n. sp.). The dominance of suspension feeders, and the presence of several deposit feeders and chemosymbiotic taxa point to well diversified inshore settings, including low intertidal mudflats, as well as seagrass meadows. An abundance of primary and secondary hardgrounds is reflected in the high number of cementing and byssate species, as well as in the occurrence of species drilling actively into hard substrate. Finally, the dominance of active burrowers suggests a patchwork of habitats, where sandy and muddy soft bottoms occur interspersed. Biostratigraphic analysis constrains the deposits to the early to middle Ottnangian, based on the presence of the index species Flexopecten davidi and the concurrence of several taxa, which have their last or first occurrences within this interval. These are predominantly taxa persisting into the Badenian, therefore allowing for a straightforward differentiation between late Eggenburgian and early Ottnangian assemblages. While a few Central Paratethys endemics reflect a continued semi-isolated position of the area, the majority of the newly arriving species are shared with the Mediterranean and NE Atlantic, documenting the establishment of a faunal migration route via the North Alpine Foreland Basin. In the present study the lectotypes of Nucula mayeri Hörnes, 1865, Saccella subfragilis (Hörnes, 1875) and Lucinoma wolfi (Hoernes, 1875) are designated.

Lower Palaeolithic archaeology and submerged landscapes in Greece: The current state of the art

The Balkan Peninsula lies on a key geographical location between Africa and Eurasia. The southern part of the Balkan Peninsula, referred to as the Aegean region, was a passageway for faunal migrations throughout the Pleistocene. Recent advances in the Lower Palaeolithic archaeology of Greece and in the research of the submerged landscapes of the Aegean region prompt a reconsideration of the biogeographical role of this area in Middle Pleistocene hominin settlement and expansion. In this paper, we articulate and elaborate on a working hypothesis, namely that the Aegean region was not a barrier during the Middle Pleistocene but instead it offered attractive lands for occupation and viable pathways for dispersal. Several methodological challenges emerge associated with the dynamic nature of the Aegean context. We propose an interdisciplinary approach to address the challenges. Using available archaeological and palaeogeographical evidence within a GIS-based framework, we seek to explore the ‘hominin factor’ in relation to the changing Aegean landscapes and geographical affordances. Shifting away from the ‘terrestrial Eurocentric’ point of view in the discussion of the patterns of early colonisation of Europe and the dispersal routes followed by hominins, we propose a revised understanding of early European settlement and its eastern gateways.

Evidence for seasonal cycles in deep-sea fish abundances: A great migration in the deep SE Atlantic?

Animal migrations are of global ecological significance, providing mechanisms for the transport of nutrients and energy between distant locations. In much of the deep sea (>200m water depth), the export of nutrients from the surface ocean provides a crucial but seasonally variable energy source to seafloor ecosystems. Seasonal faunal migrations have been hypothesized to occur on the deep seafloor as a result, but have not been documented. Here, we analyse a 7.5-year record of photographic data from the Deep-ocean Environmental Long-term Observatory Systems seafloor observatories to determine whether there was evidence of seasonal (intra-annual) migratory behaviours in a deep-sea fish assemblage on the West African margin and, if so, identify potential cues for the behaviour. Our findings demonstrate a correlation between intra-annual changes in demersal fish abundance at 1,400m depth and satellite-derived estimates of primary production off the coast of Angola. Highest fish abundances were observed in late November with a smaller peak in June, occurring approximately 4months after corresponding peaks in primary production. Observed changes in fish abundance occurred too rapidly to be explained by recruitment or mortality, and must therefore have a behavioural driver. Given the recurrent patterns observed, and the established importance of bottom-up trophic structuring in deep-sea ecosystems, we hypothesize that a large fraction of the fish assemblage may conduct seasonal migrations in this region, and propose seasonal variability in surface ocean primary production as a plausible cause. Such trophic control could lead to changes in the abundance of fishes across the seafloor by affecting secondary production of prey species and/or carrion availability for example. In summary, we present the first evidence for seasonally recurring patterns in deep-sea demersal fish abundances over a 7-year period, and demonstrate a previously unobserved level of dynamism in the deep sea, potentially mirroring the great migrations so well characterized in terrestrial systems.

Recalculating route: dispersal constraints will drive the redistribution of Amazon primates in the Anthropocene

Climate change will redistribute the global biodiversity in the Anthropocene. As climates change, species might move from one place to another, due to local extinctions and colonization of new environments. However, the existence of permeable migratory routes precedes faunal migrations in fragmented landscapes. Here, we investigate how dispersal will affect the outcome of climate change on the distribution of Amazon's primate species.We modeled the distribution of 80 Amazon primate species, using ecological niche models, and projected their potential distribution on scenarios of climate change. Then, we imposed landscape restrictions to primate dispersal, derived from a natural biogeographical barrier to primates (the main tributaries of the Amazon river) and an anthropogenic constraint to the migration of many canopy‐dependent animals (deforested areas). We also highlighted potential conflict zones, i.e. regions of high migration potential but predicted to be deforested.Species response to climate change varied across dispersal limitation scenarios. If species could occupy all newly suitable climate, almost 70% of species could expand ranges. Including dispersal barriers (natural and anthropogenic), however, led to range expansion in only less than 20% of the studied species. When species were not allowed to migrate, all of them lost an average of 90% of the suitable area, suggesting that climate may become unsuitable within their present distributions.All Amazon primate species may need to move as climate changes to avoid deleterious effects of exposure to non‐analog climates. The effect of climate change on the distribution of Amazon primates will ultimately depend on whether landscape permeability will allow climate‐driven faunal migrations. The network of protected areas in the Amazon could work as ‘stepping stones’ but most are outside important migratory routes. Therefore, protecting important dispersal corridors is foremost to allow effective migrations of the Amazon fauna in face of climate change and deforestation.

The oldest record of the bivalve Dosinisca Dall and its implications

Certain species of Dosinia occurring in the Miocene of Kachchh and the Pliocene of Balochistan in reality belong to the subgenus Dosinisca (Veneridae, Dosiniinae). This subgenus was hitherto known from the Quaternary of the Western Pacific Zoogeographic Province. The present study reveals that the first occurrence of Dosinisca is in the Khari Nadi Formation (Aquitanian) of Kachchh, India. The faunal affinity of the Kachchh Basin with the Alpine–European region through the Tethys fauna until Oligocene came to an end in the Lower Miocene due to the uplifting of the Himalayas. Later, during Lower Miocene, faunal migration took place between Kachchh and the Barrow Island off the northwestern coast of Australia, through the East Indies and Timor Island. After Dosinisca thrived in the Indian Subcontinent during Lower Miocene, the receding of marine waters endangered its very existence in this part of the globe. It somehow survived in Balochistan during Pliocene due to an episode of marine transgression. However, it must have migrated eastwards to the East Indies to be eventually established in the Western Pacific Zoogeographic Province.

Linguliform brachiopods across a Cambrian–Ordovician (Furongian, Early Ordovician) biomere boundary: the Sunwaptan–Skullrockian North American Stage boundary in the Wilberns and Tanyard formations of central Texas

AbstractThe Cambrian-Ordovician Diversity Plateau, between the Cambrian Explosion and the Ordovician Radiation, is punctuated by a series of well-documented Laurentian trilobite extinction events. These events define the bounding surfaces of trilobite ‘biomeres’ that correspond to North American stages, including those of the Sunwaptan and Skullrockian. Trilobites show a consistent pattern of recovery across these boundaries, and commonly each extinction and replacement of taxa is interpreted as a single event as changing environmental conditions spurred shoreward migration of shelf or oceanic faunas that displaced established cratonic faunas. Linguliform brachiopods are also abundant in strata of this interval, and we investigate their stratigraphic distribution across the Sunwaptan–Skullrockian Stage boundary in Texas through high-resolution stratigraphic sampling of subtidal sediments. We document complete genus- and species-level turnover of the linguliform brachiopod fauna coincident with trilobite extinction events, suggesting that these brachiopods were affected by the same factors that affected trilobites. The Skullrockian replacement fauna was cosmopolitan, with ties to Gondwana and Kazakhstan and to the Laurentian shelf environment. The timing of appearances of taxa suggests that the faunal migration onto the Laurentian shelf came from elsewhere during a transgression. The disappearance of the Sunwaptan fauna and the arrival of the Skullrockian fauna are distinct events. We suggest that ‘biomere’ events may be complex, and the cause of the extinction is not necessarily the same event that facilitates the appearance of a replacement fauna. We describe one new species,Schizambon langei.UUID:http://zoobank.org/f6a5c11f-cd3d-4c16-b184-d808d3a5285f

Pliocene and Pleistocene chronostratigraphy of continental sediments underlying the Altiplano at La Paz, Bolivia

Continental sediments underlying the Altiplano plateau provide insight into the late Cenozoic evolution of the Central Andes. We characterize the magnetostratigraphy and lithostratigraphy of the upper part of this fill sequence along a transect extending southwestward from the Cordillera Real at La Paz, Bolivia, where it is best exposed. Multiple polarity reversals and the locally extensive, 2.74-Ma Chijini Tuff enable correlation between our six sections and three previously reported sections. The tuff ties the composite polarity sequence to the geomagnetic polarity time scale, demonstrating that the stratigraphic record extends from the latest Gilbert Chron (ca. 3.8 Ma) to the late Olduvai subchron (ca. 1.8 Ma), or possibly Jaramillo subchron (ca. 1.0 Ma). The sequence provides Earth's longest known record of low-latitude glaciation and the only record of Pliocene tropical glaciation. It includes evidence for 16 late Pliocene and Early Pleistocene glaciations, separated by interglacials of sufficient length (>103-104 a) to produce mature soil profiles. Successively larger ice caps formed directly before, during, and after the globally warm mid-Piacenzian (3.265–3.025 Ma), and throughout Plio-Pleistocene climate deterioration. The late Pliocene glacial units predate the onset of widespread Northern Hemisphere continental glaciation and in most cases unambiguously correspond to specific cool peaks of the astronomically tuned, benthic oxygen isotope (δ18O) record, including marine isotope stages MG2, M2, KM2, and G10. The glacial events broadly coincide with those nearer both poles, suggesting inter-hemispheric climate linkages. The early formation and subsequent expansion of ice caps beyond glacier margins of the Last Glacial Maximum suggest that the Cordillera Real likely attained its modern height before ca. 3.4 Ma. The number and timing of glaciations, and long-term sediment accumulation and incision rates suggest that the local Altiplano surface formed by ca. 1.8 Ma, after which headwaters of the Amazon River system breached the Cordillera Real and began to incise the fill sequence. The sequence spans at least 2 Ma before and during the first main pulses of the Great American Biotic Interchange, providing an important record of faunal migration. The arrival of savanna-adapted North American mammals in the Central Andes during this period points to the influence of glaciation on faunal migration in the southern tropics, similar to influences proposed in North and Central America.

Late Pleistocene hares of the Japanese archipelago: Paleobiogeographic implication at the Last Glacial Maximum

AbstractThe Tsugaru Strait is often referred to as Blakiston's Line in biogeography. Although this strait is thought to have become narrower during the Last Glacial Maximum, it did not close completely to form a land bridge. Sea‐level drawdown associated with cooling nevertheless weakened the influence of the Tsugaru Strait as a barrier to faunal migration. The currently accepted hypothesis is that only some large and highly mobile ungulates were able to migrate to Honshu over this strait to the exclusion of small mammals. However, this remains problematic as very few fossils corroborate this idea, and quantitative identification methods for use with tiny fragments of teeth have not been developed. In this study, we determine which of the species Lepus timidus (now distributed on Hokkaido and to the north) and Lepus brachyurus (now mainly distributed on Honshu, Shikoku, and Kyushu) can accurately be identified within a sample of Late Pleistocene Lepus sp. fossils recently unearthed from the Shitsukari‐Abe cave to the immediate south of the Tsugaru Strait. This is because we are unable to exclude the possibility that these fossils are referable to L. timidus on the basis of site location alone. Thus, utilising images of mandibular third premolar teeth obtained via microcomputed tomography scanning, we report (a) linear measurements, (b) a survey of the frequency of appearance of nonmetric traits, and (c) principal component analysis using landmark methods. The results show that fossil representatives of the genus Lepus can be differentiated from extant L. timidus and closely resemble L. brachyurus. Considering the past allopatric distribution of the 2 species suggested by other studies as well as fossil records around the Tsugaru Strait, this result corroborates the existing hypothesis that only large and highly mobile ungulates were able to navigate the Tsugaru Strait.

Preliminary study of the rodent assemblages of Goda Buticha: New insights on Late Quaternary environmental and cultural changes in southeastern Ethiopia

Given its proximity to the Strait of Bab el Mandeb and the Red Sea, the Horn of Africa is particularly important for understanding human and faunal migration events to and from Africa. Towards the end of the Pleistocene, the Middle/Later Stone Age (MSA/LSA) transition represents a critical step in human cultural evolution. However, in the Horn of Africa, the environmental conditions associated with this transition remain poorly understood. The Goda Buticha (Buticha cave) sequence, located in southeastern Ethiopia, and dated from ca. 63 ka cal BP to ca. 1 ka cal BP, provides a rare opportunity to examine the environmental contexts associated with major cultural sequences documented in the region during this time period. A preliminary analysis of the rich microvertebrate (and especially rodent) remains recovered from the levels dated between 43 and 4 ka BP identified fourteen different rodent genera, including two species that are locally extinct in southeastern Ethiopia today. While the taphonomic signature is similar throughout the sequence, indicating an in situ accumulation by an owl without major perturbation, the palaeoecological analysis showed environmental change through time, characterized by open-dry setting during the Late Pleistocene, shifting to wetter and more wooded conditions heading to the Holocene. These results are generally consistent with other diverse records which include the large mammals, speleothems and lake basins records, and allow a better understanding of the dynamics of environmental contexts associated with observed cultural change and continuity in eastern Africa from the Late Pleistocene to Late Holocene.