Biostratigraphy

In the Mid to Late Ordovician the area of the Ougarta Range in north-west Africa occupied a position in relative
proximity to the South Pole. Eight successive low diversity brachiopod faunas, including the lingulide association
dominated by unnamed species of Lingulobolus, the Darriwilian ?Sivorthis fraterna and Tissintia convergens, the
Sandbian to early Katian Drabovinella regia and Tafilaltia destombesi–Rostricellula ambigena associations, the
mid Katian Drabovinella maxima and Svobodaina cf. havliceki associations and the late Hirnantian Plectothyrella
crassicostis chauveli Association are recognised. The brachiopod based correlation with the Middle to Upper
Ordovician succession of the Anti-Atlas in Morocco, suggests the presence of some gaps in the Ougarta section.
The occurrence of Svobodaina cf. havliceki in the Bou MʼHaoud Formation Upper Member suggests its correlation
with the upper part of the Lower Ktoua Formation of the Anti-Atlas. Among the other brachiopod taxa Drabovinella
regia, Orbiculothyris cf. costellata, Tafilaltia destombesi, Rostricellula ambigena, together with the genera Fehamya,
Mezotreta and Leptaena were previously unknown from Algerian Sahara. • Key words: Brachiopoda, Ordovician,
taxonomy, biostratigraphy, Algeria, Gondwana.

The degree of anthropogenic modification of land cover through the mid to late Holocene is of significant interest for archaeologists, climate modellers and conservation ecologists, amongst others. Spatially extensive pollen data provide an appropriate resource for the reconstruction of land-cover change; however, traditional simple methods (e.g. the AP/NAP ratio) do not provide the degree of detail required for these user groups. A range of more sophisticated methods have been developed (e.g. mechanistic model-based methods), but they require a high degree of understanding of the pollen—vegetation relationship, which is resource- and time-consuming. This paper proposes a method of intermediate complexity by which major land-cover changes can be assessed for individual sites and regions. A pseudobiomisation approach is used, in which pollen taxa are assigned to different land-cover classes (LCC), and the sum of adjusted pollen proportions for each class used to determine an LCC affinity score for individual pollen samples within stratigraphic pollen sequences. In a pilot study, data from pollen core sites from northwest Scotland and southwest England for the last 8000 cal. BP have been classified into ten land-cover classes, including predominantly wooded, semi-open and open types. Results highlight how land-cover change was punctuated rather than gradual through the mid to late Holocene, and show how habitat diversity increased after ~6000 cal. BP with the arrival of agriculture, before reaching a minimum in early modern times. This pollen-based method is potentially applicable to the reconstruction of long-term land-cover change within Europe and other temperate-zone regions.

This work provides a detailed taxonomic study of ostracod species from the Dalazi and Tongfosi formations of the Yanji Basin (Jilin Province, NE China). Fourteen species including one new species belonging to nine genera have been recovered: Scabriculocypris tonfosiensis, Scabriculocypris yanbianensis, Cypridea concinaformis, Mongolocypris yanjiensis, Mongolianella kyranbeki sp. nov., Lycopterocypris infantilis, Lycopterocypris sp., Yumenella toorojensis, Candona spp., Cyprois sp., Vlakomia ustinovskii and Vlakomia jilinensis. With the recovery of well-preserved specimens, the sieve pore, ontogeny and sexual dimorphism of Vlakomia jilinensis and Vlakomia ustinovskii are recognized for the first time. The ostracod biostratigraphic correlations suggest that the age of the Tongfosi Formation is Albian and may extend upwards into the Upper Cretaceous, and the Dalazi Formation is not older than the Albian, probably of early Late Cretaceous age. The ostracod faunas of the Tongfosi and Dalazi formations show affinities to faunas of Eastern Mongolia and South Korea, providing evidence of potential faunal exchanges between Northeastern China, Eastern Mongolia and South Korea during the Albian to early Late Cretaceous time. On the basis of their ostracod faunas, the Tongfosi and Dalazi formations represent a shallow-littoral lacustrine depositional environment that potentially included small ephemeral water bodies.

Eighteen rodent species are recognized from the Fitterer Ranch fauna of North Dakota on the basis of more than a thousand collected specimens. Of the species recognized, four are new: the prosciurine aplodontiids Prosciurus hogansoni and Altasciurus leonardi, the heliscomyid Heliscomys borealis, and the cricetid Eumys lammersi. A previously described castorid from this fauna, Oligotheriomys primus Korth, 1998, is considered a synonym of “Eutypomys” magnus Wood, 1937, on the basis of the recovery of lower dentitions but is retained in the genus Oligotheriomys. A single specimen is questionably referred to Microparamys, a genus elsewhere limited to the Eocene (Clarkforkian-Chadronian land mammal ages). The rodent fauna appears to be a combination of predominantly Orellan and Whitneyan species (early Oligocene), suggesting that the section might transcend the Orellan-Whitneyan boundary. However, the rodent fauna does not alter significantly from the lowest to the highest horizons.

New pollen data from four Oligocene floras in volcanic landscapes of Colorado record important climatic shifts that reshaped the local flora and promoted the development of sub-arid vegetation types. We combined new pollen data with previous megafossil evidence to assess vegetation changes during the Eocene–Oligocene Transition (EOT). Pollen data are the basis for updating the list of flora identified at Creede. Local extinctions in response to lower summer rainfall abruptly removed many of the exotic woody taxa of eastern North American and Asian affinity. This loss was followed by the appearance of xeric shrubland taxa of the Ponderosa pine-fir woodland and sagebrush flora that characterize the Colorado area today. Tell-tale genera appear and suggest an understory of shrubs such as Artemisia, Elaeagnus, Ribes, Ephedra, Jamesia, and Shepherdia. Poaceae are also present. Significantly, herbaceous taxa of the Asteraceae, Rosaceae, Cucurbitaceae, Euphorbiaceae, and Caryophyllaceae make their first appearances in the fossil record of Colorado here.

The new Oligocene pollen data record a significant drop in summer rainfall and a climatic cooling at 33.8 Ma of several degrees that relates to the Oi-1 glaciation in Antarctica. The particular taxa that continued after the EOT were a basis for estimating changes in soil moisture during this time. The conditions in Colorado are reminiscent of Wolfe’s “terminal Eocene event.” This remarkable shift precipitated the development of a local pollen and megafossil flora more “modern” in aspect (e.g., a larger proportion of extant local genera are present). The impressive floristic turnover was probably a response to the increasingly continental climate that embraced the area during the Oligocene.

... Burney 1, 5 , Helen F. James 2 , Lida Pigott Burney 7 , Storrs L. Olson 8 , William Kikuchi 3 , Warren L. Wagner 10 , Mara Burney 9 , Deirdre McCloskey 9 ... Because the present floor is only 1–2 m above sea level in most places, it is likely that a lake or marsh was present in the site ...

... Burney 1, 5 , Helen F. James 2 , Lida Pigott Burney 7 , Storrs L. Olson 8 , William Kikuchi 3 , Warren L. Wagner 10 , Mara Burney 9 , Deirdre McCloskey 9 ... Because the present floor is only 1–2 m above sea level in most places, it is likely that a lake or marsh was present in the site ...

This study includes some details of the biostratigraphy of the Northern Thrace Basin, Turkey based on the fossil fungal and algal palynomorphs. These fossils are encountered in the (?) Middle-Upper Eocene turbiditic-deltaic to Oligocene deltaic-Iagoonal-Iacustrine-paludal and Miocene-Pliocene lacustrine-fluvial sediments. Seven new morphological species belonging to six form-genera are erected. Three already established species are also emended.

Terrestrial floras underwent important changes during the Lopingian (late Permian), Early Triassic, and Middle Triassic, i.e., before, during, and after the end-Permian mass extinction. An accurate account of these developments requires reliable correlation. Macrofossils of land plants can only provide a low-resolution biostratigraphy, while detailed zonation schemes based on palynomorphs are available for many regions. Their applicability is still limited due to several factors, such as (micro-)floral provincialism, a lack of suitable marker taxa commonly occurring at important boundaries, and in many cases a lack of independent age control. Nevertheless, these palynostratigraphic schemes are regularly used for dating and correlation of successions between different regions. To support such efforts, the biozonation schemes based on palynomorphs from the Lopingian up to and including the Middle Triassic from across the world are summarized and revised. Thus, a consistent correlation of palynozones with the currently recognized international stages is established.

Late Pliocene-Pleistocene fossil diatom assemblages from Ocean Drilling Program (ODP) Leg 145 Hole 884B in the western subarctic Pacific were investigated to improve the diatom biostratigraphy. Moreover, the paleoceanographic records at Hole 884B were compared with those in Integrated Ocean Drilling Program (IODP) Expedition 323 Holes U1341B and U1343E in the Bering Sea for the time interval of 2.5-0 Ma in order to clarify the differences in the diatom assemblage fluctuations and the history of past ocean circulations around the subarctic Pacific. In Hole 884B, five diatom zones from the Neodenticula koizumii-N. kamtschatica Zone to the N. seminae Zone were identified. The decreases in the relative abundance of temperate-water species were recognized at ca. 1.9 Ma in Hole U1343E, ca. 2.1 Ma in Holes 884B and U1341B. The decreases of the temperate-water species at these sites indicate that a widespread cooling event must have occurred over the subarctic Pacific at ~2 Ma. In addition, the continuous low occurrences of the sea-ice related species from around 2 Ma onward, which indicate the presence of sea-ices, were observed in Sites 884 and U1341. We also point out that the age differences in decrease of temperate-water species at the three sites (i.e., delay in response of the temperate-water species at Site U1343) may be related to changes of seawater inflow from the North Pacific to Sites U1341 and U1343 and of the East Kamchatka Current from the Bering Sea to Site 884.

The presence of abundant age-diagnostic dinoflagellate cysts in Ocean Drilling Program (ODP) Hole 913B (Leg 151), Deep Sea Drilling Project Hole 338 (Leg 38) and ODP Hole 643A (Leg 104) has enabled the development of a new biostratigraphy for the Eocene–Oligocene interval in the Norwegian–Greenland Sea. This development is important because the calcareous microfossils usually used for biostratigraphy in this

Five mandibular and dental specimens referred to the extinct South American ungulate clade Astrapotheria are described. They originate from late middle Miocene deposits of the Ipururo Formation in the Río Inuya-Río Mapuya area, Peruvian Amazonia. The first Peruvian ...

The long-term isolation of South America during most of the Cenozoic produced a highly peculiar terrestrial vertebrate biota, with a wide array of mammal groups, among which caviomorph rodents and platyrrhine primates are Mid-Cenozoic immigrants. In the absence of indisputable pre-Oligocene South American rodents or primates, the mode, timing and biogeography of these extraordinary dispersals remained debated. Here, we describe South America's oldest known rodents, based on a new diverse caviomorph assemblage from the late Middle Eocene (approx. 41 Ma) of Peru, including five small rodents with three stem caviomorphs. Instead of being tied to the Eocene/Oligocene global cooling and drying episode (approx. 34 Ma), as previously considered, the arrival of caviomorphs and their initial radiation in South America probably occurred under much warmer and wetter conditions, around the Mid-Eocene Climatic Optimum. Our phylogenetic results reaffirm the African origin of South American rodents and support a trans-Atlantic dispersal of these mammals during Middle Eocene times. This discovery further extends the gap (approx. 15 Myr) between first appearances of rodents and primates in South America.

Five mandibular and dental specimens referred to the extinct South American ungulate clade Astrapotheria are described. They originate from late middle Miocene deposits of the Ipururo Formation in the Río Inuya-Río Mapuya area, Peruvian Amazonia. The first Peruvian ...