Millennial-scale climatic cycles in the Early Pliocene pollen record of Ptolemais, northern Greece

Early Pliocene lacustrine sediments from the Ptolemais Basin, northern Greece, exhibit a climatically induced cyclicity, which can be correlated with the orbital cycle of precession. Superimposed on precession-controlled cycles, palynological time-series data reveal a higher-order climatic cyclicity with periodicities of ∼10, ∼2.5, and ∼1.5 ka. These millennial-scale vegetation changes are likely to reflect changes of the soil-moisture gradient on mountain slopes, caused by fluctuations in orographic winter-precipitation. Such fluctuations corroborate the concept of a NAO-like North Atlantic climatic teleconnection during Early Pliocene times. The periodicities are similar to those of climate oscillations inferred from Quaternary records. The occurrence of millennial-scale cyclicity in a time interval when the Northern Hemisphere was essentially ice-free, implies an ultimate forcing mechanism that operated independently of changes in the thermohaline circulation in the Atlantic Ocean. The cycles are likely to be related to long-period variations in solar activity.     

Integrated analyses of litho- and biofacies in a Pliocene cyclothemic, alluvial to shallow marine succession (Tuscany, Italy)

Lithofacies analysis of the upper part of the Pliocene succession of the Valdelsa basin (central Italy) unravelled a number of depositional environments, ranging from alluvial plain to coastal, to marine. Strata are arranged in a hierarchy of elementary and composite unconformity-bounded units. A palaeoecological study of macro- (molluscs) and microfossils (pollen, dinocysts, foraminifera) allowed to finely reconstruct sub-environments within fine-grained terrestrial, coastal and marine deposits and thence to track the spatial and temporal change of physical conditions. The stacking pattern of sedimentary units highlights the lateral switching of onshore-offshore gradients and documents relative sea-level changes. These units are interpreted in a sequence stratigraphic framework. Elementary depositional sequences are arranged to form six composite depositional sequences, in turn encased within two major synthems. This hierarchy of unconformity-bounded sedimentary units suggests that sea-level variation has occurred at different time-frequencies. Glacio-eustasy and active tectonism are discussed as the main forcing factors regulating the different scales of sedimentary cyclicity.     

Microendoliths in Lower Pliocene Oysters from the Alt Empordà Basin,NW Mediterranean: Paleoenvironmental Inferences

The study of traces made by microendoliths on Neopycnodonte cochlear shells from a coquina in the Vilacolum area (Alt Empordà basin) has permitted us to identify for the first time 18 ichnotaxa in the Lower Pliocene sediments of the NW Mediterranean. A shallow, euphotic environment with local shaded zones (corresponding to deep shallow conditions) is proposed for this shell bed, owing to the presence of abundant heterotroph microborings and rare cyanobacterial traces as well as to the high number of Rhopalia catenata and Ichnoreticulina elegans. This refines a former interpretation, mainly based on body fossils and macroborings, which suggested simply a shallow depositional environment. The ichnospecies Ichnoreticulina elegans, Rhopalia catenata, ?R. clavigera, Saccomorpha clava, S. terminalis, Polyactina araneola, Entobia mikra, Orthogonum lineare and Aurimorpha varia are identified for the first time in marine Pliocene materials, thus furnishing a more complete picture of the temporal span of some microborers.     

Hominin diversity in the Middle Pliocene of eastern Africa: the maxilla of KNM-WT 40000

The 3.5-Myr-old hominin cranium KNM-WT 40000 from Lomekwi, west of Lake Turkana, has been assigned to a new hominin genus and species, Kenyanthropus platyops, on the basis of a unique combination of derived facial and primitive neurocranial features. Central to the diagnosis of K. platyops is the morphology of the maxilla, characterized by a flat and relatively orthognathic subnasal region, anteriorly placed zygomatic processes and small molars. To study this morphology in more detail, we compare the maxillae of African Plio-Pleistocene hominin fossils and samples of modern humans, chimpanzees and gorillas, using conventional and geometric morphometric methods. Computed tomography scans and detailed preparation of the KNM-WT 40000 maxilla enable comprehensive assessment of post-mortem changes, so that landmark data characterizing the morphology can be corrected for distortion. Based on a substantially larger comparative sample than previously available, the results of statistical analyses show that KNM-WT 40000 is indeed significantly different from and falls outside the known range of variation of species of Australopithecus and Paranthropus, contemporary Australopithecus afarensis in particular. These results support the attribution of KNM-WT 40000 to a separate species and the notion that hominin taxonomic diversity in Africa extends back well into the Middle Pliocene.     

Repetitive changes in Early Pliocene vegetation revealed by high-resolution pollen analysis: revised cyclostratigraphy of southwestern Romania

A high-resolution pollen analysis has been carried out on the Lupoaia section (SW Romania) in order to check whether the repetitive clay–lignite alternations correspond to cyclic changes in climate. Increases in altitudinal tree pollen content appear to have been caused by drops in temperature, while developments of thermophilous elements correspond to rises in temperature, still under humid conditions. Such repeated changes in vegetation, on the whole consistent with the clay–lignite alternations, have been forced by cycles in eccentricity. On the basis of a comparison between the Lupoaia pollen record and (1) European climatostratigraphy (based on reference pollen diagrams documenting global changes), and (2) global climatic curves (eccentricity, δ¹⁸O), the age of the section has been reconsidered. The Lupoaia section (i.e. from lignite IV to lignite XIII) starts just before the C3n.3n Chron and probably ends just before the C3n.1n Chron. The section represents a time span of about 600 kyr, i.e. from about 4.90 Ma to about 4.30 Ma.     

The late Neogene rodent succession of the Guadix–Baza Basin (south‐eastern Spain) and its magnetostratigraphic correlation

In this paper a magnetostratigraphically calibrated biozonation of the Miocene–Pliocene continental record of the Guadix–Baza Basin (south‐eastern Spain) is presented. This biozonation is based on a rodent succession which ranges from the latest Miocene (c. 6 Ma) to the latest Pliocene (c. 2.6 Ma). A total of nine biozones have been defined for the late Miocene and Pliocene, all of them based on the range or concurrent‐range of rodent species: Apodemus gudrunae – Apocricetus alberti Zone, Apocricetus barrierei Zone, Paraethomys aff. abaigari Zone, Trilophomys Zone, Mimomys davakosi Zone, Dolomys adroveri Zone, Mimomys hassiacus Zone, Mimomys polonicus Zone and Kislangia ischus Zone. A magnetobiostratigraphical correlation has been established between these biozones and the standard ATNTS scale, on the basis of the palaeomagnetic analysis carried out on the sections of Negratín, Botardo‐1 and Gorafe. The correlation has been completed with previous palaeomagnetic analysis in the sections of Galera and Zújar. The magnetobiostratigraphical correlation here established indicates a late Messinian age for the Apodemus gudrunae – Apocricetus alberti Zone, a Zanclean age for the Apocricetus barrierei, Paraethomys aff. abaigari, Trilophomys and Mimomys davakosi zones and a Piazencian age for the Mimomys hassiacus, Mimomys polonicus and Kislangia ischus zones. The Dolomys adroveri Zone is mostly Zanclean in age, but its uppermost part belongs to the Piazencian. Therefore, unit MN13 is correlated with the late Messinian, MN14 is correlated with the early Zanclean, most of MN15 is correlated with the late Zanclean, while the uppermost part of MN15 and MN16 are correlated with the Piazencian.     

Distinct protoconchs recognised in three of the larger Mediterranean Cerithium species (Caenogastropoda: Cerithiidae)

The gastropod genus Cerithium includes several polymorphic species which are hardly distinguishable using a morphological approach based on teleoconch characters. Here we show that protoconch characters can be reliably used to identify the larger Mediterranean species (Cerithium alucastrum, C. repandum and C. vulgatum), and to assess their intraspecific variability. Based on a large amount of morphological data, we show that a multispiral, strongly sculptured protoconch (traditionally associated with C. vulgatum) is found in C. alucastrum. This species originated in the Pliocene. A multispiral, weakly sculptured protoconch, not observed previously, is reported for C. vulgatum. A paucispiral protoconch, distinct from those observed previously for C. lividulum and C. renovatum, is reported for C. repandum and can be used for recognising its wide intraspecific variation and understanding its geographical distribution. Cerithium repandum, previously doubtfully recorded outside its type locality, extends back to the mid-Pliocene and is today rather widely distributed in the Mediterranean, although absent from the Aegean Sea and the Alboran Sea. We describe the larval development of C. repandum and C. vulgatum for the first time, confirming their respective non-planktotrophic and planktotrophic development previously inferred from protoconch morphology. Also, we report a possible case of morphological convergence between C. repandum and C. vulgatum occurring in harbour sites, where we found a distinct (possibly Anthropocene) shell form not described previously from other Recent or fossil material.     

New palaeobatrachid records from Asia

This paper describes fossil remains of palaeobatrachid frogs from the Lower Pleistocene of Baturino (south Trans-Ural region) and the lower Pliocene of Rostovka (Western Siberia) localities. The palaeobatrachid remains from Baturino and Rostovka do not show any taxonomically relevant characters and are assigned to Palaeobatrachidae indet. The described remains are the second and youngest occurrence of the family outside Europe. These records show that the geographic distribution of Palaeobatrachidae during the late Cenozoic was much wider than previously known and included an extensive trans-Eurasian area.