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Rio graben is a region of significant stratigraphic and palaeontological interest where several environmental changes have been recorded during the Quaternary. These changes are a result of active tectonism, related to the well-known rifting process that has been occurring in the geotectonic region of the Corinth-Patras Rift, as well as of the influence of continuous eustatic and climatic changes. Fossil assemblages from Middle to Upper Pleistocene transitional to marine and terrestrial sedimentary sequences located at Sichaena (Rio Graben) on the west side of Charadros river in NW Peloponnesus, Greece, are analyzed herein in order to distinguish tectonic and eustatic controls. The name of the studied section is Vigla 1 (50 m thickness), belonging to the NE-trending Rio graben, a structure bridging the Corinth graben to the east and the Patras graben to the west. The presence of two normal antithetic second order faults and an unconformity were identified separating the studied stratigraphic section into four distinct sedimentological sequences. The purpose of this work is to determine the palaeoenvironmental conditions of the studied section and to unravel the Middle-Late Pleistocene palaeoenvironmental changes. The micro-fauna evidences oligohaline lagoon sediments at the lower sequence (Sequence 1). Conversely, at the middle (Sequence 2) and at the upper sequence (Sequence 3), the recorded species indicate lagoonal to shallow marine depositional environments. At the top of the section, an unconformity brings into contact Sequence 3 with a sequence consisting a red conglomerate (Sequence 4) that indicates an alluvial fan environment. In order to constrain chronologically the sediments Optically Stimulated Luminescence (OSL) dating was applied. According to the OSL dating results, an Upper Middle Pleistocene age has been attributed for the studied sequences. Moreover, projecting the dating results to the marine isotope curve, a high degree of consistency can be seen between the OSL ages and MIS 7e, 7c and 6d, where the transition from lagoonal facies to shallow marine alternations in sequence 2 correlates well with the MIS 7c highstand, and sequence 3 with MIS 7e and the MIS 6d low stand. Thus, our results indicate the spatial palaeoenvironmental evolution of the studied area which during the Upper Middle Pleistocene is characterised by intense local tectonic movements in conjunction with eustatic sea level changes.

The use of life tables in age-graded mandibles of the endemic pygmy hippopotamus Hippopotamus minor from Aetokremnos Cyprus suggests that death occurred by natural causes such as accidents, genetic abnormalities and endemic diseases rather than catastrophic causes. Comparison of H. minor and modern Hippopotamus amphibius life tables suggests the birth of one offspring per female per year and the occurrence of mating and birth seasons. Hunting by prehistoric humans whose tools were found in proximity with the hippopotamus bones is not justified by the life tables that have been produced. The use of the wet rockshelter of Aetokremnos as a living area during the day, in the same way that extant H. amphibius use lake water, is instead proposed as a probable explanation for the extensive accumulation of bones.

The complex interaction of local tectonics and volcanism usually produces palaeoenvironments that require to be studied in detail in order to define the role of each factor in the local palaeoenvironmental evolution. This is the case for the Sousaki Basin lying at the eastern part of the Gulf of Corinth. It presents a complex Pliocene and Pleistocene stratigraphy, affected by deformational processes due to the local tectonic regime. The Sousaki volcano is a low standing volcano that constitutes the western endpoint of the South Aegean Volcanic Arc and may also contribute to the palaeoenvironmental evolution of the basin. The studied section, in the Sousaki Basin, consists of marly and conglomeratic layers with intercalations of organic rich sediments. The base of the section consists of impermeable volcanic products. A micropalaeontological analysis based on 29 samples has been conducted in order to reconstruct the palaeoenvironment after the termination of the activity of the last volcanic period. A diversified fauna has been retrieved, consisting of Gelasian (early Pleistocene) ostracods, gastropods, diatoms, charophyte gyrogonites, thecamoebians, fish otoliths and teeth. Count-based statistical treatments performed on ostracod species revealed that a volcano-tectonic lake evolved after the emplacement of the volcanic products in the basin. Afterwards, a braided river environment dominated the landscape. Due to the lateral migration of the riverbed, several laterally evolving sub-environments were established, ranging from marginal lakes to marshes. Ultimately, the palaeoenvironmental reconstruction of the study area revealed the formation, evolution and demise of a tectonically controlled volcanic lake.

Sedimentological studies of the Upper Cretaceous–lower Eocene limestones in the western part of the Ionian basin (Araxos area) indicate that these deposits are composed of calciturbidites interbedded with breccia-microbreccia. Breccia - microbreccia deposits are structureless, display channelized geometry with calciturbiditic blocks internally to the channels. Most of the clasts were sourced from the underlying Lower Cretaceous “Vigla limestones”. Calciturbidites include Ta to Te Bouma sub-divisions, and are organized in cycles that form channelized deposits with a high degree of amalgamation. Statistical analysis confirms the presence of order in the sub-division sequence. The thickness of event beds in the studied section shows a lognormal statistical distribution, typical of turbidite successions. Limestone microfacies suggest deep-water deposits and reworked shelf deposits. The intense extensional tectonic activity in the Ionian basin during the Early Cretaceous, with synthetic and antithetic faults, produced active platform margins and asymmetrical grabens. In this regime, large amounts of coarse-grained material became available and accumulated in the basin. High slope gradients led to slumping. During the Late Cretaceous, the uplifted margins of the grabens caused erosion of the pre-existing deposits of the Lower Cretaceous “Vigla Formation”. This event led to the accumulation of channelized microbreccia and breccia units and transport of platform deposits by turbidity currents. The Early Cretaceous to early Eocene depositional history in the Ionian Basin indicates that the regional tectonic activity, rather than the eustatic sea-level changes, was the major factor that influenced the basin evolution, suggesting a syn-rift stage being active from the Jurassic to the early Eocene.

Pollen analysis was performed on a Lower Pleistocene lacustrine sedimentary sequence outcropping in Sousaki Basin, eastern Gulf of Corinth, Greece for the first time. The palynological assemblages revealed a stable climate, with regard to the glacial/interglacial climate variability timescale, with minor fluctuations in humidity, expressed as a relatively wet phase between 13.1 and 19.3 m and some transient increased aridity and humidity events. A Mediterranean type of vegetation presenting altitudinal zonation was evidenced for the first time in this region. Pinus and Quercus dominate, accompanied by other arboreal and non arboreal plants. The presence of rare taxa such as Taxodiaceae, Engelhardia, Liquidambar, Tsuga and Cedrus in very low percentages shows that these taxa remained in the area as relicts sometime between 2.8 and 1.5Ma. Palaeovegetation patterns from the Balkan Peninsula are lacking, especially during the Early Pleistocene. Thus, in this study a palaeoclimate reconstruction of the Early Pleistocene Sousaki Basin based on palynological data, is presented accentuating the effect of global climate changes in an area where no other similar records exist.

The fossil remains of the genus Pinus are common in the European Paleogene and Neogene record. Apart from seed cones, most of the vegetative remains are difficult or even impossible to accurately classify in the modern systematic schemes of the genus. In the late Miocene assemblage of Pitsidia (Messara Basin, southern Crete) Pinus and Myrica remains dominate with thousands of vegetative and fertile specimens. The outcrop comprises a 4.5 to 5.0 m thick sequence of silts and sands, rich in plant fossils. The exceptional preservation of some specimens provides significant micro-morphological and anatomical details of taxonomic value. The Pitsidia pine remains include dwarf shoots, long shoots, isolated needles, fascicle bracts, bud scales, male cones, isolated scales of male cones, seeds and ovulate cone scales. We were able to classify the material to at least subgenus and in some cases section. Both subgenera Pinus and Strobus occur in the assemblage. Concerning the dwarf shoots, three different pine species were identified, Pinus sp. – two-needled fascicles (subgen. Pinus ), Pinus sp. – five-needled fascicles (subgen. Strobus ) and the proposed new species Pinus pitsidiensis (subgen. Pinus ) for the abundant three-needled fascicles. Lastly, we reconstruct the whole plant of P. pitsidiensis sp. nov. and discuss its paleoecology.

Ostracods are important palaeoenvironmental tools and for this reason the study of their palaeoecology and geographic distribution must be enhanced in the frame of a unified geographic approach. The PLOSTRAC’s project (Study of Pleistocene ostracods from central and southern Greece: Digital imaging of a palaeoenvironmental tool) main aim is to study the Pleistocene ostracods deriving from sedimentary successions from central and southern Greece and provide a bibliographic database of Pleistocene ostracod-bearing sequences in the study area accompanied by SEM pictures of the identified species. This output can be used as a reference point for future studies not only in Greece but also in the Eastern Mediterranean region as well. This work presents new data from brackish and marine Pleistocene sequences in Peloponnesus, the Ionian Islands (Zakynthos and Cephalonia) and Crete. A total number of 166 taxa were identified from the processed samples. The ostracods belong mainly to the families Trachyleberididae and Hemicytheridae. The studied sedimentary sequences cover the entire Pleistocene Age and range between purely brackish to deep marine assemblages. Moreover, according to both the palaeoenvironmental interpretation of the studied sections and the published literature, across Northern Peloponnesus during the Pleistocene mostly brackish to shallow marine conditions prevailed. Moving to the south and also to the Ionian Islands and Crete deep marine palaeoenvironments were observed.

Climatic oscillations during the Pleistocene were controlled by glacial/interglacial cycles. Such oscillations are commonly imprinted into sediments and fossils from transitional marine environments, as is also the case in Sousaki Basin (Eastern Gulf of Corinth, Greece). Nevertheless, the records become scarcer as we go back in time. During the Lower Pleistocene, Sousaki Basin (Eastern Gulf of Corinth, Greece), was dominated by transitional marine environments. Micropalaeontological analysis has been carried out in sedimentary sequences to identify the evolution of the palaeoenvironments in an area where intense tectonic activity occurred, being at the western end of the Hellenic volcanic arc and at the eastern end of the Corinth rift. The recovered ostracod assemblage revealed a primarily brackish environment. Deposition took place in a coastal lagoon which was subjected to constant salinity changes. The palaeoenvironment in the basin evolved from a delta fan environment to an outer lagoon with possible connection to a sublittoral marine environment at the top. This evolution coincides and therefore is attributed to minor climate oscillations that occurred during the Early Pleistocene.

In the present study, results from the examination of mammalian teeth from the cave of Kalamakia with modern techniques, as well as a qualitative overview of the microvertebrate and lithic material, are presented together with a revision of previous related work done for the site, in order to assess the palaeoenvironmental conditions in the area and the role they played in the Neanderthal's repeated occupation of the cave. Geometric morphometrics analyses performed on the first lower molars of Microtus spp. individuals revealed persistent populations of the subgenus Terricola, in which the presence of Microtus thomasi and Microtus subterraneus are continuous through the stratigraphic units. Mesowear analyses performed on ruminant teeth showed no significant variation in toothwear through time, except for relatively elevated levels of dietary abrasion for the more recent samples. The study of the lithics revealed that Neanderthals visited the cave in alternating short and more permanent episodes of occupation, with the human occupants exhibiting special concern for raw material economy, while exploiting poor raw materials for the construction of their tools. The overview of the microvertebrate remains showed a growing trend towards the upper stratigraphic units, where taxa typical of temperate climate, open woodland and shrubland become more dominant. These results, along with observations derived from previous studies, suggest that temperate climate and open environment were the factors that mainly contributed to making the cave of Kalamakia attractive as a habitation site to the humans of the area., Earth Sciences, Paleobiology, Paleoecology, Paleontology, Culture heritage, Late Pleistocene, palaeoenvironment, Geometric morphometrics, mesowear analysis, Kalamakia Cave, Middle Palaeolithic, Palaeoecology, Microtus.

Cyprus, the largest Eastern Mediterranean island, hosted a highly impoverished endemic mammalian fauna during the Pleistocene to early Holocene times. This was a result of its extreme biogeographic isolation since its formation, which prevented the immigration of most terrestrial mammals, except for those with apparent sea channel crossing abilities. The main faunal elements are the extremely dwarfed hippo Phanourios minor, commonly found in many sites across the island, and the dwarf elephant Palaeoloxodon cypriotes. The latter is a very small-sized elephant species, comparable in size with the Siculo-Maltese Palaeoloxodon falconeri. Larger dental specimens found sporadically during the last century, raised the possibility that a second endemic elephant, larger than P. cypriotes, may have also existed in Cyprus. Here we describe a skull recently excavated in the coastal area of Xylophagou, SE Cyprus, which provides evidence that, indeed, two elephant species have existed on the island. The larger species, Palaeoloxodon xylophagou n. sp., is still strongly dwarfed and characterised by elongated, low and wide skull, diverging tusk alveoli and comparatively large molars. Dimensionally the dentition is distinctly larger than P. cypriotes and close to Palaeoloxodon tiliensis, though the skull size is intermediate between P. tiliensis and P. falconeri. Both Cypriot elephant species exhibit morphological affinities with Palaeoloxodon antiquus, which is their probable ancestor. Stratigraphic data suggest that P. xylophagou is older (late Middle Pleistocene), while P. cypriotes is more recent (latest Pleistocene to early Holocene) and may have descended from the former or – less probably – evolved as a result of a separate, more recent colonisation event.

Two requirements for pivoting a cumulative distribution function (CDF) in order to construct exact confidence intervals or bounds for a real-valued parameter θ are the monotonicity of this CDF with respect to θ and the existence of solutions of some pertinent equations for θ . The second requirement is not fulfilled by the CDF of the maximum likelihood estimator of the exponential scale parameter when the data come from some life-testing scenarios such as type-I censoring, hybrid type-I censoring, and progressive type-I censoring that are subject to time constraints. However, the method has been used in these cases probably because the nonexistence of the solution usually happens only with small probability. Here, we illustrate the problem by giving formal details in the case of type-I censoring and by providing some further examples. We also present a suitable extension of the basic pivoting method which is applicable in situations wherein the considered equations have no solution.

This study presents sedimentological, palaeontological, geochemical, mineralogical, and organic petrography data from a 30 m deep core representing a Mid- to Late Holocene lagoonal depositional environment, of a coastal area of Amvrakikos Gulf, Western Greece. Three horizons were dated using 14C. The sedimentological, palaeontological and geochemical interpretations of the lagoonal sediments reveal three major lithological units deposited between around 5200 and 1600 BP. The upper lithological unit extended to a depth of 11.20 m, the middle from 11.20 to 21.30 m, and the lower one from 21.30 to 30.00 m. A mean rate of sedimentation of 5.7 mm/y and a maximum rate of 12.6 mm/y were estimated. The mineralogical analysis and the magnetic susceptibility of the core points to a constant sediment – source supply. The Mid- to Late Holocene depositional environment mainly reflects inundation by the braid plain of the Arachthos and secondarily by the Louros River. The reconstruction of the depositional environments corresponds to a shallow marine and deltaic brackish lagoon and specifically to an environment proximal to river supply. The high rates of sedimentation, as well as the interpretation of depositional environments, indicate that the coastal sedimentological processes during the Mid- to Late Holocene were mainly controlled by the progradation of river deltas. Moreover, the geochemical proxies, the recovered molluscs and the microfauna, as well as the organic petrography analyses indicate periods of dysoxic and hypoxic conditions. These Holocene dysoxic and hypoxic events indicate that the recent dystrophic crises in the Amvrakikos Gulf are not only the result of human activities but also the contribution of natural processes.

In this paper, we consider random variables counting numbers of observations that fall into regions determined by extreme order statistics and Borel sets. We study multivariate asymptotic behavior of these random variables and express their joint limiting law in terms of independent multinomial and negative multinomial laws. First, we give our results for samples with deterministic size; next we explain how to generalize them to the case of randomly indexed samples.

In this paper, we establish some Pitman closeness results concerning the sample median from a symmetric continuous distribution. We show that when an odd sample size is increased by one, the sample median becomes Pitman-closer to the population median, while when an even sample size is increased by one, the sample median need not be Pitman-closer. We establish the former through probabilistic derivations while the latter is through a counterexample. We also discuss the situation when the sample is increased by two observations.

A simple iterative estimation procedure for computing the nonparametric maximum likelihood estimator (NPMLE) in biased sampling models is discussed and studied in detail. A proof of convergence is provided. Numerical experiments show that the algorithm is significantly faster in terms of CPU time compared with the standard procedure.

We report analytical work undertaken in order to identify the geochemical taphonomy of the osteological collection (human and animal bones) recovered from a 1950s excavation at Katsambas, a small cavity in the marly limestone on the west bank of Kairatos River, Crete. The site had funerary use and yielded material of Neolithic and Minoan age with poor stratigraphical association. Disintegration of provenance labels from bags has introduced further uncertainty about the contexts of recovery. Samples of human and animal bones that macroscopically appear to belong to three taphonomic categories were studied by means of FT-IR spectroscopy, TEM microscopy and REE analysis to explore the taphonomical processes the bones have undergone. Although not novel in palaeontological research the use of REE opens a new path to investigating poorly provenanced osteological collections from old excavations. Such geochemical work offers a proxy to their relative dating through the evaluation of the time span bones have remained in the sediments and their respective taphonomic histories.

In this paper, boselaphine material from several localities in the area of the Hasnot Pakistan, is described, identified, and discussed. Four species that belong to three different genera of the tribe Boselaphini have been found: Selenoportax vexillarius, S. lydekkeri, Pachyportax latidens and Eotragus sp. Eotragus sp. is reported for the first time from the Hasnot and consequently from other Upper Middle Siwalik sediments of Pakistan and equivalent strata of the world, extending the range of the genus from the Lower to the Middle Siwaliks. Reviewing the Siwaliks’ Selenoportax species, S. dhokpathanensis Akhtar and S. tatrotensis Akhtar are synonymized with S. lydekkeri and S. vexillarius, respectively.

In this paper, Pitman closeness of order statistics to the median of a distribution is discussed. In particular, it is shown that the sample median is the Pitman-closest order statistic to the population median in some general situations, and expressions for probabilities of closeness are also derived.

Coral skeletons are archives of chemical proxies which enable paleoenvironmental reconstructions to be made at subannual resolution. Stable oxygen isotope ( δ 18 O) ratios of these archives reflect sea surface temperature (SST) as well as the δ 18 O composition of ambient seawater. The δ 18 O seawater composition is not only controlled by global ice build-up, but river discharge and the hydrological balance of evaporation and precipitation, all influencing sea surface salinity (SSS), also play an important role in marginal seas. New sub-annually resolved coral δ 18 O data were measured and evaluated together with published data from reef coral communities of Late Miocene age from Crete (Eastern Mediterranean). This time-window is of particular importance for the paleoceanographic evolution of the Mediterranean Sea, because it covers the successive closure of the marine gateways connecting the Mediterranean with the Atlantic Ocean, which culminated in the onset of the Messinian salinity crisis (MSC) at 5.96 Ma. Corals were recovered from eight time-slices dated by 87 Sr/ 86 Sr chronostratigraphy and cover a time-window from ∼ 10 to ∼ 7 Ma to monitor pre-MSC environmental changes. The oxygen isotope composition of the reef corals Porites and Tarbellastraea document significant changes in mean annual δ 18 O as well as in mean δ 18 O seasonality during the Late Miocene. Tortonian and Messinian coral mean annual δ 18 O values differ by up to 1.72‰ and exhibit substantial variability. Since SSTs can be considered rather constant over the Late Miocene according to lithological, paleobotanical and geochemical evidence, the mean annual δ 18 O variations in the corals appear to result from changing SSS during the Late Miocene prior to the MSC. This result is in contrast to earlier concepts that, despite increasing isolation of the Mediterranean basin starting at about 9 Ma ago, SSS did not change until only 300 kyr prior to the deposition of the first MSC evaporites. Mean seasonal δ 18 O amplitudes are lower by 0.4‰ in the Messinian compared to those of the Tortonian corals, which may be due to enhanced summer evaporation. Spectral analyses of Tortonian and Messinian coral δ 18 O records indicate significant interannual variability with periods of 2–3 and 4–5 years. Such variability is similar to that found in modern records. In the modern case, the Iceland Low and Azores High pressure centers influence climate in the Circum-Mediterranean region. Combined with evidence from other studies, the coral records of this study suggest that a similar pressure field system was already in existence in the early Late Miocene.

In this paper, we prove that blocks of ordered data formed by some conditioning events are mutually independent. We establish this result by considering the usual order statistics, progressively censored order statistics, and concomitants of order statistics.

The Bayesian estimation of a special case of mixtures of normal distributions with an unknown number of components is considered. More specifically, the case where some components may have identical means is studied. The standard Reversible Jump MCMC algorithm for the estimation of a normal mixture model consisting of components with distinct parameters naturally fails to give precise results in the case where (at least) two of the mixture components have equal means. In particular, this algorithm either tends to combine such components resulting in a posterior distribution for their number having mode at a model with fewer components than those of the true one, or overestimates the number of components. This problem is overcome by defining-for every number of components-models with different number of parameters and introducing a new move type that bridges these competing models. The proposed method is applied in conjunction with suitable modifications of the standard split-combine and birth-death moves for updating the number of components. The method is illustrated by using two simulated datasets and the well-known galaxy dataset.

Identifiability, existence and uniqueness of the non-parametric maximum likelihood estimator (NPMLE) in biased sampling models are thoroughly investigated. The conditions for existence and uniqueness are considered from a different perspective and proofs are simplified. An extension to semi-parametric models is provided.

Recently a power study of some popular tests for bivariate independence based on ranks has been conducted. An alternative class of tests appropriate for testing not only bivariate, but also multivariate independence is developed, and their small-sample performance is studied. The test statistics employ the familiar equation between the joint characteristic function and the product of component characteristic functions, and may be written in a closed form convenient for computer implementation. Simulations on a distribution-free version of the new test statistic show that the proposed method compares well to standard methods of testing independence via the empirical distribution function. The methods are applied to multivariate observations incorporating data from several major stock-market indices. Issues pertaining to the theoretical properties of the new test are also addressed.

The multinomial distribution is a key-distribution for several applications. For this reason, many methods have been proposed so far in the literature in order to deal with the problem of simulation from it. A slight modification is suggested which can be used in conjunction with any of the standard schemes. The proposed variation is a two-stage procedure based on the property of the multinomial distribution that for any partition of the set of outcomes the vector of total frequencies of each part follows also a multinomial distribution with parameters adjusted accordingly. It is empirically exhibited that this variation is faster than the original procedures in case the numbers of independent trials and possible outcomes are both large. The time reduction is illustrated via a simulation study for several programming languages such as R, Matlab, and others.

We describe a partial skeleton of Metailurus parvulus from the Turolian site of Kerassia 1 (Northern Euboea, Greece). The material, which consists of a mandible, the anterior and posterior limb-bone elements, some sternal bones and some vertebrae, is the most complete known of this species. The dental material is compared to specimens from Pikermi and Chomateri (Greece), and China. The limb-bones available offer us the possibility to discuss the status of some previously described specimens from Pikermi. The limb proportions indicate that M. parvulus had elongated posterior limbs relative to the anterior ones, which reflects developed jumping skills. M. parvulus had moderately developed cursorial abilities, intermediate between open and closed habitat felids, and probably frequented primarily relatively open woodlands.

This paper considers estimation of the ratio of means and the regression function in Downton's (J. Roy. Statist. Soc B 32 (1970) 408) bivariate exponential distribution. Unbiased estimators are given and, by presenting improved estimators, they are shown to be inadmissible in terms of mean squared error. The results are derived by conditioning on an unobserved random sample from a geometric distribution which provides conditional independence for the statistics involved.

This paper deals with decision theoretic estimation of the middle among three ordered location parameters under an arbitrary strictly convex loss function. Double-shrinkage estimators are produced which use all the available data and improve on single-shrinkage ones. The case of estimation of the middle among three ordered scale parameters with the possible existence of nuisance parameters is also discussed.

We consider the problem of decision-theoretic estimation of the ratio of generalized variances of two matrix normal distributions with unknown means under a general loss function. The inadmissibility of the best affine equivariant estimator is established by exhibiting various improved estimators. In particular, under certain conditions on the loss, two classes of improved procedures based onallthe available data are presented. As a preliminary result of independent interest, an improved estimator of an arbitrary power of the generalized variance of a matrix normal distribution with an unknown mean is derived under a general strictly bowl-shaped loss.

A confidence interval for the generalized variance of a matrix normal distribution with unknown mean is constructed which improves on the usual minimum size (i.e., minimum length or minimum ratio of endpoints) interval based on the sample generalized variance alone in terms of both coverage probability and size. The method is similar to the univariate case treated by Goutis and Casella (Ann. Statist. 19 (1991) 2015–2031).