An Artiodactyl Tracksite at Musandam Peninsula,Sultanate of Oman

Here we report an artiodactyl trackway from Musandam Peninsula, Sultanate of Oman. Epireliefs of the tracks are preserved in poorly consolidated aeolian deposits now making up the ceiling of a coastal cave. As an interesting morphological feature, the trackway documents the trackmaker negotiating a slippery dune slope at an angle.     

Taxonomic diversity gradients through geological time

Abstract. There is evidence from the fossil record to suggest that latitudinal gradients in taxonomic diversity may be time‐invariant features, although almost certainly not on the same scale as that seen at the present day. It is now apparent that both latitudinal and longitudinal gradients increased dramatically in strength through the Cenozoic era (i.e. the last 65 my) to become more pronounced today than at any time in the geological past. Present‐day taxonomic diversity gradients, in both the marine and terrestrial realms, are underpinned by the tropical radiations of a comparatively small number of species‐rich clades. Quite why these particular taxa proliferated through the Cenozoic is uncertain, but it could be that at least part of the explanation involves the phenomenon of evolutionary escalation. This is, in essence, a theory of biological diversification through evolutionary feedback mechanisms between predators and prey; first one develops an adaptive advantage, and then the other. However, there may also have been some form of extrinsic control on the process of tropical diversification, and this was most likely centred on the phenomenon of global climate change. This is especially so over the last 15 my Various Late Cenozoic (Neogene) vicariant events effectively partitioned the tropics into a series of high diversity centres, or foci. It has been suggested that, in the largest of these in the marine realm (the Indo‐West Pacific or IWP centre), a critical patterns of islands acted as a template for rapid speciation during glacioeustatic sea level cycles. The same process occurred in the Atlantic, Caribbean and East Pacific (ACEP) centre, though on a lesser scale. Tropical terrestrial diversity may also have been promoted by rapid range expansions and contractions in concert with glacial cycles (a modified refugium hypothesis). We are beginning to appreciate that an integrated sequence of Neogene tectonic and climatic events greatly influenced the formation of contemporary taxonomic diversity patterns.     

First record of late middle Miocene Moschidae from Turkey: Micromeryx and Hispanomeryx from Catakbağyaka (Muğla,SW Turkey)

Here, we describe remains of Micromeryx sp. and Hispanomeryx sp. from the middle Miocene locality Catakbağyaka (MN 7/8). This is the first record for Miocene Moschidae for the late middle Miocene in Turkey and verifies the importance of Turkey as a corridor for the dispersal of Eurasian mammals. Furthermore, the record from Catakbağyaka confirms that the sympatric co-occurrence of two Miocene moschid taxa in one locality appears to be a common phenomenon.     

西秦岭地区东昆仑-秦岭断裂系晚新生代左旋走滑历史及其向东扩展

要通过在TM遥感图像解译和野外观测的基础上,描述了东昆仑断裂带东段活动形迹的组成和活动断层地貌特征,阐述了甘南高原西秦岭地区新近纪拉分盆地的沉积-构造特征,提出了该区东昆仑-秦岭断裂系晚新生代左旋走滑伸展-走滑挤压-走滑伸展的3个阶段的构造变形模式。指出,中新世晚期至上新世早期,东昆仑-秦岭断裂系以左旋走滑伸展活动为主,伴随着西秦岭地区拉分盆地的形成和超基性火山岩群的发育。这期左旋走滑伸展活动向东扩展导致了渭河盆地新近纪引张应力方向由早期的NE-SW向转变为晚期的NW—SE向。上新世晚期以来(约3．4Ma以前),东昆仑-秦岭断裂系以左旋走滑挤压活动为主,导致早期拉分盆地的轻微褶皱变形,走滑挤压活动主要集中在东昆仑东段玛沁-玛曲主断裂带上。该期构造变动持续到早更新世,它的向东扩展产生了广泛的地壳形变效应,包括青藏东缘岷山隆起带的快速崛起、华北地区汾-渭地堑系的形成和发展以及郯庐断裂带右旋走滑活动等。中、晚更新世时期,断裂系以走滑伸展变形为主,主要集中在东昆仑断裂带东段3个分支上,地块向东挤出伴随着顺时针旋转。     

Gastropod palaeohabitats of Miocene Lake Randeck Maar and its hinterland defined by an actualistic genus-level approach

The Randeck Maar lake sediments from SW Germany were deposited during a climatic phase known as the Mid-Miocene Climatic Optimum, providing a unique window into this last favourable period for a more thermophilous fauna in Central Europe. Previous palaeoecological reconstructions of Randeck Maar's environment focused on the flora and vertebrate fauna. Here, we present a palaeoecological analysis using gastropods as proxies by means of an actualistic genus-level approach. This approach is grounded in comparisons of habitat preferences between extant and fossil congeners and thus obviously requires a sound taxonomic framework. Despite being commonly applied in the literature, this approach has hardly been defined so far. Therefore, we thoroughly delineate it, exploring its applicability, potential and shortcomings. The molluscan fauna of Randeck Maar counts with 32 species of continental snails, mostly terrestrial pulmonates, related to the following palaeohabitats: littoral, supralittoral, rocky walls, shrubland, forests and open habitats. The gastropods indicate a warm-temperate climate with a dry season, in line with previous works on Randeck Maar's flora and vertebrates.     

渤海湾盆地沾化凹陷新近系馆陶组储层敏感性

储层敏感性分析是判别储层伤害程度的重要手段，对后期高效开发和剩余油挖潜具有重要意义。选取渤海湾盆地沾化凹陷垦西油田新近系馆陶组储层岩心样品，结合薄片观察、X射线衍射分析及压汞测试、流动水驱实验，对馆陶组上段和下段储层伤害指数和敏感性特征进行了分析。研究结果表明：①渤海湾盆地沾化凹陷新近系馆陶组储层岩石胶结疏松，孔隙结构总体孔径较大，孔喉分布较均匀，连通性较好；岩石矿物组成以石英、斜长石、钾长石和岩屑为主，黏土矿物主要包括高岭石、伊利石、绿泥石及伊蒙混层；馆上段以细粒为主，馆下段以中粒为主。②馆陶组储层普遍具中等速敏性、弱碱敏性、弱盐敏性特征；上下两段的酸敏性特征差异较大，上段具有非酸敏性特征，而下段具有强酸敏性特征，酸敏指数达78.28%；③研究区馆陶组铁白云石、绿泥石含量及孔隙结构对储层敏感性具有控制作用。④控制注采流速是研究区开发方案中的重要内容，对馆下段酸敏带来的储层伤害要进行防护和治理。     

A seedsnipe (Aves,Charadriiformes, Thinocoridae) from the Ensenadan Age/Stage (early-middle Pleistocene) of Buenos Aires,Argentina

The fossil record of the Charadriiformes in South America is scarce and limited to the Neogene of Argentina and Peru. In the present contribution, we present and describe a nearly complete tarsometatarsus of Thinocorus rumicivorus (Least Seedsnipe) from the Ensenadan Age/Stage (early-middle Pleistocene) of Punta Hermengo, Buenos Aires province, Argentina, which constitutes the youngest record for the species to date. We also compare the material with extant and fossil Thinocoridae. The stratigraphic range of the fossil predates the Matuyama/Brunhes boundary and is coincident with the biozone of Mesotherium cristatum, which indicates a more humid and warmer climate than the present for the species.     

Subspecies divergence and pronounced phylogenetic incongruence in the East-Asia-endemic shrub Magnolia sieboldii

Background and AimsThe biogeographic patterns of the East-Asia-endemic shrub Magnolia sieboldii, in which the range of the subsp. sieboldii is interposed with the disjunct distribution of subsp. japonica, implies a complex evolutionary history, involving rapid speciation and hybridization. Here, we aim to reveal the evolutionary and phylogeographic histories of the species with a particular focus on the time of subspecies divergence, the hypothesis of secondary hybridization and the Pleistocene survival of each subspecies, using a combination of genetic analyses and ecological niche modelling.MethodsGenetic variation, genetic structures and phylogenetic relationships were elucidated based on nuclear low-copy genes, chloroplast DNA, and nuclear simple sequence repeats (SSRs). A scenario selection analysis and divergence time estimation were performed using coalescent simulation in DIYABC and *BEAST. Ecological niche modelling and a test of niche differentiation were performed using Maxent and ENMTools.Key ResultsAll marker types showed deep, but pronouncedly incongruent, west–east genetic divergences, with the subspecies being delineated only by the nuclear low-copy genes. Phylogenetic tree topologies suggested that ancient hybridization and introgression were likely to have occurred; however, this scenario did not receive significant support in the DIYABC analysis. The subspecies differentiated their niches, but both showed a dependence on high humidity and were predicted to have persisted during the last glacial cycle by maintaining a stable latitudinal distribution via migration to lower altitudes.ConclusionsWe found a deep genetic divergence and a pronounced phylogenetic incongruence among the two subspecies of M. sieboldii, which may have been driven by major paleogeographic and paleoclimatic events that have occurred since the Neogene in East Asia, including global cooling, climate oscillations and the formation of land bridges. Both subspecies were, however, considered to persist in situ in stable climatic conditions during the late Pleistocene.     

A review of Bulgarian Hipparion: Mammalia,Perissodactyla

The species of the fossil genus Hipparion found in Bulgaria to this date, and their affinities, are discussed. Of the earlier described 8 different species, only 3 are here considered possibly valid.