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1.
Vullo R 《Die Naturwissenschaften》2011,98(6):545-549
Sharks are known to have been ammonoid predators, as indicated by analysis of bite marks or coprolite contents. However, body
fossil associations attesting to this predator–prey relationship have never been described so far. Here, I report a unique
finding from the Late Jurassic of western France: a complete specimen of the Kimmeridgian ammonite Orthaspidoceras bearing one tooth of the hybodont shark Planohybodus. Some possible tooth puncture marks are also observed. This is the first direct evidence of such a trophic link between these
two major Mesozoic groups, allowing an accurate identification of both organisms. Although Planohybodus displays a tearing-type dentition generally assumed to have been especially adapted for large unshelled prey, our discovery
clearly shows that this shark was also able to attack robust ammonites such as aspidoceratids. The direct evidence presented
here provides new insights into the Mesozoic marine ecosystem food webs. 相似文献
2.
The first definitive carcharodontosaurid (Dinosauria: Theropoda) from Asia and the delayed ascent of tyrannosaurids 总被引:2,自引:0,他引:2
Stephen L. Brusatte Roger B. J. Benson Daniel J. Chure Xing Xu Corwin Sullivan David W. E. Hone 《Die Naturwissenschaften》2009,96(9):1051-1058
Little is known about the evolution of large-bodied theropod dinosaurs during the Early to mid Cretaceous in Asia. Prior to
this time, Asia was home to an endemic fauna of basal tetanurans, whereas terminal Cretaceous ecosystems were dominated by
tyrannosaurids, but the intervening 60 million years left a sparse fossil record. Here, we redescribe the enigmatic large-bodied
Chilantaisaurus maortuensis from the Turonian of Inner Mongolia, China. We refer this species to a new genus, Shaochilong, and analyze its systematic affinities. Although Shaochilong has previously been allied with several disparate theropod groups (Megalosauridae, Allosauridae, Tyrannosauroidea, Maniraptora),
we find strong support for a derived carcharodontosaurid placement. As such, Shaochilong is the first unequivocal Asian member of Carcharodontosauridae, which was once thought to be restricted to Gondwana. The
discovery of an Asian carcharodontosaurid indicates that this clade was cosmopolitan in the Early to mid Cretaceous and that
Asian large-bodied theropod faunas were no longer endemic at this time. It may also suggest that the ascent of tyrannosaurids
into the large-bodied dinosaurian predator niche was a late event that occurred towards the end of the Cretaceous, between
the Turonian and the Campanian.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
3.
A new assemblage of basal dichobunoid artiodactyls from the middle-Eocene Shanghuang fissure fillings includes the diacodexeid
Jiangsudon shanghuangensis gen. and sp. nov., a new species of the lantianine dichobunoid Elaschitotherium, Elaschitotherium crepaturus sp. nov., and an indeterminate suoid which is presently the earliest record of this clade. Diacodexeids are also represented
by two forms provisionally referred to cf. Diacodexis sp. and to an indeterminate Diacodexeidae, respectively. The occurrence of diacodexeids in Shanghuang contrasts with the
early and earliest middle-Eocene chronological range of the family in Europe and North America and suggests that the stratigraphic
range of the family in Asia extends up to the middle Eocene. This may reflect particular habitats in coastal China that may
have been relatively stable during the early and middle Eocene, thus preserving forest-dwelling artiodactyls that became extinct
in the other Holarctic regions. Compared to other supposedly coeval North American, European, and Asian faunas, the Shanghuang
mammalian assemblage is most similar to early Uintan faunas of North America but is also remarkable in recording forms close
to taxa that are characteristic of the Wasatchian and Bridgerian North American Land Mammal Ages. The Irdinmanhan age of the
Shanghuang fauna is supported by the mammalian assemblage recovered from the fissure D, but an Arshantan age cannot be completely
ruled out at this point. Although the Shanghuang assemblage is biased towards preservation of small components of the mammalian
fauna, the Shanghuang fauna provide an important and unique window into the Eocene diversity and early evolution of cetartiodactyls
in eastern Asia. 相似文献
4.
Arctostylopids are common in Late Palaeocene and Early Eocene mammal faunas of Asia, but they are rare in North America. From the time of their first discovery, arctostylopids were grouped with the strictly endemic South American Notoungulata based on their strikingly similar dental morphology. This relationship was challenged based on dental morphology of more recently discovered arctostylopids and on supposed tarsal morphology (based on unassociated material) of the Asian arctostylopid Palaeostylops. Therefore, Arctostylopidae were placed in a separate order, Arctostylopida, of enigmatic affinities. Many authors, however, continue to unite Arctostylopidae and Notoungulata based on dental similarities. In the Late Palaeocene Subeng site in Inner Mongolia, we identified the Palaeostylops tarsals based on their size and abundance. This identification is supported by comparison to unpublished Arctostylops tarsals from the North American Clarkforkian, derived from a semi-articulated skeleton also including dental material. Tarsal morphology shows moderate similarity to the gliriform Pseudictops, and strong resemblance to the tarsally conservative gliroid Rhombomylus. Hence, Arctostylopidae may best be grouped with Asian non-gliroid Gliriformes, which we interpret as having dispersed into North America in the Late Palaeocene.Pieter Missiaen is an aspirant of the Research Foundation-Flanders (RF-Flanders) 相似文献
5.
Assessing risk of and adaptation to sea-level rise in the European Union: an application of DIVA 总被引:4,自引:2,他引:2
Jochen Hinkel Robert J. Nicholls Athanasios T. Vafeidis Richard S.J. Tol Thaleia Avagianou 《Mitigation and Adaptation Strategies for Global Change》2010,15(7):703-719
This paper applies the DIVA model to assess the risk of and adaptation to sea-level rise for the European Union in the 21st century under the A2 and B1 scenarios of the Intergovernmental Panel on Climate Change. For each scenario, impacts are estimated without and with adaptation in the form of increasing dike heights and nourishing beaches. Before 2050, the level of impacts is primarily determined by socio-economic development. In 2100 and assuming no adaptation, 780?×?103 people/year are estimated to be affected by coastal flooding under A2 and 200?×?103 people/year under B1. The total monetary damage caused by flooding, salinity intrusion, land erosion and migration is projected to be about US$ 17?×?109 under both scenarios in 2100; damage costs relative to GDP are highest for the Netherlands (0.3% of GDP under A2). Adaptation reduces the number of people flooded by factors of 110 to 288 and total damage costs by factors of 7 to 9. In 2100 adaptation costs are projected to be US$ 3.5?×?109 under A2 and 2.6?×?109 under B1; adaptation costs relative to GDP are highest for Estonia (0.16% under A2) and Ireland (0.05% under A2). These results suggest that adaptation measures to sea-level rise are beneficial and affordable, and will be widely applied throughout the European Union. 相似文献
6.
Fossils from the central Transantarctic Mountains in Antarctica are referred to a new species of the Triassic genus Kombuisia, one of four dicynodont lineages known to survive the end-Permian mass extinction. The specimens show a unique combination
of characters only present in this genus, but the new species can be distinguished from the type species of the genus, Kombuisia frerensis, by the presence of a reduced but slit-like pineal foramen and the lack of contact between the postorbitals. Although incomplete,
the Antarctic specimens are significant because Kombuisia was previously known only from the South African Karoo Basin and the new specimens extend the taxon’s biogeographic range
to a wider portion of southern Pangaea. In addition, the new finds extend the known stratigraphic range of Kombuisia from the Middle Triassic subzone B of the Cynognathus Assemblage Zone into rocks that are equivalent in age to the Lower Triassic Lystrosaurus Assemblage Zone, shortening the proposed ghost lineage of this taxon. Most importantly, the occurrence of Kombuisia and Lystrosaurus mccaigi in the Lower Triassic of Antarctica suggests that this area served as a refuge from some of the effects of the end-Permian
extinction. The composition of the lower Fremouw Formation fauna implies a community structure similar to that of the ecologically
anomalous Lystrosaurus Assemblage Zone of South Africa, providing additional evidence for widespread ecological disturbance in the extinction’s
aftermath. 相似文献
7.
The economic impact of substantial sea-level rise 总被引:1,自引:0,他引:1
David Anthoff Robert J. Nicholls Richard S. J. Tol 《Mitigation and Adaptation Strategies for Global Change》2010,15(4):321-335
Using the FUND model, an impact assessment is conducted over the 21st century for rises in sea level of up to 2-m/century and a range of
socio-economic scenarios downscaled to the national level, including the four SRES (IPCC Special Report on Emissions Scenarios)
storylines. Unlike a traditional impact assessment, this analysis considers impacts after balancing the costs of retreat with
the costs of protection, including the effects of coastal squeeze. While the costs of sea-level rise increase with greater
rise due to growing damage and protection costs, the model suggests that an optimum response in a benefit-cost sense remains
widespread protection of developed coastal areas, as identified in earlier analyses. The socio-economic scenarios are also
important in terms of influencing these costs. In terms of the four components of costs considered in FUND, protection dominates, with substantial costs from wetland loss under some scenarios. The regional distribution of costs
shows that a few regions experience most of the costs, especially East Asia, North America, Europe and South Asia. Importantly,
this analysis suggests that protection is much more likely and rational than is widely assumed, even with a large rise in
sea level. This is underpinned by the strong economic growth in all the SRES scenarios: without this growth, the benefits
of protection are significantly reduced. It should also be noted that some important limitations to the analysis are discussed,
which collectively suggest that protection may not be as widespread as suggested in the FUND results. 相似文献
8.
Grohé C Chaimanee Y de Bonis L Yamee C Blondel C Jaeger JJ 《Die Naturwissenschaften》2010,97(11):1003-1015
We report new dental remains of Mustelidae from the late middle Miocene of Mae Moh Basin, northern Thailand, improving the
poor fossil record of the family in Southeast Asia. Siamogale thailandica is a poorly known mustelid, previously recorded from just a single tooth. Here we present over a hundred new specimens attributable
to this species. S. thailandica shows a combination of primitive and convergent features of the dentition that makes its original subfamilial assignment
to Lutrinae doubtful. Evidence from the dental morphology suggests that it belongs to a bunodont otter-like mustelid that
evolved in convergence with “true” otters (Lutrinae) toward a semi-aquatic way of life. Autapomorphic features such as the
height and the position of the m1 metaconid and the shape of the P4 lingual shelf make S. thailandica unique among Mustelidae. The morphology of this species is mostly similar to Mionictis species and Lartetictis dubia, reported in the Miocene of North America and Europe, respectively. These similarities could imply immigration events to
Thailand in the early or middle Miocene. Alternately, the lineage leading to Siamogale might have deeper origins from an endemic early Miocene Southeast Asian mustelid. 相似文献
9.
The fossil record of late Campanian tyrannosauroids of western North America has a geographic gap between the Northern Rocky
Mountain Region (Montana, Alberta) and the Southwest (New Mexico, Utah). Until recently, diagnostic tyrannosauroids from the
Southwest were unknown until the discovery of Bistahieversor sealeyi from the late Campanian of New Mexico. Here we describe an incomplete skull and postcranial skeleton of an unusual tyrannosaurid
from the Kaiparowits Formation (Late Cretaceous) of Utah that represents a new genus and species, Teratophoneus curriei. Teratophoneus differs from other tyrannosauroids in having a short skull, as indicated by a short and steep maxilla, abrupt angle in the
postorbital process of the jugal, laterally oriented paroccipital processes, short basicranium, and reduced number of teeth.
Teratophoneus is the sister taxon of the Daspletosaurus + Tyrannosaurus clade and it is the most basal North American tyrannosaurine. The presence of Teratophoneus suggests that dinosaur faunas were regionally endemic in the west during the upper Campanian. The divergence in skull form
seen in tyrannosaurines indicates that the skull in this clade had a wide range of adaptive morphotypes. 相似文献
10.
海平面上升和氮负荷增加是入海河流河口面临的两个主要全球性环境问题.揭示河口潮滩沼泽湿地CO2垂直通量对二者及交互作用的响应,对于科学评估全球变化背景下的河口潮滩沼泽湿地生态系统蓝碳功能具有重要的科学意义.本研究以闽江河口鳝鱼滩中潮滩短叶茳芏湿地为研究对象,在野外原位实施模拟海平面上升、氮负荷增加及二者交互作用的实验处理近1年后,在2019年冬季各月的大潮日白天涨潮前、平潮期及落潮后3个阶段,运用透明静态箱(或遮光布遮光)+Li-6800光合作用仪对短叶茳芏湿地生态系统净CO2交换(NEE)和生态系统呼吸(ER)进行测定.结果发现,与对照处理相比,冬季尺度3种处理下短叶茳芏湿地生态系统NEE均显著增加;模拟海平面上升影响下短叶茳芏湿地生态系统ER无显著变化;氮负荷增加及二者交互作用下,短叶茳芏湿地ER均显著增加.模拟海平面上升、氮负荷增加及二者交互作用情景下,短叶茳芏湿地生态系统总初级生产力(GPP)均明显增加.研究表明,在未考虑甲烷排放的情景下,即使在冬季,海平面上升、氮负荷增加及二者交互作用将可能增加亚热带河口潮滩半咸水沼泽湿地的碳汇功能. 相似文献
11.
12.
Marcelo H. Cassini Laura Fasola Claudio Chehébar David W. Macdonald 《Die Naturwissenschaften》2009,96(5):593-599
The Southern river otter or ‘huillin’, Lontra provocax, is an endangered species endemic of the Andean Patagonian region of Argentina and Chile. It feeds almost exclusively on
the genera of macro-crustacea: Aegla and Sammastacus. The aim of this study was to analyse the role of food availability on the huillin’s distribution using a scale-dependent
analysis of crustacean and otter distributions. We compared the distributions of otters and macro-crustaceans along a north–south
regional gradient, between river basins of northern Patagonia, in an altitudinal gradient within a river basin, and between
habitat types within a lake. We investigated the distribution of otters by sign surveys along lake shores, river banks and
marine coasts, and of crustaceans using surveys in the water, undigested remains in mink (Mustela vison) scats, presence of external skeletons at the waterside and through interviews with local people. Our results show that there
were heterogeneities in the distributions of macro-crustaceans at four scales and these were generally reflected in the distributions
of freshwater otters. We conclude that the main factor limiting the distributions of L. provocax in freshwater environments is the availability of macro-crustaceans. This paper shows how scale-dependent type analyses of
population distribution serves as a method for identifying key environmental factors for species for which the use of long-term
demographies is unfeasible. 相似文献
13.
During the Mesozoic, one of the most significant evolutionary processes was the secondary adaptation of tetrapods to life
in water. Several non-related lineages invaded from the terrestrial realms and from the oceans of the entire world. Among
these lineages, ichthyosaurs were particularly successful. Advance parvipelvian ichthyosaurs were the first tetrapods to evolve
a fish-shaped body profile. The deep skeletal modifications of their bodies, as well as their biology, depict advance ichthyosaurs
as the paradigm of secondary adaptation of reptiles to marine life. Functional inferences point to them as off-shore cruising
forms, similar to a living tuna, and some of them were capable of deep diving. Bone histology of some genera such as Temnodontosaurus, Stenopterygius, Ichthyosaurus, and Caypullisaurus, characterized by overall cancellous bone, is consistent with the idea of a fish-shaped ichthyosaurs as fast and far cruisers.
Here, we provide histological examination of the ribs of the Middle Jurassic parvipelvian Mollesaurus. Contrasting with the bone histology of other parvipelvian, Mollesaurus ribs are characterized by a compact and thick cortex. Our data indicate that the rib cage was heavy and suggest that not
all advanced ichthyosaurs were fast cruisers. The compact and dense ribs in these parvipelvian show that advance ichthyosaurs
were ecologically more diverse than previously thought and that the lightening of the skeleton reversed, as also occurred
in the evolution of cetacean, at least once along the evolutionary history of ichthyosaurs. 相似文献
14.
Vanessa Bonatti Zilá Luz Paulino Simões Fernando Faria Franco Tiago Mauricio Francoy 《Die Naturwissenschaften》2014,101(1):17-24
Melipona subnitida, a tropical stingless bee, is an endemic species of the Brazilian northeast and exhibits great potential for honey and pollen production in addition to its role as one of the main pollinators of the Caatinga biome. To understand the genetic structure and better assist in the conservation of this species, we characterized the population variability of M. subnitida using geometric morphometrics of the forewing and cytochrome c oxidase I gene fragment sequencing. We collected workers from six localities in the northernmost distribution. Both methodologies indicated that the variability among the sampled populations is related both to the environment in which samples were collected and the geographical distance between the sampling sites, indicating that differentiation among the populations is due to the existence of at least evolutionary lineages. Molecular clock data suggest that this differentiation may have begun in the middle Pleistocene, approximately 396 kya. The conservation of all evolutionary lineages is important since they can present differential resistance to environmental changes, as resistance to drought and diseases. 相似文献
15.
Rüdiger Riesch Martin Plath Francisco J. García de León Ingo Schlupp 《Die Naturwissenschaften》2010,97(2):133-141
The majority of studies on ecological speciation in animals have investigated the divergence caused by biotic factors like
divergent food sources or predatory regimes. Here, we examined a system where ecological speciation can clearly be ascribed
to abiotic environmental gradients of naturally occurring toxic hydrogen sulfide (H2S). In southern Mexico, two genera of livebearing fishes (Poeciliidae: Poecilia and Gambusia) thrive in various watercourses with different concentrations of H2S. Previous studies have revealed pronounced genetic differentiation between different locally adapted populations in one
species (Poecilia mexicana), pointing towards incipient speciation. In the present study, we examined female reproductive life-history traits in two
species pairs: Gambusia sexradiata (from a nonsulfidic and a sulfidic habitat) and Gambusia eurystoma (sulfide-endemic), as well as P. mexicana (nonsulfidic and sulfidic) and Poecilia sulphuraria (sulfide endemic). We found convergent divergence of life-history traits in response to sulfide; most prominently, extremophile
poeciliids exhibit drastically increased offspring size coupled with reduced fecundity. Furthermore, within each genus, this
trend increased with increasing sulfide concentrations and was most pronounced in the two endemic sulfur-adapted species.
We discuss the adaptive significance of large offspring size in toxic environments and propose that divergent life-history
evolution may promote further ecological divergence through isolation by adaptation. 相似文献
16.
Arzarello M Marcolini F Pavia G Pavia M Petronio C Petrucci M Rook L Sardella R 《Die Naturwissenschaften》2007,94(2):107-112
Some flint lithic artifacts were discovered in the fissure fillings of the well-known Pirro Nord site (Apulia, Southern Italy).
The lithic industry, composed by three cores and some flakes, has been found to be associated to an Early Pleistocene vertebrate
fossil assemblage. The fossil association contains a wide range of micromammals, including Allophaiomys ruffoi and Episoriculus gibberodon and large mammals including Bison degiulii and Equus altidens together with African elements as the gelada baboon Theropithecus and the saber-toothed cat Megantereon whitei. It defines the latest Villafranchian chronological unit (Pirro Nord Faunal Unit) in the Western European mammal biochronology.
The lithic industry of Pirro Nord represents the oldest occurrence of the genus Homo in Europe as it is attributable to a chronological interval between 1.3 and 1.7 Ma. This supports the hypothesis that the
genus Homo, with Oldowaian technology, extended its range in Europe, probably from western Asia, during the first half of the Early
Pleistocene. The new discovery from Pirro Nord changes the chronology of the first arrival of hominids in Europe and offers
new perspectives in the debate about the human dispersal in the Early Pleistocene. 相似文献
17.
J. N. Proust J. F. Deconinck J. R. Geyssant J. P. Herbin J. P. Vidier 《Geologische Rundschau》1995,84(2):255-271
An interdisciplinary approach based on high-resolution physical stratigraphy, biostratigraphy, organic matter analysis and clay mineralogy has been applied to the mixed siliciclastic/carbonate Kimmeridgian/Tithonian deposits of the Boulonnais (north-western France). These rocks are the age-equivalents of some of the offshore marine source rocks of the North Sea and were deposited in an overall storm-dominated homoclinal ramp setting which may represent one of the most shore-proximal sediments of this age cropping out in north-western Europe. Comparison with data from the Yorkshire, Dorset, Lorraine and Aquitaine areas allows the discrimination of three major transgressive-regressive sediment packages with disconformities of interregional extent: (1) from the Baylei Zone to top Eudoxus Zone; (2) from the Autissiodorensis Zone to base Scitulus Zone; (3) from the upper Scitulus Zone to the Pectinatus Zone. The lower two regionally correlative disconformities correspond to the sequence boundaries at the top of the Eudoxus Zone and the top of the Autissiodorensis Zone, formed by high-frequency relative sea-level variations during the periods of maximum transgression of the platform. The latter disconformity (the P1 nodule bed) reflects a major tectonically induced reorganization of the north-west European intrashelf sedimentary basin, characterized by a shift in both the location of the main depocentre and the sources of sediment production. 相似文献
18.
Globally, sea level has been rising for more than the last one hundred years, and is expected to do so into the foreseeable
future, and at an accelerating rate. The direct influences of sea-level rise on water resources come principally from the
following: new or accelerated coastal erosion; more extensive coastal inundation and higher levels of sea flooding; increases
in the landward reach of sea waves and storm surges; seawater intrusion into surface waters and coastal aquifers; and further
encroachment of tidal waters into estuaries and coastal river systems. The impacts of sea-level rise are likely to be felt
disproportionately in certain areas, reflecting both natural and socio-economic factors that enhance the levels of risks.
The opportunity to learn about the likely nature of, and most appropriate adaptation to, the anticipated impacts of sea-level
rise on water resources is arguably best developed in rapidly subsiding coastal areas, and especially in low-lying deltas
where subsidence rates are typically much larger than the historic rise in global mean sea level. Significantly, such areas
are often major centres of population and of economic activity, thereby highlighting the human dimensions of sea-level rise.
Sound management of the risks to water resources associated with sea-level rise requires enhancing adaptive capacity, mainstreaming
adaptation, harmonizing responses to extreme events, variability and long-term change and strengthening regional and international
cooperation and coordination. In this regard, the policies and initiatives of international organisations are not always entirely
consistent with the needs of developing countries. 相似文献
19.
Ferganodon
narynensis gen. et sp. nov. is represented by a lower molariform tooth from the Middle Jurassic (Callovian) Balabansai Svita in Kyrgyzstan.
The new genus is allied with Klamelia zhaopengi Chow and Rich 1984 from the Middle Jurassic Shishugou Formation in Xinjiang, northwest China to the new family Klameliidae based on parallelogram-shaped
lower molariforms, imbricating rather than interlocking of cusps e-d-f, by a peculiar distolabial cingulid cusp, and by vertical folding of the enamel on the labial crown side. The new family
Klameliidae fam. nov. is most similar to Gobiconodontidae by the structure of the molariform teeth and represents a previously
unrecognized radiation of eutriconodontan mammals possibly endemic to Central Asia. 相似文献
20.
The Cretaceous Carcharodontosauridae is the latest clade of carnosaurs, including the largest predatory dinosaurs yet recorded. Albeit spectacular for their size, the skeletal anatomy of these theropods remains poorly-known, and their diversity was until recently restricted to two Cenomanian species: the highly derived Giganotosaurus carolinii, from southern South America, and the incompletely known Carcharodontosaurus saharicus, from northern Africa. Here we describe an older and basal member of the group, Tyrannotitan chubutensis gen. et sp. nov., from Aptian strata of Patagonia, Argentina. The new taxon gives new insights into the systematics and evolution of carcharodontosaurids and offers a better understanding of the evolution of Southern theropod faunas. We suggest that carcharodontosaurids radiated in Gondwana sharing with spinosaurids the role of top-predators until their extinction in Cenomanian–Turonian times. During this interval, the diplodocoid sauropods and giant titanosaurians went extinct (probably as part of a global-scale crisis), and the smaller abelisaurid theropods took dominance, reigning until the end of the Cretaceous. Electronic Supplementary Material is available.Electronic Supplementary Information Supplementary material is available for this article at 相似文献