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1.
A giant termite is described and figured from the Late Miocene of the Styrian Basin in southeastern Austria. Gyatermes styriensis gen. n. et sp. n. is represented by a relatively complete forewing, with basal scale. The fossil approximates in size the largest of all termites today and is the largest fossil termite on record. The presence of this species in the Late Miocene fauna of Europe indicates that climatic conditions were appropriate for the persistence of species and colonies requiring relatively stable, warm conditions. The genus is primitive in overall features but shares some similarity with the dampwood termites.  相似文献   

2.
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.
Although Asia is thought to have played a critical role in the radiation of artiodactyls, the fossil record of stem selenodonts (“dichobunoids”) remains dramatically poor in tropical Asian regions. In this study, we report a new dichobunid genus and species Cadutherium kyaukmagyii and a new basal ruminant genus and species Irrawadymeryx pondaungi, from the late Middle Eocene Pondaung Formation, Central Myanmar. Although the scarcity of the present material prevents any attempts to investigate the phylogenetic relationships of Cadutherium with contemporaneous forms from other Holarctic landmasses, this new form shed new light on the diversity of these small rabbit-like ungulates during a key period of their evolutionary history. Reexamination of the small-bodied artiodactyls from Pondaung leads us to propose new identifications of certain published specimens and, in turn, to investigate the temporal and geographic distribution of taxa recognized in the Pondaung Formation. Although fragmentary, these potential new taxa reveal an unsuspected diversity of small forms among artiodactyls of Pondaung. This addition to the Eocene record of dichobunoids and early ruminants provides further insight in the diversity of dental patterns among small artiodactyls from the Pondaung Formation and attests to the antiquity of these groups in Southeast Asia.  相似文献   

4.
In the Brazilian Amazon, colonization is modifying the landscape at an exceedingly fast pace. Recently established households practice slash-and-burn agriculture and participate in the overall deforestation of the Amazon. Near the Transamazon highway, these family agricultural practices are the main cause of deforestation. The study presented here is oriented toward a better understanding of the impacts of farming practices on soil chemical composition. This study used a sampling design based on soil samples taken on farm plots, which had been submitted to a wide range of spatial and temporal sequential land-uses, including soils that were only recently denuded. The data shows that soil responses (organic matter (OM) content, fertility and mercury (Hg) retention) to these varied land-uses were relatively similar, suggesting that the most important event determining the responses was deforestation itself. This is well illustrated by the Hg content of soils, which changed immediately after deforestation and then only slightly thereafter. This phenomenon could also be seen in the base cation (calcium (Ca), potassium (K) and magnesium (Mg)) content which rose drastically after deforestation and tended to stay high for a period up to 10 years of cropping and pasture. This lasting cation rise is reflected by ammonium (NH4) displacement from surface soils. Indeed, inorganic nitrogen (N) is the most important nutrient loss upon deforestation. Nonetheless, when time spent in fallow was greater than 15 years, base cations (Ca, Mg, K), available N and phosphorus (P) contents tended to go back to initial forest soil values and in some cases to exceed them. Soil type was seen to mediate responses to land-use. Clay-sandy soils showed a lower content of available N and carbon (C) than clayey soils at the soil surface, a difference that was accentuated by deforestation. Conversely, the higher initial content of Hg in clayey soils was associated with a more important Hg loss from the soil's surface. By shedding light on the consequences of family practices for OM, nutrient status and Hg depletion, this paper gives a new perspective on soil responses to agricultural practices. These conclusions need to be addressed in a strategy plan to limit family land-use impacts on soils and the surrounding ecosystems. Recommendations for more sustainable land uses are proposed based on what has been learned about soil responses to local agricultural practices.  相似文献   

5.
Codfishes, the Gadiformes, are quite abundant in modern temperate and polar waters with a fossil record ranging back into the Palaeogene. The oldest records are from the Danian and Selandian of Europe and South Australia. The bipolar distribution early in their evolutionary history implies that their origin must have occurred quite early in the Palaeocene, or even in the Late Cretaceous with subsequent rapid diversification. By the Eocene, gadiforms were highly abundant and widespread. With the exception of gadiforms, no Eocene Antarctic teleostean group is present in the modern Antarctic fauna. Here, we review the early evolution and diversification of gadiforms in general and of macrouroids in particular. We also describe the undoubtedly oldest skeletal macrourid specimen with otoliths preserved in situ. It is the first definitive record of this group from the Eocene of Antarctica filling a gap in its stratigraphic distribution. The fossil record of gadiforms in general and macrouroids in particular indicates that the origin of both was in shallow shelf environments but with adaptations to deep-water settings early in their evolution. While gadoids seemingly originated in the earliest Palaeogene and rapidly experienced a first major radiation event in the eastern North Atlantic and/or North Sea Basin, macrouroids evolved in the Southern Ocean and migrated northwards into the South Atlantic before the establishment of the circum-Antarctic current and subsequent isolation of the Antarctic fish fauna. These two timely and regional separated adaptive radiation events in the Palaeogene gave rise to their modern taxonomic diversity and global distribution.  相似文献   

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