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1.
Assemblages with blades are rare in the south of Europe and most of them are dated from the isotopic stages 4 and 3. The blades are, otherwise, often produced on Levallois cores with unipolar and bipolar methods. According to the sites, the blades are more or less retouched as different kinds of tools. However, there are no specific links between this blank and the tools, and never between the artefacts and the fauna remains (activities). The hypothesis of traditions or needs among time and space are asked without answer, while the blades are present in the north of Europe and the Near East in far older periods. Several sites can be considered to describe the variability of the technical behaviour and the archaeological context of the blades in south-east France, extending to north Italy. The two sites, Abri du Maras and Baume Flandin, located in the middle Rhône valley, yield evidence of a laminar debitage linked to a Levallois method and a “direct” method. The technical choices used in the two sites are accorded to the specificity of the laminar assemblages in the southern Europe.  相似文献   

2.
The region of Eger town at the foot of the Bükk Mountains in Northeastern Hungary has particular importance for the understanding the Middle and Upper Palaeolithic periods of the Carpathian Basin. One of the key-problems is the association of carinated tools and foliate points in the lithic assemblages of the sites. New investigations at the Egerszalók-K?vágó site give fundamental data for the animated discussion on the relation between Aurignacian and Szeletian.  相似文献   

3.
《L'Anthropologie》2021,125(4):102937
The hominin presence during Lower Palaeolithic in Central Europe was sporadic and followed cold-warm climatic cycle connected with spreading of Scandinavian ice sheet. Up to now there had been discovered about 50 archaeological assemblages from 17 sites from 700 ka years, mostly from second part of it, during c. 300 ka between MIS 15 and 9. The Lower Paleolithic hominins visited Central Europe during warmer periods with deciduous or coniferous forests, even during open domination of open or partly open landscape. Incredible finds, like Bilzingsleben and Schöningen show how complex was life of early hunter-gatherers. In opposite to the previous concept, according to which Lower Palaeolithic hominins were mostly scavengers. The discovery of wooden tools, like spears in lakeshore in opencast mine Schöningen, denies this concept. Contrary to that, early hominins were smart hunters following animal herds and hunted distant way and experienced gatherers. Local lithic technology based on core-flake processing in opposite to Western and Southern Europe dominated by handaxes. Moreover, the preferred usage of “small tools”, which are difficult to use only by fingers may be explained by identification of wooden hafts on few lithic artifacts in Schöningen. However, very long duration of unchanged lithic technology is surprising. An intense accumulation of glacial, eolian and alluvial sediments covered large part of Central Europe and this way Lower Palaeolithic sites are very difficult to discover. All known sites were identified in deep travertine quarries or opencast mines. Future research must be focused on systematic prospection of such outcrops.  相似文献   

4.
Since the sixties, the National Indonesian Center for Archaeological Research, in collaboration with the Gajah Mada University, organizes field excavations on open-air sites in the Sangiran dome, one of the most famous places of palaeoanthropological discoveries in Southeast Asia. That project led to the discovery of Homo erectus more or less fragmentary fossils, and to the collection of numerous mammal fossils in open-air localities such as Tanjung, Sendang Busik, Ngrejeng Plupuh, Grogol Plupuh and Bukuran. Most of the bone assemblages from these sites come from the volcanic-sedimentary Kabuh layers (Early Middle Pleistocene) deposited in a fluvial context. The herbivores dominate the assemblages. The best-represented species are large bovids like Bubalus palaeokerabau or Bibos palaesondaicus and smaller cervids like Axis lydekkeri. The carnivore are very rare, only a Pachycrocuta brevirostris in Bukuran. The taphonomical study of the collections, involving several common and also modern methods, is among the first carried out on Javanese sites. The high degree of fragmentation is attested by the dominance of splinters among the fossils. In most sites, teeth and member extremities (autopodial) prevail. Conservation and fragmentation of fossil bones is not the same at all sites. Water action, either chemical or mechanical, is predominant, regarding the origin and the modification of the assemblages. The climato-edaphic traces like oxides and concretions are well represented on the bone surface. Different methods were applied to study transportation and to document the sites contexts in the frame of the ancient riverine paleogeography. Carnivores are almost absent in the material and traces of their action are rare, only in Bukuran and Ngrejeng. The tools are rare, only a bola in Tanjung 82 and chalcedony flakes in Tanjung 63–64. Anthropic influence is only obvious at Ngebung 2, a site in the west part of the dome, supported by fossil observation and correlated to the occurrence of lithic artefacts. This site was excavated during the 1990’s by a French-Indonesian team and it is a site of comparison for our study. Several analytical methods could be applied for the first time on Pleistocene faunal assemblages from Java, for example, the study of the fragmentation, that of fissuration and the characterization of the fluviatile transport undergone by the fossils.  相似文献   

5.
《L'Anthropologie》2014,118(4):408-436
The lithic assemblages of five open-air sites offer the opportunity to observe and compare Final Acheulean series located in the Loire department (South-East France). The sites were probably multi-activity places including large tools and flakes, according to the strategies used by humans. Three main categories of large bifacial tools mainly made of flint can be described, with a triangular or oval shape and with a transversal cutting edge. The ratio and intensity of flaking oppose the series. The Levallois flaking is always present and associated to various other types of methods. The sites, located on plateaus on the two banks of a small valley, suggest human circulating between the Saône-Rhône corridor and the interior basins of the Massif Central Mountains. The Rhodanian corridor yielded little evidence of Acheulean open-air settlements while in the Centre of France, they are numerous. These sites prove that systematic prospecting in this area will permit in future to complete the map of the Acheulean occupations in south-east France and discuss about the variability.  相似文献   

6.
《L'Anthropologie》2023,127(1):103100
The article is devoted to the traceological study of points and geometric microliths that are characteristic of the Epipaleolithic sites of the northwestern Caucasus and the Elbrus region. The regularities between the type of stone tools and their functional use are analyzed. Composite hunting weapons were effectively used in hunting a variety of ungulate herd animals. The composition of faunal assemblages largely depended of climatic and landscape conditions of the sites in different periods of the Late Glacial period: from the Oldest Dryas to the Pleistocene–Holocene transition. The proximity of lithic industries within a vast region in the North Caucasus, similar shapes of projectiles and lithic inserts into composite hunting weapons could be associated with active human movements, which are confirmed by the transportation of obsidian from the Elbrus region to the northwestern Caucasus and the transportation of high-quality flint from the west to the Elbrus region in the north-central Caucasus.  相似文献   

7.
Bizat Ruhama is a lower Palaeolithic site in the southern coastal plain of Israel. The site was recently dated to ca. 1ma. In terms of lithic industry, Bizat Ruhama is a unique phenomenon amongst the Lower Palaeolithic sites in the Levant. The lithic assemblage of the site is characterized by the production of small (ca. 25mm) tools, flakes and cores. An in-depth technotypological study was made in attempt to reconstruct the production mode of these artifacts. The results presented here reveal a well-developed cognitive production process, which includes selection of special-sized raw material, production of desired blanks and their subsequent shaping into tools. The implications of this study contribute significantly to our understanding of the phenomenon of lower Palaeolithic microlithic industries in Eurasia.  相似文献   

8.
末次盛冰期环境恶化对中国北方旧石器文化的影响   总被引:10,自引:0,他引:10  
末次冰期间冰段时,中国北方地区水热条件普遍较好,旧石器文化也比较发达。然而,进入末次盛冰期后,随着气温的普遍降低和降水量的明显减少,草原和沙漠带急速向南扩张,动物群也大举南迁。对于这种严酷的生存环境,中国北方的旧石器文化是如何响应的呢?本文以宁夏彭阳PY01-02,PY03和PY05等地点的地层剖面和石制品的研究为基础,首先提出彭阳地点群地层沉积相由河湖相沉积迅速转变为黄土堆积说明由末次冰期间冰段到末次盛冰期自然环境发生了剧烈变化。其次,通过对上述两种不同沉积相中出土石制品的大小、重量、原料以及技术上的比较说明随着环境的变化石制品本身也发生了相应的变化。下层河湖相堆积中出土的石制品粗大笨重,主要以各种石英岩为原料,与同期泾水上游旧石器文化的特征相近,应是当地文化特征的一种具体体现。上层马兰黄土中的石制品的普遍较小,主要以石英和燧石为原料,其中用燧石制成的细石器具有宁夏灵武水洞沟下文化层同类制品的特征,而用石英制成的小石器则同海原一带的史前文化有着较为密切的联系,据此作者推测这可能与史前人类在环境日益恶劣的情况下向南迁移有关。山西南部地区的下川和柿子滩遗址的地层和石制品证据亦表明,末次盛冰期前后该地区旧石器文化的明显差异可能也与末次盛冰期环境恶化时人类的迁徙有关。最后,中国北方地区考古遗址的空间分布变化为上述史前人类南迁的推测提供了有力证据。因此,作者认为末次冰期的环境恶化对中国北方旧石器文化的影响具有普遍性。  相似文献   

9.
Eastern European grasslands are still inhabited by a rich arthropod fauna, but the drivers and mechanisms influencing their communities have to be understood to ensure their future survival. Heteroptera communities were studied in 20 plot-pairs in Pannonic salt steppe–salt marsh mosaics in Hungary. The effects of vegetation characteristics, landscape diversity and the proportion of surrounding grasslands on the composition, species richness and abundance of different feeding groups of true bugs (carnivores, specialist and generalist herbivores) were examined using ordinations and mixed-effect models. We found distinct herbivorous assemblages corresponding to microtopography-driven differences in water regime and vegetation between steppe and marsh plots, but this pattern was less pronounced in carnivorous assemblages. A higher species richness of true bugs was found in the more diverse steppe vegetation than in the salt marsh vegetation, while the abundance pattern of true bugs was opposite. Landscape diversity had a positive effect on the species richness and abundance of generalist herbivores and carnivores. Our results suggested that generalist herbivores and carnivores appear to drive diversity patterns in the local landscape due to their high dispersal abilities and the broader range of resources they can utilize. Specialist herbivores strongly influence the local insect biomass in relation to the distribution and density of their host plants. The present study highlights the importance of both habitat and landscape diversity for local insect diversity in Pannonic salt grasslands and suggests that the main threats for arthropod diversity are those processes and activities that homogenize these areas.  相似文献   

10.
As one of the most important Lower Pleistocene sites of the Nihewan basin in North China, Donggutuo (DGT) site is well known for its fine retouched small tools and characters of flake industry. However, new excavations still reveal some new discoveries and educe some new issues to us. For example, the “DGT core” introduced in this article is a new discovered typotechnology and indicates new economic strategy of the local people, which was never known before in this area at the time of 1.1 Ma B.P. The paper provides general background and statistic analysis of DGT industry including special method applied to the “DGT core” and discusses possible influence of environmental change for the emerging of the “DGT core”. The “DGT core” shows a germinated microlithic tradition and reflects a cultural diversity of early humans in the Lower Paleolithic in North China.  相似文献   

11.
PLEISTOCENE HISTORY OF THE BRITISH VERTEBRATE FAUNA   总被引:1,自引:0,他引:1  
  • 1 This review covers the Pleistocene history of British non-marine Pisces, Amphibia, Reptilia and especially Mammalia, which alone have a good fossil record. Aves are also briefly discussed.
  • 2 The fossil material available is often inadequate for purposes of taxonomy and identification. Further problems arise because many groups of Mammalia have undergone rapid evolution during the Pleistocene.
  • 3 In this paper the fossil record is related to the currently accepted stratigraphic table of the British Pleistocene (Shotton & West, 1969). Wherever possible, fossil records have been assigned to pollen assemblage zones. Throughout, emphasis is placed on the relationship between faunal history and vegetational history, as determined from fossil pollen and macroscopic plant remains.
  • 4 Although fossils are relatively scarce in the fluviatile and lacustrine deposits of open sites, compared with the often rich cave assemblages, the stratigraphy of the former is usually much clearer and the sediments commonly contain pollen. It is difficult to correlate cave sequences with those of open sites.
  • 5 It is important to take into account possible bias in a fossil assemblage according to its mode of accumulation, e.g. assemblages from occupation sites may represent only those animals which were hunted by man.
  • 6 Lower Pleistocene vertebrates are rather poorly-known. The majority of fossils are from the marine Crags of East Anglia (Pre-Ludhamian to Pastonian) and a single cave assemblage of this age is known (Dove Holes). Few records can be related to particular stages, but a few finds from Easton Bavents are assigned to Antian and Baventian stages.
  • 7 Early Middle Pleistocene vertebrates are represented mainly by the rich assemblages from the marine and fresh-water Weybourne Crag and Cromer Forest Bed Series (Baventian to Early Anglian) of Norfolk and Suffolk. The East Runton fauna appears to be of pre-Cromerian (?Pastonian) age. A good fauna is known from the type Cromerian deposits at West Runton (zone Cr 11). A few records are available for zone ?Cr III and one for the Early Anglian. The assemblages from other localities appear to represent more than one stage at each site, e.g. the so-called ‘Bacton Forest Bed’ fauna is composite, including both Cromerian and ?Pastonian taxa. Outside East Anglia one open site (Sugworth) and one cave fauna (Westbury) of probable Cromerian age are known.
  • 8 Many of the fossils found in lacustrine and river-terrace deposits of the Middle and Upper Pleistocene glacial-interglacial succession (Anglian to present day) can be assigned to particular stages, zones or even subzones. Cave assemblages rarely predate the Ipswichian. No pre-Devensian records are available for either Scotland or Ireland. The Anglian fauna is very poorly known. The Hoxnian is represented principally by the Clacton (zone Ho IIb) and Swanscombe faunas. The Baker's Hole deposit, the basal gravels of the Summertown-Radley Terrace and the Glutton and Bear Strata in Tornewton Cave have yielded faunas of probable Wolstonian age. The early Ipswichian is poorly represented (Selsey), many fossils are known from zone Ip Iib (e.g. Trafalgar square, Swanton Morley, Aveley), there are a few records from early zone Ip III (Aveley, Swanton Morley) and fairly good faunas from zone Ip III/IV (Histon Road, Stutton). Several open and cave-site faunas resemble those of zones Ip II and Ip III and the assemblages from Ilford, Brundon, etc., appear to date from the end of this interglacial. The Early Devensian is represented by the Wretton fauna and probably by some cave faunas. Middle Devensian faunas are fairly well known (e.g. Upton Warren) and there are a number of records for the Late-Devensian (Ballybetagh, High Furlong, Nazeing). Many cave faunas date from the Middle or Late Devensian. Good faunas are available from the early Flandrian, zone F1 I (e.g. Star Carr). The present-day native fauna (zone F1 111) is also discussed.
  • 9 The main faunal characteristics for each subdivision of the Pleistocene are summarized in the Conclusions. There is a major faunal change between the predominantly Tertiary fauna of the Red Crag Nodule Bed (Probably Pre-Ludhamian and older) and that of the Red Crag (Pre-Ludhamian and Ludhamian). There appears to have been comparatively little change in fauna through the rest of the Lower Pleistocene but the more intense climatic fluctuations of the Middle and Upper Pleistocene were accompanied by rapid faunal change and the appearance of characteristic ‘steppe-tundra’ faunas in the Wolstonian and Devensian cold stages. The Late-Devensian and Flandrian faunas are impoverished in comparison to earlier stages. This may be partly due to the activities of man as well as climatic and vegetational changes.
  • 10 There is usually good agreement between fauna and vegetational conditions when these can be compared, but a few taxa (e.g. Cricetus cricetus, Equus) have clearly changed their ecological requirements during the Pleistocene. Changes of fauna in response to vegetational changes within interglacials are known from the Hoxnian and especially the Ipswichian. The ‘steppe-tundra’ vegetation of cold stages was accompanied by a mixture of animals nowadays extinct or living in either steppe or tundra.
  相似文献   

12.
The site of Les Auzières 2 (Méthamis, Vaucluse) was excavated from 2001 to 2005. It yielded an original and diverse fauna, unique in southeastern France (Provence). The spectrum of large mammals comprises 14 species including hyena, horse, ibex, woolly rhinoceros, giant deer and mammoth. Lithic artifacts are rare but testify to the presence of a Mousterian industry. All of these remains derive from layers that have been dated to 60 ± 10 ka by ESR/U-series method. Les Auzières 2 is of special importance for examining the issue of human/carnivore interaction in the Pleistocene since it has yielded a large assemblage of carnivore remains, and probably represents a hyena den. The diverse fauna offers a more comprehensive picture of Upper Pleistocene biodiversity in southeastern France than that usually provided by sites with a stronger anthropogenic signal.  相似文献   

13.
小口子史前地点发现的石制品研究   总被引:7,自引:5,他引:2  
张森水 《人类学学报》1999,18(2):81-101
本文记述了小口子史前地点发现的石制品,可分为两组:非细石器工业制品和细石器工业制品,前者中的大多数石器,加工精致,形制规整,清楚可见用指垫法(莫斯特技术)修理,其中有些可与水洞沟文化层出土者对比,至少是中、西方旧石器文化交流的证迹。细石器工业制品中的石叶脊背具多种形式和端刃刮削器中锐刃较多,未见于以往记述的发现于中国境内细石器工业制品的文献中。  相似文献   

14.
In African large herbivore assemblages, megaherbivores dominate the biomass and utilise the greatest share of available resources. Consequently, they are considered a separate trophic guild that structures the food niches of coexisting large herbivores. However, there exists little empirical evidence on how food resources are shared within this guild, and none for direct competition for food between megaherbivores. Using the histological analysis of faeces, we explore this phenomenon for African elephant Loxodonta africana and black rhinoceros Diceros bicornis in the Addo Elephant National Park, South Africa, where the accumulated impacts of elephant have reduced browse availability. Despite being unable to generalise beyond our study sites, our observations support the predictions of competition theory (as opposed to optimality theory) by showing (1) a clear seasonal separation in resource use between these megaherbivores that increased as resource availability declined, and (2) rhinoceros changed their selectivity in the absence of elephant (using an adjacent site) by expanding and shifting their diet along the grass-browse continuum, and in relation to availability. Although black rhinoceros are generally considered strict browsers, the most significant shift in diet occurred as rhinoceros increased their preferences for grasses in the presence of elephant. We speculate that the lack of specialised grazing adaptations may increase foraging costs in rhinoceros, through reduced harvest- and handling-efficiencies of grasses. In the short-term, this may be off-set by an enhanced tolerance for low quality food and by seasonally mobilising fat reserves; however, the long-term fitness consequences require further study. Our data suggest that managing elephant at high densities may compromise the foraging opportunities of coexisting browsers. This may be particularly important in small, fenced areas and overlapping preferred habitats where impacts intensify.  相似文献   

15.
Currently, only Tréhougol’naya Cave has reliably dated evidence for human settlement in Eastern Europe and Caucasus, from the beginning through the middle of the Middle Pleistocene. In Eastern Europe, assemblages from Khriatchi and Mikhailovskoé, and possibly Darvagchai I, appear to be the only stratified locations that tentatively can be compared (despite problems with these materials) with Tréhougol’naya. In the eastern limits of Central Europe, layer VI in Korolevo I is the only stratified assemblage that may be compared with Tréhougol’naya. All these Lower Paleolithic occupations yielded the Pre-Mousterian small tool industries with some pebble tools, but without Acheulean bifaces and Levallois technique. These data suggest that Eastern Europe lies outside the distribution range of the Acheulean techno-complex demarcated with the “Movius Line”. In the Southern Caucasus, the Dmanissi hominine and lithic records document the fact that the earliest small-brained humans – probably later H. habilis-rudolfensis or earlier H. ergaster-erectus hominids bearing Pre-Oldowan technology – initially left Africa and appeared in Western Asia as early as 1.8 Ma ago. However, in the Southern Caucasus, the available chronological data indicate that the Acheulean complex has a later temporal appearance here compared to the Upper Acheulean or Acheulo-Yabrudian in Western Asia. Two main Upper Acheulean industrial variants currently can be recognized in the Southern Caucasus. The first, called the Kudarian by the author (from the caves of Kudaro I, Kudaro III, and Azyk), is characterized by lithics made from mostly siliceous rocks, rare Acheulean bifaces, and non-Levallois flaking technique. The second variant is characterized by lithics made from volcanic rocks, numerous Acheulean bifaces, and often more laminar or Levallois debitage. It can be suggested that there are independent origins for these Southern Caucasus Upper Acheulean industrial variants. Possible roots of the Acheulean assemblages of Kudarian variant might be in the local earlier Lower Paleolithic small tool assemblages with some pebble tools but without Acheulean bifaces. The other Caucasus variant of the Upper Acheulean appears to be related to the Levantine Upper Acheulean.  相似文献   

16.
Two sites in the Villány Hills, Hungary, have yielded rich fish assemblages from Middle to Late Triassic shallow marine deposits. The collected material comes from the Ladinian Templomhegy Dolomite Member and from the Carnian Mészhegy Sandstone Formation. The ichthyofauna is composed of both chondrichthyans (Hybodontidae indet., Palaeobates angustissimus, ‘Polyacrodus’ sp., ?Lissodus sp.) and osteichthyans (Gyrolepis sp., Birgeria sp., and further indeterminate actinopterygians). Despite the large sample size, no remains of neoselachians have been found. The Ladinian Templomhegy Dolomite is dominated by durophagous hybodontiforms (Palaeobates angustissimus, ?Lissodus sp.), but the piscivorous hybodontid and the generalist ‘Polyacrodus’ sp. are missing, while in the fish fauna collected from the Carnian Mészhegy Formation indeterminate piscivorous hybodontids are the most common elements and durophagous forms are much less abundant. The dominance of piscivorous hybodontids in the Carnian Mészhegy Sandstone could be related to the global decrease of diversity of marine fish-eating reptiles (e.g., nothosaurs) or to a change of paleoenvironmental conditions. The present study improves our knowledge on the poorly known Triassic vertebrate faunas of the Tisza Mega-unit, which formed a segment of the passive Neotethys margin of the European Plate and shows an important example of a potential vertebrate faunal shift during the Middle to Late Triassic.  相似文献   

17.
  • 1 Analysis of insect ‘death assemblages’ from ancient natural and anthropogenic deposits can provide valuable information about conditions in the past but the theoretical basis of such investigations is weak, especially with respect to the quantification of habitats on archaeological sites.
  • 2 Evidence is presented for the existence of a transported component, termed ‘background fauna’, in death assemblages, as well as the remains of insects derived from the immediate surroundings.
  • 3 The background component is derived principally from airborne insects and from bird droppings and may seriously detract from the accuracy of reconstructions of past ecological conditions. Factors affecting its relative importance are discussed.
  • 4 As well as including species from distant habitats, the background fauna may be biased in favour of species from temporary habitats.
  • 5 Some solutions to the problems presented by the background fauna are discussed. A high proportion of a species or ecological group will usually be evidence that its habitat existed near to the deposit enclosing the fauna, although there may be exceptions.
  • 6 The structure of the background rain of insects has probably altered with changes in town and countryside brought about by man. Attempts to recognize background fauna in ancient assemblages must take account of this.
  • 7 Many ancient assemblages, especially if small, will give no useful ecological information.
  相似文献   

18.
《L'Anthropologie》2021,125(4):102914
Linking southeastern Europe and central Europe, the Danube Valley plays a key role in the models of the first colonization of Europe by anatomically modern humans about 40 thousand years ago (Danube Corridor hypothesis). The middle course of the river, the Carpathian Basin occupies a fundamental place in the search for archaeological evidences of the expansion of modern humans. Surveys carried out in northern Hungary in the last two decades have discovered numerous open-air sites whose lithic material can be attributed to the period concerned. Our excavations carried out in the region of Eger demonstrated the presence of the Aurignacian but also allowed the recognition of a macrolaminar industry of the Initial Upper Palaeolithic. The lithic material collected on the surface of the Andornaktálya 2 site provided rich assemblages of these two industries. The macrolaminar industry has techno-morphological connections with the leptolithic tools of Sokyrnytsia and Korolevo in Transcarpathian Ukraine. The Aurignacian industry has several characteristics in common with those of Košice-Barca and Seňa in southeastern Slovakia. Unfortunately, the chronological position of the macrolaminar and Aurignacian industries cannot be specified at the sites of the Eger region, although their age of Interpleniglacial seems evident from the stratigraphic considerations and the dating of the sediments. Despite these chronological inaccuracies, our results support the model, published by J.K. Kozłowski in 2010, of two waves of the immigration of modern humans across the Danube Corridor.  相似文献   

19.
Two Upper Paleocene and one Lower Eocene localities from Morocco (Ouarzazate basin) have yielded terrestrial assemblages that stand among the rare herpetofaunas from the Paleogene of the African Plate. The collections include one of the rare frogs and the only lizards known from the Paleogene of Africa. One of the two Upper Paleocene localities, Adrar Mgorn 1, has produced an indeterminate anuran and the most diverse assemblage of squamates from the Mesozoic and Cenozoic of Africa. It has yielded the earliest known scolecophidian snake and the earliest Gekkonidae, amphisbaenians, Tropidophiidae, and perhaps Boidae from Africa. Moreover, a specimen represents either the last sphenodontian or the earliest acrodontan lizard from this continent. One of the amphisbaenians represents a very distinct new taxon, Todrasaurus gheerbranti gen. and sp. nov. Indeterminate scincomorphans, lacertilians, Madtsoidae, and Aniliidae are also present. The fauna from the Lower Eocene is less diverse than that from the Upper Paleocene, but some taxa are common to both levels. Contrary to nearly all other Paleogene herpetofaunas from the African Plate, these Paleocene and Eocene assemblages include taxa that were terrestrial, not aquatic.  相似文献   

20.
In Lake Pátzcuaro in the Mesa Central of México, a total of 19 species of helminths was found in 598 fishes and comprised five digeneans, two monogeneans, four cestodes, one acanthocephalan and seven nematodes, of which ten species were represented by larval or immature states. The richest and most diverse helminth communities were found in the native carnivorous goodeid Alloophorus robustus. In general, the helminth communities in the different fish species were not particularly species rich and the parasite assemblages were numerically dominated by larvae of the bird trematode, Posthodiplostomum minimum. Patterns of helminth community richness and diversity were similar to those previously observed in north-temperate freshwater fishes. Most enteric helminths occurred with low abundance and only a small proportion of the gut helminth communities was numerically dominated by any one species. Helminths dominating their enteric communities showed some level of host specificity. Helminth communities in carnivorous fish species were generally richer than those in herbivores and detritivores, with the exception of the predominantly herbivorous Goodea atripinnis. The helminth fauna of introduced fishes, Cyprinus carpio, Micropterus salmoides and Oreochromis niloticus , consisted of either few or no host-specific adult helminth(s) translocated from their original geographical areas and by larval stages of helminths of piscivorous birds. Based on the geological history of the area and the biogeography of the endemic fish fauna, it is hypothesized that host-switching and relationships with the nearctic fauna have been fundamental in determining the helminth fauna of the endemic fish hosts.  相似文献   

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