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记述了采自美国内布拉斯加州中新统的一保存较完整的美獾（Ｌｅｐｔａｒｃｔｕｓ）头骨化石。与美獾属的其他已知种相比,该标本的颊齿粗壮,Ｐ４臼齿化,近方形,宽略大于长,齿尖磨蚀均匀,Ｉ３犬齿化,且向大齿方向弯曲;Ｍ１宽略大于长,且比已知种的Ｍ１大;听泡具钩状突,突起上有一明显的舌骨关节面。依据上述与已知种的差别,我们将其定为一新种Ｌｅｐｔａｒｃｔｕｓｍａｒｔｉｎｉｓｐ ｎｏｖ。新种的牙齿形态及齿尖磨蚀状况显示其为杂食动物。 相似文献
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珠江口盆地白云凹陷L2-X井中新世地层沉积连续,含丰富的有孔虫化石,是研究区较为典型的中新统钻井剖面之一。在L2-X井1 490～2 640 m井段内分析有孔虫岩屑样品127个,共鉴定有孔虫71属110种,其中浮游有孔虫12属37种,底栖有孔虫59属73种。根据浮游有孔虫标志种,在中新世地层中共识别出10个有孔虫化石带或联合化石带。依据有孔虫分异度、丰度及组合特征,对早中新世—中中新世的沉积环境演化特征进行了分析。井段2 565～2 640 m(下中新统下部),受白云运动影响,为浅水大陆架向深水大陆坡过渡的沉积环境,之后开始稳定地接受深水大陆坡沉积;井段2 050～2 040 m(N8b亚带,中中新统下部),浮游有孔虫的含量急剧降低,这表明L2-X井在该时期可能发生了一次快速沉降,水体进一步加深;井深1 680 m之上(N13带,中中新统上部),浮游有孔虫的百分含量升高、玻璃质底栖有孔虫逐渐占据优势,底栖深水种逐渐消失,指示了在该界面之上,L2-X井的水体逐渐变浅,由深水大陆坡逐渐向浅海外陆架沉积环境转变。L2-X井识别出的胶结质壳有孔虫,形态类型以M4a和M4b占主导地位,可用于指示... 相似文献
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广西二叠纪深海硅质岩系中瓜德鲁普统至乐平统界线地层牙形石分带及动物群特征 总被引：1，自引：0，他引：1
在广西钦州地区小董镇大虫岭深海硅质岩剖面中,首次处理出了层序连续的牙形石化石,并由老至新划分了二个牙形石带,即Jinogondolella granti带和Clarkina dukouensis带。通过这二个牙形石带与斜坡相和盆地相碳酸盐岩硅质岩系中的牙形石带进行对比,划分了本剖面中乐平统生物地层底界。本文对深海硅质岩系中这一界线地层牙形石动物群特征进行了简要的描述。 相似文献
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作者在贵州紫云县坝寨上泥盆统弗拉阶响水洞组硅质岩中发现了Helenifore robustum放射虫动物群,共描述7属13种,其中包括1个未定种和2个新种.作者还讨论了这个动物群的特征及与国内外的对比关系,并指出产于我国云南、贵州、广西和泰国北部的这个动物群是属于古特提斯洋中原地型浮游动物群,而在美国内华达州Roberts 山脉推覆体的硅质岩和澳大利亚东部新英格兰造山带的硅质粉砂岩中发现的这个动物群是后来的板块运动把这些含有H.robustum动物群的地层碎块拼贴到北美和东澳大陆上去的结果,属于异地型动物群. 相似文献
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首次系统描述云南丽江鸣音下胖罗、当子落两地奥陶纪鹦鹉螺10属19种,Meitanoceras subglobo-sum disoides,Changyangoceras gaojiabianense,Michelinoceras elongatum,M.paraelongatum,M.parasquamatulum,Michelinocera variabilum,M.xuanxianense?,M.aff.M.xuanxianense,M.zangbeiense,Eosomichelinoceras guizhouense,Archigeisonoceras elegatum,A.sp.1,A.sp.2,Stereoplasmocerina sp.1,S.?sp.2,Cameroceras cf.C.compressum,Dideroceras sp.,Discoceras cf.rarospira,Trocholites aff.T.lativentrosus。依据鹦鹉螺组合特征,认为含鹦鹉螺地层时代为Darriwilian中期及Caradoc中期。 相似文献
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记云南禄丰发现的Lophochoerus一新种 总被引：1，自引：0，他引：1
本文对1981年冬在云南省禄丰古猿化石地点发现的脊齿猪(Lophochoerus)进行了描述和对比。禄丰脊齿猪与仅发现于西瓦立克的同属几种之间在前臼齿和臼齿上有一定的区别,为此,另建立一新种Lophochoerus lufengensis sp,nov., 代表我国晚中新世地层该类化石的首次发现。 相似文献
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It is more and more clear that the fossil materials from the Ramapithecus locality of Lufeng respresent a very complete association of Vertebrates and the most rich assemblage in the Pontian mammalian faunas of South China. Seven forms of Carnivora were reported by the author in 1979. Up to now, twenty seven forms of the order have been found. The taxonomic unit, distribution in the different layers of the Seetion D and the specimen count of each form can be seen in Table 1. This paper only reports the preliminary results of the Carnivora fossils of the Lufeng mammalian fauna. A detailed study of these specimen will be published in future article.<br>Most of the new forms added to the list of Carnivora are bears, civets and mustelids. Four, ten and three forms have been referred to Ursidae, Mustelidae and Viverridae respectively.<br>Among the fossils, only a few specimens of two forms (Sivaonyx bathygnathus and Ictitherium gaudryi) were collected from the first layer and the rest came from the second layer and below. This fact indicates that possibly the required living conditions for most of the forms had changed and they no longer existed in the first layer. It tallies with the situation shown in the deposits such as a clear erosin surface between the first and second layers and difference of the upper and lower layers in composition.<br>Ictitherium gaudryi is the most abundant one of twenty seven forms (67 specimens) . Secondly, Sivaonyx bathygnathus (29 specimens) , Epimachairodus fires (19 specimens) and Pseudaelurus sp. (14 specimens) are also common. In addition, Ursavus depereti, Indarctos sp. and Ursinae indet. are represented by more than 12 specimens. The rest are quite rare.<br>In the Carnivora of Lufeng, sixteen forms can be identified to the genus level. At least two genera (Sivaonyx and Ursavus) were not reported from chinese Neogene deposits before and it is possible that certain forms of mustelids and civets are also new for the fossil record of Baodean (or Pontian) in China. Miocene linsang and binturrong may exist in the Viverridae and another form, previsionally attributed to Mustelidae indet. (2) is also a problematical one.<br>Compared to the late Miocene faunas of Europe and North America, Lufeng fauna shows close relations to them. Considering the Carnivora, at. least ten genera (Indarctos, Ursavus, Martes, Eomellivora, Lutra, Sivaonyx, Ictitherium, Epimachairodus, Pseudae-lnrus and lelis) can be found in Europe and six genera (Indarctos, Martes, Eomellivora, Lutra, Pseudaelurus and Felis) exist also in North America. Some affinities to Africa were indicated by a few genera (Ictitherium and Felis) .<br>In comparison with the \"Hipparion fauna\" of North China and middle Siwalik fauna of India-Pakistan subcontinent, Lufeng fauna has its own distinguishing features. As shown in Table 2, five families (Ursidae, Mustelidae, Viverridae, Hyaenidae and Felidae) all appear in the three faunas. Seven genera (Indarctos, Martes, Eomellivora, Ictitherium, Epimachairodus, Pseudaelurus and Felis) are common for all faunas. Proputorius and Lutra are present at Lufeng and other localities of North China. Sivaonyx is common to that of Lufeng and Siwalik.<br>Of eight forms identified to species level, two (Proputorius lufengensis and Epimachairodus fires) are new species. Ursavus depereti can only be found in the Torolian fauna of Europe. Four (Indarctos sinensis, Eomellivora wimani, Martes palaeosinensis and Ictitherium gaudryi) of the forms are limited to the Baodean of North China. Sivaonyx bathygnathus not only lived in Dhok Pathan fauna (corresponding to Turo lian of Europe) , but also occured as early as Nagri (corresponding to Vallesian of Europe) of South Asia.<br>Judging from the comparisons of the micromammalian fauna and the other orders of Lufeng fauna, it is possible that the geological age of Lufeng fauna corresponds to Dhok Pathan of the middle Siwalik of South Asia (or Selenoportax lydekkeri IntervalZone offered by Barry J. C. et al. in 1982) and Turolian of Europe.<br>The composition of Lufeng Carnivora lacks canids and amphicyonids as in the Baodean of North China and some forms of civets fossils are relatively rather common. In general, the living forms of many civets are typical beasts inhabiting tropic or subtropic forests. The otters and some mustelids reflect restricted palaeoecological enviroments generally associated with aquatic conditions. The large cats and bears are said to be \"forest-dwelling\"usually.<br>Further research with the Lufeng fauna and associated conditions may be resolved in the near future. 相似文献
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Lufeng rhizomyid fossils collected by exeavation and underwater sieving of fossili-ferous sediments, are studied in this paper.<br>The specimen referable to Brachyrhizomys nagrii is a left lower dentition with M1—M3(V. 8126) . Length of M1-M3, is 11. 75 mm. Both size and characters (such as short M3 and an elongated mesolophid on M3 ) agree well with Siwalik specimens (Fig. 4).<br>The specimens identifiable to Brachyrhizomys ef. B. pilgrimi are a left dentary with M1—M3 (V8127. 1) , a right M3 (V8127. 2) and an I1 (V8127. 3) . This is a large species with heavy deep dentary (depth below M=15. 4 mm) and massive incisors. It also is the biggest one of three species of Lufeng Brachyrhizomys. An apparent trait is suppression of mure on Mo-3. The narrow connection may not be present in early wear. Length of M-Ms is 15. 6 mm and more closer to B. ef. pilgrimi than to B. pilg- rimi of Siwaliks in size (Fig. 5, A, B and C).<br>The third species is B. tetracharax to which the most of the rhizomyine fossils from Lufeng Ramapithecus locality belong. The materials include an incomplete skull and associated lower jaw (V8128. 1) , five maxilla fragments (V8128. 2—6) . fourteen lower jaws (V8128. 7-20) . Fifty five isolated upper and lower ehack teeth (V8128. 21-75) , eleven isolated upper and lower incisors (V8128. 76—86) . Unfortunately, the skull and assoeiated lower jaw are crushed and fiattened laterally (Fig. 6, A) . The portions of it preserved are the ear region of two sides, partial right palate and left zygoma、partial maxilla, premaxilla, temporal bone and nasal. The infraorbital foramina were damaged and the shape of their ventral slit ean not be observed. The dentary is deep. In general, the upper dentition is longer than the lower one. Average length of them is 12. 28 mm and 14. 30 mm respectively. It is undoubtedly to refer the specimens from Lufeng to B. tetracharar, although there is discrepaney between the dimensions of the cheek teeth of Lufeng and Siwalik. M' has four roots. Ma elongates transversely. There is a strong mesolophid on M2 and an evident mure on worn M2-3. M, extends longitudinally. These traits distinguish the specimens from the other speeies easily. The yariations of upper and lower eheek teeth manifested by differences of wear stage in size and pattern of occlusal surface are shown in Fig. 6.<br>In addition, two isolated cheek teeth are referred to Rhizomyidae indet. A right M' with four roots (V8129) possesses an antero-lingual flexus (Fig. 7) . Another right M5 with a root (V8130) has been well worn and only retained lingual reentrant and three enamel lakes on oeclusal surface (Fig. 8).<br>The best known record of rhizomyid evolution is doeumented in Siwaliks of Pakistan. It is considered to be a standard for comparison of fossil rhizomyids through. out the world especially Asia. Three species of Brachyrhizomys mentioned above have known temporal ranges in Pakistan and eoexisted for a short time at 8 Ma. So Lufeng hominoid fauna can be placed about 8 Ma or perhaps a bit later. 相似文献
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新疆准噶尔盆地北缘中中新世食肉类 总被引：1，自引：0，他引：1
1995年和1996年在新疆准噶尔盆地北缘乌伦古河沿岸中中新世地层中新发现的食肉类,经研究有8属9种,包括一新种：Nimravussp．、Pseudaeluruscuspidatussp.nov.、Protictitheriumintermedium、Protictitherium小种、Thalassictischinjiensis、Gobicyonsp．、Oligobunis？sp．、Alopecocyongoeriachensis和Simocyon小种．新材料虽较破碎,但其发现扩大了一些已知属种的地层和地理分布范围。通过对标本的观察和对比,对各属种的系统发育作了讨论。各属种与通古尔、丁家二沟、下草湾等动物群以及欧洲、南亚相关动物群的食肉类分子的比较结果尚不能肯定含化石地层的确切时代,但有可能早于通古尔组。 相似文献
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Richard Arnold Davis R. H. B. Fraaye Charles Hepworth Holland 《Lethaia: An International Journal of Palaeontology and Stratigraphy》2001,34(1):37-45
'Sheltered preservation' of the remains of trilobites within the shells of nautiloid cephalopods is not especially uncommon. In most cases, of course, both the trilobites and the nautiloids were dead, and the association, merely due to post-mortem happenstance. However, on the basis of state of preservation and occurrence, a number of live individuals of the trilobite genera Acidaspis, Flexicalymene, and Isotelus from the Ordovician of the United States and of Alcymene and Encrinuraspis from the Silurian of Wales and the Czech Republic seem to have entered conchs of dead cephalopods, presumably for refuge. 相似文献