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1.
产自陕西府谷晚中新世喇嘛沟组红色砂质泥岩中的爪兽化石,其颌骨及牙齿保存得相当完好,为研究有关牙齿的细微结构及分类提供了宝贵材料。其颌骨及牙齿都很粗壮厚实。上齿列颊侧弯曲;臼齿菱形或斜方形;原尖粗大,孤立;原小尖发育,靠近前尖,甚至与前尖相接呈短的前脊;无原脊;前、中附尖粗大;前、后齿带皆发育很好。下犬牙较粗大;下颊齿呈一条直线排列;下前臼齿退缩不太大;下后附尖发育较好,磨用后,常与下后尖连成并联蒂状。除第四前臼齿臼齿化外,其他前臼齿皆未臼齿化。府谷爪兽归入奈王爪兽属(Nestoritherium),但与已发表过的种都有明显差异,特建一新种:府谷奈王爪兽(Nestoritherium fuguense sp.nov.)。当时动物之大量死亡,可能主要是突发的自然灾害如沙尘暴所引起,死后未经长距离搬运。  相似文献   

2.
中国云南下禄丰组的早侏罗世中国尖齿兽的新材料显示出从前未曾认识到的早期哺乳动物牙齿特征.中国尖齿兽的门齿和犬齿,像非哺乳类犬齿兽一样,是多次替换的。新的中国尖齿兽幼体标本保存有前臼齿,前臼齿替换一次之后,在较大(更老)的标本上就永久消失。犬后齿分化为前臼齿与臼齿,以及前臼齿仅替换一次是现代哺乳动物的衍生特征。中国尖齿兽前边的臼齿可能无后继齿替换而消失;后边的臼齿替换一次.中国尖齿鲁当其成体的牙齿还在经受替换期间,头骨仍在继续生长。中国尖齿首是所有其他哺乳动物的姊妹类群。中国尖齿兽的牙齿替换方式可解释为从爬行类原始多出齿系向哺乳动物进步的二出齿系进化的中间过渡类型。由中国尖齿兽的多出齿系和其头骨无期限式生长推知,该类动物尚不具备现代哺乳动物所具有的有期限生长方式和哺乳特征。  相似文献   

3.
文章描述了中国湖北李官桥盆地早始新世一奇蹄类新材料,建立了一个新属新种:秉志丹江兽(Danjiangiapingigen,etsp.nov.),,经过系统分析将其归入了爪兽类群。秉志丹江兽是迄今发现的时代最早的爪兽。该文对爪兽的早期形态演化、爪兽类与古马类可能存在的亲缘关系以及爪兽类的起源等问题也进行了探讨。  相似文献   

4.
真三尖齿兽类是了解亚洲白垩纪哺乳动物群演化和转变的重要成员之一。到目前为止沙海组和阜新组(下白垩统上部)已经发现了两种戈壁尖齿兽科以及两种三尖齿兽科的真三尖齿兽类。描述了这些地层产出的真三尖齿兽类的其他材料,包括一新属新种——常氏阜新尖齿兽(Fuxinoconodon changi gen. et sp. nov.)和一枚左下臼齿(鉴定为?Gobiconodontidae gen. et sp. indet.)。这种新的真三尖齿兽类被归入戈壁尖齿兽科(Gobiconodontidae),其特征为:第一下门齿大、门齿和前臼齿的数目变少、臼齿b尖和c尖较大而独立,以及臼齿具有分别属于Gobiconodon第一代或第二代臼齿上独有特征的组合。新材料与同一地区相同层位已经报道的4种真三尖齿兽类表明,虽然科级和属级的多样性似乎已经减少,但亚洲早白垩世晚期仍存在比较多样的真三尖齿兽类。  相似文献   

5.
辽宁早白垩世义县组一新的三尖齿兽类   总被引:2,自引:1,他引:1  
描述了戈壁锥齿兽科 (Gobiconodontidae)一个新的属种———陆家屯弥曼齿兽 (Meeman nodonlujiatunensisgen .etsp .nov.)。标本产于辽宁西部朝阳市上园镇陆家屯下白垩统义县组一段的凝灰质砂岩层中 ,为一具完整齿列的左下颌骨。新属与戈壁锥齿兽 (Gobiconodon)共有以下区别于其他三尖齿兽类的特征 :2颗下门齿 ,i1增大 ,后部门齿、犬齿和前部前臼齿尖锥形 ,前臼齿具有高的中央尖和小的附尖 ,i~p1向前平伏。因此 ,新属被归入戈壁锥齿兽科。弥曼齿兽与戈壁锥齿兽及其相近属的区别在于 :下门齿和下犬齿更加平伏 ,i1在比例上更大 ,而i2则更小 ;最后一枚下前臼齿与第一枚下臼齿之间没有齿隙 ;前臼齿退化 ;下臼齿长度大于高度 ,主尖向后倾斜 ,与b尖和c尖相比 ,a尖较低 ,m1显著小于m2~ 4。新属下臼齿没有齿带 ,与爬兽 (Repenomamus)相似 ,而与戈壁锥齿兽不同。基于与爬兽齿列的对比 ,讨论了戈壁锥齿兽类的齿式 ,认为其应具有两颗门齿 ,而不是以前认为的 1颗门齿 ,从而将戈壁锥齿兽类下齿列齿式修订为 :2·1·2~ 3·5。  相似文献   

6.
广西柳城巨猿洞是迄今我国所发现的含爪兽化石最丰富的第四纪化石点。该化石点的爪兽上颊齿原尖强壮,呈圆锥状;次尖发育,呈新月形;原脊完全退失;m3齿带更发育;可归入我国第四纪较常见的中国黄昏爪兽(Hesperotherium sinense)。但柳城巨猿洞的标本明显比我国其他第四纪地点的爪兽较小,尤其是比早更新世晚期的代表小很多。在形态特征方面,柳城巨猿洞的爪兽与重庆巫山的最为接近,而与安徽繁昌及湖北建始的差异较大;但在牙齿的宽/长比值方面,却与安徽繁昌的最为接近。我国已发现的爪兽化石以单个牙齿为主,在分类鉴定方面存在诸多问题,通过牙齿测量的点散布图,可以有效地检验对零散爪兽牙齿齿序的鉴别是否正确。  相似文献   

7.
爪兽在我国新近纪地层中发现的数量和种类都相当稀少。本文根据产自甘肃省临夏盆地晚中新世柳树组的一批化石材料建立的一个爪兽化石新种临夏奈王爪兽(Nestoritherium linxiaense sp.nov.)是此属目前所发现的最原始的种类。新种以鼻骨与泪骨相接触、上臼齿原小尖萎缩、原脊不太发育、下颌粗壮、齿隙短、下犬齿可能存在但发育较弱以及p4下内尖孤立而区别于其他各种。根据新发现的化石,确立了Nestoritherium属名的有效性,并将修订后的Nestoritherium wuduense(Xue&Coombs,1985)归入其中,认为此属是Hesperotherium的祖先类型。  相似文献   

8.
记兰州盆地第三纪中期的爪兽(奇蹄目)化石   总被引:3,自引:1,他引:2  
记述了兰州盆地新发现的三种爪兽化石:Schizotheriumordosium,Phyllotillonhuangheensissp.nov.和Chalicotheriinae亚科未定属种的一类。在咸水河组下段南坡坪地方动物群(早渐新世晚期)中发现S.ordosium。这个种的材料较多,其中有保存完好的下颌吻部。这使我们第一次了解了这个属的吻部的构造:吻部很长、具大的铲形下门齿和双叶形的下犬齿.在咸水河组中段(早中新世)张家坪地方动物群中发现了Phyllotillonhuangheensis和Chalicotheriinaegen.etsp.indet。前者比巴基斯坦Bugti层中的P.naricus个体稍小,形态上也更原始些。这可能表明,张家坪地方动物群在时代上比Bngti稍早。后一类爪兽的性质还不很清楚,但Chalicotheriinae亚科在我国早中新世的出现则无疑义。  相似文献   

9.
根据正型标本的印痕和翻制的模型,重新研究了产于辽宁阜新新邱阜新组的早白垩世真兽类哺乳动物新带氏远藤兽(Endotherium niinomii Shikama,1947)。对照Shikama(1947)的原始描述,将E.niinomii的主要特征归纳为:下臼齿从m1到m3逐渐变小;下三角座和下跟座的高差不是很大;下臼齿的齿尖钝;下原尖比下前尖和下后尖大,并且下前尖和下后尖高度相近;可能有5个前臼齿,并且p3不明显变小。这些特征组合足以将该属与其他的白垩纪真兽类相区别,因此认为Endotherium niinomii是一个有效种。  相似文献   

10.
记述了在广东南雄盆地中古新世地层中发现的岭南(犭亚)兽一新种——进步岭南(犭亚)兽(Linnania progressus sp.nov.)。新种比属型种罗佛(犭亚)兽(L.lofoensis)下臼齿下前尖退化、跟座增长。  相似文献   

11.
甘肃临夏盆地的渐新世巨犀化石   总被引:5,自引:2,他引:3  
描述了 2种巨犀化石 :霍尔果斯准噶尔巨犀 (Dzungariotheriumorgosense)和牙沟副巨犀(新种 ) (Paraceratheriumyagouensesp .nov.)。新种的主要特征是 :个体小 ;上颊齿齿冠高 ,有薄层白垩质覆盖 ;DP2~M1反前刺大 ,原尖后收缩沟明显 ,次尖有深的前收缩沟 ,中谷和后凹中常有附属小柱等。巨犀的演化历史可能比过去想象的更复杂。Indricotherium、Dzungariotherium和Paraceratherium为代表不同进化水平和支系的 3个属 ,不应合并为Paraceratherium一属。牙沟含巨犀化石层位的地质时代为晚渐新世。  相似文献   

12.
内蒙古晚始新世的仓鼠化石   总被引:3,自引:3,他引:0  
描述了产自内蒙古晚始新世地层中的3属5种仓鼠化石(Pappocricetodon antiquus,Pap- pocricetodon sp.,Pappocricetodon?sp.,Eocricetodon borealis sp.nov.和Oxynocricetodon erenensis sp.nov.),建立了Eocricetodon和Oxynocricetodon两个新属。Eocricetodon属的特点是:齿尖较钝,横脊较细;M1前叶中等大小,前边尖单一,原尖前臂伸达前边尖,原脊与原尖后臂连,后脊与次尖连;m1三角座特别短而窄等。Eocricetodon borealis的特点是:M1前叶相对更细窄,具明显的原小尖。m1下原尖和下后尖位置彼此相对,m1和m2的下次脊与下次尖连等。Oxynocricetodon属的主要特征为:颊齿具相对较细锐的主尖和较细长的横脊;上臼齿原脊和后脊均为前连;M1前叶较大;前边尖孤立;原尖前臂不伸达前边尖等。Oxynocricetodon erenensis的特征主要是:M1前边尖为较大的新月形;无中脊和中附尖;M1和M2无原尖后臂;M3较少退化等。对早期仓鼠的演化趋势作了归纳和补充。讨论了产仓鼠化石地点的地层的时代,认为额尔登敖包的乌兰戈楚组的"下白层"的时代较二连浩特的呼尔井组的稍早,为晚始新世的较早期,而呼尔井组的时代为晚始新世的较晚期。  相似文献   

13.
汉水上游旧石器的新发现   总被引:6,自引:3,他引:3  
汉中盆地地处我国华南与华北的一个中间过渡带。在汉中盆地内旧石器又有新的发现,同时和旧石器一起还发现了哺乳动物化石,有9属9种。哺乳动物化石的发现,对于确定旧石器的时代有所帮助。  相似文献   

14.
Although amoebic gill disease (AGD) has emerged as one of the most severe health problems in the fish industry, proof of the identity of AGD agents from various localities is still missing. Six strains of amoebae designated until recently as Paramoeba species (the agents of AGD) were studied in cultures by light and electron microscopy. Although they were isolated from gills of different hosts (Dicentrarchus labrax and Scophthalmus maximus) and from distant localities, their morphology was identical. The strains differed from Paramoeba eilhardi, the type species of the genus, in that they lacked the boat-shaped microscales on the cell surface but could be safely identified as belonging to the genus Neoparamoeba Page, 1987. Transmission electron microscopy revealed the presence of a symbiotic organism, Perkinsiella amoebae Hollande, 1980, in all strains under study. The only difference among the strains examined was found in the size of trophozoites, which could be attributed to the different origins of the strains, but until more refined diagnostic methods are available, in addition to N. pemaquidensis, the closely related species N. aestuarina also has to be taken into consideration as the agent of AGD.  相似文献   

15.
In contrast to the opinion of Miki (1952 b, p. 349) the genus Hemitrapa Miki (Trapellaceae) is not only found in Asia and America but also in Europe. Wrongly determined fossils of the type „Trapa silesiaca Goeppert”︁ (the original species from Schoßnitz in Poland is under research by M. Lancucka-Srodoniowa, Krakow) belong to the genus Hemitrapa Miki. Some other Bavarian fossils are newly decribed here as Hemitrapa heissigii sp. nov. Hemitrapa fossils grew not only in the Senftenberg area (Menzel 1906), in Silesia (Kräusel 1920) or the Niederlausitz area (Menzel in Gothan & Sapper 1933), at Konin (Raniecka-Bobrowska 1954), but possibly also near Cologne (Kilpper 1969 and Kramer 1974) and at Ponholz (Gregor 1980). Especially in the Middle Miocene Upper Freshwater Molasse of Bavaria the fossil species Hemitrapa heissigii is found in numerous specimens near Eberstetten, Haag a. d. Amper and Rauscheröd (all in southern Bavaria). Hemitrapa heissigii can be used as an index-fossil and signs Uppermost Miocene sediments (Badenian, Samartian). The occurence in Pliocene localities is to be prooved. The whole group around Hemitrapa is considered to be a “late element” (Upper Miocene) in Europe.  相似文献   

16.
Previously undescribed remains of a new large giraffid have been identified from the late Miocene Siwaliks Hills of the Potwar Plateau in Pakistan. This taxon is very intimately related to the late Miocene giraffid genus Decennatherium, previously only certainly identified in the Iberian Peninsula, and with some possible remains assigned to Decennatherium crusafonti from Aliäbäd (Iran). The new material collected in the Siwaliks Hills shows a high morphological similarity with the Spanish remains of the genus, especially the early Vallesian Decennatherium pachecoi. Two previously undescribed ossicone fragments from the same area are also described and identified as cf. Decennatherium. These findings represent the easternmost occurrence of the genus Decennatherium and show a late Miocene migration of the genus throughout the Iberian Peninsula and Southern Asia.  相似文献   

17.
Fossil remains of beetles are described from two Lower Triassic localities: Entala (Induan) and Tikhvinskoe (Olenekian). Only one beetle fossil was previously known from the Lower Triassic of Tikhvinskoe. The fossils are rather few and poorly preserved, but they are worth describing as finds rare for the Lower Triassic. Five fossils from Entala most probably belong to beetles of the same species of the formal genus Pseudochrysomelites. Beetles of this genus are especially abundant in deposits close to the Permian–Triassic boundary and can be considered “disaster taxa.” There are no known cases, either in the Permian or in the Middle–Upper Triassic, of a random sample of five specimens belonging to a single species. This suggests that in the Entala oryctocenosis the species diversity of beetles is extremely low. All three beetle fossils found in Tikhvinskoe belong to beetles of different species, showing that diversity had already started to increase. However, it remained low, and all fossils belong to the formal family Schizocoleidae, and two of the three belong to the same genus, Pseudochrysomelites. The Khei-Yaga locality, which immediately follows Tikhvinskoe in time (topmost Olenekian or early Anisian), already contains beetles of the families Asiocoleidae and Permosynidae. In the Lower Anisian of the Buntsandstein, such typical Mesozoic beetles as Cupedidae and Coptoclavidae have been recorded. The appearance of such advanced beetles as early as the Lower Anisian suggests that the famous Permian–Triassic crisis was not as deep as it is usually believed, and many beetles survived it, disappearing, however, from the fossil record in the Early Triassic.  相似文献   

18.
H.H.LEE 《古生物学报》1955,(3):181-188
Among the plant fossils collected by Messrs.K.C.Yang,S.Wang and S.F.Peng during the geological investigation in southeastern Shansi in 1954,thereare some considerable well-preserved specimens of Callipteridium-like frond whichappear referable to the present genus.Most of the specimens were found fromthe Shansi Series at several localities:Changtsun,Shihkutsun,and Chaochiakouof Luanhsien,a few very fragmentary specimens have also been gathered fromWuhsianghsien,S.E.Shansi.  相似文献   

19.
New omomyid fossils from the Purple Bench locality of the Devil's Graveyard Formation, middle Eocene (Uintan) of southwest Texas, are described. One specimen represents a new genus and species, herein named Diablomomys dalquesti. This new species is allocated to the tribe Omomyini, sister taxon to Omomys and Chumashius. A second specimen represents a range extension of the Utah species Mytonius hopsoni to the Trans-Pecos region of Texas. Previously, only one omomyid species (Omomys carteri) had been documented from Purple Bench and other late Uintan localities in the Devil's Graveyard Formation. These new omomyid fossils are of particular significance because Purple Bench is stratigraphically intermediate between the older late Bridgerian/early Uintan localities and the younger Duchesnean localities of Trans-Pecos Texas. With a more southerly location in the continental United States, the Devil's Graveyard Formation amplifies our understanding of patterns of North American primate richness at a time when the higher-latitude sites of the western interior were undergoing significant climatic cooling and increases in seasonality with commensurate faunal reorganization. Although the Uintan (approximately 46.5-40Ma) was a time in which anaptomorphine richness decreased dramatically, the results of this analysis suggest that Uintan omomyine richness is higher than was previously appreciated, particularly at lower latitudes.  相似文献   

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