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1.
报道了甘肃天水地区武山县四门镇南峪村地点发现的一件残破的未成年维曼嵌齿象(Gomphotherium wimani)下颌,标本保存有完整的p3,dp4,m1齿列。颊齿齿冠显示出嵌齿象属(Gomphotherium)的一些进步特征,例如齿脊前后压缩,齿谷宽阔,副齿柱后中心小尖凸显,中附锥和中心小尖趋于分裂,有弱的白垩质发育,符合维曼嵌齿象的鉴定特征。维曼嵌齿象此前发现于甘肃的中中新统,而南峪村地点的含化石地层可与周围其他地点的中中新统对比,因此,南峪村地点维曼嵌齿象层位的地质时代为中中新世。同时,结合孢粉学研究的结果,可能说明中中新世时期,天水地区气候温暖湿润,适宜低齿冠的哺乳类如嵌齿象等动物生存。  相似文献   

2.
The taxonomic history of South American Gomphotheriidae is very complex and controversial. Three species are currently recognized: Amahuacatherium peruvium, Cuvieronius hyodon, and Notiomastodon platensis. The former is a late Miocene gomphothere whose validity has been questioned by several authors. The other two, C. hyodon and N. platensis, are Quaternary taxa in South America, and they have distinct biogeographic patterns: Andean and lowland distributions, respectively. South American gomphotheres became extinct at the end of the Pleistocene. We conducted a phylogenetic analysis of Proboscidea including the South American Quaternary gomphotheres, which resulted in two most parsimonious trees. Our results support a paraphyletic Gomphotheriidae and a monophyletic South American gomphothere lineage: C. hyodon and N. platensis. The late Miocene gomphothere record in Peru, Amahuacatherium peruvium, seems to be a crucial part of the biogeography and evolution of the South American gomphotheres.  相似文献   

3.
The objective of this study is to estimate changes in feeding preferences of the proboscidean species Gomphotherium subtapiroideum (Schlesinger 1917) by means of dental microwear analyses. The dietary changes are first evaluated through the ontogeny of this species, between juveniles and adults, and are then studied through geological time, from early Middle Miocene (MN5) to middle Late Miocene (MN8–9) localities of the German Molasse Basin. The microwear patterns of juvenile and adult individuals of G. subtapiroideum from Sandelzhausen (MN5) differ merely by the variable “length of scratches”, emphasizing longer jaw movements during mastication in adults. The microwear signatures of G. subtapiroideum do not vary significantly between the two geological time periods studied, but reflect mixed feeding preferences in both cases. These results imply that, despite an important environmental change at that time (drying and opening), the ecology of G. subtapiroideum and, especially, its feeding habits were not affected. Its dental microwear pattern is then compared with those of other species of Proboscidea from the Middle-Late Miocene of Germany, namely Deinotherium giganteum and Gomphotherium steinheimense.  相似文献   

4.
云南开远新发现的腊玛古猿化石   总被引:2,自引:0,他引:2  
本文描述的标本是1980年6月和1982年5月,在云南开远小龙潭晚中新世褐煤层中发现的古猿化石。标本有左下第一至第三臼齿列和一件带十二枚牙齿的上颌骨。从标本反映的形态特征观察,应归为腊玛古猿。  相似文献   

5.
云南开远小龙潭动物群的性质及时代的进一步探讨   总被引:4,自引:2,他引:2  
本文在前人工作的基础上,结合新材料,对小龙潭动物群作了新的补充与论述.小龙潭动物群在组合面貌上与西瓦立克的 Chinji, Nagri 层动物群相近,动物群的时代不早于 Chinji 层而早于云南禄丰石灰坝动物群,为晚中新世.  相似文献   

6.
We report Miocene mammalian faunas from three nearby localities: Kangping, Nanyu, and Yangping, in the Wushan Subbasin, Gansu Province, China. From the Kangping locality, we identified four species, Platybelodon grangeri, Hispanotherium wushanense n. sp., Kubanochoerus sp., and Turcocerus cf. kekemaidengensis, which indicate that this fauna can be correlated with MN7/8. From the Nanyu locality, we identified Platybelodon aff. tongxinensis, which, together with the previously reported specimens of Gomphotherium wimani and Micromeryx cf. flourensianus, enables us to correlate this fauna with MN6. The Yangping locality is found to be early Miocene in age based on the presence of cf. Gomphotherium sp. This occurrence is the earliest record of proboscideans in China, and thus represents the “Proboscidean Datum Event”. Evolutionary trends of Platybelodon and Hispanotherium are figured and discussed. The possibility of a geographic boundary associated with the eastern and western differentiation of species of Turcocerus and bunodont listriodonts in China is also evaluated. This boundary was consistent with the major division of the eastern and western mammalian faunas of the middle Miocene in China. The localities in Inner Mongolia suggest a large area with transitional habitats.  相似文献   

7.
Limb-bone allometry was investigated for 19 species of proboscideans, spanning almost the entire phylogenetic spectrum. More archaic proboscideans ('gompthotheres') have substantially thicker long-bone diaphyses relative to length than elephantids, as has been suggested previously, but contrary to previous suggestions it could not be confirmed that Mammuthus had more massive long-bone diaphyses on average than extant Elephas and Loxodonta . When correcting for phylogeny, the circumference of the limb bones to their length in proboscideans as a group generally scale with negative allometry, becoming stouter with increased length, as would be expected from limb mechanics. Few slopes were, however, statistically significantly negatively allometric. Correcting for phylogeny produced better correlations than traditional regression analyses, in contrast to most other studies where the reverse is the case. Intraspecific analyses of extant Elephas and Loxodonta , in addition to Mammuthus primigenius , Mammut americanum, and Gomphotherium productum , also resulted in negatively allometric regression slopes, frequently conforming to the theory of elastic similarity, as could be expected from the columnar posture of proboscideans. At present the reasons for the more massive limbs of gomphotheres s.l. are not fully understood. © 2007 The Linnean Society of London, Zoological Journal of the Linnean Society , 2007, 149 , 423–436.  相似文献   

8.
Pascal Tassy 《Geobios》1977,10(5):655-669
The Vindobonian locality of Malartic (Gers),yielded a mammalian fauna characterized by the association of Brachypotherium brachypus and Zygolophodon turicensis. One can demonstrate the controversial existence of Z. turicensis in the french Miocene from a near complete dentition belonging to one specimen. This species can be clearly distinguished from the bunodont mastodont Gomphotherium angustidens from numerous characters of the tusks and molars. Z. turicensis immigrated in France in the middle Burdigalian (zone of Artenay in the Orléanais Sands), together with G. angustidens and Eotragus artenensis. This immigration puts a further point to establish the major event in continental stratigraphy of the middle Burdigalian mammalian immigration. Z. turicensis seems to be a forest animal and G. angustidens an inhabitant of savannah.  相似文献   

9.
10.
柴达木盆地晚中新世三趾马化石   总被引:4,自引:3,他引:1  
Bohlin描述的柴达木动物群中的三趾马材料非常少 ,仅能证明三趾马在这个地点的存在。近年来新的野外考察在这一地区发现了更多的三趾马化石材料 ,至少包括 3个种 ,即Hipparioncf.H .chiai、H .weihoense和H .teilhardi。H .cf.H .chiai和H .weihoense在柴达木盆地的发现进一步证实了晚中新世早期 (保德早期 )动物群在这个地区的存在。柴达木盆地的H .teilhardi基本上与H .cf.H .chiai和H .weihoense产自同一层位 ,其时代也应为保德早期。H .cf.H .chiai和H .weihoense在柴达木盆地的发现为该地区在晚中新世早期为草原型环境的判断提供了更多的证据。H .teilhardi更细长的远端肢骨也是对开阔环境的一种适应性状  相似文献   

11.
Recent fieldwork at Woranso-Mille, Ethiopia led to the recovery of an abundant, diverse mammalian fauna that includes remains of the early hominid Australopithecus afarensis. Proboscideans are among the taxa well sampled at the site, primarily by gnathodental specimens, dated to the mid-Pliocene interval of 3.8–3.6 Ma. These fossils document traces of the last anancine gomphotheres (Anancus ultimus) in eastern Africa and several elephant taxa. Comparative study of the elephant fossils indicates the presence of cf. Mammuthus sp. “Hadar-type,” cf. Elephas ekorensis, E. recki brumpti, and cf. Loxodonta adaurora adaurora. Proboscidean evolution in the mid-Pliocene is interesting because during this time archaic elephants were completely replaced by basal members of crown elephant lineages, taxonomic diversity was high (multiple elephant species, anancine gomphotheres, stegodonts, and deinotheres), and elephants were undergoing substantial reorganization of the craniodental masticatory apparatus, presumably in response to the spread of more open habitats and greater competition for grazing resources. The Woranso-Mille sample is important because this interval is only represented elsewhere in eastern Africa by a small number of sites, and because adaptive diversification among early crown elephants requires greater clarification. Morphometric contrasts among the fossil dentition from Woranso-Mille presage the differential success of elephant lineages in eastern Africa during the Pleistocene, providing hints about the beginnings of competitive displacement. Differences between E. recki brumpti from Woranso-Mille and the slightly younger Sidi Hakoma Member of the Hadar Formation reveal the beginnings of continuous, directional morphometric change that characterized the lineage. Reconsideration of E. recki subspecies indicates that they are arbitrary lineage divisions tied to geochronological boundaries (with utility for biochronological correlation at well sampled sites) rather than real phylogenetic entities, but does not reject monophyly or anagenetic evolution of the lineage.  相似文献   

12.
The evolution of increased tooth crown height is considered to be an adaptation for coping with excessive rates of dental wear associated with abrasive herbivorous diets, such as grazing and(or high levels of exogenous grit (e.g. dust, sand, ash). Evolutionary trends in the crown heights of North American ungulates are grossly consistent with a transition from closed forests in the early Eocene to open grasslands in the late Miocene. However, the evolutionary proliferation of hypsodonty (high crowned teeth) in the early and middle Miocene occurs later than the apparent origin of open grassland habitats in North America. The paleoecology of species from the interval between the appearance of grasslands and the evolutionary proliferation of hypsodonty is critical to understanding the role of Cenozoic climate change in mammalian evolution. The paleodiets of late Eocene to middle Miocene oreodonts (Merycoidodontidae) were reconstructed by examining the relative facet development of molars (mesowear). A two-phase diet trend was discovered. Phase 1 suggests either an average reduction in the amount of exogenous grit from the late Eocene to early Oligocene or a decrease in fruit consumption related to the disappearance of more wooded habitats. Phase 2 is a gradual transition from early Oligocene low-abrasion browsing to high abrasion diets similar to mixed feeding and grazing in the Miocene. According to mesowear data, oreodont diets similar to those of modern grazers in terms of abrasion are not seen until the early Miocene (early Hemingfordian land mammal age). The coevolutionary relationship of molar crown height and diet, as represented by mesowear, was examined using phylogenetically independent contrasts. No significant coevolutionary relationship was found. In several instances, diet was found to shift over time despite morphological stasis (i.e. within a single species). These results do not clearly indicate that the overall trend of increasing dietary abrasion imposed sufficient selection to drive crown height evolution in oreodonts. Therefore, direct fossil evidence of dietary abrasion as a causal factor in the evolution of crown height, at least in this clade, is elusive.  相似文献   

13.
The proboscidean fauna of the middle Miocene of Thailand consists of five taxa, including four elephantoids and one deinothere. The Thai association is dominated by the genera Stegolophodon and Gomphotherium. Stegolophodon is represented by S. nasaiensis and S. praelatidens. The latter species, considered invalid and possibly conspecific with S. latidens, is re‐erected. Its phylogenetic relationships are discussed. The Thai Gomphotherium matches with G. browni from the middle Miocene of Indo‐Pakistan. However, the open nomenclature is employed for the Thai material because it differs from G. browni in terms of curvature of the upper tusk. Intraspecific molar size variation observed in G. cf. browni and Stegolophodon praelatidens is attributed to sexual dimorphism. The Thai proboscidean asssemblage is mainly endemic compared with other contemporaneous Asian faunas although the recognition of Gomphotherium cf. browni denotes faunal affinities with Pakistan. The biostratigraphical implications of the taxa are examined in a regional context. © 2009 The Linnean Society of London, Zoological Journal of the Linnean Society, 2009, 155 , 703–721.  相似文献   

14.
Herons (Aves: Ardeidae) are rare in the fossil record globally. Fossil taxa referred to Ardeinae and Nycticoracini are known from as early as the early Oligocene and ardeids undetermined to subfamily include some as old as the early Eocene. In Australasia, the pre-Pliocene record is restricted to one species from the early Miocene of New Zealand. On the basis of a tarsometatarsus and a coracoid we describe a new species of bittern (Ardeidae: Botaurinae) from the St Bathans Fauna, of early Miocene age, from Otago, New Zealand. This is only the third and the oldest pre-Quaternary record for Botaurinae globally.  相似文献   

15.
内蒙古宝格达乌拉晚中新世副竹鼠化石(英文)   总被引:1,自引:0,他引:1  
描述了1996-2007年间在内蒙古阿巴嘎旗晚中新世宝格达乌拉组采集的副竹鼠化石。材料包括下颌骨1件、牙齿14枚和肢骨4件,分别采自该组的2个地点。根据标本较大的尺寸、形态特征,以及颊齿的釉质曲线高度,宝格达乌拉材料被归入三趾马层副竹鼠Pararhizomys hipparionum Teilhard de Chardin Young,1931。Pararhizomys是一类具高冠、脊形和冠面构造简单颊齿的啮齿动物。该属目前发现的化石地点少,材料也不多,主要集中于中国北方和蒙古高原周缘,其地史分布为晚中新世早期至上新世中期。与鼢鼠类(siphneids)和鼠平类(arvicolids)一样,Pararhizomys属的颊齿有由低冠到高冠发展的趋势,具体表现为牙齿侧面釉质曲线(dentine tract)由平直、远离内外两侧谷底到起伏、接近甚至超过内外两侧谷底。为方便比较,本文为釉质曲线的高度设立"H"指数,即从每侧最深谷的谷底和釉质曲线的最高处取平行于冠面的平行线,此两平行线之间的垂直距离为"H"。H值越大,表明齿冠越低,反之则齿冠越高。尽管目前发现的副竹鼠标本不多,但似乎可以看到从早期到晚期,其颊齿的个体有从小变大,釉质曲线高度H值逐渐减小,即齿冠逐渐增高的趋势。由于Pararhizomys的牙齿形态多少与竹鼠类的低冠竹鼠Brachyrhizomys和竹鼠属Rhizo-mys及拟速掘鼠属Tachyoryctoides有相似之处,故常被与Brachyrhizomys和Rhizomys一起归入竹鼠科(Rhizom yidae),但该属的牙齿不具中脊和下中脊,褶沟少,一般为2-3个,与上述三属有明显的不同。本文对下门齿所作的切片观察也表明,Pararhizomys的釉质层结构与Brachyrhizomys,Rhizomys和Tachyoryctoides者相差甚远,其内层(PI)明显增厚,釉柱和釉柱间质(IPM)的排列方式存在明显差别。颊齿的冠高、冠面形态,以及下门齿的釉质层结构,似乎都表明了Pararhizomys属不大可能归入竹鼠科或速掘鼠科(Tachyorictoididae)。而下门齿釉质层切片显示了Brachyrhizomys与Rhizomys有着高度相似的釉质结构,进一步证明了两者有较接近的亲缘关系。地理分布上,Pararhizomys与Tachyoryctoides属只发现于古北区,伴生的哺乳动物显示了其可能适应偏冷、干旱的草原环境,而Brachyrhizomys和Rhizomys主要局限于东洋区,共生的哺乳动物多能适应温暖、湿润的树林环境。  相似文献   

16.
鼠兔科虽然是地质历史时期较为繁盛的一个门类,但现在仅有一个属(鼠兔属Ochotona)。Ochotona被认为与Bellatona有密切的亲缘关系,可能是由后者衍生而来。详细描述了内蒙古大庙上猿化石地点发现的鼠兔科化石,识别出一种古老类型Desmatolagus moergenensis以及其他三个种Bellatona cf.B.forsythmajori,Bellatonoides eroli,Ochotonacf.O.lagreli。归入Bellatona,Bellatonoides和Ochotona的这三个种的p3具有相似的形态,并呈现出连续变化的特征。Bellatona的p3具有两个唇侧褶沟,但无舌侧褶沟;Bellatonoides的p3具有浅的舌侧前褶沟,但与唇侧前褶沟分开较宽;Ochotona的p3则具有深的舌侧前褶沟,与唇侧前褶沟之间仅以很窄的齿质桥连接。M2从无后突起、较小的后突起至发育的后突起,也呈现出连续变化的特征。中间颊齿则难以区分。因此,推测这三个种之间存在连续的线性演化关系,Ochotona可能直接起源于Bellatonoides。磁性地层学与生物地层学对比结果显示该地点的年代约为12Ma,与根据分子钟推测的Ochotona的分化时间基本一致。  相似文献   

17.
Abstract:  A new genus and species of hipposiderid bat is described from an early Miocene cave deposit (Bitesantennary Site) in the Riversleigh World Heritage fossil property, northern Australia. Eight hipposiderid genera are now recorded from Riversleigh's Miocene sediments: Hipposideros , Brachipposideros, Rhinonycteris , Riversleigha, Xenorhinos , Miophyllorhina , Archerops and Brevipalatus gen. nov. The new taxon appears to be most closely related to Australian endemic Rhinonycteris and Brachipposideros species, but its autapomorphically very short palate distinguishes it from other members of this relatively plesiomorphic group. It is one of eight hipposiderid species recovered from the Bitesantennary Site deposit, and one of 11 recorded from Riversleigh's early Miocene sediments. Compared with modern bat faunas, the early Miocene Riversleigh bat community differs strikingly in its high hipposiderid diversity but may differ less in its overall trophic structure.  相似文献   

18.
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   

19.
Chalicotheriids are rare in the late Miocene mammal localities of Axios Valley, Macedonia (Greece). The new campaign of excavations, since 1972, has provided some specimens, which are studied in this article. They are coming from two different localities. The late early Vallesian locality of Pentalophos 1 (PNT) has provided a skull and a mandible of an Ancylotherium. The morphological characters of the PNT material as the small size, the long snout, the shallow mandibular corpus, the strong cingulum in the teeth, the short tooth rows and the short M3/m3 indicate that it differs from the known Turolian species A. pentelicum and allow the erection of a new species, named Ancylotherium hellenicum n. sp., which can be used as a biostratigraphic marker of the Vallesian. The middle Turolian locality Prochoma 1 (PXM) has provided only one M3, which is determined to the chalicotheriine Anisodon macedonicus. This species was earlier described from the middle Turolian locality Vathylakkos 3 (VAT) and the late Turolian one of Dytiko 3 (DKO) of Axios Valley. The biogeography and biostratigraphy of the late Miocene chalicotheres of the Greco-Iranian Palaeoprovince (GRIP), as well as their palaeoecology are also discussed. The common chalicothere of GRIP is A. pentelicum, expanded from the Balkans to Afganistan and ranging stratigraphically from the early to the late Turolian. Chalicotherium goldfussi is certainly present in GRIP and it also ranges from the early to the late Turolian; its possible Vallesian occurrence needs confirmation. The other two late Miocene chalicotheres of GRIP A. macedonicus and Kalimantsia bulgarica are restricted to the Turolian of the Balkan Peninsula.  相似文献   

20.
铲齿象一新种在甘肃省党河地区下中新统的发现   总被引:6,自引:4,他引:2  
记述了甘肃省党河地区的铲齿象化石一新种———党河铲齿象 (Platybelodondangheen sis)。其主要特征是 :下颌联合和下门齿构成宽短的铲形 ;下门齿薄 ,由单层稀少的齿柱组成 ;具较大的p3 ,p4前窄后宽 ,前齿带和跟座较小 ,m1构造简单 ,齿冠较低 ,第一齿脊无前斜脊 ,前齿带和后跟座较小。它是欧亚大陆目前所知时代最早 (早中新世 )、构造最原始的一种铲齿象。  相似文献   

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