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1.
科氏仓鼠(Kowalskia)一新种   总被引:6,自引:5,他引:1  
山东沂南马牧池区双泉西山红棕色角砾岩层中的Kowalskia yinanensis sp.nov.头骨和下颌是该属迄今所发现的最完整的材料。这种仓鼠大小接近波兰晚上新世的K.magna,具有和Cricetinua varians相似性状的头骨及下颌。臼齿尖(嵴)发育程度较捷克最晚上新世的K.intermedia稍原始,时代上大致可与之相对比。  相似文献   

2.
鄂西荆当盆地的九里岗组,化石植物比较丰富。本文着重报道其中两种,即疏脉蕉羊齿(新种)(Compsopteris laxivenosa sp.nov.)和西河蕉羊齿(新组合)[C.xiheensis(Feng),comb.nov.]此外,还订正了副镰羽叶属(Paradrepanozamites),描述了大道场副镰羽叶(新订正)(Paradrepanozamites dadaochangensis Chen,emend.nov.)和小副镰羽叶(新种)(P.minorsp.nov.)等中生代新资料。在本植物组合中,中生代和古生代植物化石属同层位出现,这一现象说明九里岗组的地质时代,可能属晚三叠世的卡尼期—诺利期的早期。  相似文献   

3.
孙革 《古生物学报》1979,(3):312-325
本文记述了吉林汪清县天桥岭地区晚三叠世地层中准苏铁果属(Cycadocarpidium)的发现和该属的两个新种:巨大准苏铁果(C.giganteum sp.nov.)和雅致准苏铁果(C.elegans sp.nov.),并讨论了它们在确定地层时代、恢复古地理古气候等方面的意义。  相似文献   

4.
通过对南海北部琼东南盆地渐新世—上新世3个钻井剖面412个沟鞭藻样品的系统分析,发现了较丰富的沟鞭藻化石。根据沟鞭藻化石丰度、分异度变化以及特征性的环境指示种,对琼东南盆地渐新世至上新世的沉积环境进行了详细研究。认为研究区从早渐新世早期海水开始入侵,至早渐新世晚期海侵范围进一步扩大,一直持续到晚渐新世;早中新世沟鞭藻化石数量和种类明显出现低谷,发生了一次较为明显的海退;中中新世至晚中新世,沟鞭藻化石较丰富,丰度和分异度增加,海水明显比早中新世沉积时期加深;早上新世早期,指示海侵的化石属种较丰富,反映了温暖浅海的沉积环境;早上新世晚期,指示一种开阔的海洋环境,水体较深;晚上新世早期,沟鞭藻化石属种面貌反映了热带浅海环境,但水体可能比早上新世晚期沉积时要浅;晚上新世晚期,指示海侵的沟鞭藻化石属种达到最繁盛时期,海侵范围进一步扩大。  相似文献   

5.
通过对南海北部琼东南盆地渐新世—上新世3个钻井剖面412个沟鞭藻样品的系统分析,发现了较丰富的沟鞭藻化石。根据沟鞭藻化石丰度、分异度变化以及特征性的环境指示种,对琼东南盆地渐新世至上新世的沉积环境进行了详细研究。认为研究区从早渐新世早期海水开始入侵,至早渐新世晚期海侵范围进一步扩大,一直持续到晚渐新世;早中新世沟鞭藻化石数量和种类明显出现低谷,发生了一次较为明显的海退;中中新世至晚中新世,沟鞭藻化石较丰富,丰度和分异度增加,海水明显比早中新世沉积时期加深;早上新世早期,指示海侵的化石属种较丰富,反映了温暖浅海的沉积环境;早上新世晚期,指示一种开阔的海洋环境,水体较深;晚上新世早期,沟鞭藻化石属种面貌反映了热带浅海环境,但水体可能比早上新世晚期沉积时要浅;晚上新世晚期,指示海侵的沟鞭藻化石属种达到最繁盛时期,海侵范围进一步扩大。  相似文献   

6.
本文记述金长足虻属Chrysosoma 5新种:大明山金长足虻C.damingshanum sp.nov.,指突金长足虻C.digitatum sp.nov.,长芒金长足虻C.longum sp.nov.,铜壁关金长足虻C.tongbiguanum sp. nov.,和周氏金长足虻C.zhoui sp. nov.。编制该属中国种类的检索表。  相似文献   

7.
河北阳原—蔚县晚上新世兔形类化石   总被引:14,自引:11,他引:3  
本文记述河北阳原——蔚县晚上新世小哺乳动物群中的兔形类化石共3属5种:Pliopent-alagus nihewanensis sp.nov.,Hypolagus sohreuderi,Ochotona cf.lagrelii,Ochotona minor和Ochotona erythrotis.。对首次发现于亚洲的Pliopentalagus进行了起源和演化方面的探讨;并就华北上新世一早更新世常见的Hypolagus作了一些评述。本文指出:Hypolagus—Plio-pentalagus组合已延至早维拉方期;Ochotona lagrelii—Ochotona minor则为已知的最晚代表。  相似文献   

8.
江苏句容青山早三叠世鱼类   总被引:5,自引:1,他引:4  
记述了在江苏句容东昌青山早三叠世下青龙组上部发现的鱼类,计有6属8种,其中4新属6新种,为属两目两科。属裂齿鱼目裂齿鱼科的有Perleidus piveteaui,Perleidus aff.P.madagascariensis.“Perleidus”eu-rylepidotrichia sp.nov.和Zhangina cylindrica gen.et sp.nov;属骨鱼目副半椎鱼科的有Stensionotus dongchangensis sp.nov.,Jurongia fusiformis gen.et sp.nov.,Qingshania cercida gen.et sp.nov.和Suius brevis gen.et sp.nov.。上列绝大部分属种的特征充分显示这个鱼群与马达加斯加北部早三叠世鱼群的亲密关系,少数属种的特征也反映其与东格陵兰早三叠世鱼群有某些关系。  相似文献   

9.
山西榆社上新世山羊类一新属   总被引:2,自引:1,他引:1  
本文记述山羊族(Caprini)—新属种:小型中国山羊(Sinocapra minor gen. et sp. nov.).化石产于山西榆社地区云簇盆地晚上新世麻则沟组中.它的主要特征是:角心短小,较直立于眼眶之上,不旋转,明显内外侧扁,无稜脊,角内中空或有窦;角基部之间的额面高于眼眶面,有一浅的角后窝存在.  相似文献   

10.
近年,作者在安徽淮南大居山陆续发现了数量很多的上新五褶兔化石,其中包括保存较完整的数十个头骨及上百个下颌骨,均产自新洞、无名洞及铁四局洞穴、裂隙堆积,分别记述为大居山上新五褶兔Pliopentalagus dajushanensis sp.nov.和安徽上新五褶兔Pl.anhuiensis sp.nov.两新种。淮南地区的晚新生代洞穴和裂隙堆积十分发育,其中常含有丰富的脊椎动物化石,而且在时、空分布上有一定的规律。区内洞穴和裂隙堆积垂直分布至少有6个水平层,最高的第6层海拔高度为160 m(如大居山老洞),第5层(如大居山新洞、无名洞)及第4层(如大居山铁四局洞穴)的海拔高度分别为130 m和90 m,属于新近纪,常含有丰富的上新五褶兔化石;第3层为第四纪早期(如大居山西裂隙),未见上新五褶兔,代之出现丝绸兔(Sericolagus sp.),第2层为中更新世(如大顶山西裂隙),出现野兔(Lepus sp.)。迄今为止,安徽淮南地区共发现了3种上新五褶兔化石,即淮南上新五褶兔Pl.huainanensis (金昌柱,2004)、大居山上新五褶兔Pl.dajushanensis sp.nov.及安徽上新五褶兔Pl. anhuiensis sp.nov.,至少涉及了3个不同地质时期的动物群:一为Pl.huainanensis,Kowalskia neimengensis,Adcrocuta eximia等代表的老洞晚中新世动物群,二为Pl.dajushanensis sp.nov.和Promimomys asiaticus等代表的新洞早上新世动物群,三为Pl.anhuiensis sp.nov.和Kowalskia yinanensis所代表的晚上新世动物群。淮南地区发现的3种上新五褶兔地史分布较连续,演化特征明显,它们构成上新五褶兔连续的进化系列。从晚中新世至晚上新世,淮南大居山上新五褶兔体型从小变大;p3较原始的釉岛状后内褶沟逐渐向舌侧开放(晚中新世种Pl. huainanensis的后内褶沟均为釉岛状,早上新世种Pl.dajushanensis为83.9%,晚上新世种Pl. anhuiensis为33.3%);p4-m2的前外褶沟逐渐退化,其下跟座舌侧的釉质层越来越变细。依性状分析,安徽发现的3种上新五褶兔化石与日本琉球奄美黑兔(Pentalagus furnessi)具有密切的亲缘关系,但从日本奄美黑兔的p4-m2完全缺失前外褶沟、颊齿褶沟釉质层的褶曲异常复杂等衍生性状看,上新五褶兔和奄美黑兔的系统演化关系较为复杂,尚有待发现更多早更新世的材料进一步探讨。  相似文献   

11.
One group of mantellid frogs from Madagascar (subgenus Pandanusicola of Guibemantis) includes species that complete larval development in the water-filled leaf axils of rainforest plants. This group consists of six described species: G. albolineatus, G. bicalcaratus, G. flavobrunneus, G. liber, G. pulcher, and G. punctatus. We sequenced the 12S and 16S mitochondrial rRNA genes ( approximately 1.8 kb) from multiple specimens (35 total) of all six species to assess phylogenetic relationships within this group. All reconstructions strongly supported G. liber as part of the Pandanusicola clade, even though this species does not breed in plant leaf axils. This result confirms a striking reversal of reproductive specialization. However, all analyses also indicated that specimens assigned to G. liber include genetically distinct allopatric forms that do not form a monophyletic group. Most other taxa that were adequately sampled (G. bicalcaratus, G. flavobrunneus, and G. pulcher) likewise consist of several genetically distinct lineages that do not form monophyletic groups. These results suggest that many of the recognized species in this group are complexes of cryptic species.  相似文献   

12.
泥河湾盆地上新世小哺乳动物生物地层学及相关问题讨论   总被引:5,自引:3,他引:2  
在泥河湾盆地稻地组与壶流河组、蔚县组命名剖面上分别筛洗小哺乳动物化石。其中花豹沟剖面选取 3个层位 ,发现小哺乳动物化石 1 0种 ;稻地剖面 6个层位 ,发现化石 2 5种。结合小哺乳动物化石组合 ,以及岩石地层追索对比 ,认为壶流河组与蔚县组从岩性上无法分开 ,应予合并 ,保留蔚县组 ;稻地组与蔚县组为同时期沉积 ,二者之间存在一定的相变关系 ,建议废止稻地组 ;仅保留蔚县组作为泥河湾组之下风成红黏土之上的岩石地层单位 ,其时代为中上新世晚期至晚上新世。  相似文献   

13.
A new species of African clawed toad, Xenopus kigesiensis sp.n., has been recorded from Lake Mutanda in South-west Kigezi, Uganda. Information on the biology and morphological variation of the species has been compiled from a sample preserved in the field and from a collection of living specimens maintained in the laboratory. An analysis of the characters of the species has been conducted and its relationships with the six known species of the genus assessed.
In the early part of this century the clawed toad populations occupying the lakes of South-West Kigezi exclusively comprised a Xenopus laevis subspecies. It appears that X. kigesiensis sp.n. has recently migrated into Lake Mutanda and has replaced the previous form. Hybridization experiments have demonstrated the reproductive isolation of X. kigesiensis sp.n. from two subspecies of X. laevis. There is evidence of a change in the ecology of the lakes during the period of apparent invasion.
The locality of X. kigesiensis sp.n. lies close to one of the main watersheds of Central Africa; taxonomically the toad forms an important link in the series of known Xenopus species.  相似文献   

14.
An osteological study and a taxonomic diagnosis are presented for the mesopelagic, oviparous ophidioid fish genus Brotulataenia. Its relationships are probably with a large group of benthic deep-sea oviparous genera. Brotulataenia has been known previously from three North Atlantic specimens assigned to two species. The present study is based on 33 specimens from the North and South Atlantic and Pacific Oceans and the Indian Ocean, and placed in four species, two of which are described as new. Two species are excessively elongate and are interpreted as being derived forms; they are lighter in color than are the two short-bodied species and may live higher in the water column.  相似文献   

15.
Two species of Myxobolus are reported from the gills of Mugil cephalus collected at Goa, India: M. goensis n. sp. and M. parvus Shulman, 1962. Myxobolus goensis n. sp. forms digitiform or rounded plasmodia between the gill rakers. Their spores are oval in frontal view, with tapered anterior extremity, and lemon-shaped in lateral view, measuring 9.7 (9.5-10.5) microm in length, 6.6 (6-7.5) microm in width, and 5.2 (5-6) microm in thickness. The polar capsules are pyriform and unequal in size. The larger ones are 5.3 (4.5-6) microm long and 2.4 (2-3) microm wide; the smaller ones are 2.4 (2-3) microm long and 1.8 (1.5-2) microm wide. The polar filament forms five turns aligned perpendicularly to the longitudinal axis of the larger polar capsules. Within the smaller polar capsules the polar filament is difficult to observe and, apparently, forms three coils. The spores are distinctly different from other Myxobolus species infecting M. cephalus and other Mugil spp. Furthermore, the present material is also different from 204 Myxobolus species presenting differently sized polar capsules, representing nearly all the known species with this characteristic. The fact that only the M. cephalus specimens were infected among a sample of 206 fish specimens, comprising 27 different species, strongly suggests that this parasite is specific to M. cephalus.  相似文献   

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Aim To reassess the relationships between Tarentola geckos from the Cape Verde Islands by including specimens from all islands in the range. To determine the variation within forms by sequencing over 400 specimens, thereby allowing the discovery of cryptic forms and resolving some of the issues raised previously. This extensive sampling was also used to shed light on distributions and to explain genetic diversity by comparing the ages and ecological and geological features of the islands (size, elevation and habitat diversity). Location The Cape Verde Islands: an oceanic archipelago belonging to the Macaronesian biogeographic region, located around 500 km off Senegal. Methods A total of 405 new specimens of Tarentola geckos were collected from nine islands with very different geological histories, topography, climate and habitats. Mitochondrial cytochrome b (cyt b) gene and 12S rRNA partial sequences were obtained and analysed using phylogenetic methods and networks to determine molecular diversity, demographic features and phylogeographic patterns. Results The phylogenetic relationships between all known forms of Cape Verdean Tarentola specimens were estimated for the first time, the relationships between new forms were assessed and previously hypothesized relationships were re‐examined. Despite the large sample size, low intraspecific diversity was found using a 303‐bp cyt b fragment. Star‐like haplotype networks and statistical tests suggest the past occurrence of a rapid demographic and geographical expansion over most of the islands. Genetic variability is positively correlated with size, elevation and habitat diversity of the islands, but is not linearly related to the age of the islands. Biogeographical patterns have, in general, high concordance with phylogenetic breaks and with the three eco‐geographical island groups. Volcanism and habitat diversity, both tightly linked with island ontogeny, as postulated by the general dynamic model of oceanic island biogeography, as well as present and historical size of the islands appear to be the main factors explaining the genetic diversity of this group. Main conclusions The Tarentola radiation was clarified and is clearly associated with the geological and ecological features of the islands. Two factors may account for the low intraspecific variation: (1) recent volcanic activity and high ecological stress, and (2) poor habitat diversity within some islands. More studies are needed to align taxonomy with phylogenetic relationships, whereas GIS modelling may help to predict precise species distributions.  相似文献   

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