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首次报道了伊朗西北部 Varzeghan 附近发现的大型哺乳动物化石,材料包括三趾马和恐象。根据个体大小和形态特征,将三趾马标本暂时分为一个小至中型类似 Hipparion moldavicum 的种和一个中至大型类似 H. prostylum 或 H. dietrichi 的种。Deinotherium giganteum 也出现于这一地区。依据与其他晚中新世地点哺乳动物化石的对比,这些新化石地点的时代推测为吐洛里期( Turolian) 中期或相当于欧洲哺乳动物带的 MN12。  相似文献   

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The existence of cryptic species in the midday jird (Meriones meridianus) has been suggested in literature, although based on little empirical data to support this hypothesis. In this study, a two‐dimensional landmark‐based geometric morphometric approach was used to investigate whether patterns in intraspecific variation in skull shape and size exist, using 110 skull specimens from more than 20 different localities along the distribution range of M. meridianus. This is the first study of morphological differences on such a big sample size and geographical range, and it tries to find whether skull shape variation in this species is best described as being clinal or rather reflecting cryptic diversity. The latter seems to be the case, as a dimorphic skull phenotype was found, reflecting a geographic disparity between the Middle East and the Far East specimens both in shape and in size. Distinct cranial differences were found in the overall cranial size and, also at the level of the inflation of the bulla, the elongation of the nasal, the length of the teeth row and the incisive foramen, as well as the distance in between the latter two. It thus seems that M. meridianus from Middle East is morphologically distinct from that of the Far East. Furthermore, our results also demonstrate that clinal variation could explain variation within Middle East populations, whereas a more heterogenous pattern is found for those of the Far East. The hypothesis that the observed phenotypic variation may reflect cryptic species is discussed, with the recommendation for a thorough taxonomical revision of the genus in the region.  相似文献   

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Reports of the Dwarf Sperm whale (Kogia sima) in Chinese waters exist only for four specimens, which stranded along the coast of the East China Sea. Records of this species in the South China Sea consist of one skull noted as present in a Vietnamese ‘whale temple’. Recently recognized material in the biological sciences building of the University of Hong Kong, confirms the presence of both the Dwarf (K. sima) and the Pygmy (K. breviceps) Sperm whales in Hong Kong. In addition, close examination of Hong Kong stranding records reveals that of the four specimens identified as K. breviceps one is, in fact, K. sima. A comparison of the Hong Kong material, the holotype of K. sima and other Asian specimens of Kogia spp. affirms that most of the features already used elsewhere to distinguish the two species are reliable.  相似文献   

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吴秀杰  张玄 《人类学学报》2018,37(3):371-383
颅内模保存有脑表面的形态结构,是脑演化研究的直接证据。中国最早复原和研究的颅内模来自20世纪20年代北京周口店遗址发现的3号猿人头骨;此后虽然中国境内也相继发现了一些古人类的头骨化石,但由于古人类标本非常珍贵,不允许对其进行实体解剖,加上多数头骨破碎或者内部附有地层胶结物,导致颅内模无法成功复原。受技术水平及研究手段的限制,研究者一般只是侧重于化石外表形态结构的研究。高分辨率工业CT和3D软件的应用,可以在不损坏标本的情况下,虚拟复原出化石的内部解剖结构,使得一些重要的古人类化石标本的颅内模被复原出来,促进了脑演化的研究。近年来,本文第一作者采用新技术、新方法复原了南京直立人、柳江人等一些重要的中国古人类头骨的颅内模,通过对其颅容量、脑沟回特征、脑不对称性、脑表面的动、静脉血管压迹、各脑叶的大小、形状及比例的研究,获取了中国古人类脑形态特征变化的数据,为探讨东亚地区古人类的演化提供了参考信息。  相似文献   

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Four partial mandibles and three isolated teeth of Homo from East Rudolf, Kenya, are described. They represent only part of the 1972 fossil collection that has been assigned to Homo; results of detailed studies of this material will be published in a monograph.  相似文献   

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INTRODUCTION     
.In view of the growing importance of fish for native consumption, the resources of the African lakes are sure to be exploited in the near future, but it is essential to have a sound understanding of the fish and other fauna and flora in each lake before exploitation is started. This paper places on record the available data for Lake Rudolf and Lake Baringo, on which no previous ecological work had been attempted.
Lake Rudolf is characterized by a high temperature and very alkaline water, and contains a variety of environments inhabited by different fish-associations. The fauna has pronounced nilotic affinities, except that there is only one member of the family Mormyridae. Several species, however, have come to differ from their nilotic ancestors, and the comparison of the fauna with that of other waters can be used as evidence for past changes in the drainage systems of East Africa.
The fish fauna of Lake Rudolf is roughly divisible into three main associations of species–one in the inshore waters, one in the open water, and one near the bottom. Prom data supplied by large numbers of stomach examinations, the food-chains for each of these habitats can be reconstructed.
Lake Baringo is less warm, the water has a relatively low alkalinity, and is uniformly shallow and muddy. The fish fauna consists of few species, and shows affinities with that of the East African rivers which flow to the Indian Ocean.
Owing to the shallowness of Lake Baringo, there is no differentiation into species-associations, and the food-chains are complicated by the presence of food from the bottom in all the species of fish.
The bulk of this paper contains analyses of field-observations on the size, feeding and breeding habits of each of the species found in the lakes,  相似文献   

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IutroduCtionTertiaryrodentfossilshavebeenrarelyfoundinJapan.TomidaandSetoguchi(l994)reportedninesPecimensfromtheEarlyMiocenesedimentsintheMisunamiandKhnibasins,GifuPrefecture,centralJapanwithabridreviewoftheTertiaryrodentsfromtheJapaneseIslands.Accordingtotheirreport,therodentfaunainthesebasinsiscomposedofthesPechoensreferredtoCastoridae,Eomyidaeandunidentifiedrodents.Amongthem,CastoridaeincludesYoungoNersinensis,acharacteristicChineseMiocenebeaver.TheoccurrenceofYoungofthersinensiss…  相似文献   

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A new species of Scyphophyllidium inhabits Mustelus mento near La Paloma, Uruguay. It resembles Scyphophyllidium giganteum from the Atlantic Ocean and specimens identified as S. giganteum from California by having anapolytic strobilae 155-258 mm long, 250-300 craspedote proglottids, scoleces 1.2-1.4 mm wide, necks 34-41 mm long, immature and mature proglottids wider than long, gravid proglottids wider than long to longer than wide, genital pores averaging 28% of proglottid length from the anterior end, relatively flat ovaries with digitiform lobes reaching the lateralmost extent of the testicular field, vitellaria in 2 fields converging toward the proglottid midline, straight and short cirrus sacs, and postvaginal vas deferens. The bothridia of the new species have accessory bothridial suckers that are smaller than those of California specimens; European specimens reportedly lack accessory bothridial suckers. The new species possesses a uterine duct that joins the uterus at the level of the genital atrium and ventral osmoregulatory ducts medial rather than lateral to the dorsal ducts, an arrangement described for Californian but not European specimens. It differs from both European and Californian specimens by having longer cirri, more testes per proglottid, prominent scales covering the neck, and vaginae and uterine ducts coiled immediately preovarially. Pithophorus, Marsupiobothrium, and Scyphophyllidium may form a clade.  相似文献   

11.
Two genera and four species of discosauriscids, Discosauriscus potamites, D. pulcherrimus, Letoverpeton austriacum and L. moravicum , have previously been described from the Boskovice Furrow in Moravia. These laxa were differentiated primarily on the basis of proportional differences of the skull together with other morphological characters.
Excavations at two localities in the Boskovice Furrow have produced new, relatively abundant, skeletal material. The specimens are preserved three-dimensionally. In order to evaluate the differences in skull proportions, 17 variable characters on 70 skulls were measured. Statistical analysis demonstrates the existence of several morphological trends in the shape of the skull. However, no trend permits the division of this set of specimens into two clearly differentiated groups. The morphological differences used previously to define genera and species seem to be incorrect. Pending the discovery of distinct morphological differences, the Moravian discosauriscids can be considered as belonging to only one taxon: Discosauriscus austriacus (Makowsky, 1876).  相似文献   

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The human brain and skull are three dimensional (3D) anatomical structures with complex surfaces. However, medical images are often two dimensional (2D) and provide incomplete visualization of structural morphology. To overcome this loss in dimension, we developed and validated a freely available, semi-automated pathway to build 3D virtual reality (VR) and hand-held, stereolithograph models. To evaluate whether surface visualization in 3D was more informative than in 2D, undergraduate students (n = 50) used the Gillespie scale to rate 3D VR and physical models of both a living patient-volunteer's brain and the skull of Phineas Gage, a historically famous railroad worker whose misfortune with a projectile tamping iron provided the first evidence of a structure-function relationship in brain. Using our processing pathway, we successfully fabricated human brain and skull replicas and validated that the stereolithograph model preserved the scale of the VR model. Based on the Gillespie ratings, students indicated that the biological utility and quality of visual information at the surface of VR and stereolithograph models were greater than the 2D images from which they were derived. The method we developed is useful to create VR and stereolithograph 3D models from medical images and can be used to model hard or soft tissue in living or preserved specimens. Compared to 2D images, VR and stereolithograph models provide an extra dimension that enhances both the quality of visual information and utility of surface visualization in neuroscience and medicine.  相似文献   

13.
The paper describes a deinothere palate preserving both deciduous tooth rows from the area of Veles, Republic of Macedonia. The specimen is referred to Deinotherium gigantissimum, the largest and latest European deinothere species. Similar finds from the late Miocene of Southeast Europe and Asia Minor are discussed.  相似文献   

14.
An attempt was made to determine the species composition, density and biomass density of lizards in some of the principal land units in South Turkana. Thirteen species were recorded. Density estimates were determined from quadrat sampling in representative habitats. Because the number of lizards active was found to vary with time of day and temperature, minimum density estimates were obtained by confining counts to peak activity periods. Biomass density was calculated from the product of species density and the mean population weight measured from shot specimens. The biomass density estimate of the lizard fauna was found to be about 4–5% of the large mammal fauna, and appreciably more in the more arid land units. The species composition of South Turkana lizards show affinities to the Somali fauna, though not to the extent of the East Rudolf fauna, suggesting a more recent penetration of arid–adapted species.  相似文献   

15.
中国古人类进化连续性新辩   总被引:6,自引:2,他引:4  
本文通过对一些形态特征的分析说明研究人类起源和进化应该注意的一些思维方法的问题,并且为多地区进化说增添了新的证据:1)中国更新世头骨共同具有的眼眶及其外侧下缘形状等特征在近代头骨中已有所改变,在考虑其意义时不应该忽略时间和基因交流起过的作用;2)中国更新世头骨的共同特征并不因为它们也可见于其他地区而丧失其意义,因为证明连续性的共同特征不需要是地区独有的;3)铲形门齿的结构在近代人中变弱,不削弱它作为连续进化证据的价值,这种弱化的现象是人类进化过程中形态纤巧化的一种表现;4)在辩论时不要对有关形态作不正确的观察和曲解对方的观点和论据;5)头骨正中矢状突隆、下颌圆枕、夹紧状鼻梁和第三臼齿先天性缺失等四项特征在近代非洲人中阙如,却存在于东亚近代人,本文的分析认为这种现象增强多地区进化说的说服力。  相似文献   

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Thirty-five new fossil hominid specimens are described. They were recovered from the Plio-Pleistocene sediments to the east of Lake Turkana (formerly Lake Rudolf). They include cranial and mandibular parts, teeth, and postcranial bones of upper and lower limbs. Parts of a single skeleton are also described. All of the specimens are described in anatomical detail and selected measurements are given. Some of the specimens are illustrated. It is proposed that they should be attributed to the family Hominidae, with genus and species undetermined until detailed comparative studies have been undertaken.  相似文献   

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The abundant Late Miocene proboscidean remains of Greece have never been studied in detail and compared with those of Eurasia in order to determine their taxonomy and their biostratigraphical and palaeoecological significance. The first results of such study are given in this article. During the past decades, several new proboscidean specimens have been added to the old collections, significantly enriching the available material. The Axios Valley (Macedonia, Greece) proboscidean fossils belong mainly to two species of Choerolophodon: C. anatolicus of early Vallesian age and C. pentelici of late Vallesian–Turolian age. Deinotherium giganteum is rare and recognized only in the late Vallesian locality Ravin de la Pluie of Axios Valley. A zygodont form has also been identified in the Turolian of Axios Valley, attributed to “Mammut” sp. The Late Miocene localities of Nikiti (Macedonia, Greece) revealed several remains of C. pentelici, which are similar to the Turolian ones of Axios Valley. The Samos proboscidean collection includes C. pentelici, “Tetralophodonatticus, “Mammut” sp. and Deinotherium gigantissimum. The taxonomy of the Late Miocene peri-Mediterranean Choerolophodon is given, and the biostratigraphy and palaeoecology of the Greek Late Miocene proboscideans are discussed.  相似文献   

19.
The taxonomy of the spotted dolphins has been confused. Two apparent species exist, one endemic to the Atlantic and the other pantropical. They have sharply different color patterns and non-overlapping vertebral counts. However, the holotype specimens for most of the names that have been applied to the spotted dolphins (including S. attenuata, S. frontalis, S. plagiodon and others) are skulls only, with no information on coloration or number of vertebrae. The two species overlap in all skull characters; geographical variation in both is pronounced. We used a discriminant analysis based on tooth counts and three skull measurements (standardized to skull width) to identify the type specimens to the two species. We used other criteria for assignment of nominal species for which holotype specimens do not exist. We propose that Stenella frontalis (G. Cuv., 1829) be used for the Atlantic endemic species and Stenella attenuata (Gray, 1846) for the pantropical species and here redescribe the species. Proposed common names are Atlantic spotted dolphin and pantropical spotted dolphin. S. frontalis now includes Delphinus froenatus F. Cuv., 1829, D. doris Gray, 1846 and D. plagiodon Cope, 1866. S. attenuata (a nomen conservandum) includes D. velox G. Cuv., 1829, D. pseudodelphis Wiegmann, ≤ 1840, D. brevimanus Wagner, 1846, D. microbrachium Gray, 1850, D. albirostratus Peale, 1848, Steno capensis Gray, 1865, Clymene punctatus Gray, 1866, Steno consimilis Malm, 1871 and Prodelphinus graffmani Lönnberg, 1934. Unidentifiable to either of the two valid species are D. dubius G. Cuv., 1812, D. pernettensis de Blainville, 1817 (suppressed), D. malayanus Lesson, 1826 and D. Rappii Reichenbach, 1845; these must remain incertae sedis.  相似文献   

20.
Abstract:  A new dipnoan fish, Pinnalongus saxoni gen. et sp. nov., is described from a suite of recently discovered specimens from Caithness and East Sutherland, northern Scotland. The stratum where Pinnalongus occurs is within the middle Eifelian of the Middle Devonian. Pinnalongus has a skull roof consisting of a mosaic of small bones at the anterior end, a feature more typically found in Early Devonian dipnoans. The posterior part of the skull roof is more typical of later advanced Middle Devonian dipnoans with the B-bone separating the I-bones. The postcranial body is now considered not to be so important with respect to the classification of dipnoans as originally proposed by Dollo in 1895, who thought there was an evolutionary transformation series. Nevertheless, the postcranial body of Pinnalongus has more in common with later Middle and Late Devonian dipnoans such as Scaumenacia , with a very long second dorsal fin. Based on the skull morphology, Pinnalongus is most closely related to Tarachomylax from the Lower Devonian of Severnaya Zemlya, Russia. Pinnalongus represents the earliest known complete articulated dipnoan with tooth plates.  相似文献   

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