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The archaeological site of ‘Ubeidiya provides a unique, rich faunal assemblage, as well as evidence for the presence of early hominins in the Levant. Paleontological analysis of the faunal community is pertinent to understanding the biochronology and the timing of hominin dispersal events from Africa to Eurasia. This study presents the large carnivores from the recent seasons of excavations (1989-1999) and previously published material. Based on biochronological correlations of the carnivore guild and paloemagnetism, the age of the site is 1.5-1.2 Ma. This date is 100-200,000 years earlier than previous estimates. Of specific importance is the presence of the African origin saber tooth Megantereon cf. M. whitei and the Eurasian origin canids Canis moschbachensis and Lycaon lycoanoides. 相似文献
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Galila M. Khalil Harry Hoogstraal James H. Oliver 《International journal for parasitology》1980,10(4):253-259
Khalil G. M., Hoogstraal H. and Oliver J. H. Jr. 1980. Biological evaluation of the systematic validity of the African Argas (Persicargas) arboreus and the Asian-Australian A.(P.)robertsi (Ixodoidea: Argasidae). International journal for Parasitology10: 253–259. The closely related A. (P.)arboreus (Ethiopian Faunal Region) and A. (P.) robertsi (Oriental and Australian Faunal Regions) interbreed readily and produce partially fertile progeny. Intrahybrid crosses are much less productive than P1 homogamic crosses. Results of backcrosses indicate that the progeny of the robertsi ♂ × arboreus ♀ cross are less fertile than the progeny of the reciprocal cross. The fertility of F1 hybrid progeny is lower than that of the P1 pure species as expressed in lower female fecundity, egg hatch, and/or viability of immature stages. These 2 species probably originated from a common ancestor and geographic isolation caused genetic incompatibility. 相似文献
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Jean-Marie Le Tensorer Hélène Le Tensorer Pietro Martini Vera von Falkenstein Peter Schmid Juan José Villalain 《L'Anthropologie》2015,119(5):581-594
At present, the oldest traces of human cultures are found in Eastern Africa. New discoveries set anew the questions about human and animal dispersal into Eurasia. For over 1.8 million years, humans have been present in the Levant. An extensive program of surveys and excavations in the Syrian Desert showed that this part of the world was a very ancient land of settlement. In Central Syria, the oldest site, Aïn al Fil in the region of El Kowm, was excavated in 2008 and 2010. The lithic industry in the lowest layer can be characterized by numerous unretouched flakes, pebble-tools and core-like artefacts. This assemblage is typical in a broad sense of archaic Palaeolithic the debitage of which corresponds to mode 1. From a techno-typological point of view, this industry tallies quite well with the so-called Oldowan stage. It shows remarkable similarities with the oldest African assemblages. From a chronologic point of view, these levels occur before three positive events in the Matuyama paleomagnetic sequence. It seems consistent to place the Oldowan sequence around 1.8 Ma BP within the Olduvai subchron or just before Olduvai/Matuyama reversal limit. Together with those of the neighbouring site Hummal, these levels would be the oldest traces of human presence ever found in Syria. In the Levant, the first humans not only occupied favourable zones but regularly ventured deep into less welcoming environments suggesting an astonishing flexibility in their behavioural and survival skills. 相似文献
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Yasamin Kh. Ibrahim Lim Tze Tshen Kira E. Westaway Earl of Cranbrook Louise Humphrey Ros Fatihah Muhammad Jian-xin Zhao Lee Chai Peng 《Journal of human evolution》2013
Nine isolated fossil Pongo teeth from two cave sites in Peninsular Malaysia are reported. These are the first fossil Pongo specimens recorded in Peninsular Malaysia and represent significant southward extensions of the ancient Southeast Asian continental range of fossil Pongo during two key periods of the Quaternary. These new records from Peninsular Malaysia show that ancestral Pongo successfully passed the major biogeographical divide between mainland continental Southeast Asia and the Sunda subregion before 500 ka (thousand years ago). 相似文献
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145 rotifer species were previously known from Sudan, mostly from the Nile valley and the NE of the country. In the present paper planktonic, periphytic and benthic samples from the Western provinces of Darfur and Kordofan are examined. They contained 77 species, in one or different forms, of which 67% were cosmopolitan, 15% thermophilic, 14% tropicopolitan, and 4% temperate-boreal. No new taxa were found, but 23 species and one subspecies are new to Sudan, while one is new to Africa. 相似文献
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Sylvia Schäffer Günther Krisper Tobias Pfingstl Christian Sturmbauer 《Zoologischer Anzeiger》2008,247(4):249-258
The oribatid mite Scutovertex pileatus sp. nov. is described on the basis of adult individuals originating from southern Austria (Carinthia). The new species shows the typical habitus of Scutovertex and is distinguished by the cerotegument and cuticle forming irregular nodules and bars over the entire body; the rostrum with two visor-like projections, with the ventral projection larger and arched ventrally; short lamellar setae; two pairs of converging ridges between the lamellae; small notogastral setae that are not broadened distally; and a sclerotized rib across the mentum. Furthermore, DNA sequences of the COI gene (region 2, 567 bp) of S. pileatus were compared with those of S. minutus, S. sculptus, using Cymbaeremaeus cymba as the outgroup. Molecular data unambiguously support the discreteness of all three species by placing them reciprocally monophyletic, as well as by large genetic divergences. Interspecific distances among C. cymba, S. minutus, S. pileatus and S. sculptus amounted to 13.7-29.9%. 相似文献
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Adults and deutonymphs of a new water mite species of the genus Hygrobates Koch, 1837 (Acari, Hydrachnidia, Hygrobatidae) were found to parasitize the Hong Kong Newt, Paramesotriton hongkongensis Myers and Leviton, 1962 (Amphibia, Caudata, Salamandridae), endemic to Hong Kong and coastal areas of Guangdong Province: Hygrobates aloisii sp. nov. Males and females, as well as deutonymphs and larvae are described. A new subgenus - Lurchibates subgen. nov. - is defined to accommodate the species of the Hygrobates salamandrarum-group. The parasite-host association, infestation rate, attachment sites and the impact of mite infestation on the newts behaviour and body condition are investigated. These ecological aspects of the parasite-host association between freshwater mites and newts are examined for the first time in detail in their natural habitat. 相似文献
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A new species of hemiurid is described from a sea snake. 相似文献
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Euprimate grasping feet are characterized by a suite of morphological traits, including an enlarged peroneal process on the base of the first metatarsal, which serves as the insertion site of the peroneus longus muscle. In prosimians, a large process has typically been associated with a powerful hallucal grasp via the contraction of the peroneus longus to adduct the hallux. Recent electromyography (EMG) studies have documented that peroneus longus does not contribute substantially to hallucal grasping in lemurids (Boyer et al., 2007). However, non-lemurid prosimians have a I-V opposable grasp complex that is morphologically different and phylogenetically more primitive than the I-II adductor grasp complex of the lemurids previously studied. Therefore, it is possible that peroneus longus did function during grasping in early euprimates, but lost this function in large-bodied lemurids. The present study tests the hypothesis that a large peroneal process is related to powerful grasping ability in primates displaying the more primitive I-V grasp complex. We use EMG to evaluate the recruitment of peroneus longus, other crural muscles, and adductor hallucis in static and locomotor grasping activities of the slow loris (Nycticebus coucang). Results show that peroneus longus is active during grasping behaviors that require the subject to actively resist inversion of the foot, and likely contributes to a hallucal grasp in these activities. Peroneus longus activity level does not differ between grasping and power grasping activities, nor does it differ between grasping and non-grasping locomotor modes. Conversely, the digital flexors and hallucal adductor are recruited at higher levels during power grasping and grasping locomotor modes. Consequently, we reject the hypothesis that an enlarged peroneal process represents an adaptation specifically to enhance the power of the I-V grasp, but accept that the muscle likely plays a role in adducting the hallux during grasping behaviors that require stabilization of the ankle, and suggest that further work is necessary to determine if this role is sufficient to drive selection for a large peroneal process. 相似文献
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We describe a new species of Dolichopithecus, D. balcanicus sp. nov., from the Pliocene (late Ruscinian) of the Balkans. Although known by mandibular remains only, it is readily distinguished from the common European species, D. ruscinensis, by its smaller size, much shallower mandibular corpus, and crowding of the premolars. Ukrainian finds of "Adelopithecus" can be accommodated within D. ruscinensis as a separate, smaller subspecies, D. ruscinensis hypsilophus, but the specimens reported from Asia are more distinct, and they probably represent a separate subgenus of Dolichopithecus, the valid name of which is D. (Parapresbytis) Kalmykov and Mashchenko. 相似文献
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Kwaku Aduse-Poku Eric Vingerhoedt Niklas Wahlberg 《Molecular phylogenetics and evolution》2009,53(2):463-478
Despite the long popularity of Charaxes among collectors and researchers, their evolutionary history is largely unknown. The current and accepted species groupings and relationships within the genus are based exclusively on adult morphology and life histories. Here, we examine the monophyly and evolutionary affinities of the species-groups within the genus Charaxes and explore how they relate to members of their closest genera (Euxanthe, Polyura and Palla) using 4167 bp of sequence data from five (1 mitochondrial and 4 nuclear) gene regions. Within the proposed phylogenetic framework, we estimate ages of divergence within the genus and also reconstruct their historical biogeography. We included representatives of all known species-groups in Africa and Asia, all known species of Euxanthe and Palla and two exemplar species of Polyura. We found the genus Charaxes to be a paraphyletic group with regard to the genera Polyura and Euxanthe, contrary to the earlier assumption of monophyly. We found that 13 out of 16 morphologically defined species-groups with more than one species were strongly supported monophyletic clades. Charaxes nichetes is the sister group to all the other Charaxes. Polyura grouped with the Zoolina and Pleione species-groups as a well-supported clade, and Euxanthe grouped with the Lycurgus species-group. Our results indicated that the common ancestor of Charaxes diverged from the common ancestor of Palla in the mid Eocene (45 million years ago) in (Central) Africa and began diversifying to its extant members 15 million years later. Most of the major diversifications within the genus occurred between the late Oligocene and Miocene when the global climates were putatively undergoing drastic fluctuations. A considerable number of extant species diverged from sister species during the Pliocene. A dispersal–vicariance analysis suggests that many dispersal rather than vicariance events resulted in the distribution of the extant species. The genus Polyura and the Indo-Australian Charaxes are most likely the results of three independent colonizations of Asia by African Charaxes in the Miocene. We synonymize the genera Polyura (syn. nov.) and Euxanthe (syn. nov.) with Charaxes, with the currently circumscribed Charaxes subdivided into five subgenera to reflect its phylogeny. 相似文献
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Two orthothecid hyoliths, Gracilitheca astronauta n. sp. and Nephrotheca sophia n. sp. are described from the “middle” Cambrian Buchava Formation of the Skryje-Tý?ovice Basin in the Czech Republic. The new forms are based on about thirty well-preserved external and internal moulds of both conchs and opercula. Gracilitheca astronauta n. sp. is classified under the family Gracilithecidae Sysoev, 1972 and may be distinguished by clearly triangular cross-section of the conch, whereas Nephrotheca sophia n. sp. is characterized by transversally elongated cardinal processes reaching the lateral opercular margin and is combined with the family Orthothecidae Sysoev, 1958 emended Malinky, 2009. Several specimens of G. astronauta show operculum preserved inside of the conch. Stratigraphic ranges and geographic distributions within the Skryje-Tý?ovice Basin are established for both taxa. 相似文献
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The ultrastructure of the sheath, cuticle and hypodermis of the microfilaria of Cardianema sp, is described from electron micrographs of in utero- and blood-stages. The trilaminiar sheath invests the microfilaria throughout development in utero and it acquires a superficial coat after the microfilaria enters the blood stream of its reptile host. The cuticle consists of external and internal cortex, fibrillar and subfibrillar layers. The cuticle is attached to the hypodermis without the intervention of a basal lamina. The structure of the external cortex is modified in the annular furrows in the cuticle. The cellular hypodermis forms a complete subcuticular layer, although over much of the circumference the cells exist as thin cytoplasmic processes and where these overlap there are extensive tight junctions. The case for classifying the microfilaria of Cardianema a first stage larva is advanced and a functional but speculative, role for the sheath is proposed. 相似文献
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Tripti Shrivastava 《Journal of molecular biology》2009,392(4):1007-1019
Rv3291c is a member of the feast/famine regulatory protein family that is known to form stable protein-DNA complexes. We report a specific oligomeric transition between hexadecameric and octameric/lower-order oligomers in the presence of Phe that supports an effector-mediated model for the disassembly of a nucleosome-like particle. We had generated two mutants, Gly102Thr and Glu104Ala, which are part of the essential 100-106 effector-binding loop. The Gly102Thr mutant adopts an unusual ‘open’ quaternary structure and offers interesting functional insights co-related to the binding of an effector. This is similar to the previously reported Escherichia coli Lrp co-crystallized in the presence of DNA where the interactions of the substrate with the N-terminal DNA binding domain presumably lead to symmetry deviations to the oligomeric association. The present structure represents a direct evidence to support that changes made to the effector-binding domain at the C-terminus also result in a functionally relevant quaternary structural change. Conversely, the Glu104Ala mutant retains the closed quaternary association observed in the native protein and reveals nonsymmetrical interaction effects in the two subunits of the dimer. We also report that the native protein unexpectedly binds Lys but does not recognize Arg and offer a structural explanation for it. Error-scaled difference distance matrix analysis suggests that the protein has a relatively flexible core that is presumably needed to mediate the structural changes necessary for the protein's regulatory functions. 相似文献