首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 15 毫秒
1.
Late Jurassic Mammals from Tendaguru, Tanzania, East Africa   总被引:1,自引:0,他引:1  
Records of Mesozoic mammals are extremely rare in Africa. The only previous record from the Upper Jurassic of Africa is a fragmentary mandible without teeth of Brancatherulum tendagurense. Here I report the discovery of two new mammals from the Upper Jurassic of Tendaguru, Tanzania. The fossils were recovered from the Middle Saurian Bed of the Tendaguru Series. A lower molar of a triconodontid mammal is described as Tendagurodon janenschi gen. et sp. nov., and a fragmentary dentary of a eupantothere as Tendagurutherium dietrichi gen. et sp. nov. The eupantothere in particular contributes to documenting the evolution of mammals during the Mesozoic. The posterior portion of the mandible of Tendagurutherium dietrichi gen. et sp. nov. shows that the angular (tympanic) bone was not yet completely separated from the dentary, a previously undocumented stage of eupantotherian middle ear evolution.  相似文献   

2.
Fleas collected from rodents in the Negev Desert in southern Israel were molecularly screened for Bartonella species. A total of 1,148 fleas, collected from 122 rodents belonging to six species, were pooled in 245 pools based on flea species, sex, and rodent host species. Two Bartonella gene fragments, corresponding to RNA polymerase B (rpoB) and citrate synthase (gltA), were targeted, and 94 and 74 flea pools were found positive by PCR, respectively. The Bartonella 16S-23S internal transcribed spacer (ITS) region was also targeted, and 66 flea pools were found to be positive by PCR. Sixteen different Bartonella gltA genotypes were detected in 94 positive flea pools collected from 5 different rodent species, indicating that fleas collected from each rodent species can harbor several Bartonella genotypes. Based on gltA analysis, identified Bartonella genotypes were highly similar or identical to strains previously detected in rodent species from different parts of the world. A gltA fragment 100% similar to Bartonella henselae was detected in one flea pool. Another 2 flea pools contained gltA fragments that were closely related to B. henselae (98% similarity). The high sequence similarities to the zoonotic pathogen B. henselae warrant further investigation.Bartonellae are small Gram-negative bacilli belonging to the alpha-2 subdivision of the Proteobacteria. Different Bartonella species were detected in a wide range of vertebrate animals. There are currently 30 known species or subspecies, among which 14 have been associated with human diseases (7). Bartonella organisms are parasites of mammalian erythrocytes and endothelial cells and are transmitted by fleas and lice and potentially by other blood-feeding arthropods such as ticks and flies (2). Infection in the natural host commonly causes a chronic bacteremia, which is asymptomatic in most cases.Rodents are being extensively studied and were found to have a high prevalence of Bartonella infection, with a high diversity of Bartonella spp. and strains (3). The close contacts between human and rodent populations around the world create excellent conditions for transmission of Bartonella spp. from animals to humans (28). The transmission routes of Bartonella bacteria by arthropod vectors among rodents and between rodents and other mammalian hosts have public health implications. In order to understand the extent to which rodents serve as source of human infections, investigations of rodent-borne Bartonella are essential (28). A few cases of human infections with Bartonella bacteria of rodent origin have been reported: B. elizabethae was associated with endocarditis, B. washoensis was associated with cases of myocarditis and meningitis, B. vinsonii subsp. arupensis was reported to cause fever and neurologic symptoms, and B. grahamii was isolated from the intraocular fluids of a patient with neuroretinitis (5, 11, 12, 25, 29).An earlier survey carried out in the Tel Aviv region, Israel, demonstrated the occurrence of Bartonella strains closely related to B. elizabethae and B. tribocorum in commensal rats (Rattus rattus) (8). Another study has surveyed wild rodents and their fleas for Bartonella spp. in 19 geographical locations in Israel from the Upper Galilee in the north to Beer Sheba in the south. Bartonella DNA was detected in spleen samples of 19 out of 79 (24%) black rats (R. rattus), in 1 of 4 (25%) Cairo spiny mice (Acomys cahirinus), and in 15 of 34 (44%) flea pools collected from black rats (R. rattus) (21). The objectives of the current study were to screen fleas collected from rodents inhabiting the Negev Desert south to Beer Sheba for Bartonella infection and to compare Bartonella prevalences between male and female fleas.  相似文献   

3.
《Palaeoworld》2016,25(4):467-495
Terebratulide brachiopods are found throughout the New Zealand Mesozoic, and by the Jurassic are second only to rhynchonellides in abundance and diversity. Only two species have been described from the Late Jurassic, Kutchithyris hendersoni Marwick, 1953 and Holcothyris (?) kaiwaraensis Campbell, 1965. In this study, one new genus and 14 new species are described, and three additional forms placed in open nomenclature.Nearly all the material comes from the Murihiku Terrane on the west coast of the North Island south of Auckland, and most from a small number of shellbeds with diverse faunas. Two key localities for Middle Jurassic (Bajocian–Bathonian) brachiopods are Opuatia Cliff at Port Waikato, and a quarry in the Marokopa Valley. Two species of fairly large terebratulide, Loboidothyris waitomoensis n. sp. and L. grantmackiei n. sp. are tentatively assigned to the genus Loboidothyris. A further species which may also belong to this genus, L. awakinoensis n. sp. is found in the Awakino Valley to the south. Two species of Zeilleria, Z. opuatiaensis n. sp. and Z. waiohipaensis n. sp. and one of Aulacothyris, A. waikatoensis n. sp. are also recognised. A new species of Kutchithyris, K. marokopaensis n. sp., less strongly folded than K. hendersoni, is also present.Captain King's Shellbed is a metre-thick Oxfordian shellbed that can be traced from Kawhia to the Awakino Valley. It has a rich and diverse fauna in which terebratulides are prominent. Kutchithyris hendersoni is the most abundant, followed by Crispithyris nauarchus n. gen. n. sp. The fauna also includes the same two species of Zeilleria as in the Middle Jurassic, and the costellate terebratulide Terebratulina leeae n. sp.Brachiopods are much less common in the later part of the Jurassic (Kimmeridgian and Tithonian). A further species of Kutchithyris, K. challinori n. sp., a second species of Terebratulina, T. putiensis n. sp. and one of Zeilleria (Z. sp.) are present. A rare form is the small subcircular Disculina mancenidoi n. sp. Holcothyris kaiwaraensis is known only from the Late Jurassic Pahau Terrane of North Canterbury, but a second species of Holcothyris, H. campbelli n. sp. is present in the Late Oxfordian and Kimmeridgian of the Kawhia area.Aulacothyris, Terebratulina, and Zeilleria are cosmopolitan. Kutchithyris and Holcothyris are Tethyan. Loboidothyris is more widely distributed but generally Tethyan. Disculina is described from Southern England and France, but has since been recognised in the Caucasus and Japan, and may also have a Tethyan distribution.  相似文献   

4.
Throughout the Negev Desert highlands, thousands of ancient petroglyphs sites are susceptible to deterioration processes that may result in the loss of this unique rock art. Therefore, the overarching goal of the current study was to characterize the composition, diversity and effects of microbial colonization of the rocks to find ways of protecting these unique treasures. The spatial organization of the microbial colonizers and their relationships with the lithic substrate were analysed using scanning electron microscopy. This approach revealed extensive epilithic and endolithic colonization and close microbial–mineral interactions. Shotgun sequencing analysis revealed various taxa from the archaea, bacteria and some eukaryotes. Metagenomic coding sequences (CDS) of these microbial lithobionts exhibited specific metabolic pathways involved in the rock elements' cycles and uptake processes. Thus, our results provide evidence for the potential participation of the microorganisms colonizing these rocks during different solubilization and mineralization processes. These damaging actions may contribute to the deterioration of this extraordinary rock art and thus threaten this valuable heritage. Shotgun metagenomic sequencing, in conjunction with the in situ scanning electron microscopy study, can thus be considered an effective strategy to understand the complexity of the weathering processes occurring at petroglyph sites and other cultural heritage assets.  相似文献   

5.
6.
Sixteen dogs were studied for infestation with R. sanguineus in Kibbutz Ze'elim in the north-western part of the Negev Desert over a period of one year. The mean number of ticks per dog per month was 16.4. The majority of the ticks were adults: males (48.6%) and females (34.4%). The cars and abdomen of the dog were the predilection sites for the ticks. Male ticks were more abundant on the ears, whereas female ticks were more abundant on the ears and the abdomen. A strong correlation between tick numbers and the ambient temperatures was found. The mean percentage of dogs infested in the winter months was 16.6% and increased in the summer months to 34.4%. During winter, ticks were found more often on the ears and head of their hosts whereas in summer they were distributed mainly on the ears, headd and abdomen. The male: female ratio was higher in winter (2.3:1) than in summer (1.1:1).  相似文献   

7.
The type specimens of the Jurassic turtles from the Sichuan Basin (China) previously referred to plesiochelyid Plesiochelys are revised, which confirm that they belong to the family Xinjiangchelyidae. The study of a large number of additional shell material shows, as the dominant group, the Xinjiangchelyidae were greatly diversified in the Late Jurassic of the Sichuan Basin. By the absence of mesoplastron and other shell characters, Chengyuchelys baenoides is moved to Xinjiangchelyidae and considered as a valid taxon. Of the xinjiangchelyids from the Late Jurassic of Sichuan Basin, four genera are recognized: Chengyuchelys, Tienfuchelys, Yanduchelys and cf. Protoxinjiangchelys. The phylogenetic analysis results in that Chengyuchelys includes C. baenoides, C. latimarginalis and C. radiplicatus, and Tienfuchelys consists of T. tzuyangensis, T. chungkingensis and T. zigongensis. All xinjiangchelyids from the Sichuan Basin are more primitive than Xinjiangchelys in the plastron sutured to the carapace.  相似文献   

8.
A theropod assigned to Ceratosaurus was previously reported from the Portuguese Lusitanian Basin based on a limited number of elements of a single individual. Here, we describe newly discovered elements that likely pertain to same, earlier described, specimen. The new elements provide additional evidence that the range of Ceratosaurus spanned from what is now North America into Europe. Previously, some differences were noted between the Portuguese specimens and the North American Ceratosaurus. We consider these differences to be trivial and attribute them to individual variation and/or ontogeny. The following set of features (lesser trochanter positioned low on the femur; crista tibiofibularis obliquely oriented with respect to the axis of the femoral shaft; infrapopliteal ridge present posteriorly on the femur; large cnemial crest; and medial condyle of the tibia continuous with proximal end) indicate that the Portuguese specimen is assignable to Ceratosaurus. This record constitutes one of the scarce evidence of basal ceratosaurian theropods in the Late Jurassic of Europe. Despite the abundance, diversity and wide geographical distribution of ceratosaurs during the Late Cretaceous, its early evolutionary history remains poorly understood. The Portuguese specimens constitute an important evidence for the knowledge of the paleobiogeographic evolution of the clade during the Late Jurassic.  相似文献   

9.
We studied the endolichenic fungal communities from saxicolous lichens occupying the cobbles at Nahal Boker, the central Negev Desert, Israel. Overall, 101 species belonging to 64 genera were isolated from 12 lichen species collected in three seasons from the south-facing slope (SFS) and north-facing slope (NFS) of the wadi. The endolichenic communities possessed a set of traits, which helped them to cope with harsh internal and external conditions. It included a prevalence of melanin-containing fungi with thick-walled and multicellular spores and a comparatively high contribution of thermotolerant species and species with meiospore-producing life cycle stage at the more microclimatically severe SFS. Species richness and isolate density of endolichenic communities was the highest in fruticose lichens with thick and wrinkled thalli, and the lowest in endolithic species possessing thin and smooth thalli. The communities from lichens formed a more diverse group than those from surrounding cobbles probably due to the influence of various species of lichens belonging to different growth forms.  相似文献   

10.
A new genus Amblomma gen. nov. of fossil beetles is erected and can be assignedto the family Ommatidae because its two procoxal cavities are contiguous and the articulations of the abdominal ventrites are abutting. The new genus is similar to Zygadenia Handlirsch, 1906 (=Notocupes Ponomarenko, 1964), Tetraphalerus Waterhouse, 1901,Rhobdocupes Ponomarenko, 1966 and Sinocupes Lin, 1976, but can be distinguished from other genera according to the following characters: the second segment of antennae is shorterthan the third one in length; the posterior tarsi with the basal segment is obviously shorter than the three following taken together in length; the antennae reach the posterior ridge of prothroax in length, and the sides of the prothroax with serrulate margin. Four new species of the new genus are described and figured: Amblomma psilata gen. et sp. nov., Amblomma rudis gen. et sp. nov., Amblomma epicharis gen. et sp. nov., and Amblomma stabilis gen. etsp. nov. A key to species within this new genus is provided. All the specimens are collected from the Late Jurassic Yixian Formation of western Liaoning and are now housed in the College of Life Science, Capital Normal University, Beijing, China.  相似文献   

11.
Sampling of a lenticular concentration of vertebrate debris and associated sediments from the lower Kimmeridgian of southern England has allowed the study of a diverse and abundant assemblage of chondrichthyan remains. A number of previously undescribed species are recorded, of which three new species are named; Squatina? frequens, Synechodus plicatus and Protospinax planus. Additional diagnosis of the genus Paracestracion Koken is given to allow its identification from dental remains. Several nominal batoid species are synonymised with Spathobatis bugesiacus Thiolliere. This assemblage is considered to be typical of Middle–Late Jurassic neritic environments, and is compared to other contemporaneous selachian faunas.  相似文献   

12.
Clutch-size, nestling growth and predation rates on eggs and nestlings in two sympatric alaudids, the Crested Lark Galerida cristata and the Desert Lark Ammomanes deserti, were studied in the Negev desert of Israel. Logistic growth constants were similar for both species, and experimental brood reduction did not accelerate the growth rate of their nestlings. It is suggested that the predation rate on nests of both species has been sufficiently high to select for maximal growth rate of nestlings. Overall probability of predation was 0.85 on a Desert Lark nest and 0.76 on a Crested Lark nest. The smaller clutch-size of the Desert Lark (3.7) may be an adaptation to a higher predation risk, as compared to that of the Crested Lark (4.6) which is more vigilant and nests in more concealed sites.  相似文献   

13.
Aim To evaluate the influence of geographical distribution on the extinction risk of benthic marine invertebrates using data from the fossil record, both during times of background extinction and across a mass‐extinction episode. Total geographical range is contrasted with proxies of global abundance to assess the relationships between the two essential components of geographical distribution and extinction risk. Location A global occurrence data base of fossil benthic macro‐organisms from the Triassic and Jurassic periods was used for this study. Methods Geographical distributions and biodiversity dynamics were assessed for each genus (all taxa) or species (bivalves) based on a sample‐standardized data set and palaeogeographical reconstructions. Geographical ranges were measured by the maximum great circle distance of a taxon within a stratigraphic interval. Global abundance was assessed by the number of localities at which a taxon was recorded. Widespread and rare taxa were separated using median and percentile values of the frequency distributions of occurrences. Results The frequency distribution of geographical ranges is very similar to that for modern taxa. Although no significant correlation could be established between local abundance and geographical range, proxies of global abundance are strongly correlated with geographical range. Taxon longevities are correlated with both mean geographical range and mean global abundance, but range size appears to be more critical than abundance in determining extinction risk. These results are valid when geographical distribution is treated as a trait of taxa and when assessed for individual geological stages. Main conclusions Geographical distribution is a key predictor of extinction risk of Triassic and Jurassic benthic marine invertebrates. An important exception is in the end‐Triassic mass extinction, which equally affected geographically restricted and widespread genera, as well as common and rare genera. This suggests that global diversity crises may curtail the role of geographical distribution in determining extinction risk.  相似文献   

14.
A low-diversity cockroach assemblage from the Upper Jurassic of the Houtiyn-Hotgor locality in Mongolia is described, comprising Solemnia alexandri gen. et sp. nov. (Caloblattinidae), Blattula choutinensis sp. nov. (Blattulidae) and a presumed Triassic relict Irreblatta relicta gen. et sp. nov. (incertae familiae). The carnivorous Raphidiomimidae supposedly originated directly from the Caloblattinidae.  相似文献   

15.
16.
17.
The largest known sauropod trackway site from the Upper Jurassic in Europe has been found in the northern Jura Mountains of Switzerland. Since the initial discovery of the site in 1988, detailed ichno‐facies mapping of the sites has been undertaken and completed. Six separate sites (from 5 to 45km apart) have been located to date; the largest one, displaying 345 single imprints, extends over a surface of 7000 m2. As all of the reported sites occur within the same bed, these vertebrate prints form a megatracksite covering an area of more than 360 km2. All localities are stratigraphically within the Reuchenette Formation. Two biostratigraphically diagnostic ammonites have been found within the sequence (Aulacostephanus; Gravesia), indicating an Upper Kimmeridgian age (sensu gallico). In the easternmost sites, imprints occur on mud‐cracked tidal pond deposits, whereas the western tracksites are found in supratidal algal marsh deposits. The track‐bearing horizon is immediately below a trans‐gressive event at all the sites, suggesting that the ichnofaunas represent dinosaur activity during a relative sea‐level low‐stand. Footprint size and morphology, as well as trackway dimensions, suggest that the track producers belong to the largest sauropods yet recorded in the European Jurassic, closely resembling the Breviparopus tracks from the Middle Jurassic of Morocco.  相似文献   

18.
A juvenile cup, disarticulated arm plates, and columnals of the crinoid Arachnocrinus sarizensis n. sp. are described from the Eastern Taurus Mountains of central Turkey. This is the first Paleozoic crinoid based on a cup and arm plates reported from Turkey. Suggested revision of the Gasterocomidae includes transfer of Arachnocrinus and Ancyrocrinus to the family and rejection of Kopficrinus from the family. The stratigraphic range of Arachnocrinus is extended upward into the Middle Devonian from the Early Devonian. The Devonian of Turkey is of special interest because it includes Laurasian and Gondwanan components on different tectonic blocks. The paleogeographic range of Arachnocrinus is extended from the North American plate onto the Anatolian block, which would have been located on the southern edge of the Paleotethys Sea in the Middle Devonian in a shelf basin off the northern coast of Gondwana at approximately 42° south latitude.  相似文献   

19.
We examined the depthwise distribution of microfungi through 0–40 cm of sandy profiles under bare surface and different shrub species at the Nizzana research site (NRS) in the Negev Desert, Israel. A total of 125 species from 61 genera were isolated using the soil dilution plate method. At the topsoil of all profiles melanin-containing species with large multicellular conidia predominated. In the middle depths at the majority of the profiles, mesic group of microfungi, Penicillium spp. substantially increased in abundance. Density of microfungal isolates decreased with depth under shrubs and did not substantially vary in the nonshaded profiles, highly positively correlating with electrical conductivity and organic matter (OM) content. Substantial increase in isolate densities at the undercanopy habitats, especially in the interdune depression with higher substrate stability raising the accumulation of OM, highlights the role of shrubs as “islands of fertility” for microfungal communities at NRS.  相似文献   

20.
The Callovian Zohar and Matmor formations in the Negev, southern Israel, consisting of marls, shales and limestones, have yielded 13 brachiopod species (2 rhynchonellids, 11 terebratulids), referred to 12 genera, of which one genus and five species are new: Apatecosia inornata, Bihenithyris mediocostata, Digonella boylani sp. nov., Dissoria bretti sp. nov., Burmirhynchia jirbaensis, Kutchithyris landeri sp. nov., Pleuraloma triangulatum, Polyplectella debriani gen. et sp. nov., Ptyctothyris daghaniensis, Somalirhynchia africana, Striithyris saudiarabica, S. telemi sp. nov., and Zeilleria sp. The brachiopods described herein from Hamakhtesh Hagadol (Kurnub Anticline) comprise a fauna located at the northernmost part of the Indo-African Faunal Realm within the Jurassic Ethiopian Province.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号