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1.
Two species of the genus Boysidia Ancey, 1881 were reported as new to science, Boysidia(Boysidia) xianfengensis sp. nov. and B.(B.) xiaoguanensis sp. nov., while the distribution of the 23 species of Boysidia from China was discussed. The materials of the new species were collected from Hubei Province, China by authors. The shell of B.(B.) xianfengensis sp. nov. looks small(height 4.90 mm, diameter 3.10 mm), and has five apertural teeth: one large parietal tooth, one long columellar tooth, one small nipple-shaped upper palatal tooth, one large flake-shaped lower palatal tooth, one small infrapalatal tooth. The shell of B.(B.) xiaoguanensis sp. nov. looks small(height 3.55 mm, diameter 2.20 mm), and has four apertural teeth: one large parietal tooth, one long columellar tooth, one large flake-shaped upper palatal tooth, one slightly small flake-shaped lower palatal tooth. The type specimens of the new species are deposited in the Institute of Zoology, Chinese Academy of Sciences, China.  相似文献   

2.
The genetic diversity and species-diagnostic markers in the introduced apple snail, Pomacea canaliculata and in the native Thai apple snails; Pila ampullacea, P. angelica, P. pesmei, and P. polita, were investigated by restriction analysis of COI and are reported for the first time. Twenty-one composite haplotypes showing non-overlapping distributions among species were found. Genetic heterogeneity analysis indicated significant differences between species (P < 0.0001) and within P. pesmei (P < 0.0001) and P. angelica (P < 0.0004). No such heterogeneity was observed in Pomacea canaliculata (P > 0.0036 as modified by the Bonferroni procedure), P. ampullacea (P = 0.0824-1.000) and P. polita (P = 1.0000). A neighbor-joining tree based on genetic distance between pairs of composite haplotypes differentiated all species and indicated that P. angelica and P. pesmei are closely related phylogenetically. In addition, the 16S rDNA of these species was cloned and sequenced. A species-specific PCR for P. canaliculata was successfully developed with a sensitivity of detection of approximately 50 pg of the target DNA template. The amplification of genomic DNA (50 pg and 25 ng) isolated from the fertilized eggs, and juveniles (1, 7, and 15 d after hatching) of Pomacea canaliculata was also successful, and suggested that Pomacea canaliculata and Pila species can be discriminated from the early stages of development.  相似文献   

3.
Following the first records of Chthonius (Ephippiochthonius) boldorii Beier, 1934 in central Europe, a species which was previously assumed to occur exclusively in Mediterranean caves, 116 series (595 specimens) of the cryptic taxa C. (E.) boldorii and C. (E.) fuscimanus Simon, 1900 (Syn. C. (E.) austriacus Beier, 1931) were re-examined. Although multivariate analyses suggest specific separation, there is only one unequivocal character for discrimination: the presence or absence of a single isolated tooth on the moveable finger of the chelicerae. The distributions were found to be largely allopatric, therefore it is concluded that the species rank of the two morphospecies is justified. North of the Alps, an almost vicariant pattern emerged: east of 14° E fuscimanus occurs, west of this line boldorii occurs. The results provide a basis for discussing the relevance of minute morphological differences in pseudoscorpion taxonomy.  相似文献   

4.
Morrison WE  Hay ME 《PloS one》2011,6(3):e17227
Enemy release and biotic resistance are competing, but not mutually exclusive, hypotheses addressing the success or failure of non-native plants entering a new region. Enemy release predicts that exotic plants become invasive by escaping their co-adapted herbivores and by being unrecognized or unpalatable to native herbivores that have not been selected to consume them. In contrast, biotic resistance predicts that native generalist herbivores will suppress exotic plants that will not have been selected to deter these herbivores. We tested these hypotheses using five generalist herbivores from North or South America and nine confamilial pairs of native and exotic aquatic plants. Four of five herbivores showed 2.4-17.3 fold preferences for exotic over native plants. Three species of South American apple snails (Pomacea sp.) preferred North American over South American macrophytes, while a North American crayfish Procambarus spiculifer preferred South American, Asian, and Australian macrophytes over North American relatives. Apple snails have their center of diversity in South America, but a single species (Pomacea paludosa) occurs in North America. This species, with a South American lineage but a North American distribution, did not differentiate between South American and North American plants. Its preferences correlated with preferences of its South American relatives rather than with preferences of the North American crayfish, consistent with evolutionary inertia due to its South American lineage. Tests of plant traits indicated that the crayfish responded primarily to plant structure, the apple snails primarily to plant chemistry, and that plant protein concentration played no detectable role. Generalist herbivores preferred non-native plants, suggesting that intact guilds of native, generalist herbivores may provide biotic resistance to plant invasions. Past invasions may have been facilitated by removal of native herbivores, introduction of non-native herbivores (which commonly prefer native plants), or both.  相似文献   

5.
Three measures (gape, tip and tooth row) of pharyngeal bones from 13 Eurasian cyprinid fish species caught in north-eastern Germany were used to establish species specific bone measurelength relationships for reconstruction of prey fish length. Left and right bones were symmetrical in the case of gape, tip and length of tooth row in 69, 46 and 8%, respectively. Gape and tip showed significantly lower maximum values of relative error than the tooth row measure. A comparison of bone measures established for roach Rutilus rutilus (L.) and bream Abramis brama (L.) from north-eastern and from southern Germany showed significant differences. Left and right bone measure-length relationships are not generally identical. Gape and tip measures allow more accurate back-calculation of length than tooth row measures and locality specific relationships should be established.  相似文献   

6.
A new species, Psephellus turcicus A.Duran & Hamzaoğlu (Asteraceae) in sect. Psephelloidei (Boiss.) Wagenitz & Hellwig is described and illustrated from Anatolia, Turkey. The species grows on limestone crevices in Kazankaya Canyon (A5 Yozgat) in central Anatolia. A neo-endemic confined to Kazankaya Canyon, it is closely related to Psephellus psephelloides (Freny & Sint.) Wagenitz. Diagnostic morphological characters from closely similar taxa are discussed, and arranged in a key of Turkish similar Psephellus Cass. The ecology, biogeography and conservation status of the species are also presented. Achene surface morphology of P. turcicus and P. psephelloides are examined by SEM. The geographical distribution of the new species and other related species is mapped.  © 2005 The Linnean Society of London, Botanical Journal of the Linnean Society , 2005, 148 , 495–500.  相似文献   

7.
Most nonmammalian species replace their teeth continuously (so-called polyphyodonty), which allows morphological and structural modifications to occur during ontogeny. We have chosen Pleurodeles waltl, a salamander easy to rear in the laboratory, as a model species to establish the morphological foundations necessary for future molecular approaches aiming to understand not only molecular processes involved in tooth development and replacement, but also their changes, notably during metamorphosis, that might usefully inform studies of modifications of tooth morphology during evolution. In order to determine when (in which developmental stage) and how (progressively or suddenly) tooth modifications take place during ontogeny, we concentrated our observations on a single tooth family, located at position I, closest to the symphysis on the left lower jaw. We monitored the development and replacement of the six first teeth in a large growth series ranging from 10-day-old embryos (tooth I1) to adult specimens (tooth I6), using light (LM), scanning (SEM), and transmission electron (TEM) microscopy. A timetable of the developmental and functional period is provided for the six teeth, and tooth development is compared in larvae and young adults. In P. waltl the first functional tooth is not replaced when the second generation tooth forms, in contrast to what occurs for the later generation teeth, leading to the presence of two functional teeth in a single position during the first 2 months of life. Larval tooth I1 shows dramatically different features when compared to adult tooth I6: a dividing zone has appeared between the dentin cone and the pedicel; the pulp cavity has enlarged, allowing accommodation of large blood vessels; the odontoblasts are well organized along the dentin surface; tubules have appeared in the dentin; and teeth have become bicuspidate. Most of these modifications take place progressively from one tooth generation to the next, but the change from monocuspid to bicuspid tooth occurs during the tooth I3 to tooth I4 transition at metamorphosis.  相似文献   

8.
Catadiscus pomaceae sp. n. from the intestine of the prosobranch mollusc Pomacea canaliculata (Lamarck, 1801), is described. The host snail was collected from a lenitic biotope belonging to the Riachuelo basin (Corrientes province, Argentina) during 1985-1986. So far the species of the genus Catadiscus Cohn, 1904 have been recorded in amphibians and reptiles. This is the first instance of a species of that genus parasitizing a mollusc.  相似文献   

9.
A total of 34 scaled chrysophyte taxa (18 Mallomonas spp., 6 Synura spp., 2 Chrysosphaerella spp., 6 Spiniferomonas spp. and 2 Paraphysomonas spp.) were recorded by SEM techniques in 61 samples from 59 lakes locating in 8 national parks of southern and central Finland in July 1987. Most of the lakes were small forest and peat bog lakes with acid (pH 4.6–7.2) and soft-water and with variable water colour (10–350 mg Pt/l). The number of taxa per lake varied from 0 to 15 and it correlated very significantly with the water pH. The species structure was rather typical for the oligotrophic and acid lakes. Besides the eurytypic and common species like Mallomonus caudata (fr. 72.1% of lakes), M. crassisquama (65.6%), M. allorgei (62.3%) and M. akrokomos (52.5%) also M. canina (41.0%) and M. hamata (21.3%) were frequently observed. M. calceolus, M. costata, M. papillosa, M. pugio and M. paludosa were more rare but typical for acid lakes. Synuru splendida which occurred in two lakes was the most rare and a new species for Finland.  相似文献   

10.
蓖麻籽提取液对福寿螺毒杀效果及作用机制   总被引:1,自引:0,他引:1  
采用生物浸泡法,以草本植物蓖麻籽提取液制备植物源毒杀剂,研究不同提取液浓度(0、0.5、1.5、3.0、4.5、6.0 g/L)对福寿螺毒(Pomacea canaliculata Lam)杀作用效果,并通过福寿螺在亚致死浓度1.58(LC25)、3.82(LC50)和6.05 g/L(LC75)处理条件下的肝脏组织生...  相似文献   

11.
Abstract The potential for using imidacloprid (a neonicotinoid) and indoxacarb (an oxadiazine) as grain protectants was investigated in bioassays against resistant strains of five stored grain beetles. The species investigated were Rhyzopertha dominica (F.) (the lesser grain borer), Sitophilus oryzae (L.) (the rice weevil), Tribolium castaneum (Herbst) (the rust‐red flour beetle), Oryzaephilus surinamensis (L.) (the saw tooth flour beetle), and Cryptolestes ferrugineus (Stephens) (the flat grain beetle). Each of these species has developed resistance to one or more protectants, including organophosphorus insecticides, synthetic pyrethroids and the juvenile hormone analogue methoprene. Mortality and reproduction after a 2‐week exposure of adults to treated wheat depended on species, dose and insecticide. Imidacloprid had no effect on S. oryzae at any dose, but none of the other species produced any live progeny at 10 mg/kg. Indoxacarb had no effect on T. castaneum at any dose, but none of the other species produced any live progeny at 5 mg/kg. The results show that although both imidacloprid and indoxacarb can control at least four of the five key pests tested at doses comparable to those used for organophosphorus protectants, more potent neonicotinoid or oxadiazine insecticides would be needed than either of these to provide broad spectrum protection of stored grain.  相似文献   

12.
在全球气候变化背景下, 福寿螺在我国及全球进一步扩散。极强的生态耐受力及快速适应力是福寿螺能够在入侵地区迅速扩散的重要原因。其中, 环境温度对福寿螺的生存、生长、发育及繁殖至关重要, 是影响福寿螺分布、扩散及暴发的重要因素之一。文章在综述温度耐受范围的基础上, 总结了福寿螺高低温适应的生理生化及分子机制, 并对从温度适应性角度揭示入侵机制的研究前景进行展望。当前, 福寿螺温度适应的生理生化机制研究主要针对化合物以及相关酶活性变化开展, 分子机制研究主要集中在HSP基因的表达差异上。在染色体水平基因组完成测序的基础上, 福寿螺快速适应性进化的生理生态耐受性机制和表型可塑性机制有待深入开展。  相似文献   

13.
14.
本文描述铗蠓属二新种(岭南铗蠓 Forcipmyia(Euprojoannisia)lingnanensis Liu et Yu和空洞铗蠓Forcipomyia (Forcipomyia) cavatus Liu et Yan两性成虫的形态特征。岭南铗蠓雌虫触须第 3节细长(PR> 3.5),大颚无齿;雌虫阳茎中叶形状特异,端部钩状。空洞铗檬雄虫 AR 0.80,前、中足淡色,中足仅股节和胫节部分棕色;雄虫阳茎中叶中部具明显的几丁质片。  相似文献   

15.
Terao  K.  Mayama  S.  Kobayasi  H. 《Hydrobiologia》1993,(1):75-80
Cymbella mexicana (Ehrenb.) Cleve var. mexicana was collected from Tama-gawa (Tama River), Tokyo. The fine structure of the species was examined by scanning electron microscopy (SEM), with special reference to colony formation and band morphology. A mature cingulum of this species is usually composed of four open bands. The correlation between the position of the second band (B2) of the cingulum and the attaching pole of the frustule is discussed.  相似文献   

16.
The hydrated iron(III) oxide limonite is reported for the first time as a biomineral. In situ laser Raman spectra of the tooth cores from major lateral teeth of the chiton Plaxiphora albida are compared with those of synthetic and mineral iron phosphates and iron oxides. Raman spectra measured on iron phosphate and iron oxide standard materials are shown to be easily distinguishable from one another. The central tooth cores of mature P. albida teeth do not show any evidence for the presence of a separate iron phosphate mineral. Rather, in each tooth a narrow band of the hydrated iron(III) oxide limonite is shown to separate the magnetite of the tooth surface from a central core region comprising both lepidocrocite and limonite. The high concentration of phosphorus in P. albida tooth cores, previously observed by energy dispersive spectroscopy, is not associated with a separate iron phosphate mineral, indicating that this element may be adsorbed onto the surface of the iron oxide minerals present. The failure to detect a separate iron(III) phosphate is discussed with reference to other chiton species that display high levels of iron and phosphorus in the cores of their mature major lateral teeth.  相似文献   

17.
The isolation and some structural features of heparan sulfates and chondroitin sulfates from three species of molluscs (Pomacea sp., Tagelus gibbus, and Anomalocardia brasiliana) are reported. It is shown that heparan sulfates with structural similarities to the ones found in mammals are present in the three molluscs analyzed. All the heparan sulfates were degraded by heparitinases I and II to four distinct unsaturated disaccharides with the same properties as the ones present in heparan sulfates of mammalian origin. This suggests that these four disaccharide units are maintained through the evolution. Furthermore, the proportion of these units varied in the heparan sulfates according to the species of origin. The chondroitin sulfates, on the other hand, exhibit different structural features according to the species of origin. For instance, by the action of chondroitinase AC, 4- and nonsulfated disaccharides are produced from Pomacea chondroitin, whereas 4- and 6-sulfated disaccharides are formed from Tagelus and Anomalocardia. The possible role of these compounds in cell recognition and/or adhesiveness is discussed in view of the present findings.  相似文献   

18.
At least 14 species of apple snail (Ampullariidae) have been released to water bodies outside their native ranges; however, less than half of these species have become widespread or caused appreciable impacts. We review evidence for the impact of apple snails on natural and managed wetlands focusing on those studies that have elucidated impact mechanisms. Significant changes in wetland ecosystems have been noted in regions where the snails are established: Two species in particular (Pomacea canaliculata and Pomacea maculata) have become major pests of aquatic crops, including rice, and caused enormous increases in molluscicide use. Invasive apple snails have also altered macrophyte community structure in natural and managed wetlands through selective herbivory and certain apple snail species can potentially shift the balance of freshwater ecosystems from clear water (macrophyte dominated) to turbid (plankton dominated) states by depleting densities of native aquatic plants. Furthermore, the introductions of some apple snail species have altered benthic community structure either directly, through predation, or indirectly, through exploitation competition or as a result of management actions. To date much of the evidence for these impacts has been based on correlations, with few manipulative field or mesocosm experiments. Greater attention to impact monitoring is required, and, for Asia in particular, a landscape approach to impact management that includes both natural and managed-rice wetlands is recommended.  相似文献   

19.
摘要:藤山柳属Clematoclethra为中国特有属,属内物种划分争议颇大。利用扫描电镜观察了该属14个居群的花粉形态,结果表明藤山柳属的花粉为小粒花粉,多为圆球形,具三拟孔沟,根据外壁纹饰可分为皱波状花粉、颗粒状花粉和细疣状花粉3种类型。花粉类型与植株毛被特征有一定相关性,对澄清藤山柳属的分类问题具有一定意义。  相似文献   

20.
A taxonomic reevaluation of the Ceylonese species of the paleotropic genus of Gentianaceae, Exacum L. (ca. 40 species), is made. Eight species are recognized. Five of the species are endemic to Ceylon and three are also found in India. One species new to Ceylon is presented, viz. E. pedunculalum L., and one new combination is made, viz. E. pallidum (Trim.) Klack. Typifications, maps and a key to the species are given. The micromorphology of seeds, pollen grains, and cuticular structures as seen by means of SEM is also given and its implications for taxonomy discussed.  相似文献   

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