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1.
We present an updated diagnosis of 13Streptocephalus species of North America. Three new species are included. A key to the species is provided.The phylogeny of the group is discussed on the basis of (1) a systematic approach (Maeda-Martinezet al., 1995; this volume), which considers the entire distal antennal outgrowth, the frontal appendage, and the morphology of the ovaries as essential in defining different genetic lineages or species-groups, and (2) a cladistic analysis. We suggest that of nine monophyletic groups, three are represented in both the Old and New World. Thus, contrary to former disparsalist hypotheses, we argue that the New World species represent relict forms of ancestral groups fragmented by continental drift (vicariance model).  相似文献   

2.
Floral morphology in all ten species ofCrossostylis, one of the inland genera of Rhizophoraceae and is distributed in the South Pacific Islands, was studied to increase our knowledge on floral features of individual species as well as on relationships among the species. Flowers ofCrossostylis, unlike those of the other Rhizophoraceae, always have semi-inferior ovaries and entire petals, but are diversified concerning the number and arrangement of stamens and carpels, the presence or absence of staminodia, sexuality and the structure of nectaries. Despite some doubt of the presence of apomorphies restricted to the whole genus, we tentatively definedCrossostylis by a combination of the presence of the semi-inferior ovary, entire petals, and arillate seeds, and then performed cladistic analysis on the basis of 24 floral and other morphological characters and withCarallia andGynotroches as outgroups. Our phylogenetic analysis suggested that the species ofCrossostylis are divided into two monophyletic groups: one comprising six species distributed in the Solomon Islands, Vanuatu and the Fiji Islands, and the other comprising four species distributed in New Caledonia and Polynesia.  相似文献   

3.
Antenna grooming in more than 100 species of bees (Apoidea), representing 34 genera of the 7 major bee families is recorded and quantitatively analysed. Most species of bees fall into one of two groups with respect to repetitive antenna cleaning: “Uniscrapers” predominantly clean their antennae with one stroke, “biscrapers” mostly with two subsequent strokes. Uniscrapers are more consequent in their behaviour than biscrapers. Most biscrapers occasionally clean their antenna with one or three strokes. Individual variation in the ratio of stroke repetition is considerably larger in bi- than in uniscrapers. In several species males and females differ with respect to their antenna cleaning behaviour, females tend to be more uniscraping. Most species of the families Colletidae, Halictidae, and Andrenidae, as well as the species of the genera Ceratina and Nomada (Anthophoridae) are biscrapers. Almost all species of Melittidae, Megachilidae, Apidae, and Anthophoridae (except Ceratina and Nomada) are uniscrapers. Bees with an antenna cleaner with ancestral (plesiomorphic) morphology are mostly, but not always, biscrapers, those with a derived antenna cleaner are always uniscrapers. Bees with a derived antenna cleaner perform on average less cleaning actions and strokes than those with an ancestral antenna cleaner. Uniscrapers with an ancestral strigilis do on average more cleaning actions per minute than biscrapers, thus they compensate partly for the fewer number of strokes. But nevertheless the uniscrapers do fewer strokes than the biscrapers (both with an ancestral strigilis). Females clean their antennae on average more often than males. It is interpreted that the behaviour of uniscraping and a derived morphology of the antenna cleaner result in greater efficiency than the status which is ancestral for Apoidea (biscraping and a plesiomorphic antenna cleaner).  相似文献   

4.
We studied the morphology of some members of the Chydorus piger-group, using populations from Karelia (Russia), France, Germany, the Azores, Magadan (East Siberia), Newfoundland (Canada), Venezuela, Zambia, and Bolivia, and move Chydorus piger Sars, 1861 to the genus Paralona Sramek-Husek et al., 1962, which we redefine using traditional characters (first antenna with subapical and apical esthetascs, second antenna with only six setae, ventral valve rim fully setulated with setae in marginal position except between anterior bend and well-developed anterior flange), as well as structural features of the trunk limbs, especially 1 and 2. Chydorus and Pleuroxus are the nearest relatives of Paralona.The genus presently contains only the species P. pigra (Sars, 1861). This, however, shows considerable morphological variation and might therefore be composed of several related taxa, in need of a closer definition.  相似文献   

5.
The morphology and function of the flowers of three species of the genusCallicarpa, C. glabra, C. nisnimurae andC. subpubescens, endemic to the Bonin Islands, revealed that all three species were dioecious. Male plants had short-styled flowers with sterile ovaries, while female plants had long-styled flowers with non-germinating inaperturate pollen grains. Such dioecism has never been reported from the family Verbenaceae. This curious sexual system with non-germinating pollen grains may have been maintained as a reward to insect pollinators.  相似文献   

6.
M. Alonso  D. Jaume 《Hydrobiologia》1991,212(1):221-230
Branchipus cortesi, n. sp. (Anostraca, Branchipodidae) is characterized by the broadly enlarged distal segments of male antenna 2, and a combination of morphological features concerning thoracic limbs, abdominal segments and egg morphology. The species occurs in temporary fresh water bodies in flatlands with temperate Mediterranean climate; it is distributed in the south-western part of Spain. Our study includes a morphological analysis using optical and scanning electronic microscopes. Questions about ecology and distribution of the new species are also discussed.  相似文献   

7.
半蓝角伪叶甲Cerogria basalis(Hope,1831)为角伪叶甲属Cerogria Borchmann,1909的1个大型种,过去仅知道分布于印度,尼泊尔,波斯尼亚和黑塞哥维那,一直缺乏详细和正式的形态描述。近年来,我们从云南采集到该种的雌虫和雄虫。本文对该种雌性和雄性成虫,特别是触角、腹板和雄性外生殖器特征作了详细描述。提供了该种雌、雄两性成虫的背面观和腹面观以及生境照片,以及触角、雄性末节腹板以及雄性外生殖器特征图片。本文还讨论了种内变异。这些工作为该种的正确鉴定提供了依据。  相似文献   

8.
A smut fungus onPrimula sieboldii was newly found in Japan and identified asUrocystis tranzscheliana by comparative morphology. This species causes systemic infection ofP. sieboldii and produces sori in its ovaries.Contribution No. 121, Laboratories of Plant Pathology and Mycology, Institute of Agriculture and Forestry, University of Tsukuba.  相似文献   

9.
The seed morphology of 79 species of neotropical Miconieae (Melastomataceae) is presented. These species have been chosen, in majority, from the polyphyletic genus Leandra. A few other species from the polyphyletic genera Miconia, Ossaea, and Clidemia were also sampled, because of potential similarities. Sixteen morphological seed types are defined after analysis through light microscopy and scanning electron microscopy. The seed morphology appears to possess a great deal of variability on the level of the overall shape as well as the structure and the surface of the testa. The different types defined here do not match with genera or sections, but rather are composed of species coming from different genera. In comparison with a preliminary molecular phylogeny study done on Leandra, some types of seeds are related to well supported clades. In some cases seed morphology corresponds with natural groups of species, thus being of high phylogenetic importance.  相似文献   

10.
采用扫描电镜观察了中国四川雅安地区13种凤仙花属植物的花粉形态,并对其花粉形态进行了主成分分析和聚类分析,基于孢粉学和SRAP聚类结果的比较,讨论不同孢粉学特征对分类结果的影响。结果显示:(1)雅安地区13种凤仙花属植物花粉粒均为中等大小,花粉粒形状从超扁到扁球形变化,花粉粒极面观形状从矩形和椭圆形到四边形、圆形、三角型变化,且只有湖北凤仙、峨眉凤仙和匙叶凤仙是三沟花粉粒,其余种均为四沟花粉粒;外壁纹饰仅扭萼凤仙和齿萼凤仙为细小网状,其余均为网状纹饰。(2)依据不同指标进行的孢粉学聚类均将13种凤仙花属植物划分为3个类群,而SRAP聚类结果则将13种凤仙花属植物划分为5个类群;不同孢粉学聚类结果的相似率只有30.77%。(3)孢粉学聚类并未与分子聚类显示严格的对应关系,以花粉大小和形状、外壁纹饰为指标进行的孢粉学分类与SRAP分类的相似率最高(69.23%)。研究认为,选择不同的花粉形态特征作指标对分类的准确性影响较大,花粉大小和形状、外壁纹饰这2个指标对凤仙花属植物分类具有意义,而萌发沟的特征则很难作为分类的依据,花粉形态特征在分类上有局限性;进行该属植物孢粉学分类需要选择有价值的分类指标,并结合形态学、分子生物学等综合研究。  相似文献   

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