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1.
A systematic revision for the species of Launaea Cass. in Egypt has revealed the presence of fourteen taxa belonging to 12 species, of which L. acanthodes (Boiss.) Kuntze is a new recorded. One new combination “L. fragilis subsp. tenuiloba (Boiss.) Zareh & Mohamed” is made. Achene diversity of the studied taxa of Launaea was studied using light and scanning electron microscopy. The taxonomic relationships between the studied taxa were discussed as well as SEM micrographs of achenes are provided. Synonyms and key for the identification of the investigated taxa based on morphological characters as well as notes on distribution are provided.  相似文献   

2.
Spatial and seasonal variation in macrozoobenthic composition, abundance and diversity in Aiba Reservoir were investigated bimonthy between June 2004 and April 2005 using a van Veen grab. A depauperate fauna of nine taxa was recorded. Generally, larger numbers of taxa were recorded during the dry season than in the wet season. Melanoides tuberculata and chironomid larvae dominated the macrozoobenthos and showed wide spatial distribution. Diversity and evenness were lower during the wet season than in the dry season, when densities of the major species were low. Melanoides tuberculata and chironomid larvae were recorded from maximum depths of 3.9 m and 2.6 m, respectively. Both taxa were also recorded from all substrate texture types, regardless of the amount of macrophyte material present. The benthic fauna is characterised as being poor in terms of density, taxonomic richness and diversity  相似文献   

3.
This paper continues the publication of newly obtained results from a continuing taxonomic investigation of the genus Aspidistra in Laos and Vietnam. It includes illustrated diagnoses of two new species, A. melanaster Aver., K.S. Nguyen & Tillich, A. obliqua K.S. Nguyen & Aver., two new varieties, A. semiaperta Aver. & Tillich var. globulifera Aver., K.S. Nguyen & Tillich, A. lutea Tillich var. luteo-rubra K.S. Nguyen, Aver. & Tillich, and notes on two species, A. austroyunnanensis G.W. Hu, Lei Cai & Q.F. Wang and A. hekouensis H. Li, C.L. Long & Bogner newly recorded in the flora of Vietnam. Color illustrations, new or updated data on morphology, ecology, phenology, tentative relationships, distribution and conservation status are provided for all the mentioned taxa.  相似文献   

4.
Species diversity of Ulva in Vietnam was investigated using three commonly used genetic markers, the nuclear encoded rDNA ITS region and the plastid encoded rbcL and tufA genes. Single locus species delimitation methods, complemented with morphological and ecological information resulted in the delimitation of 19 species. This diversity is largely incongruent with the traditional understanding of Ulva diversity in Vietnam. Only four species identified in this study, U. lactuca, U. reticulata, U. spinulosa, and U. flexuosa, have been previously reported, and seven species, U. ohnoi, U. tepida, U. chaugulii, U. kraftiorum, U. meridionalis, U. limnetica, and U. aragoënsis, are recorded for the first time from Vietnam. Seven genetic clusters could not be associated with species names with certainty. A new species, U. vietnamensis, is described from marine to brackish coastal areas from southern Vietnam based on its morphological and molecular distinctiveness from the currently known Ulva species. A comparison with recent molecular-based studies of Ulva diversity showed that species composition in Vietnam is similar to that of adjacent countries, including Japan, China, as well as Australia. Our study emphasizes the importance of molecular data in the assessment of Ulva diversity, and indicates that a lot of diversity may still remain to be discovered, especially in tropical regions.  相似文献   

5.
石蝴蝶属(Petrocosmea Oliv.)植物的现代分布与分化中心位于中国的西南山地以及周边国家和地区,如印度(阿萨姆邦)、缅甸、泰国、越南等也有分布。近年来,中国和中南半岛上各个国家和地区的新分类群和国家级新记录层出不穷,进一步加深了研究人员对中国和中南半岛植物区系以及该属植物在上述区域的多样性的理解。例如,滇黔石蝴蝶[Petrocosmea martinii (H. Léveillé)H. Léveillé]和丝毛石蝴蝶(P. sericea C.Y. Wu ex H. W. Li)曾被认为是中国的特有种,前者分布于贵州、广西北部和云南东南部,而后者仅见于云南东南部。该文报道了这两种石蝴蝶属植物的越南国家级分布新记录。这两个新记录种的发现,使得越南分布的石蝴蝶属植物种的数量上升到了5 种,这些新记录种的报道或暗示未来在与中国西南山地邻近的地区还将会有更多该属的新分类群或新记录有待发现。该文还同时提供了这两个国家级分布新记录物种的描述、图示、濒危等级现状评价以及目前所有越南已知分布的石蝴蝶属植物的检索表以备检索和核对。  相似文献   

6.
《Journal of bryology》2013,35(1):9-22
Abstract

This work analyzes the phytogeographic patterns of the liverwort flora of the Atlantic Forest of the Rio de Janeiro State, south-eastern Brazil. The analysis was based on inventories made in fragments of Atlantic Forest in the state, collections from the RB herbarium, and information from the checklist and database of the bryoflora of Rio de Janeiro. The phytogeographic pattern for each taxon was characterized based on its current distribution. Three hundred and sixty liverwort taxa are recognized for Rio de Janeiro. The liverwort flora varies along an altitudinal gradient within the Atlantic Forest, with the montane belt having the greatest species richness (238), the highest number of exclusive taxa (63) and the greatest number of endemic species (23). The predominant phytogeographic element is of neotropical species (49%), followed by disjunct liverworts (18%). Forty-one taxa (11%) are endemic to the country, of which 34 are restricted to the Atlantic Forest. In the lowland and submontane formations species are wide-ranging, whereas the montane and upper montane formations are characterized by endemic species or those disjunct with the Andes. The liverwort flora emphasizes the importance of the fragments of Atlantic Forest in Rio de Janeiro as a centre of diversity and endemism, supporting 50% of the total liverwort species known in Brazil, 72% of those recorded from Atlantic Forest and 55% of the endemic species of the country. Species with an Afro-American and Andean disjunction make up a characteristic part of the liverwort flora, probably reflecting the effects of long-distance dispersal by air currents, migration over land before the breakup of the continents and climatic similarities between the high-altitude grasslands and the northern Andes.  相似文献   

7.
Flattened Gracilaria species are widely distributed along the coasts of the South China Sea with more than 20 species recorded. Within the South China Sea, Gracilaria mammillaris has only been reported from Vietnam, but this species is likely restricted to the western Atlantic. This study aimed to reevaluate the taxonomic status of Vietnamese specimens of ‘G. mammillaris’ using combined morphological and molecular data. Our data clearly indicated that Vietnamese specimens were morphologically and genetically distinct from authentic G. mammillaris from the western Atlantic, and also other described flat Gracilaria species. We, therefore, propose that specimens from Vietnam originally identified as G. mammillaris be designated as a new species, Gracilaria phuquocensis sp. nov. Morphologically, G. phuquocensis can be distinguished from other flat Gracilaria species by its small thallus size, narrower blades, many medullary layers, abundant basal nutritive filaments within mature cystocarps, and tetrasporangial nemathecium. Our rbcL sequence analyses showed that the new species was sister to Gracilaria rhodymenioides from Thailand, and these two species formed a clade with cylindrical Gracilaria species. Our study contributes to clarification of the taxonomic status of misidentified specimens attributed to the flattened Gracilaria species in the South China Sea.  相似文献   

8.
Following previous reports indicating a remarkable high diversity of sessile rotifers in Southeast Asian freshwaters, we report on an extensive study of the diversity of Collothecidae rotifers from fifteen freshwater habitats in Thailand. A total of 13 species, including two additional infraspecific variants, of Collothecidae are recorded, one of which is described as a new species of Collotheca. We further add taxonomic remarks on some of the taxa on record and illustrate the uncinate trophi of several representatives by scanning electron microscopic images. Finally, we provide illustrated identification keys to the Collothecidae recorded to date from Southeast Asia.  相似文献   

9.
《Journal of bryology》2013,35(2):104-107
Abstract

At present, the available information about the liverworts of Sphagnum magellanicum Brid. mires from South America is very limited. The main aim of this paper is to present a comprehensive study of the liverwort flora of this habitat, as well as details on the chorology and ecology of the taxa involved. Four different environmental units were examined, based on the water table level and plant cover, in three representative raised bogs from Tierra del Fuego National Park Ushuaia. Floristic relevs were recorded in 93 square plots 050050m2, distributed at random in the environmental units. Twentyfour liverwort species have been identified the majority have a Subantarctic distribution and there were a remarkable number of Magellanean endemics 11 species. Among the rare species, there were two new records for the Argentinian Province of Tierra del Fuego, Cephaloziella byssacea and Chiloscyphus notophyllus. The ecological preferences of the species were analysed based on their frequencies in the four environmental units examined. Only six species demonstrated significant correlation with some of the environmental units. Riccardia pallidevirens, R. georgiensis, R. alcicornis, and Cephaloziella varians, showed a preference for waterlogged and wet habitats, while Calypogeia sphagnicola and Cephalozia chilensis were linked to dense carpets of Sphagnum magellanicum.  相似文献   

10.
Abstract One new species, four newly recorded genera, and two newly recorded species of diatoms are described from China. They are Sellaphora fuxianensis sp. nov. Li, Sellaphora Mereschkowsky, Karayevia Round & Bukhtiyarova, Placoneis Mereschkowsky, Fallacia Stickle & Mann, Placoneis prespanensis Levkov, Krstic & Nakov, and Fallacia lucinensis (Hustedt) D. G. Mann. All taxa were collected from Lake Fuxian in Yunnan Province, China. These species were observed with light and scanning electron microscopes, and their taxonomic characters are discussed.  相似文献   

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12.
Previous researchers suggested that gibbon song repertoire is genetically determined and song characteristics are useful for assessing systematic relationships. The southern white-cheeked crested gibbon is regarded as either a subspecies of Nomascus leucogenys or its own species (Nomascus siki). I studied vocal diversity among different wild populations of Nomascus in central Vietnam and southern Laos to assess their taxonomic relationships and to examine whether their vocal patterns correspond to forms previously described for Nomascus siki. I examined the songs of 7 Nomascus populations in Vietnam and Laos. I analyzed 192 song bouts from different gibbon groups including 173 phrases of 42 females and 192 phrases of 42 males. Linear discriminant analysis, classification trees, and multidimensional scaling revealed marked separation of groups in the northern and southern populations. Within the 2 geographic populations, there is little variability and the vocal characteristics exhibited no apparent cline. I conclude that the northern and southern geographic populations may represent 2 distinct taxa. I postulate that a taxonal boundary such as large rivers existing between southern Quang Binh province and northern Thua-Thien Hue province in Vietnam and northern Phou Xang He NBCA and southern Dong Phou Vieng NBCA in Laos has limited gene flow between the populations. Differing topographic features could also serve as a selective force for improved sound transmission in a highly territorial species, driving the divergence between the 2 populations.  相似文献   

13.
The alpha taxonomy of the globally distributed shark genus Squalus has been under intense investigation recently, and many new species have been described over the last decade. However, taxonomic uncertainty remains about several taxa. Without consistent nomenclature and the ability to reliably distinguish between the different Squalus species, basic data collection, downstream conservation and management efforts are seriously compromised. To aid in clarifying the taxonomic status of Squalus species in the eastern Atlantic and Mediterranean, we assessed species diversity at the molecular level and evaluated the consistency in species identification in the region. Samples from all nominal Squalus species recognized in the above regions were collected in an international effort and sequenced for regions of the mitochondrial COI and ND2 genes. These data were further analysed alongside publicly available sequences, including 19 of the 26 Squalus species globally recognized, to compare the regional genus‐level diversity with that found elsewhere. Our results confirm inconsistent species identification in the eastern Atlantic and Mediterranean Squalus, particularly concerning S. blainville and S. megalops, and reinforce the need to revise the status of S. megalops and S. mitsukurii as they may include several distinct species distributed around the world. The status of S. blainville is also discussed in the light of the current findings and its problematic taxonomic history.  相似文献   

14.
淫羊藿是我国特有且传统的重要药用植物,逐渐步入大宗品种行列。物种的准确鉴定是药效保障和用药安全的前提,为促进其资源的合理开发和利用,该文对淫羊藿属分类学研究进行系统梳理,并对其中存在的问题及存疑类群进行阐述。淫羊藿属共发表68种,中国58种(85.3%),其中57种为特有分布,具有显著的资源优势。淫羊藿属中国类群的分类学研究较为特殊,共26种集中发表于1990s,共31种(53.4%)为国外研究者命名,且绝大多数依据少量栽培个体命名。由于缺乏广泛的形态调查和性状变异分析,导致大量类群的形态描述不准确或不全面,后续20个类群被归并或降级。依据栽培个体命名的类群是补充描述和分类修订的重点。花色、根茎类型、花茎叶的数量及着生方式等性状在中国类群中存在广泛变异。经分类修订后,该属目前包括46种、1亚种和2变种。淫羊藿属中国组类群仍处于活跃进化中,其形态变异复杂,种间关系无法得到解决,为该属分类的最大挑战。但种质资源的研究和利用需要建立在清晰的分类学基础上。未来研究应基于居群调查,完善各物种的形态描述;在此基础上,整合形态变异特征、地理分布格局和基因序列特征,检测自然种间杂交事件,从而揭示物种的分化和进化历程。  相似文献   

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18.
This study investigated the taxonomic identities and diversity of fungal endophytes isolated from four Rhizophoraceae mangrove plant species, Ceriops tagal, Rhizophora apiculata, R. stylosa and Bruguiera sexangula var. rhynchopetala, using a combination of morphological and molecular approaches. Two hundred ninety-five isolates were classified into 38 taxa by morphological characteristics. The representative 38 isolates from each taxa were selected for further molecular identification using nuclear ribosomal DNA sequences, including both the internal transcribed spacers (ITS1 and ITS2) and the 5.8S gene region. The 38 representative endophytes were identified to various taxonomic levels. These results suggest that Pestalotiopsis and Phomopsis were the most frequent endophytes in the four host species. Some of the endophytes exhibit host and tissue specificity. The colonization frequencies of endophytic fungi in the stems of the four host plants are evidently higher than in the roots. The four Rhizophoraceae mangrove species have low similarities of endophyte communities.  相似文献   

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20.
The genus Lantana has many species complexes, and L. camara is one of the aggressive alien weedy species complexes; species delimitation in these complexes is a nightmare for taxonomists. We examined the diversity in the chemical composition of foliar essential oils among morphotypes of Lantana species complexes inhabiting the same ecological gradient, and its taxonomic and ecological significance. The yields of essential oils varied from 0.1 to 0.79% in foliar hydrodistillates of eleven morphotypes, and a total of 39 chemical constituents were detected by GC/MS. The quantitative and qualitative variability in the composition of essential oils among morphotypes was very high, and hence they represent chemotypes. The diversity observed in the composition of essential oils appears to be of genetic origin and thus of taxonomic value. The formation of distinct clusters and sub‐clusters at high distance cluster combine values also substantiates that the patterns of distribution of chemical constituents among morphotypes can be used in delimiting species and infraspecific taxa within the species complexes. The presence of β‐caryophyllene and other such compounds, which are known to prevent herbivory, in morphotypes of Lantana species complexes suggest that these compounds may provide selective advantage to Lantana over native species in the invasion of new and disturbed habitats.  相似文献   

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