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The genusLens includes 5 taxonomic species:L. culinaris is cultivated andL. orientalis, L. odemensis, L. ervoides, andL. nigricans are wild. All the species are annual and almost exlusively selfers. The wild lentils are distributed over a large geographical area and form small disjunct populations which are composed of a small number of plants. 67Lens populations were assayed electrophoretically for 9 enzyme systems; 15 enzymic genes with 37 alleles were identified. The genetic distances (D) measured between the pairs of populations indicated a significantly greater similarity between populations belonging to the same taxonomic species. Assuming the populations represent a random sample of the variability in each of the species the genetic distances (D) between the 5 taxa were calculated. The shortest genetic distance was found betweenL. orientalis andL. culinaris. Another significant feature of the data is the apparent isolation ofL. nigricans from the other 4 species. The genetic distances between theLens species are compared to the patterns of crossability barriers between them.  相似文献   

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The tropical Indo-Pacific genus Excoecaria L. (Euphorbiaceae) has several closely related species in Australia whose taxonomic relationships are unclear. The most widely reported species in Australia is the mangrove species Excoecaria agallocha L. (type species), whose taxonomic and geographic limits are difficult to define from its closely related species or sub-species. Two additional taxa have also been described but not clearly differentiated from the type species: Excoecaria dallachyana Baillon and Excoecaria ovalis Endl. This project aimed to determine the taxonomic relationships of the Australian Excoecaria species using both leaf morphological data and DNA sequence data from the internal transcribed spacer (ITS) region of ribosomal genes. The nucleotide differences in the examined ITS1 region show that E. agallocha from eastern Australia and E. ovalis from Western Australia respectively, are genetically uniform within species but differ from each other consistently, thus supporting species status. The leaf morphological data also support this view: single factor analysis of variance consistently separated E. ovalis from E. agallocha on the basis of leaf width, leaf length and length of petiole. In contrast, E. ovalis from the Gulf of Carpentaria differs only slightly from E. ovalis in Western Australia, but no evidence was found to suggest any leaf morphological differentiation within this species. The analysis also suggests that E. dallachyana is not closely related to either mangrove species E. agallocha or E. ovalis, despite superficial morphological similarities.  相似文献   

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The Japanese otter (Lutra nippon), once inhabited in most islands of Japan, is now considered as an extinct species. Although the Japanese otter is regarded as a distinct species from the Eurasian otter (L. lutra), its phylogeny and taxonomic status are based on limited information on morphological and genetic data, and thus further clarification is required. Here, we assessed the phylogenetic relationship among the genus Lutra and taxonomic status of L. nippon by using the complete sequences of cytochrome b gene of its holotype. The present phylogenic trees supported that the genus Lutra specimens largely formed monophyletic group, with L. sumatrana as a basal to other Lutra species. Within Lutra species, L. nippon was distantly related with L. lutra. The European otter population of L. l. lutra were clustered together with its subspecies, L. l. chinensis rather than the same subspecies, Korean otter population. The discrepancy between the genetic data and traditional taxonomy justifies the necessity of reexamination of the current subspecific classification system of Eurasian otters. Level of genetic divergence between the holotype of L. nippon and L. lutra was two to three-fold lower than those among the other sister species of the Lutrinae. Based on the level of divergence between the L. nippon and L. lutra, and insufficient evidence of morphological difference between them, it is suggested that designation of Japanese otter as a separate species from L. lutra will be reconsidered.  相似文献   

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The taxonomic placement of four antarctic species of the marine red algal family Phyllophoraceae (Gigartinales) is assessed within a preliminary molecular phylogeny of the family based on direct sequence analysis of the chloroplast gene rbcL. Parsimony analysis of rbcL sequences indicates that Gymnogongrus antarcticus and Gymnogongrus turquetii cluster in a clade consisting predominantly of southern hemisphere species currently placed in Gymnogongrus and Ahnfeltiopsis, whereas Phyllophora ahnfeltioides and Phyllophora antarctica cluster in a separate clade that is widely divergent from the northern hemisphere Phyllophora clade. Results from molecular and morphological data challenge the current taxonomic concept that type of life history is a phylogenetically valid criterion for recognition of genera in the Phyllophoraceae.  相似文献   

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SYNOPSIS. A list is given of 67 named species of Leucocytozoon considered valid at present. Another list is given of 1 reptilian and 146 avian hosts of named species of Leucocytozoon. A 3rd list is given of 34 synonyms. Leucocytozoon has been named from about 0.7% of the approximately 8600 species of birds that exist. The following new taxonomic names are included: L. danilewskyi var. hirundinis Sergent & Sergent, 1905 is emended to L. hirundinis; Saurocytozoon tupinambi Lainson & Shaw, 1969 is changed to Leucocytozoon (Saurocytozoon) tupinambi (Lainson & Shaw, 1969).  相似文献   

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Morphological, behavioural and biochemical characters of 9 cosmopolitan, benthic species of the nemertean genus Lineus are used both to clarify their taxonomy and to discuss their phylogenetic relationships. Data analysis shows that all fissiparous species of Lineus collected in the world seas up to date can be placed in a single species, L. sanguineus, with three recognisable subspecies, L. s. sanguineus, L. s. nigricans and L. s. pseudolacteus. These taxa were originally described as separate species mainly according to their geographic origin under the names L. sanguineus (shores of European seas), L. socialis (Atlantic North American shores), L. vegetus (Pacific North American shores), L. pseudolacteus (shores of the English Channel) and L. nigricans (Mediterranean coasts of Italy and France). Examination of the character value matrix suggests a phylogenetic tree developing from two ancestral branches. The first branch includes the two related species L. ruber and L. viridis, the second branch the three species L. longissimus, L. lacteus and L. sanguineus. This approach to the taxonomic and phylogenetic relationships of Lineus nemertean species is in agreement with the intra- and interspecies histocompatibility data in nemerteans: (i) grafts transplanted from donors to recipients of the same species succeed and grafts transplanted from donors to recipients of different species fail; (ii) grafts are rejected more rapidly when the donor and recipient species diverged earlier in evolution and, a contrario, grafts are accepted better when the donor and recipient species have been more recently isolated.  相似文献   

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Analyses were made of the allozyme frequencies of sympatric populations of the capitulum weevils L. latus Herbst and Larinus cyarae F. in Greece. It was found that the two taxa are genetically isolated and that they can therefore be considered as separate species. This complemented ecological data showing separation of the L. latus and L. cynarae populations by their choice of Onopordum illyricum L. and Cynara cardunculus, respectively, as hosts. Onopordum spp. are serious weed problems in Australia while Cynara contains several crop plants. L. latus is a potential biological control agent of Onopordum spp., but its use had been compromised by the uncertainty of the taxonomic distinctness from L. cynarae, biotypes of which are pests of artichoke Cynara scolymus L. Clarification of its taxonomic status lifts these reservations and clears the way for the introduction of L. latus into Australia for the biological control of Onopordum thistles.  相似文献   

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The paper presents the results of the study on seed morphology of four following Ornithogalum species: O. boucheanum Asch., O. nutans L., O. pyrenaicum L., and O. umbellatum L. Several macro-and micro-morphological characters were observed using stereoscope and scanning electron microscope. Differences were found especially in micromorphological characters of the seed surface, the shape of raphe and micropylar pole. These characters can be used as an additional taxonomic criterion at specific level for this genus. Only the seeds of O. boucheanum and O. nutans — two closely related and morphologically very similar species are practically undistinguished.  相似文献   

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The recent revision on the taxonomic status of Lepadogaster lepadogaster resulted in the division of this species into L. lepadogaster and L. purpurea, the clarification of each species’ distribution ranges and the elimination of L. zebrina (now in synonymy with L. lepadogaster). This new taxonomic status led to the need of clarifying the early development of the two species. Embryonic development lasted 21 days in L. purpurea at a mean temperature of 14.2°C, and 16 days in L. lepadogaster at a mean temperature of 16.5°C. Newly hatched larvae of both species measured 5.2 mm, had the mouth and anus opened, pigmented eyes and almost no yolk. At hatching and throughout development the two species can be distinguished by the ventral pigmentation which is absent in L. purpurea. The change to a benthic mode of life was gradual in both species, with larvae increasingly spending more time close to the bottom until definitely settling. Larval development lasted 33 days in L. purpurea at a mean temperature of 14.6°C and 18 days in L. lepadogaster at a mean temperature of 16.5°C. Locomotion and foraging behaviours are described for both species. L. lepadogaster showed a higher frequency of swimming and foraging behaviour when compared with L. purpurea.  相似文献   

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本文报道了甘肃小陇山地区鸢尾科(Iridaceae)鸢尾属(Iris L.)植物2个新分布记录种:长柄鸢尾(Iris henryi Baker)和薄叶鸢尾(Iris leptophylla Lingelsh.)。通过整理重新编制了小陇山地区鸢尾属植物的分种检索表。两种植物的发现进一步丰富了鸢尾属在全国的分布格局和本属在秦岭地区的种类,并为小陇山地区的物种多样性研究提供了新的分布信息。凭证标本存放于陇南师范高等专科学校植物标本室。  相似文献   

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通过形态学及化学研究,结合nrDNA ITS序列的系统发育分析,该文报道了茶渍属(Lecanora Ach.)和石蕊属(Cladonia P. Browne)地衣4中国新记录种:莱氏茶渍(Lecanora layana Lendemer)、白头山茶渍(L. baekdudaeganensis B. G. Lee&Hur)、伪银茶渍(L. pseudargentata Lumbsch)和草皮石蕊[Cladonia caespiticia (Pers.) P. Gaertn., B. Mey&Scherb.]。该文对这些物种的分类学特征进行了详细描述,并与相似种进行了对比,同时提供了各种的地理分布图和形态图。这为中国茶渍属和石蕊属地衣物种多样性及资源利用提供了基础资料。  相似文献   

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