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The retinas of the rear-faned snakes Psammodynastes pulverulentus and Telescopus fallax have been examined. P.pulverulentus has a simplex retina in which the proportion between the numbers of outer and inner nuclear layers is 1:8 which means that P.pulverulentus has a typical diurnal retina. This is further stressed by the find of a shallow, temporal fovea until now only known from a single snake genus, Ahaetulla. T. fallax has a two-tier retina with double cones, with almost the same numbers of outer and inner nuclear layers (1:1.3) which means that T.fallax has a typical nocturnal retina. - The two species are usually regarded as belonging to the boigine (s. str.) snakes, but the presence of double cones in both species and not least the presence of a retinal fovea in Psammodynastes, makes this assignment dubious, and their probable relationships to other Colubroids are discussed.  相似文献   
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我国几种蛇的种下分类   总被引:8,自引:6,他引:2  
赵尔宓 《四川动物》1995,14(3):107-112
本文研究了海南闪鳞蛇、紫沙蛇、山烙铁头蛇与竹叶青蛇各地居群的鳞被特征,采用经典的亚种划分标准,描述了海南闪鳞蛇大陆亚种、紫沙蛇台湾亚种、山烙铁头蛇贡山亚种及竹叶青蛇海南亚种第4个新亚种。  相似文献   
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2020年7月,在四川省凉山彝族自治州雷波县采集到1号蛇类标本,基于形态比较和线粒体细胞色素b(Cyt b)基因序列重建的分子系统关系,确定该标本为屋蛇科(Lamprophiidae)紫沙蛇属(Psammodynastes)的紫沙蛇(P. pulverulentus),系四川省蛇类分布新记录种。基于Cyt b基因序列计算的遗传距离显示,来自四川、广西、广东、云南、海南、福建、纳米比亚的紫沙蛇个体之间遗传距离为3.6%~9.9%,差异较大,其种下关系亟待进一步研究和厘定。  相似文献   
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The morphology of three colubrid snakes, Elaphe subradiata, Psammodynastes pulverulentus, Lycodon aulicus capucinus , and the viper Trimeresurus albolabris , were examined from populations throughout the Lesser Sunda islands using canonical variate analysis. The Lesser Sundas form the western part of two extensive Island chains, the Banda Arcs, that lie between the large islands on the Sunda (Asian) and Sahul (Australian) continental shelves. The snakes of the Lesser Sunda islands show considerable intraspecific variation in morphology. Populations of Trimeresurus albolabris from Wetar and Psammodynastes pulverulentus from Alor show the greatest morphological separation from conspecifics. The most pronounced morphological differentiation in multidimensional space occurs between populations on islands that remained separated throughout the Pleistocene, when sea levels were about 120 m lower than present. Consensus tree evaluation of Mahalanobis distance for populations of these four species and Dendrelaphis pubis on the islands of Lombok, Sumba, Flores, Lembata and Alor, supports the finding that populations from islands that remained isolated throughout the Pleistocene by sea barriers show the greatest morphological divergence.  相似文献   
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