94 resultados para Cyprinidae - Ecology - Malaysia


Relevância:

20.00% 20.00%

Publicador:

Resumo:

We determined the complete mitochondrial DNA sequences for two species of surface- and cave-dwelling-cyprinid fishes, Sinocyclocheilus grahami and S. altishoulderus. Sequence comparison of 13 protein-coding genes shows that the mutation pattern of each single gene is quite similar to those of other vertebrate animal species. Analysis of the ratios of Ka/Ks at these loci between Sinocyclocheilus and two other cyprinid species (Cyprinus carpio and Procypris rabaudi) show that Ka/Ks ratios are differed, consistent with purifying selection and variation in functional constraint among genes. Bayesian analysis and maximum likelihood analysis of the concatenated mitochondrial protein sequences for 14 cyprinid taxa support the monophyly of the family Cyprininae, and further confirm the monophyly of the genus Sinocyclocheilus. The two Sinocyclocheilus species fall within the Cyprinion-Onychostoma lineage, including Cyprinus, Carassius, and Procypris, rather than among the Barbinae, as previously suggested on morphological grounds.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

1. The stripe-backed weasel Mustela strigidorsa is one of the rarest and least-known mustelids in the world. Its phylogenetic relationships with other Mustela species remain controversial, though several unique morphological features distinguish it from congeners. 2. It probably lives mainly in evergreen forests in hills and mountains, but has also been recorded from plains forest, dense scrub, secondary forest, grassland and farmland. Known sites range in altitude from 90 m to 2500 m. Data are insufficient to distinguish between habitat and altitudes which support populations, and those where only dispersing animals may occur. 3. It has been confirmed from many localities in north-east India, north and central Myanmar, south China, north Thailand, north and central Laos, and north and central Vietnam. Given the limited survey effort, the number of recent records shows that the species is not as rare as hitherto believed. Neither specific nor urgent conservation needs are apparent.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

运用多变量形态度量学和框架结构形态学的方法,测量了采自滇池流域6个不同地点的149尾滇池金线鲃(Sinocyclocheilus grahami)的标本.应用多变量形态度量学分析,选择了20个框架结构性状和19个常规性状,进行主成成分分析.主成成分分析结果的散布图显示,6个不同地点的标本聚在一起没有分开,表明滇池金线鲃的各居群之间在可数性状和可量性状上均未表现出明显的差异,说明滇池金线鲃在形态上还未发生明显的种下分化.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

2003年4月,于怒江二级支流镇康县境内的大叉河中采获一批墨头鱼属(Garra)鱼类标本,经鉴定为一新种,命名为怒江墨头鱼(G.nujiangensis Chen and Yang,sp.nov.).该新种主要鉴别特征:围尾柄鳞12~14:侧线鳞48~50:在小个体中有一对微小的吻须;背鳍分支鳍条8~9;侧线上鳞5~6,侧线下鳞3~4;体高小于头长;臀鳍起点处的小于眼后至吻端的距离;腹鳍前长为体长的50.0%~53.7%;肛门前长为体长的58.9%~63.9%:体宽为体长的16.7%~19.6%:体高为体长的19.2%~22.6%.本研究证实,在缺须的墨头鱼属的一些物种中,如高体墨头鱼(G.alticorpora)和怒江墨头鱼(G.nujiangensis),其幼体中往往具有一对很小的吻须.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

以雅罗鱼亚科为外群,采用分支系统学的原理和方法对亚科17个属(须鳊属除外)进行了系统发育和动物地理学的分析。结果表明,(1)亚科这17个属为一个单系群,并由4个较小的单系群组成;(2 )亚科现在的地理分布格局除源自离散事件外,主要源于扩散事件。亚科的特征演化还表明,东亚地区地质历史的反转演化和平行演化可能在亚科系统发育过程中起了重要的作用。

Relevância:

20.00% 20.00%

Publicador:

Resumo:

A total of 62 variable osteological and external characters was found among the five currently recognized species of Epalzeorhynchos. When the genera Crossocheilus and Paracrossocheilus are combined as the outgroup, only 30 of these characters can be polarized. This includes six autapomorphies. The remaining 24 polarized characters form a data matrix which yields a single, 26-step tree with a Consistency Index (CI) of 1 and a Retention Index (RI) of 1, The analysis was also performed on a combined dataset in which the 32 unpolarized characters (characters for which the combined outgroup was dimorphic) were added and coded as missing data (i.e., "?"), Analyzing this data matrix with all multistate characters ordered generates the same single most-parsimonious tree with a length of 63 steps, a CI of 0.98 and a RI of 0.97, When either Crossocheilus or Paracrossocheilus is used as the sole outgroup, the same single most-parsimonious tree is produced although the numbers of informative characters and some of the polarities differ. Evidence is presented to support the following hypotheses: (1) E, kalopterus + E, frenatus + E. bicolor + E. munensis form a monophyletic group; (2) E. frenatus + E, bicolor + E, munensis form a monophyletic group with E, kalopterus as its sister group; this speciation event is congruent with the predictions of vicariant speciation mode I; and (3) E. bicolor and E. munensis are sister groups, again congruent with vicariant speciation mode I, Evidence presented here also supports the zoogeographical hypothesis that the faunas of the Indochinese region and the Greater Sundas are more closely related to each other than either of them is to the lower Salween basin fauna and that the lower Mekong, Chao Phraya, and Mac Khlong basin faunas are more closely related to each other than any of them is to the Greater Sundas, In addition, the monophyly of Epalzeorhynchos is also preliminarily discussed by including either Paracrossocheilus or Crossocheilus in the ingroup. It is demonstrated that E. bicornis clusters with Paracrossocheilus when Paracrossocheilus is included in the ingroup. It seems likely that the taxonomic position of E. bicornis will be resolved as more fishes of the Crossocheilus group are included in future studies.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Fishes of the genus Crossocheilus in China is reviewed on the basis of specimens in Kunming Institute of Zoology, Chinese Academy of Sciences. Crossocheilus multirastellus is described from the upper Irrawaddy and upper Salween rivers. It is distinguished from all of its congeners by having two black longitudinal stripes on sides of body, 36-38 lateral line scales, 18-25 gill rakers, anus at midpoint between ventral fin and anal fin insertions, ventral fin extending over anus, a large deep blue rhomboid spot above the pectoral fin, and a straight mouth gape almost equal to head width. There are presently two species of Crossocheilus fishes in China. Crossocheilus bamaensis Fang and Crossocheilus liuchengensis Liang, Liu & Wu are recognized here as members of the genus Sinocrossocheilus.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

All Sinocrossocheilus species, except S. microstomatus, are reviewed. Four new species, S. labiata, S. papillolabra, S. nigrovittata, and S. longibulla, are described. The genus Sinocrossocheilus differs from other genera of Cyprinidae by the last simple dorsal fin ray being unserrated and unossified, the last unbranched anal fin ray being unserrated and unossified, the 5-branched anal fin rays, the mouth gap being inferior, the rostral cap covering the lower jaw and connecting directly with the lower lip, a row of fleshy lobes on the lower jaw, and a cloudy black spot above the pectoral fin. Sinocrossocheilus labiata is small and has 22 predorsal scales; S. longibulla has a very large air bladder; S. papillolabra possesses a well-developed ventral fin and a wide band covered by fleshy papillae on the lower lip; and S. nigrovittata possesses black longitudinal stripes along the lateral line. Crossocheilus bamaensis and Crossocheilus liuchengensis are transferred to the genus Sinocrossocheilus. Sinocrossocheilus species are endemic to the central and eastern Yunnan-Guizhou Plateau of China, where river systems are anfractuous, including seasonal rivers, cave rivers, underground rivers, and streamlets between mountains. These separated rivers probably provide conditions for the allopatric speciation of the Sinocrossocheilus.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Ying-Gui Dai and Jun-Xing Yang (2003) Phylogeny and zoogeography of the cyprinid hemicultrine group (Cyprinidae: Cultrinae). Zoological Studies 42(1): 73-92. The hemicultrine group consists of middle-sized cyprinids in Asia which taxonomically belong to the subfamily Cultrinae in the Cyprinidae (Cypriniformes), but there has been no convincing generic phylogenetic hypothesis proposal so far. On the basis of a morphological study of 65 specimens soaked in formalin and 14 skeletal specimens of 8 species in 6 genera within the hemicultrine group as an ingroup, a 70-character matrix was obtained. The generic phylogenetic relationships of the hemicultrine group are hypothesized with the matrix by the method of cladistic analysis. When the species Rasborinus lineatus or Cultrichthys erythropterus is used as the sole outgroup, the matrix gives the same single most-parsimonious tree of generic phylogenetic relationships within the hemicultrine group which shows that the hemicultrine group forms a monophyletic group. However, when Rasborinus lineatus is used as the sole outgroup and Cultrichthys erythropterus and Paralaubuca barroni are included in the ingroup, the hemicultrine group is validated to represent a paraphyletic group, and the hemicultrine group and the genus Paralaubuca form a monophyletic group. The tree of generic relationships and zoogeography of the monophyletic group comprising the hemicultrine group and the genus Paralaubuca suggest the following: (1) The monophyletic group comprises 2 smaller monophyletic groups: the genera Hemiculterella + Pseudohemiculter + Hainania and the genera Hemiculter + Paralaubuca + Pseudolaubuca + Toxabramis. (2) The sister groups of the monophyletic group show both overlapping and vicariant distribution patterns; therefore the generic distribution pattern of the monophyletic group maybe have resulted from both dispersal and vicariance events. (3) The monophyletic group probably originated on the Asian mainland from the Yangtze River to the Pearl River and on Hainan Island in China. (4) The monophyletic group probably originated after the Japanese Archipelago was separated from the Asian mainland at the beginning of the Quaternary Period in the Cenozoic but before Taiwan, Hainan Island, and Indonesia were completely isolated from the Asian mainland after the ice age in the Quaternary Period. (5) Speciation of the genus Hemiculter should have been the earliest, and those of the genera Paralaubuca, Pseudolaubuca, and Hainania ought to be the latest in the process of evolution of this monophyletic group. http://www.sinica.edu.tw/zool/zoolstud/42.1/73.pdf.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

A new species of cyprinid fish, Mekongina lancangensis, is described from the upper Mekong River drainage in Southern Yunnan, China. The new species is distinguished from the other species of Mekongina occurring in the lower Mekong River drainage by posse

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The identity of Schizothorax griseus Pellegrin, 1931, is clarified and the species redescribed. Three new species previously identified as S. griseus are described: S. nudiventris, from the Lancang Jiang, China; S. heterophysallidos, from the Nanpan Jiang

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The black-crested gibbon, Hylobates concolor, is one of the few species of gibbons that has not yet been the subject of a long term field study. Field observations in the Ai Lao and Wu Liang Mountains of Yunnan Province, China indicate that in this area the habitat and ecology of this species differ markedly from those of other gibbons that have been studied to date. These differences are correlated with some behavioral differences. In particular, these gibbons apparently have greater day ranges than other gibbons. It has also been suggested that this species lives in polygynous groups. To demonstrate this requires observation of groups with two or more females with young. Our own observations and those from other recent studies suggest that there are alternative explanations consistent with available data.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The Yunnan snub-nosed monkey (Rhinopithecus bieti), an endangered species in China, has received more protection in theory than in practice. Therefore it is on the very verge of extinction. The population of the species was estimated less than 2,000 individuals spread in 19 distinct groups. It was confirmed that the monkey was confined to the Yunling Mountain System, the area between the Yangtze River (Changjiang, aka Jinshajiang) to the east and the Mekong River (Lancangjiang) to the west. We further concluded that a lowland belt to the east, about 100 km long and 20 - 30 km wide was not suitable habitat for the monkeys, and appeared to serve as the natural ecogeologic barrier for the species. Our results indicated that the southern limit of the distribution was at Longma (26-degrees 14'N), and that the northern limit of the distribution was at Xiaochangdu (29-degrees 20'N). The distribution area of the species was substantially smaller than previously estimated. There were substantial ecological differences between the southern and northern parts of the species range. The monkey was found only in fir-larch forest.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Molecular phylogeny of three genera containing nine species and subspecies of the specialized schizothoracine fishes are investigated based on the complete nucleotide sequence of mitochondrial cytochrome b gene. Meantime relationships between the main cladogenetic events of the specialized schizothoracine fishes and the stepwise uplift of the Qinghai-Tibetan Plateau are also conducted using the molecular clock, which is calibrated by geological isolated events between the upper reaches of the Yellow River and the Qinghai Lake. Results indicated that the specialized schizothoracine fishes are not a monophyly. Five species and subspecies of Ptychobarbus form a monophyly. But three species of Gymnodiptychus do not form a monophyly. Gd. integrigymnatus is a sister taxon of the highly specialized schizothoracine fishes while Gd. pachycheilus has a close relation with Gd. dybowskii, and both of them are as a sister group of Diptychus maculatus. The specialized schizothoracines fishes might have originated during the Miocene (about 10 MaBP), and then the divergence of three genera happened during late Miocene (about 8 MaBP). Their main specialization occurred during the late Pliocene and Pleistocene (3.54-0.42 MaBP). The main cladogenetic events of the specialized schizothoracine fishes are mostly correlated with the geological tectonic events and intensive climate shift happened at 8, 3.6, 2.5 and 1.7 MaBP of the late Cenozoic. Molecular clock data do not support the hypothesis that the Qinghai-Tibetan Plateau uplifted to near present or even higher elevations during the Oligocene or Miocene, and neither in agreement with the view that the plateau uplifting reached only to an altitude of 2000 in during the late Pliocene (about 2.6 MaBP).