8 resultados para morphometrics

em Chinese Academy of Sciences Institutional Repositories Grid Portal


Relevância:

20.00% 20.00%

Publicador:

Resumo:

Recent field studies suggest that Macaca thibetana, a large endemic Chinese macaque, may be quite folivorous, distinguishing it from most other macaque species, which tend to be primarily frugivorous. To understand how this diet affects its masticatory system, we conducted a comparative morphometric study of mandibular dimensions. We took linear measurements from male and female mandibles of this species as well as four other macaques-M. fascicularis, M. nemestrina, M. arctoides, and M. assamensis-and four species of Presbytis-P. obscura, P. rubicunda, P. cristata, and P. phayrei-and subjected to them to a variety of analyses. Based on analyses of variances and discriminant analyses on each sex individually, the mandible of M. thibetana corresponds to expected patterns for folivorous primates with respect to its wide condyles and thick corpora: However, the height of the corpus and symphysis are lower, and the anteroposterior length of the condyle is longer than predicted for a folivore. In addition to interpretations specifically relating to M. thibetana, we also discuss the functional morphology of the other species in light of what is published about their diets.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Eastern and western populations of the ranid frog Odorrano chapaensis from Vietnam and China are readily differentiated by morphology and mtDNA, and weakly differentiated by morphometrics. The western population contains the type localities of O. chopoens

Relevância:

10.00% 10.00%

Publicador:

Resumo:

A new species of horseshoe bat (Chiroptera: Rhinolophidae) is described from southwestern China. The presence of a wedge-shaped sella and pointed connecting process of the nose leaf aligns the new species to the landeri group in the Afro-Palearctic lineag

Relevância:

10.00% 10.00%

Publicador:

Resumo:

鱇鱼良白鱼(Anabarilius grahami)、大头鲤(Cyprinus pellegrini)均隶 属于鲤形目(Cypriniformes)鲤科(Cyprinidae),是中国特有鱼类之一,仅在 云南省分布,是抚仙湖和星云湖各自的主要经济鱼类。 本研究首先基于线粒体控制区全序列来研究我国抚仙湖鱇鱼良白鱼自然种群 及人工驯养种群的遗传多样性,发现鱇鱼良白鱼人工驯养种群遗传多样性较高,种 群复壮程度良好;自然种群遗传多样性匮乏,可能种群经历过“建群者效应”和 “瓶颈效应”;并且各自然地理居群具有广泛的基因交流,不存在遗传分化,建 议应被当成一个管理单元进行整体保护;同时,对照其他已报道的鱼类控制区结 构,对鱇鱼良白鱼控制区结构进行了分析,识别了其终止序列区、中央保守区和保 守序列区,找到了终止相关的序列TAS 以及保守序列(CSB-F、CSB-D、CSB-1、 CSB-2、CSB-3)。 其次,采用主成分分析方法对大头鲤及与其相关的三个鲤鱼类群——杞麓鲤 (Cyprinus chilia)、华南鲤(Cyprinus rubrofuscus)及柏元鲤(Cyprinus carpio var. yuankiang×Cyprinus pellegrini)进行了可量性状分析,了解了 不同类群的外部差异;依据主成分分析结果,运用逐步判别方法从37 个可量性 状中筛选出能有效鉴定大头鲤的10 项形态指标:头长、吻长、吻宽、眼间距、 尾柄高、头背部末端到腹鳍起点距离、背鳍起点到腹鳍起点距离、背鳍起点到臀 鳍起点距离、背鳍末端到尾鳍背部起点距离、尾鳍背部起点到臀鳍起点距离,这 些形态指标可以简单易行的从不同鲤鱼群体中筛选出大头鲤个体;同时通过60 年代、80 年代及2007 年大头鲤的对比,发现大头鲤的外部形态已经发生了很大 变化总体趋势是头部更加宽大,身体更加延长。 最后,利用线粒体控制区序列,并结合Genbank 上的已发布的鲤鱼线粒体控 制区序列,对从星云湖采集的62 尾个体进行了分子系统学研究。结果显示:星 云湖土著鲤鱼已经被大规模非土著鲤鱼入侵,大头鲤仅以杂交品系存在,星云湖 土著鲤鱼面临严重危机,迫切需要进行有效保护。

Relevância:

10.00% 10.00%

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:

10.00% 10.00%

Publicador:

Resumo:

Gobiocypris rarus, a small, native cyprinid fish, is currently widely used in research on fish pathology, genetics, toxicology, embryology, and physiology in China. To develop this species as a model laboratory animal, inbred strains have been successfully created. In this study, to explore a method to discriminate inbred strains and evaluate inbreeding effects, morphological variation among three wild populations and three inbred stocks of G. rarus was investigated by the multivariate analysis of eight meristic and 30 morphometric characters. Tiny intraspecific variations in meristic characters were found, but these were not effective for population distinction. Stepwise discriminant analysis and cluster analysis of conventional measures and truss network data showed considerabe divergence among populations, especially between wild populations and inbred stocks. The average discriminant accuracy for all populations was 82.1% based on conventional measures and 86.4% based on truss data, whereas the discriminant accuracy for inbred strains was much higher. These results suggested that multivariate analyses of morphometric characters are an effective method for discriminating inbred strains of G. rarus. Morphological differences between wild populations and inbred strains appear to result from both genetic differences and environmental factors. Thirteen characters, extracted from stepwise discriminant analysis, played important roles in morphological differentiation. These characters were mainly measures related to body depth and head size.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

We investigated the effects of the timing of first feeding (larvae in F0, F1, F2, F3 and S were first fed on day 3, 4, 5, 6 days after hatching (DAH) and unfed, respectively) on feeding, morphological changes, survival and growth in miiuy croaker larvae at 24A degrees C. The fed larvae initiated feeding on 3 DAH and reached point of no return (PNR) on 6 DAH. Larvae in F0 and F1 groups survived apparently better than F2 group at the end of the experiment on 36 DAH. High larval mortality occurred from 3 to 7 DAH in all feeding groups, accounting for 40% (F0, F1 and F2 groups) to 90% (F3 and S groups) of the total mortality. Larvae in F0 and F1 groups grew better than F2 group throughout the experiment. Eye diameter, body height, head height and mouth gape of the first feeding larvae were more sensitive to starvation than other morphometrics and could be used as indicators for evaluating their nutritional status. Results indicated that delayed first feeding over 1 day after yolk exhaustion could lead to poor larval survival and growth. To avoid starvation and obtain good growth in culturing, larvae feeding should be initiated within 1 day after yolk exhaustion at 24A degrees C.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Protospathidium serpens (Kahl, 1930) is frequent in semiterrestrial and terrestrial habitats worldwide. Conventionally, all populations are considered as conspecific because they have very similar overall morphologies and morphometrics. We studied in detail not only the morphology of the vegetative cells but also the resting cysts using live observation, protargol impregnation, and scanning electron microscopy. These revealed a cryptic diversity and biogeographic pattern in details of the dorsal brush and cyst wall morphology. The cyst wall is spiny in the Austrian specimens, while smooth in the South African and Antarctic populations. Accordingly, P. serpens consists of at least two species: P. serpens (with spiny cyst wall) and P. fraterculum n. sp. (with smooth cyst wall); the latter is probably composed of two distinct taxa differing by the absence (South African)/presence (Antarctic) of a monokinetidal bristle tail in brush row 3, the number of dikinetids comprising brush row 1 (seven versus three), and the total number of brush dikinetids (29 versus 17). Protospathidium serpens is neotypitied with the new population from Austria. The significance of resting cyst morphology is discussed with respect to alpha-taxonomy and overall ciliate diversity.