中国水域江豚颅骨的地理变异

本文根据１４４号江豚骨骼标本（其中长江种群标本４０号,黄海种群标本５９号,南海种群标本４５号）,选用４２项颅骨测量变量,研究了颅骨在各地理种群之间的差异。ｔ－检验和协方差分析表明：长江江豚成体的颅基长比较小。南海种群吻长小于其它两个种群,而吻宽则最大,长江种群次之,黄海种群最小。黄海种群的前颌骨宽、颧宽、眶前突最大宽和眶后突最大宽比其它两个种群的小。黄海种群的上颌齿较多,而南海种群则下颌齿较多,长     

菲氏叶猴和黑叶猴的齿弓

本文对菲氏叶猴(Presbytis phayrei)和黑叶猴(Presbytis francoisi)成年头颅的上下齿弓进行了比较研究。结果说明,在黑叶猴中,由于与颧骨眶低点相连,垂直于M~3根部齿弓的距离非常显著地大于菲氏叶猴,因而其面颅体积显著性地大于菲氏叶猴,而且菲氏叶猴的面颅比黑叶猴更为凸出。在对齿弓的对称性研究时发现,除黑叶猴的上齿弓向右偏离外,别的都向左侧发生偏离。这种偏离似乎与用手优势相联系。在进行多变量分析时发现,两种叶猴所研究的变量下颌的比上颌的发生了更大的变异。进一步证实了运动的器官比固定的器官易产生变异。     

中国西南部明纹花鼠三个亚种的分化

明纹花鼠是东南亚地区的特有种,在中国有3亚种（阿萨姆亚种、滇西亚种、滇南亚种）,分布于藏东南、云南西南部和南部。以往主要根据外部形态特征进行分类。为探讨3亚种头骨性状的差异,在测量15个陛状的基础上,运用统计分析软件SPSS 11．0对其可测量性状进行多变量分析。结果及推测如下：①明纹花鼠3个亚种的地位是确定的。②在头骨15个性状中,两两亚种之间具有显著差异的性状：阿萨姆亚种与滇西亚种有8个（枕鼻长、吻宽、颤宽、眶间宽、后头宽、鼻骨宽、下齿列、下颌骨高）;阿萨姆亚种与滇西亚种有7个（颅全长、枕鼻长、颧宽、眶间宽、后头宽、下颌高、下颌骨高）;滇西亚种与滇南亚种有4个（吻宽、后头宽、鼻骨宽、下颌高）。③滇南亚种与滇西亚种之间的亲缘关系近：于两者各自与阿萨姆亚种之间的亲缘关系。     

太行山猕猴牙齿与颅长的相关性

对太行山猕猴牙齿有关变量做了测量,统计,并就其与颅骨长间的异速生长和相关程度进行了研究。结果表明,太行山猕猴牙齿具有明显的性别差异,雄性牙齿的变异程度在犬齿和中央门齿表现尤为突出。在线性型或面积方面,雄性牙齿的异速生长均快于雌性和雄＋雌,此与其生活史对策相适应,在雄性,雌性或雄＋雌,下颌齿变量与颅骨长的相关程度比上颌更为密切,与有关资料的比较表明,太行山猕猴与金丝猴之间的差异小于与菲氏叶猴之间的差异。     

太行山猕猴颅骨的形态学及多变量研究

对２１例成年太行山猕猴颅骨的主要形态特征进行了描述和测量,并进行了初步的统计学分析。结果表明,成年太行山猕猴颅骨在耳点间宽（Ｘ１３）、上面宽（Ｘ１９）、左眶宽（Ｘ２７）、右眶宽（Ｘ２８）、两眶宽（Ｘ３７）等变量间存在显的性别差异。与湘鄂、闽粤猕猴颅骨有关变量相比,有显的不同。３个猕猴种群的聚类分析结果显示,湘鄂、闽粤猕猴种群间的生物学距离相对较近,而太行山猕猴与前二种种群间的距离均较远。太行山     

中国水蛇头部动脉大体解剖观察

以２０个已作血管注射的蛇头进行解剖学观察。结果：外颈动脉分布于下颌,主要分支有活动脉气管动脉、下颌各肌肉的动脉、齿动脉;内颈动脉则主要分布于上颌和脑内,分支有腭浅动脉、颞动脉、口腔动脉、咽动脉、背支（即脑内动脉）、腹支（即上颌动脉）等,静脉大与同名动脉伴行,齿静脉单独进入内颈静脉是其特点。     

猕猴颊齿大小的性差研究初报

对28例太行山成年猕猴(♂10,♀18)的上、下颌颊齿齿冠面积进行测量。运用SPSS 10.0统计软件的多变量分析,选择有关颊齿变量建立性别判别函数。结果表明:猕猴颊齿具有明显的性差。选择不同的变量和选择不同的判别函数其性别正确判别率不同。上、下颌颊齿的性差有一定差异。使用逐步判别法建立判别函数,其性别正确判别率上颌颊齿为89.3%,下颌颊齿为92.3%。     

金丝猴牙齿与体重间的相关性研究

对金丝猴牙齿与体重间关系的研究结果表明,在雄性中,无论是线性还是面积与颅长之间的相关关系均较雌性的更为紧密。而且,随着体重的增加,雄性牙齿的近中远中长(M/D)也比雌性的增长较快。在上、下颌中,上颌牙齿与颅长的关系表现出更强的相联性。与其他灵长类相比较,金丝猴在取食和咀嚼过程中主要利用颊齿;大的个体具有大的犬齿及一定比例的臼齿面积和齿弓(牙合)面面积;上齿弓(牙合)面面积大于下齿弓(牙合)面面积。也就是说上齿弓提供了比下齿弓更大的咀嚼面积。金丝猴牙齿与体重间的关系位于猴类和人猿类之间,更接近于大猩猩(Gorilla)、疣猴(Colobus)和猕猴。     

新疆哈密寒气沟墓地出土颅骨的研究

新疆考古所文物队于１９９４年在哈密地区寒气沟墓地发掘出４座墓葬共３具颅骨,其中一具男颅,两具女颅,编号为９４ＨＴＢＩＭ３：Ｂ（男颅）、９４ＨＴＢＨＩＭ２：Ｂ（女颅）、９４ＨＴＢＨＩＭ３：Ａ（女颅）。据文物判定其时代为春秋时期。在考古文化上与焉布拉克相...     

成年太行山猕猴头骨变量相关性及比较研究

对 12例成年太行山猕猴头骨变量进行测量和统计学分析的结果表明 :在耳点间宽 (X6 )、上面宽(X10 )、左眶宽 (X15)、两眶宽 (X16 )、上颌齿槽弓长 (X2 1)等变量间存在显著的性别差异。相关性分析结果显示 ,下颌角度 (X34 )、枕骨大孔长 (X36 )、枕骨大孔宽 (X37)分别与其它变量间相关不显著 ;颅骨最大长(X1)、眉间点 -人字点长 (X2 )、中眶间宽 (X13)分别与其它变量间相关性少数达到显著或极显著 ;其余头骨变量间相关性绝大多数都达到显著或极显著水平。与湘鄂、闽粤猕猴颅骨有关变量相比 ,有显著的不同。三个猕猴种群的聚类分析结果显示 ,湘鄂、闽粤猕猴种群间的生物学距离相对较近 ,而太行山猕猴与二种群间的距离均较远。     

Variation in guenon skulls (II): sexual dimorphism

Patterns of size and shape sexual dimorphism in adult guenons were examined using a large sample of skulls from almost all living species. Within species, sexual dimorphism in skull shape follows the direction of size-related shape variation of adults, is proportional to differences in size, and tends to be larger in large-bodied species. Interspecific divergence among shape trajectories, which explain within species sex differences, are small (i.e., trajectories of most species are nearly parallel). Thus, changes in relative proportions of skull regions that account for the distinctive shape of females and males are relatively conserved across species, and their magnitude largely depends on differences in size between sexes. A conservative pattern of size-related sexual dimorphism and a model of interspecific divergence in shape which strongly reflects size differences suggest a major role of size and size-related shape variation in the guenon radiation. It is possible that in the guenons, as in the neotropical primates (with whom they have obvious parallels), size has helped to determine morphological change along lines of least evolutionary resistance, influencing sexual dimorphism. In Miopithecus and Erythrocebus, the smallest and largest guenon genera, it is likely that the interaction of ecology and size contributes significantly to patterns of sexual dimorphism. The results of this study thus emphasise the need to consider allometry and size alongside ecology and behaviour when examining primate sexual dimorphism.     

Craniodental variation in the African macaque, with reference to various Asian species

Based on twenty-seven craniodental measurements and ratios derived from them, the relationship between the African macaque (M. sylvanus) and the others in Asia were examined with principal components analyses (PCA) and Euclidean distance analysis based upon prior discriminant function analyses (DFA). Results based on analyses of raw measurements indicate that the variation between species lies in the first axis of PCA; the species are dispersed according to their differences in size. The variation between sexes (sexual dimorphism) lies in the second axis. In the analyses of ratio variables, though these two patterns of separation remain orthogonal, they lie at approximately forty-five degrees to each axis. Variables relating to anterior teeth were found to play an important role in variation analysis, and this may be related to the special food preferences of these monkeys: more frequent usage of the incisor teeth for processing frugivorous diets than in other primates that are mainly folivorous. The results from Euclidean distance analyses indicate that the average distance of species within the Asian group is shorter than that between Asian and African groups regardless of sex and variable type. In addition the variation between African and Asian groups is larger than that within Asian group. Thus, it is reasonable to suggest that the African macaque has a range of measurements and ratios quite distinct from the species found in Asia (though the greatest separations result from the analyses of ratio data). These results therefore support the view that M. sylvanus may be regarded as an independent species group in the genus Macaca as proposed by Delson [1980].     

Sexual dimorphism in the canines and skulls of carnivores: effects of size, phylogency, and behavioural ecology

Sexual dimorphism in craniodental features is investigated in a sample of 45 carnivore species in relation to allometry, phylogeny, and behavioural ecology. Dimorphism is more pronounced in both upper and lower canine size and strength than in carnassial size, skull dimensions and biomechanical features, but all dimorphism indices covary. As with most morphological characters, differences in canine sexual dimorphism are significantly related to phylogeny, estimated from either taxonomic rankings or a limited matrix of molecular distances; in particular, mustelids, felids and procyonids are more dimorphic than other carnivore families. Thus, because of problems related to species dependence in comparative data, remaining analyses are based on phylogenetically transformed values using a spatial autoregressive method.
In contrast to other mammals, sexual dimorphism in carnivore canines is not correlated with differences in body weight, skull length or basicranial axis length. Nor is it correlated with categorical variables of activity pattern, habitat, or diet. In our Carnivore sample, canine dimorphism is related only to breeding system: uni-male, group-living (harem) species have significantly greater canine dimorphism than multi-male, multi-female groups and monogamous pair-bonding species. By contrast, dimorphism in carnassial size is related to dietary differences, specifically greater dimorphism in meat-eating species, and not breeding patterns. Dimorphism in estimates of jaw muscle size suggest functional demands from both diet and breeding type. It is concluded that, befitting patterns of heterodont dentition, sexual selection influences variation in canine dimorphism while feeding ecology is related to carnassial dimorphism.     

Patterns of morphological discrimination in selected human tarsal elements

A suite of measurements was collected from the talus, calcaneus, navicular, and cuboid of humans from Southern China, Victorian Britain, Roman Britain, and Zulu tribes people from the Republic of South Africa. Univariate and multivariate statistical analyses of dimensions of individual foot bones revealed subtle but distinct patterns of morphological discrimination on the basis of sex and size on the one hand, and geographical relationships on the other. These differences are largely expressed in the first three canonical variates of the multivariate analyses: the first axis expresses both sex and size differences, and the second and third, geographical group differences. Confirmation of morphological patterns obtained from individual multivariate analyses was provided by an integrated analysis of the four tarsal elements together. However, the integrated analysis also gave larger separations with discriminations along different axes. Thus the three geographical groups (Zulus, Southern Chinese, and the two British groups together) were separated by first and third variates. The discrimination of sex and size differences was found in the second axis, mirroring what was found in the first axes of the individual studies. This axis reversal implies that in examining all bones together, there is enough redundant information about sex and size in each individual bone that they are relegated to a second axis. It likewise implies that the data referring to geographic discriminations provided by each individual bone are not redundant; they sum in the integrated analysis, and therefore contribute to the overall analysis to a greater extent, with increased clarity.     

Extreme Sexual Brain Size Dimorphism in Sticklebacks: A Consequence of the Cognitive Challenges of Sex and Parenting?

Selection pressures that act differently on males and females produce numerous differences between the sexes in morphology and behaviour. However, apart from the controversial report that males have slightly heavier brains than females in humans, evidence for substantial sexual dimorphism in brain size is scarce. This apparent sexual uniformity is surprising given that sexually distinct selection pressures are ubiquitous and that brains are one of the most plastic vertebrate organs. Here we demonstrate the highest level of sexual brain size dimorphism ever reported in any vertebrate: male three-spined stickleback of two morphs in an Icelandic lake have 23% heavier brains than females. We suggest that this dramatic sexual size dimorphism is generated by the many cognitively demanding challenges that males are faced in this species, such as an elaborate courtship display, the construction of an ornate nest and a male-only parental care system. However, we consider also alternative explanations for smaller brains in females, such as life-history trade-offs. Our demonstration of unprecedented levels of sexual dimorphism in brain size in the three-spined stickleback implies that behavioural and life-history differences among the sexes can have strong effects also on neural development and proposes new fields of research for understanding brain evolution.     

Geographic variation in size and sexual dimorphism of North American weasels

Geographic variation in size (skull length) and sexual dimorphism in Mustela erminea, Mustela frenata and Mustela nivalis in North America is described and analysed in relation to latitude, longitude, climatic variables, and sympatry or allopatry of these species. Only erminea increases in size with latitude; it does so regardless of the presence or absence of frenata or nivalis. Latitude is a better predictor of size in erminea than available measures of climate, seasonality or prey size. There is no evidence for character displacement between any pair of species. The sexes covary in size in frenata and erminea , and probably in nivalis , although geographic variation in sexual dimorphism occurs in frenata and erminea. The principal cause of sexual dimorphism appears to be sexual selection for large size in males rather than the high energetic requirements resulting from an elongate body shape. However, prey size may constrain female size (and possibly also male size). Regional differences in the abundance of prey during the growth of young weasels may affect adult size much more in males than in females and contribute to geographic variation in sexual dimorphism.     

SEXUAL DIMORPHISM IN BOTTLENOSE DOLPHINS FROM THE EAST COAST OF FLORIDA

Skulls of 69 bottlenose dolphins (genus Tursiops ) from the Indian/Banana River on the east coast of Florida were examined for evidence of sexual dimorphism. The only sexual dimorphism shown by t -tests on 28 morphological and four meristic skull characters was that males have, on average, more teeth than females in all four arcades. Results of covariance analysis, employed to account for variation in size, indicate minor dimorphism in parietal width of the skull. Twenty body measurements of 29 Tursiops originating in the same area were also analysed for differences between males and females. Statistical results indicate the possibility of sexual dimorphism in the length from the snout to the umbilicus and in flipper width. No evidence was found for differences in overall skull or body length between the sexes.     

Allometric comparison of skulls from two closely related weasels, Mustela itatsi and M. sibirica

We conducted an interspecific comparison of skulls from two closely related but differently sized mustelid species, Mustela itatsi and M. sibirica (Mammalia, Carnivora, Mustelidae); a sexual comparison within the latter species showed remarkable size dimorphism. We clarified several differences in skull proportion related to size using allometric analyses and qualitative comparisons. Allometric analysis revealed that the skulls of male M. itatsi (the smaller species) have a relatively long palate; a slender viscerocranium and postorbital constriction; a broad, short, and low neurocranium; small carnassials; and a short mandible with a thin body and small ramus compared to the skulls of male M. sibirica (the larger species). Similar results were obtained when male M. itatsi were compared to female M. sibirica, although the male M. itatsi had a broader viscerocranium than female M. sibirica. A sexual comparison in M. sibirica revealed a larger skull size among the males with a relatively wide viscerocranium; wide postorbital constriction; a slender, long, and high neurocranium; short and wide auditory bullae; short carnassials; and a long and high mandible compared to females. Qualitative comparisons revealed changes in a few characters depending on skull size or with respect to some cranial components in each species. The interspecific differences observed were clearly larger than the intraspecific differences for three qualitative characters. The allometric and qualitative differences detected between these species suggest that each species is not simply the dwarf and/or giant morph of the other, and complicated differences were clarified.     

Multivariate morphometries and sexual dimorphism in the orb-web spider Metellina segmentata (Clerck, 1757) (Araneae, Metidae)

Sexual dimorphism in body size and leg length was investigated in a common orb-weaving spider of Ireland and northern Europe, Metellina segmentata (Clerck, 1757) (Araneae, Metidae). Univariate and multivariate analyses of sexual dimorphism revealed that a greater proportion of between sex variation (sexual dimorphism) was attributable to variation in shape than in size. Significant differences were found in the scores for males and females for the first two principal components. PCI (shape) accounted for 44.25% of the variation and PC2 (size) 13.01% of the variation. Although M. segmentata has been attributed with minimal sexual size dimorphism, females were markedly heavier, possibly a reflection of differential reproductive investment between the sexes, but males had markedly longer legs and broader prosoma. The results are discussed with regard to existing theories of natural and sexual selection, particularly those concerning sexual cannibalism and differential life history traits in males and females. Models that attempt to explain the evolution of sexual size dimorphism in spiders and of the web builders in particular, fail to account for the multivariate nature of dimorphism, especially with respect to shape.     

Size,shape and sex differences in three subspecies of Black-tailed Godwits Limosa limosa

ABSTRACT

Capsule: Black-tailed Godwits Limosa limosa show sexual size dimorphism and size differences between the subspecies. The shape varies slightly between the subspecies, but not between the sexes.

Aims: To investigate whether and how the three subspecies of Black-tailed Godwits, and the sexes of these subspecies, differ in size and shape.

Methods: We collected body dimensions (lengths of the bill, total head, tarsus, tarsus-toe and wing) of adult Black-tailed Godwits from three locations (Iceland, the Netherlands and northwest Australia) corresponding to the breeding or wintering grounds of three known subspecies (islandica, limosa and melanuroides, respectively). Determining sex by molecular assays, we computed degrees of sexual size dimorphism. Using principal component analysis (PCA), we compared differences in size and shape among the different subspecies.

Results: The limosa subspecies was the largest and also showed the most significant sexual size dimorphism. Sexual size dimorphism was smallest for wing length and largest for bill length. The first two axes of the PCA that included all subspecies of both sexes explained 94% of the total variation. Most body dimensions were highly correlated with each other, but wing length varied independently of the other dimensions. Males and females differed only in size (the first axis). However, one of the two small subspecies, islandica, also differed in shape (the second axis) from limosa and melanuroides.

Conclusions: In all three subspecies of Black-tailed Godwits, females are larger than males. The fact that subspecies differed in the degree of size dimorphism and slightly in shape hints at sex-related differences in the ecological selection pressures between the different flyways.