太行山猕猴颅骨变量的异速生长研究

采用定点方法 ,对太行山猕猴 (Macacamulatta)颅骨的 3 2项变量进行了测量、统计和异速生长分析 ,结果表明 ,除颅骨最小宽和冠颞点间宽外 ,其余变量统计值雄性大于雌性 ;颅骨变量的生长存在性别间及部位间的差异。这些差异与雄性和雌性在社群中的不同地位和竞争压力以及取食习性有关。     

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。     

金丝猴肩带和前肢的性二型

本文研究了两种金丝猴(Rhinopitheous bieti和R.brelichi)肩带及上肢的62项线性变量及指数的性二型,其中64.5%达到了显著性差异水平。结果表明,两性在运动行为上存在一些差异。在所分析的变量中,性别间的差异主要由于成熟时间的不同所引起(雄性比雌性具更长的生长时期),其次是生长速率的不同(雄性比雌性具有更明显的正异速生长率)。对一些指数及不同部位的性二型分析表明,在上肢利用和尺、桡骨的前旋及后旋活动方面,两性也具一些不同。     

太行山猕猴颅骨变量的波动不对称性

探讨了太行山猕猴Macaca mulatta颅骨变量波动不对称特征及影响因素。猕猴颅骨标本62例(♀43,♂19),按性别和年龄分组。选择颅骨两侧对称的24个变量,转换为标准波动不对称值(FA)。数据用SPSS 20.0进行处理。结果显示:大部分颅骨变量的FA值在性别组间和年龄组间没有统计学差异(P>0.05);不同变量的FA值大小不同;FA值的变化趋势是雌性大于雄性,亚成体组大于成体组。结果提示猕猴颅骨波动不对称特征可能与它们的肢骨不对称特征不同,可能在某种程度上反映了猕猴的生长发育及环境刺激对不对称的影响。     

甘肃密点麻蜥三个地理种群的两性异形研究

通过测量和比较采自甘肃省兰州市、张掖市和民勤县3个地区的密点麻蜥Eremias multiocellata成体样本的8个形态学量度指标,分析密点麻蜥雌雄间的两性差异和异速生长。结果表明,密点麻蜥兰州种群和张掖种群体长的两性差异无统计学意义,民勤种群雄性体长显著大于雌性。3个种群的头部大小、附肢长、尾部及最大腹宽在两性间均存在差异,具有两性异形现象。雄性个体头部较大、附肢和尾部较长;而最大腹宽在不同种群中有所不同,兰州种群和张掖种群雄性的最大腹宽显著小于雌性,民勤种群雄性则显著大于雌性。在个体发育过程中,前肢长、后肢长、头长、头宽、头高、尾长及最大腹宽均出现了不同程度的异速生长。     

水分驱动下茵陈蒿(Artemisia capillaris Thunb.)地上生物量模型与异速生长特征

构建生物量预估模型,探究生物量在各器官中的分配策略和异速生长关系及其对环境因子的响应,对理解植物群落结构、功能、碳储存和分配机制具有重要意义。本研究以内蒙古荒漠草原常见种茵陈蒿(Artemisia capillaris Thunb.)为对象,在不同水分处理下,利用易测指标,如株高、基径、分枝数、冠幅和生物量等参数建立生物量模型,采用标准化主轴分析法分析其异速生长关系。结果表明:在不同水分处理下,茵陈蒿的最佳生物量预估模型的变量选择不同;不同水分处理下茵陈蒿各器官间、各器官与地上生物量间的异速生长关系不同,但相对于自然降水量,增水和减水50%下均为等速生长,这说明在不同水分条件下茵陈蒿对各器官间的资源配置存在权衡策略,符合最优分配假说;而在极端气候条件下,各器官对资源的竞争会变弱;在荒漠草原中,对草本植物进行生物量模拟,选择预测变量和方程模型时,应考虑生长季降水量。本研究可为荒漠草原草本植物生物量预估模型的建立和异速生长关系对环境因子适应的理解等提供方法支持及理论依据。     

密度对尖头叶藜生物量分配格局及异速生长的影响

植物器官指示植物不同的功能,而植物器官生物量分配比例的变化表征了植物对资源获取能力的调整。在植物生长发育过程中,植物各器官呈一种明显的异速生长规律。利用异速生长分析方法,通过模拟不同密度(16、44.4、100、400株/m~2)下尖头叶藜(Chenopodium acuminatum)的生长特性,研究密度对尖头叶藜器官生物量分配格局及异速生长的影响。结果表明,随密度增加,尖头叶藜地上和地下器官都存在不同程度的竞争:其中,根和主茎生物量分配增加,茎和地上生物量分配减少,而叶和繁殖生物量分配不随密度变化而变化。研究发现,尖头叶藜各器官间具有显著的异速生长关系:其中叶∶主茎、根∶地上部分、根∶茎、根∶主茎、繁殖器官∶地上部分及繁殖器官∶根生物量间的异速生长不随密度变化而变化,属于表观可塑性;而叶∶地上部分、叶∶根、叶∶茎、茎∶地上部分、主茎∶地上部分、繁殖器官∶茎、繁殖器官∶主茎生物量间具有极显著的异速生长关系,异速指数和个体大小显著受密度变化影响,属于真正可塑性,这表明密度能够影响尖头叶藜各器官的生长变化。尖头叶藜叶∶主茎、叶∶根及主茎∶地上部分生物量间的异速指数在D4-密度时与3/4差异不显著(P0.05),符合生态代谢理论,而在D1—D3密度时与3/4差异显著(P0.05),表明充分竞争的植株更符合代谢理论,而竞争不激烈的植株对资源的投入具有物种特异性。     

树冠位置对香樟叶形态性状和异速生长关系的影响

为深入了解树冠位置对植物叶形态性状的影响,在常绿乔木香樟树冠上下2层和东南西北4个方位开展调查取样,系统分析了不同树冠位置间叶形态性状(叶长、叶宽、叶厚、叶柄长、叶柄直径和叶形指数)及其异速生长关系的差异性。结果表明,叶形态性状在不同树冠方位间均差异显著,但上下2层变化趋势不完全一致。在树冠上层,除叶形指数和叶炳长外,其余4个性状均表现为东侧最大。在树冠下层,除叶形指数外,其余5个性状指标均表现为东侧最小。在同一方位上,叶形态性状在上下2层间也存在一定差异,其中叶形指数多为下层高于上层,而其他形态性状多呈相反趋势。此外,树冠层次和方位的交互作用对叶片长、叶片厚、叶柄长和叶柄直径有显著影响。各层次和各方位叶形态性状间多为异速生长关系(即异速生长指数不等于1),且多无显著差异。在所有树冠层次和树冠方位,叶宽与叶厚、叶宽与叶炳长、叶长与叶厚及叶长与叶柄长之间均呈异速生长关系。可见,树冠位置对香樟叶形态性状的影响较大,但形态性状间的异速生长关系相对稳定,这是香樟叶形态性状表型可塑性和内在关系稳定性的重要体现。     

枕骨三维形态在现生人群间的变异

与面颅、脑颅和颅底不同,枕骨与人群间遗传信息的关系不明确且研究较少。传统形态测量方法对枕骨的研究难以全面反映枕骨的形态信息。为更加精细地探究枕骨形态与人群的关系,本文以亚洲、非洲和欧洲地区的103例现生男性头骨为研究对象,通过三维几何形态测量和多元统计分析的方法对枕骨三维形态和异速生长模式在人群间的差异进行了研究。研究结果表明,枕骨的大小和形状在现生人群中具有显著差异,然而这种差异并不足以区分不同人群。现代人枕骨的三维形态具有较大的变异,主要表现在枕外隆凸点的突出程度、上下相对位置以及枕平面与项平面的比例,其次表现在星点位置在前后、内外以及上下方向上的变化,斜坡的倾角变化等方面。异速生长的分析表明,不同人群中存在不同的异速生长模式,但是非洲和欧洲人群也存在相似的趋势。本研究认为枕骨三维形态在反映人群间遗传关系上作用较小,支持枕骨形态可能更多受到功能和环境等因素的影响。     

四种一年生荒漠植物构件形态与生物量间的异速生长关系

1年生草本植物是古尔班通古特沙漠夏秋季节草本层片的主要组成部分。选择4种藜科1年生草本植物(刺沙蓬、沙蓬、角果藜和对节刺)作为研究对象,对比分析了各物种构件形态特征、生物量分配以及它们之间的异速生长关系。结果表明:沙蓬个体最大,其次为刺沙蓬,角果藜和对节刺个体最小;对节刺具有最大的根冠比(R/S),其次是刺沙蓬,沙蓬和角果藜R/S最小。4种植物构件形态与生物量间均呈显著正相关,表现出强烈的协同变化趋势。R/S与绝大部分指标间呈显著负相关,表明随个体增大地下生物量分配比例逐渐减小。4种植物各构件形态、地上及地下生物量间大部分呈指数1.0的异速生长关系,但各物种间的异速生长指数绝大部分无显著差异且具有共同的异速生长指数。研究表明:尽管物种不同、个体大小迥异,但4种1年生植物构件特征间多具有相同的生长速率和协同变化特征,体现了1年生植物这一生活型内的不同物种对干旱荒漠环境的趋同适应。     

Postnatal ontogenetic scaling of Nesodontine (Notoungulata,Toxodontidae) cranial morphology

Cassini G.H., Flores D.A. and Vizcaíno S.F. 2012. Postnatal ontogenetic scaling of Nesodontine (Notoungulata, Toxodontidae) cranial morphology. —Acta Zoologica (Stockholm) 93 : 249–259. Toxodontidae is a clade of endemic South American ungulates that comprises medium to very large animals, including strict megammamals, i.e., 1000 kg or more. Adinotherium at approximately 120 kg and Nesodon at 550 kg are, respectively, the smallest and the largest Nesodontinae of Santacrucian age (early Miocene). The large number of specimens recorded and the quality of preservation (including very young animals) permit a morphometric study of cranial ontogeny. We measured 17 cranial variables on an ontogenetic series of 23 specimens of Adinotherium ovinum and 11 of Nesodon imbricatus. Bivariate analysis (standardized major axis) was performed to obtain the coefficients of allometry using skull length as the independent variable. Results indicate that eight of 16 variables show an isometric trend, seven exhibit positive allometry, and only the height of the orbit in N. imbricatus exhibits negative allometry. Contrary to expectation, neurocranial variables are positively allometric or isometric. With respect to the splanchnocranium, most variables related to the rostrum, palate, and masticatory muscles show positive allometry, suggesting a strengthening of masticatory system in adults of both taxa. The splanchnocranial allometric trends fail to support previous inferences of specialized herbivory, suggesting generalized herbivory in nesodontines.     

The effects of hybridization on growth allometry and craniofacial form in Sulawesi macaques

The present research investigates the effects of hybridization between Macaca maurus and M. tonkeana on adult male form and patterns of growth allometry. Comparisons of adult hybrid mean phenotypic values with the adult averages of the parental species indicate a condition of heterosis for cranial vault length and crown-rump length. Negative heterosis is indicated for body mass. Regression parameters describing growth allometry are generated for four craniofacial measurement variables and one body measurement using both least squares and reduced major axis regression. Comparisons of hybrid and parental regression slopes and intercepts using analysis of covariance and t-tests suggest that there is a hybrid pattern of growth allometry characterized by an increase in regression slope values coupled with lower intercept values compared to those of the parental species and the parental averages for most regression parameters. Multivariate analyses of the adult and ontogenetic morphometric data indicate significant differences across species taxa in form and shape during development and adulthood. Our finding of significant differences between hybrids and their parental taxa in growth allometry and craniofacial form and shape during development challenges the assumption often made regarding the reproductive and taxonomic significance of observed ontogenetic divergence between Neandertals and modern humans. We propose that anthropological primatology, with its goal of developing nonhuman primate models for investigating human evolution, can provide a biologically relevant means by which to empirically estimate the taxonomic significance of morphological and ontogenetic divergence observed in the hominid fossil record.     

Osteological morphometrics of Australian chelonioid turtles

Extant and fossil Australian chelonioid turtles were examined for 57 osteological morphometric variables. Data were analysed using principal components analysis and canonical variates analysis, after Burnaby isometric 'size' removal, as well as multivariate allometry. Results indicate that Lepidochelys spp. are proportionately differentiated from other Cheloniidae. The majority of chelonioid osteological variables scale isometrically, with less than a third exhibiting positive or negative allometry. Skull length and width, postero-ventral skull, mandible length, scapular and pubic variables are found to be useful for differentiating between extant and extinct chelonioids. Skull length and width, mandible height, jaw symphysis length, premaxilla height, femoral length, scapular, pelvic, plastral and rib variables are established as useful differentiators of cheloniids. Australian fossil protostegids are morphometrically more similar to cheloniids than dermochelyids, and no cranial morphometric evidence could be found for the presence of more than one protostegid species. Some osteological allometric variables may be valuable for use in determining the relationships of chelonioids; however these should be examined in conjunction with morphology-based cladistic analyses to test established phylogenies.     

Functional and ecological significance of relative growth in Alligator

Allometric coefficients are calculated for 27 cranial and 39 postcranial measurements of a growth series of Alligator mississipiensis that spans a size range of an order of magnitude. Developmental patterns are quite-well canalized, as expressed in coefficients of variation of 8 to 10 for isometric variables. A multivariate expression of allometry is discovered using principal components analysis. A number of allometric coefficients have expression in known aspects of the life history of Alligator. Negative allometry of limb lengths and limb proportions shows an ontogenetic decrease in importance of the limbs throughout life, and observations show large animals to be more dependent on water than small ones. Isometry of skull length with respect to body length represents an adaptation to ever-increasing size of prey items as body size increases. Positive allometry of snout length and size of the upper temporal fenestrae finds parallel in the structure of the highly aquatic gavial.     

Evolution of skull shape in carnivores 1. Representative modern carnivores

Fifteen variables, selected primarily to reflect functionally significant aspects of cranial morphology, were measured on one skull each of 62 species of modern carnivores, including viverrids, canids, mustelids and felids. To allow comparisons between species of different sizes without the potentially confounding effects of allometric shape changes, the measurements were transformed to dimensionless variables, based on the residuals from allometric equations. Fourteen out of 15 of the transformed variables distinguish one or more of the four family groups and the rotated first two axes of a principal components analysis distinguish all four families from each other. The following functional hypotheses are proposed: mustelids and felids have the most powerful bites and canids the weakest among the four family groups studied; mustelids and, to a lesser degree, felids have more powerful neck musculature than do canids and viverrids; and visual abilities are best developed among felids and least developed among mustelids. The first two functional hypotheses suggest possible differences in killing behaviour, which are supported by a preliminary survey of the literature on such behaviour. Allometric analysis of the 15 cranial measures shows that the neurocranial components scale with negative allometry, while most of the other measures scale approximately isometrically.     

Heterochrony and sexual dimorphism in the skull of the Liberian chimpanzee (Pan troglodytes verus)

Allometric methods and theory derived from principles of relative growth provide new and powerful approaches to an understanding of the nature and development of sexual dimorphism among living primates. The Frankfurt collection of Liberian chimpanzee skulls and mandibles provides a large skeletal sample from a single natural population of wild shot animals, including individuals of all ages and both sexes, and allows investigation of allometric and heterochronic patterns of sexual dimorphism. Univariate, bivariate, and multivariate analyses are utilized in this study in order to ascertain the ontogenetic nature of male-female differences in the skull of the Liberian chimpanzee. The results of univariate and multivariate analyses indicate that, while overall levels of sexual dimorphism in the chimpanzee skull are small, the greatest differences are in dimensions of the viscerocranium, while neurocranial dimensions and orbital size tend to be less dimorphic. Bivariate regressions of 21 cranial variables against basicranial length document positive allometry in many facial and mandibular dimensions, and isometry or negative allometry for most neurocranial dimensions. The data confirm previous work in chimpanzees and other anthropoid primates suggesting that males and females are “ontogenetically scaled” in most cranial traits. That is, males and females share the same cranial growth trajectories, although ending up at different points. Both rate and time hypermorphosis are suggested as underlying causes of ontogenetic scaling in the Liberian chimpanzee.     

Testing the cranial evolutionary allometric ‘rule’ in Galliformes

Recent comparative studies have indicated the existence of a common cranial evolutionary allometric (CREA) pattern in mammals and birds, in which smaller species have relatively smaller faces and bigger braincases than larger species. In these studies, cranial allometry was tested using a multivariate regression between shape (described using landmarks coordinates) and size (i.e. centroid size), after accounting for phylogenetic relatedness. Alternatively, cranial allometry can be determined by comparing the sizes of two anatomical parts using a bivariate regression analysis. In this analysis, a slope higher or lower than one indicates the existence of positive or negative allometry, respectively. Thus, in those species that support the CREA ‘rule’, positive allometry is expected for the association between face size and braincase size, which would indicate that larger species have disproportionally larger faces. In this study, I applied these two approaches to explore cranial allometry in 83 Galliformes (Aves, Galloanserae), ranging in mean body weight from 30 g to 2.5 kg. The multivariate regression between shape and centroid size revealed the existence of a significant allometric pattern resembling CREA, whereas the second analysis revealed a negative allometry for beak size and braincase size (i.e. contrary to the CREA ‘rule’, larger galliform species have disproportionally shorter beaks than smaller galliform species). This study suggests that the presence of CREA may be overestimated when using cranium size as the standard measurement.     

The scaling of basicranial flexion and length.

Based on correlations between the cranial base angle (CBA) and the index of relative encephalization (IRE, calculated as the cubed root of brain volume divided by basicranial length), several recent studies have identified relative brain size as the factor most responsible for determining basicranial flexion in primates. IRE, however, scales with positive allometry relative to body mass, unlike the negatively allometric relationship between brain volume and body mass. This poses new questions concerning the factors underlying the correlation between IRE and CBA. Specifically, if basicranial flexion represents a spatial solution to the problem of housing a large brain within a neurocranium of limited size, then why is it that the problem is greatest in those species whose brains are smallest relative to body mass? To address this question, the scaling relationships of IRE and the measurements used to calculate it were examined in 87 primate species. It was found that the positive allometry of IRE is due to the fact that its denominator, basicranial length (BL), scales with very strong negative allometry relative to body mass. The scaling relationship of BL may reflect the fact that the noncortical components of the brain (i.e., diencephalon, mesencephalon, medulla) also scale with strong negative allometry relative to body mass, perhaps because of energetic constraints. Importantly, BL and these three brain components scale isometrically against each other. Thus, although cranial base flexion may be an adaptation to accommodate the size of the brain relative to basicranial length, the reason why that adaptation is necessary is not the evolution of a large brain, but rather the evolution of a short cranial base. In so far as basicranial length is affected by the strong negative allometry of the diencephalon, mesencephalon and medulla, the scaling relationships of these brain components are therefore indirectly responsible for the evolution of basicranial flexion.     

Cranial ontogeny of<Emphasis Type="Italic">Lutreolina crassicaudata</Emphasis> (Didelphidae): a comparison with<Emphasis Type="Italic">Didelphis albiventris</Emphasis>

Metatherians experience the greatest developmental changes during extrauterine life. Following previous studies onDidelphis albiventris Lund, 1840, we examined the postweaning cranial allometry of size of the Neotropical marsupialLutreolina crassicaudata (Desmerest, 1804). Our aim was to compare growth patterns of both species to identify traits particular to each species and traits common to both species. This may contribute toward identifying a common developmental plan for didelphids. We measured 15 cranial variables in 32–43 specimens from just-weaned young to old adult. Total length of the skull was the estimator of overall size in least squares and reduced major axis regressions. The skull ofLutreolina crassicaudata grows at a rate slower than the overall change in size in its neurocranial components, palate, and postcanine rows, and it grows relatively faster in the rest of the splanchnocranium. This pattern closely resembles that ofDidelphis albiventris, from which it differs mainly in the allometry of the muzzle. In both species, allometry explains most postweaning changes of the trophic apparatus on functional grounds, in relation to interspecific differences in diet. We hypothesize that most local allometric departures from a generalized didelphid plan would relate to main dietary trends.     

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。