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PubMed1993

Scaling of limb proportions and limb bone diameters in three species of Chinese snub-nosed langurs (genus Rhinopithecus).

In this study, aspects of the structural mechanics of the upper and lower limbs of the three Chinese species of Rhinopithecus were examined. Linear regression and reduced major axis (RMA) analyses of natural log-transformed data were used to examine the dimensions of limb bones and other relationships to body size and locomotion. The results of this study suggest that: (1) the allometry exponents of the lengths of long limbs deviate from isometry, being moderately negative, while the shaft diameters (both sagittal and transverse) show significantly positive allometry; (2) the sagittal diameters of the tibia and ulna show extremely significantly positive allometry--the relative enlargement of the sagittal, as opposed to transverse, diameters of these bones suggests that the distal segments of the fore- and hindlimbs of Rhinopithecus experience high bending stresses during locomotion; (3) observations of Rhinopithecus species in the field indicate that all species engage in energetic leaping during arboreal locomotion. The limbs experience rapid and dramatic decelerations upon completion of a leap. We suggest that these occasional decelerations produce high bending stresses in the distal limb segments and so account for the hypertrophy of the sagittal diameters of the ulna and tibia.

Animals↗
PubMed1999

Prediction of clearance, volume of distribution and half-life by allometric scaling and by use of plasma concentrations predicted from pharmacokinetic constants: a comparative study.

Pharmacokinetic parameters (clearance, CL, volume of distribution in the central compartment, VdC, and elimination half-life, t1/2beta) predicted by an empirical allometric approach have been compared with parameters predicted from plasma concentrations calculated by use of the pharmacokinetic constants A, B, alpha and beta, where A and B are the intercepts on the Y axis of the plot of plasma concentration against time and alpha and beta are the rate constants, both pairs of constants being for the distribution and elimination phases, respectively. The pharmacokinetic parameters of cefpiramide, actisomide, troglitazone, procaterol, moxalactam and ciprofloxacin were scaled from animal data obtained from the literature. Three methods were used to generate plots for the prediction of clearance in man: dependence of clearance on body weight (simple allometric equation); dependence of the product of clearance and maximum life-span potential (MLP) on body weight; and dependence of the product of clearance and brain weight on body weight. Plasma concentrations of the drugs were predicted in man by use of A, B, alpha and beta obtained from animal data. The predicted plasma concentrations were then used to calculate CL, VdC and t1/2beta. The pharmacokinetic parameters predicted by use of both approaches were compared with measured values. The results indicate that simple allometry did not predict clearance satisfactorily for actisomide, troglitazone, procaterol and ciprofloxacin. Use of MLP or the product of clearance and brain weight improved the prediction of clearance for these four drugs. Except for troglitazone, VdC and t1/2beta predicted for man by use of the allometric approach were comparable with measured values for the drugs studied. CL, VdC and t1/2beta predicted by use of pharmacokinetic constants were comparable with values predicted by simple allometry. Thus, if simple allometry failed to predict clearance of a drug, so did the pharmacokinetic constant approach (except for actisomide). The results of this study indicate that caution should be employed in interpreting plasma concentrations predicted for a drug in man by use of pharmacokinetic constants obtained in animals.

Animals↗
PubMed1988

Ontogenesis of contractile properties of skeletal muscle and sprint performance in the lizard Dipsosaurus dorsalis.

Ontogenetic allometries of running performance in 3- to 4-m burst runs (sprints) and of the contractile properties of the fast-twitch, glycolytic region of the iliofibularis muscle (FG-IF) were measured in Dipsosaurus dorsalis. This iguanid lizard hatches at a body mass of about 4 g and reaches adult masses of 40-70 g. Running velocity was little influenced by changes in body mass during development. Stride frequency (f) declines ontogenetically and was proportional to body mass (Mb) to approximately the -0.2 power (determined by regression analysis). Stride length (Ls) appeared to be related to the allometry of hindlimb length (LHL); both Ls and LHL were proportional to about Mb0.28. Intrinsic shortening velocity of the FG-IF decreased only slightly with increasing body mass, and was consequently not proportional to f as has been assumed by various models of running dynamics. In contrast, twitch time lengthened markedly with increasing body mass, and the ratio of twitch time to stride time remained approximately constant. These results suggest that the intrinsic velocity of the muscles does not directly or solely determine maximal f, but instead limb kinematics are determined in part by other biomechanical constraints related to body dimensions. Further, the allometry of twitch kinetics supports the idea that the properties of the muscles are adjusted to allow ample time for full activation and deactivation within the biomechanically determined stride time.

Aging↗
PubMed1990

Growth of organs and tissues in carp (Cyprinus carpio L.) larvae.

Growth of some internal organs and tissues was studied in carp (Cyprinus carpio L.) in order to provide baseline information on the growth process during the first posthatching stages of fish, and to compare the trend observed in fish to that known in other animals. Growth of organs and tissues (liver, pancreas, trunk muscles, digestive tract, eyes, nervous system) was studied in rapidly growing carp (Cyprinus carpio L.) larvae by means of a quantitative histological method. Mean body weight of carp larvae rose from 1.8 mg at 2 days to 50.4 mg at 18 days. Between 4 and 18 days after hatching (yolk exhausted; exogenous food only), the average specific growth rates of organs were around 31% per day for the liver and pancreas, 28% per day for the trunk muscles, 26% per day for the digestive tract (without lumen) and 19% per day for the eyes and nervous system. Compared to the total volume of tissues, liver (k = 1.19), pancreas (k = 1.19), and trunk muscles (k = 1.09) showed positive allometry, digestive tract showed isometry (k = 1.00), and eyes (k = 0.76) and the nervous system (k = 0.73) showed negative allometry. This study demonstrated that the growth process of some organs (i.e. liver, pancreas and digestive tract) is different between larval and older stages of carp, and that the development of carp larvae exhibit the same order of allometry coefficients as do certain mammals (e.g. rabbit and lamb) in their early postnatal stages: nervous tissue, digestive tract, muscular tissue, liver.

Aging↗
PubMed1990

[Quantitative evaluation of the allometric transformation of of biological structures].

Detection and quantification of allometry is a crucial problem in understanding morphological changes, both for systematic and morphogenetic purposes. A section of S.A.M. (Shape Analytical Morphometry) software system was used for this attempt. It consists of the following steps: a) boundary detection; b) starting point detection; c) size normalization; d) extraction of the fundamental shape by Kth order polynomials; e) finding of symmetry evaluator (S.A.E.) by means of a second degree equation. This last procedure gives an arc-chord complex that expresses a vector for allometry where intercept value was for application point, first degree coefficient was for direction and second degree coefficient was for modulus and versus. The main parameters, isometry fraction and allometry fraction may be understood referring them to morphogenetic models.

Algorithms↗
PubMedDate not supplied

Growth of the body in early fetuses studied by multivariate analysis.

The growth of the body was studied in 30 human fetuses ranged from 10 to 22 weeks of gestation. The fetuses were fixed by immersion in 4 percent formaldehyde and the following dimensions were studied: a) lengths: arm, forearm, hand, thigh, leg, foot and crown-rump (sitting height), b) perimeters: head, thorax and abdomen. A covariance matrix was calculated from natural logarithms of all measurements. The relative growth of these measurement was computed by multivariate allometry using a principal components analysis (PCA). All characters were positively correlated with the first principal component which accounted for 94.65 per cent of the total variance. Considering the different measurements in the sequence of the increasing growth rates no one was considered to increase in isometric relationship. PCA showed that the following measurements grew with negative allometry: head perimeter, C-R length, thoracic perimeter, length of the forearm and abdominal perimeter. On the other hand, the following lengths grew with positive allometry: hand, foot, thigh, arm and leg. In conclusion, during the first two trimesters of prenatal life the growth of the body is allometrical. Limbs increase with greater growth rates than the perimeters of the body cavities.

Body Height↗
PubMed1996

Allometric patterns of cranial bone thickness in fossil hominids.

The interspecific allometry of five measures of total cranial bone thickness is examined in 10 extant catarrhine genera and two fossil hominid samples representing A. africanus and Asian H. erectus. Analysis of the modern sample shows that most interspecific variation in vault thickness can be accounted for by variation in body size. Correlation values are moderate to high (r = 0.75-0.98), and all variables exhibit positive allometry. The bone thickness: body mass relationship of modern humans broadly conforms with that of other primates. However, in the distribution of relative thickness throughout the skull, H. sapiens is distinguished by relative thickening of the parietal and extreme relative thinning of the temporal squama. The bone thickness: body mass relationship in the two early hominid species is examined using published mean body weight estimates generated from post-cranial predictor variables. A. africanus exhibits great similarity to modern humans in its relation to the catarrhine regression data and in the distribution of relative thickness throughout the skull. H. erectus also shows a modern human-like pattern in the distribution of its relative thickness; however, its bone thickness: body mass relationship is dissimilar to that displayed by all other taxa, including the other hominid species. On the basis of these results, it is suggested that the published body weight estimate assigned to H. erectus greatly underestimates actual mean body size for Asian members of this species.

Africa↗
PubMed2001

Primate molar crown formation times and life history evolution revisited.

Comparative studies have convincingly demonstrated that the pattern and timing of tooth emergence are highly correlated with life-history variables and brain size. Conversely, a firm relationship between molar formation time and life-history variables has not yet been established. It seems counterintuitive that one aspect of dental development should be correlated with life-history variables, whereas the other should not. In order to shed light on this apparent discrepancy this study analyzed all data on primate molar crown formations available in the published literature in relation to life-history variables, brain size, and female body mass. Crown formation times were found to be particularly highly correlated with both female body mass and brain size. Species that depart from the overall brain/body allometry by being relatively large-bodied, e.g., Gorilla gorilla and later Theropithecus oswaldi, also have shorter molar crown formation times than expected. The reverse is not found for species that depart from the overall brain/body allometry due to their larger brains, i.e., Homo sapiens. This finding is interpreted within an evolutionary and ecological framework. Specifically, by focusing on ecological commonalities, a scenario is proposed which may allow predictions to be made about the evolutionary history of other extinct primates also. If confirmed in future studies, crown formation time may again become a powerful tool in evolutionary enquiry.

Animals↗
PubMed2003

Patterns of joint size dimorphism in the elbow and knee of catarrhine primates.

Differences in body size between conspecific sexes may incur differences in the relative size and/or shape of load-bearing joints, potentially confounding our understanding of variation in the fossil record. More specifically, larger males may experience relatively greater limb joint stress levels than females, unless an increase in weight-related forces is compensated for by positive allometry of articular surface areas. This study examines variation in limb joint size dimorphism (JSD) among extant catarrhines to: 1) determine whether taxa exhibit JSD beyond that expected to simply maintain geometric similarity between sexes, and 2) test whether taxa differ in JSD (relative to body size dimorphism) with respect to differences in limb use and/or phylogeny. "Joint size" was quantified for the distal humerus and distal femur of 25 taxa. Analysis of variance was used to test for differences between sexes (in joint size ratios) and among taxa (in patterns of dimorphism). Multiple regression was used to examine differences in JSD among taxa after accounting for variation in body size dimorphism (BSD) and body size. Although degrees of humeral and femoral JSD tend to be the same within species, interspecific variation exists in the extent to which both joints are dimorphic relative to BSD. While most cercopithecoids exhibit relatively high degrees of JSD (i.e., positive allometry), nonhuman hominoids exhibit degrees of JSD closer to isometry. These results may reflect a fundamental distinction between cercopithecoids and hominoids in joint design. Overall, the results make more sense (from a mechanical standpoint) when adjustments to BSD are made to account for the larger effective female body mass associated with bearing offspring. In contrast to other hominoids, modern humans exhibit relatively high JSD in both the knee and elbow (despite lack of forelimb use in weight support). Estimates of BSD based on fossil limb bones will vary according to the extant analogue chosen for comparison.

Animals↗
PubMed1977

Developmental changes of the cranial bone thickness in the human fetal period.

The description of the developmental changes of cranial bone thickness in the fetal period is the primary aim of this paper. The materials utilized in this study consisted of the two series. One is those of dry bones of 62 Japanese fetuses ranging from the fifth month to term and the other is those of 56 Japanese fetuses ranging from the fourth month to term. The first series is mainly used for the tests of bilateral difference in the thickness of cranial bones. No statistical significance could be found. Allometry technique was then applied for the analysis in the growth of the thickness of cranial bones and an extremely positive alometric coefficient was obtained. This required us to study another material, i.e., the second series. The materials of the second series were first measured for crown-rump length, head length, head breadth and head circumference. The heads were then carefully dissected and the left side of individual bones of the cranium were removed to take further measurements for the arc length. The thicknesses at the ossification centers and midpoints were successively measured by a micrometer readable to 0.01 mm. The results of the second series were investigated from the viewpoint of absolute and relative growth. By allometric analysis, vertical and transverse arc lengths were found to be isometric with two exceptions, while every measurement of thickness shows an extremely positive allometry. This coincides with the results of the first series.

Bone Development↗
PubMed1983

Principal components for allometric analysis.

Logarithmic bivariate regression slopes and logarithmic principal component coefficient ratios are two methods for estimating allometry coefficients corresponding to a in the classic power formula Y = BXa. Both techniques depend on high correlation between variables. Interpretation is logically limited to the variables included in analysis. Principal components analysis depends also on relatively uniform intercorrelations; given this, it serves satisfactorily as a method for summarizing many bivariate combinations. Unmodified major principal component coefficients cannot represent scaling to body weight; rather, they represent scaling to a composite size vector which usually is highly correlated with body size or weight but has an unspecified allometry. Thus, the concepts of proportionality and of isometry must be kept distinct.

Animals↗
PubMed1983

The measurement of form and variation in form: an application of three-dimensional quantitative morphology by finite-element methods.

D'Arcy Thompson developed a method of coordinates which allowed for a geometrical presentation of form and form change. While his grid transformations have received much attention, little work in the geometry of form and form change has occurred since. We present a three-dimensional nonhomogeneous finite-element scaling method which allows for the mathematical and geometrical measurement of form change in addition to the graphical representation of these deformations as D'Arcy Thompson grids. This allows a reconciliation between geometrical and statistical methods for analyzing form. The method involves quantification of the transformation of one form into another in three dimensions without special registration and contains algorithms for obtaining a mean form. The method is applied to an analysis of variation in cranial form among adult male rhesus macaques from the Cayo Santiago skeletal collection. Variation was greatest in the superior-inferior direction, followed by the anterior-posterior and medial-lateral directions. The upper facial region is particularly variable. An analysis of allometry relative to local size variation shows that the larger any particular region is, the relatively greater its height, narrower its width, and shorter its length. An analysis of allometry relative to overall size showed that the upper face is positively allometric, the occipital region is strongly negatively allometric, and the other regions are isometric. After within-group variation is characterized, as described here, between-group studies, such as growth series and phylogenetic series, can be performed.

Animals↗
PubMed1984

Incisor size and diet revisited: the view from a platyrrhine perspective.

Allometric relationships between incisor size and body size were determined for 26 species of New World primates. While previous studies have suggested that the incisors of Old World primates, and anthropoids in general, scale isometrically with body size, the data presented here indicate a negative allometric relationship between incisor size and body size among New World species. This negative allometry was exhibited by platyrrhines when either upper or lower incisor row length was regressed against body weight, and when either least-squares or bivariate principal axis equations were used. When upper incisor length was plotted against skull length, negative allometry could be sustained using both statistical techniques only when the full sample of 26 species was plotted. The choice of variables to represent incisor size and body size, and the choice of a statistical technique to effect the allometric equation, had a more pronounced impact on the location of individual species with regard to lines of best fit. Platyrrhines as a group have smaller incisors relative to body size than do catarrhines, regardless of diet. Among New World primates, small incisors represent a plausible primitive condition; species with relatively large incisors manifest a phyletic change associated with a dietary shift to foods that require increased incisal preparation. The opposite trend characterizes Old World primates. In spite of the taxonomic differences in relative incisor size between platyrrhine and catarrhine primates, inferences about diet derived from an allometric equation for all anthropoids should prove reliable as long as the species with unknown diet does not lie at the upper end of the body size range for platyrrhines or catarrhines.

Animals↗
PubMed1984

Relative cheek-tooth size in Australopithecus.

Until the discovery of Australopithecus afarensis, cheek-tooth megadontia was unequivocally one of the defining characteristics of the australopithecine grade in human evolution along with bipedalism and small brains. This species, however, has an average postcanine area of 757 mm2, which is more like Homo habilis (759 mm2) than A. africanus (856 mm2). But what is its relative cheek-tooth size in comparison to body size? One approach to this question is to compare postcanine tooth area to estimated body weight. By this method all Australopithecus species are megadont: they have cheek teeth 1.7 to 2.3 times larger than modern hominoids of similar body size. The series from A. afarensis to A. africanus to A. robustus to A. boisei shows strong positive allometry indicating increasing megadontia through time. The series from H. habilis to H. erectus to H. sapiens shows strong negative allometry which implies a sharp reduction in the relative size of the posterior teeth. Postcanine megadontia in Australopithecus species can also be demonstrated by comparing tooth size and body size in associated skeletons: A. afarensis (represented by A.L. 288-1) has a cheek-tooth size 2.8 times larger than expected from modern hominoids; A. africanus (Sts 7) and A. robustus (TM 1517) are over twice the expected size. The evolutionary transition from the megadont condition of Australopithecus to the trend of decreasing megadontia seen in the Homo lineage may have occurred between 3.0 and 2.5 m.y. from A. afarensis to H.habilis but other evidence indicates that it is more likely to have occurred between 2.5 to 2.0 m.y. from an A. africanus-like form to H. habilis.

Body Weight↗
PubMed1986

Method for analyzing outlines with an application to recent Japanese crania.

If the visual image and quantitative treatment of a form could be merged, the combination could become a powerful analytical method in morphology. A method is presented for creating an averaged outline. In this method, since the averaged outline is produced statistically, hypothesis testing can be performed on the visual image of the outlines. Intra- and intergroup variation of the outlines can then be assessed by taking allometry into account. This method is applied to the analysis of sexual differences in the midsagittal outline of recent (1880s-1920s) Japanese crania. The averaged outlines of both sexes showed subtle features that could not be detected by traditional measuring techniques. Because the roundness, flatness, or protrusion of specific aspects of the morphology are clearly apparent, sexual differences in this sample could be identified. Changes resulting from allometry did not seem to be present in either sex. The shape distance (DIR) introduced here matched well the visual impression derived from comparisons of the Japanese sample with a Jomon (Neolithic) male and the Broken Hill specimen.

Cephalometry↗
PubMed1993

Relative growth of the limbs and trunk in sifakas: heterochronic, ecological, and functional considerations.

Limb, trunk, and body weight measurements were obtained for growth series of Milne-Edwards's diademed sifaka, Propithecus diadema edwardsi, and the golden-crowned sifaka, Propithecus tattersalli. Similar measures were obtained also for primarily adults of two subspecies of the western sifaka: Propithecus verreauxi coquereli, Coquerel's sifaka, and Propithecus verreauxi verreauxi, Verreaux's sifaka. Ontogenetic series for the larger-bodied P. d. edwardsi and the smaller-bodied P. tattersalli were compared to evaluate whether species-level differences in body proportions result from the differential extension of common patterns of relative growth. In bivariate plots, both subspecies of P. verreauxi were included to examine whether these taxa also lie along a growth trajectory common to all sifakas. Analyses of the data indicate that postcranial proportions for sifakas are ontogenetically scaled, much as demonstrated previously with cranial dimensions for all three species (Ravosa, 1992). As such, P. d. edwardsi apparently develops larger overall size primarily by growing at a faster rate, but not for a longer duration of time, than P. tattersalli and P. verreauxi; this is similar to results based on cranial data. A consideration of Malagasy lemur ecology suggests that regional differences in forage quality and resource availability have strongly influenced the evolutionary development of body-size variation in sifakas. On one hand, the rainforest environment of P. d. edwardsi imposes greater selective pressures for larger body size than the dry-forest environment of P. tattersalli and P. v. coquereli, or the semi-arid climate of P. v. verreauxi. On the other hand, as progressively smaller-bodied adult sifakas are located in the east, west, and northwest, this apparently supports suggestions that adult body size is set by dry-season constraints on food quality and distribution (i.e., smaller taxa are located in more seasonal habitats such as the west and northeast). Moreover, the fact that body-size differentiation occurs primarily via differences in growth rate is also due apparently to differences in resource seasonality (and juvenile mortality risk in turn) between the eastern rainforest and the more temperate northeast and west. Most scaling coefficients for both arm and leg growth range from slight negative allometry to slight positive allometry. Given the low intermembral index for sifakas, which is also an adaptation for propulsive hindlimb-dominated jumping, this suggests that differences in adult limb proportions are largely set prenatally rather than being achieved via higher rates of postnatal hindlimb growth.(ABSTRACT TRUNCATED AT 400 WORDS)

Adaptation, Biological↗
PubMed1996

Paradox of peramorphic paedomorphosis: heterochrony and human evolution.

This paper reviews Gould's clock model for heterochronic processes and uses that model to develop simple matrix representations of growth and shape change. Matrix representations of growth and development provide a common formulation for all heterochronic processes. In particular, we show how neoteny can be diagnosed using such a matrix approach. The literature is rife with contradictory representations of how neoteny affects growth allometries and the timing of developmental events, and therefore of the role of neoteny in human evolution. Through the use of multivariate models, we explore these relationships and the internal consistency of opposing views. Gould's neoteny hypothesis for human evolution has been criticized for a number of reasons. Humans do not grow slowly. The slopes of our growth allometries show no common pattern of change vis-à-vis those of our closest relatives. Humans prolong rather than reduce rates of growth and development of body parts; the brain, for example, ceases growing later in humans than in apes, but during this prolonged period of early ontogeny, it grows at a rapid pace. This paper evaluates Gould's hypothesis and its critiques by focusing on particular questions. Does neoteny imply slow growth? Does it imply a unidirectional change in the rates of growth of traits? Under neoteny, should the brain cease growing in ancestor and descendant at the same age? Does prolongation of phases of growth and development confute neoteny? On the other hand, is paedomorphosis an inevitable consequence of prolonged growth and development? We show that, for all of these questions, the answer is no.

Animals↗
PubMed2004

Geometric morphometric analysis of allometric variation in the mandibular morphology of the hominids of Atapuerca, Sima de los Huesos site.

Allometry is an important factor of morphological integration that contributes to the organization of the phenotype and its variation. Variation in the allometric shape of the mandible is particularly important in hominid evolution because the mandible carries important taxonomic traits. Some of these traits are known to covary with size, particularly the retromolar space, symphyseal curvature, and position of the mental foramen. The mandible is a well studied system in the context of the evolutionary development of complex morphological structures because it is composed of different developmental units that are integrated within a single bone. In the present study, we investigated the allometric variation of two important developmental units that are separated by the inferior nerve (a branch of CN V3). We tested the null hypothesis that there would be no difference in allometric variation between the two components. Procrustes-based geometric morphometrics of 20 two-dimensional (2D) landmarks were analyzed by multivariate regressions of shape on size in samples from 121 humans, 48 chimpanzees, and 50 gorillas (all recent specimens), eight fossil hominids from Atapuerca, Sima de los Huesos (AT-SH), and 17 Neandertals. The findings show that in all of the examined species, there was significantly greater allometric variation in the supra-nerve unit than in the infra-nerve unit. The formation of the retromolar space exhibited an allometric relationship with the supra-nerve unit in all of the species studied. The formation of the chin-like morphology is an "apodynamic" feature of the infra-nerve unit in the AT-SH hominids. The results of this study support the hypothesis that allometry contributes to the organization of variation in complex morphological structures.

Animals↗