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PubMed1985

[Postnatal development of the fatty acid composition of lipids of adipose and muscle tissue in rabbits on a low-fat diet].

The relative fatty acid profiles of perirenal adipose tissue and muscle tissue of the hind legs were studied in New Zealand rabbits 21 to 140 days old. The rabbits were fed a low-fat diet covering the essential fatty acid requirements and distributed either ad libitum or in rationed amounts. The whole of the fatty acids were established earlier in hind leg muscle tissue than in perirenal adipose tissue. In the latter, the growth allometry of fatty acids in relation to the carcass was already higher between 21 and 74 days (a = 1.39) and distinctly higher between 74 and 140 days (a = 2.68). In the muscle tissue, an isometric phase (a = 0.96) preceded a major allometric phase (a = 1.76). In young suckling rabbits, the fatty acid profile of perirenal lipids was influenced by that of the milk lipids. In the muscle tissue, the presence of a large proportion of phospholipids resulted in a higher percentage of stearic acid and polyunsaturated fatty acids of the (n-6) family (linoleic, dihomo-gamma-linolenic and arachidonic acids). After weaning, the proportion of saturated fatty acids (C greater than or equal to 14) in the perirenal adipose tissue remained constant. The endogenous production of monounsaturated fatty acids (higher allometry) caused a progressive dilution of polyunsaturated fatty acids (lower allometry). This dilution was slowed down when the diet was rationed. Changes in the fatty acid composition of muscle tissue were, in general, comparable to those of perirenal adipose tissue. The differences observed could be attributed to the more active participation of phospholipids in the total lipids of the muscle tissue. Stearic acid, abundant in the phospholipids, showed a lower allometry compared to total fatty acids. Its dilution was an expression of triglyceride dilution of the phospholipids during growth. The same was true of polyunsaturated fatty acids. Rationing had the reverse effect.

Adipose Tissue↗
PubMed1996

Mandibular form and function in North American and European Adapidae and Omomyidae.

Previous experimental and comparative studies among a wide variety of primate and nonprimate mammals provide a unique source of information for investigating the functional and phylogenetic significance of variation in the masticatory apparatus of Eocene primates. To provide a quantitative study of mandibular form and function in Eocene primates, the scaling of jaw dimensions and the development of symphyseal fusion was considered in a broad sample of North American and European Adapidae and Omomyidae. Statistical analyses indicate a significant size-related pattern of symphyseal fusion across Eocene primates, with larger taxa often having a greater degree of fusion than smaller species; this trend is also evident at the family level. As adapids are mostly larger than omomyids and these taxa show allometry of symphyseal fusion, this may explain why no omomyids evince complete fusion. Controlling for jaw size, species with greater symphyseal fusion tend to have more robust jaws than those with a lesser amount of fusion. Upon further examination, a primary reason why adapids have more robust mandibles than omomyids is associated with the presence of taxa with fused symphyses, and thus more robust jaws, in the adapid sample, whereas no omomyids have fused symphyses. In addition, there is little indication of a dietary effect, as measured by molar shear-crest development, on symphyseal fusion. Moreover, as there is no correlation between molar shear-crest development and skull size, this also points to the absence of a size-related pattern of dietary preference underlying the allometry of symphyseal fusion. Based on the interspecific and ontogenetic allometry of symphyseal ossification in Eocene primates, jaw-scaling patterns are used to further examine the functional determinants of fusion in this group. This study indicates that greater dorsoventral shear during mastication is a more likely factor than lateral transverse bending ("wishboning") in the evolution of symphyseal fusion among "late-fusing" mammals like adapids and omomyids. Given that wishboning is an important functional determinant of symphyseal form in recent anthropoids, apparently the evolutionary development of marked wishboning occurs only in taxa that shift the timing of fusion to a growth stage preceding the onset of weaning (before adult masticatory patterns are fully developed) and perhaps first ossified the symphysis to counter elevated dorsoventral shear stress. As early anthropoids probably consisted of members varying interspecifically and ontogenetically in the degree of ossification, it is especially informative to analyze the adaptive setting in which anthropoid symphyseal fusion evolved from a similar primitive "prosimian" perspective. Finally, since taxa with fused symphyses are widely distributed across mammals, a similar analytical framework could be directed profitably at unraveling the functional and evolutionary significance of symphyseal fusion in other mammalian clades.

Animals↗
PubMed1981

Relative growth of the limbs and trunk in the African apes.

Examination of relative growth and allometry is important for our understanding of the African apes, as they represent a closely related group of species of increasing body size. This study presents a comparison of ontogenetic relative growth patterns of some postcranial dimensions in Pan paniscus, Pan troglodytes, and Gorilla gorilla. Interspecific proportion differences among the three species are also analyzed. It is stressed that reliable ontogenetic information can only be obtained if subadults are examined-growth data cannot be inferred from static adult scaling. Results indicate that some postcranial relative growth patterns are very similar in the three species, suggesting differential extrapolation of a common growth pattern, whereas for other proportion comparisons the growth trends differ markedly among the species, producing distinct shape differences in the adults. Interspecific shape changes among the three species are characterized by positive allometry of chest girth and negative allometry of body height and leg length. It is suggested that relative decrease of leg length with increasing body size among the African pongids might be expected on biomechanical grounds, in quadrupedal terrestrialism. Relative to body weight or trunk length, the limbs of the bonobo (Pan paniscus) are longer than in the common chimpanzee or the gorilla, with a lower intermembral index. This may most closely resemble the primitive condition for the African apes.

Africa↗
PubMed2004

Interspecies scaling of protein drugs: prediction of clearance from animals to humans.

The objective of this study was to evaluate the interspecies scaling for therapeutic protein drugs to predict the systemic clearance in humans from animal data. This study was undertaken to examine whether the rule of exponents of Mahmood and Balian for the prediction of clearance of nonprotein drugs can also be extended to macromolecules. Three different methods were used to predict clearance in humans: (1). clearance versus body weight (simple allometry), (2). the product of clearance and maximum life-span potential (MLP) versus body weight, and (3). the product of clearance and brain weight versus body weight. Data from 15 therapeutic proteins were analyzed, and the results indicated that the clearance of protein drugs can be predicted accurately using simple allometry or brain weight depending on the exponents of the simple allometry. Furthermore, these 15 drugs were scaled up using two species and the predicted clearance was compared with the predicted clearance obtained from more than two species. It was found that more than two species are needed for a reliable prediction of clearance.

Animals↗
PubMed1992

Growth of the cranial bones in human fetuses (2nd and 3rd trimesters).

The increase of the weight of some cranial bones was studied in 30 human fetuses (from 17 to 41 weeks of gestation, both sexes together) by multivariate allometry. The study was performed with a covariance matrix of the log-transformed bony weights and the Principal Components Analysis (PCA). The first principal component in PCA accounted for 92.12% of the total variance, and all characters were positively correlated with this component. PCA scaled the growth of the bones in the following sequence: a) with negative allometry: vomer, palatine, mandible and maxillae; b) with isometry (p less than 0.05): zygomatic bone; c) with positive allometry: sphenoid, ethmoid, frontal, occipital, temporal and parietal. During the 2nd and 3rd trimesters of gestation the skull exhibited two different growth rates, i.e., the bony group of the facial skeleton presented lower eigenvalues than the bony group of the calvaria, including the base of the skull. These bones of the calvaria certainly are affected by the high increase in volume of the fetal brain during the prenatal life. The knowledge of the cranial growth is a useful information for the anatomy, anthropology, orthodontics, and several medical specialties: radiology, obstetrics, pediatrics, orthopedics and reconstructive surgery.

Cephalometry↗
PubMed2005

Prediction of human drug clearance from in vitro and preclinical data using physiologically based and empirical approaches.

PURPOSE: The aim of this study is to compare the accuracy of five methods for predicting in vivo intrinsic clearance (CL(int)) and seven for predicting hepatic clearance (CL(h)) in humans using in vitro microsomal data and/or preclinical animal data. METHODS: The human CL(int) was predicted for 33 drugs by five methods that used either in vitro data with a physiologic scaling factor (SF), with an empirical SF, with the physiologic and drug-specific (the ratio of in vivo and in vitro CL(int) in rats) SFs, or rat CL(int) directly and with allometric scaling. Using the estimated CL(int), the CL(h) in humans was calculated according to the well-stirred liver model. The CL(h) was also predicted using additional two methods: using direct allometric scaling or drug-specific SF and allometry. RESULTS: Using in vitro human microsomal data with a physiologic SF resulted in consistent underestimation of both CL(int) and CL(h). This bias was reduced by using either an empirical SF, a drug-specific SF, or allometry. However, for allometry, there was a substantial decrease in precision. For drug-specific SF, bias was less reduced, precision was similar to an empirical SF. Both CL(int) and CL(h) were best predicted using in vitro human microsomal data with empirical SF. Use of larger data set of 52 drugs with the well-stirred liver model resulted in a best-fit empirical SF that is 9-fold increase on the physiologic SF. CONCLUSIONS: Overall, the empirical SF method and the drug-specific SF method appear to be the best methods; they show lower bias than the physiologic SF and better precision than allometric approaches. The use of in vitro human microsomal data with an empirical SF may be preferable, as it does not require extra information from a preclinical study.

Animals↗
PubMed1999

Finite-element morphometry of soft tissue morphology in subjects with untreated Class III malocclusions.

Soft tissue dynamics may contribute to maxillomandibular allometry (size-related changes in shape) associated with the development of Class III malocclusions. Lateral cephalographs of 124 prepubertal European American children were traced and 12 soft tissue landmarks were digitized. Resultant geometries were normalized, and Procrustes analysis established the statistical difference (p<0.001) between mean Class III and Class I configurations. Comparing the Class III configurations with normals for size-change, color-coded finite element analysis revealed a superoinferior gradient of positive allometry of the Class III facial nodal mesh. A conspicuous area of negative allometry (approximately 40%) was localized near soft subspinale, with a approximately 70% increase in size in the mental region. For shape-change, the Class III facial mesh was isotropic, except in the anisotropic circumoral regions. Conventional cephalometry revealed that about 50% of linear and 75% of angular parameters differed statistically (p<0.001). Soft tissue dynamics during early postnatal development may contribute to the development of Class III malocclusions.

Case-Control Studies↗
PubMed1998

Facial growth in Cercocebus torquatus: an application of three-dimensional geometric morphometric techniques to the study of morphological variation.

This paper presents a study of 3-dimensional growth in the facial skeleton of the mangabey, Cercocebus torquatus. The pattern of facial cortical remodelling in this species is already well mapped from an earlier study. In this paper we consider the extent to which these remodelling maps relate to ontogenetic changes in size and shape of the face. This study is based on 31 facial landmarks taken from 49 adult and subadult faces. Our analysis draws on some of the tools of geometric morphometrics and we take this opportunity to describe our implementation of these tools for 3D data. The geometric analysis permits the known remodelling maps to be interpreted in the context of the general pattern of facial growth in this species. We are also able to examine sexual dimorphism in the face of this species and consider the extent to which males and females share similar ontogenetic allometries. Our findings indicate that the general pattern of size-related shape variation during facial growth is more or less identical for males and females up to eruption of the third permanent maxillary molar (M3). After this, ontogenetic allometries appear to diverge. The finding of a common growth allometry that is well approximated for younger specimens by a simple linear model is consistent with the earlier findings of a consistent pattern of facial remodelling up to M3 eruption. We consider the implications of these findings in terms of the potential for these approaches in the study of comparative growth in related species.

Animals↗
PubMed1998

Muscle growth in wild and domestic ducks.

1. Increases in weight of the M. pectoralis, M. iliotibialis lateralis and M. flexor cruris lateralis were measured in mallards, White Pekins, Muscovies and a Muscovy x White Pekin cross from hatching to 154 days of age. Growth with respect to age was analysed using the Janoschek growth curve. 2. The M. pectoralis was less developed at hatching than both leg muscles. Furthermore, it showed a slower growth to its final weight and a later age at maximum growth than both leg muscles. 3. Pekins exhibited a faster Pectoralis and Iliotibialis lateralis muscle growth than mallards and Muscovies. The latter attained greater weights than Pekins at later ages owing to a higher asymptote. The cross showed the fastest muscle growth. 4. With respect to body weight, the Pectoralis is characterised by isometry followed by strongly positive allometry. This multiphasic allometry implies that relative muscle weights should not be used and the value of the allometric exponent strongly depends on both the beginning and duration of the period of investigation. Leg muscles showed isometric to slightly negative, simple allometry.

Aging↗
PubMed1999

Growth of the digestive organs in ducks with considerations on their growth in birds in general.

1. Growth of the oesophagus, proventriculus, gizzard, intestine, liver and pancreas weight was investigated in Mallards, White Pekins, Muscovies and a Muscovy x White Pekin cross. The birds varied in age between hatching and 154 d. The data were analysed by fitting both the Janoschek growth curve and the allometric formula. 2. The growth rate of all organs, except the oesophagus, peaked earlier (30 d for Muscovies and 14 d for the other breeds) than body weight and they grew faster to any given percentage of their final weight. In contrast, oesophagus weight showed growth curve characteristics similar to body weight. 3. Oesophagus weight showed simple, slightly negative allometry. The remaining organs followed complex allometry that can approximately be described by 2 allometric stages. The 1st phase was isometric to positive allometric. The 2nd showed marked negative allometry. 4. These growth patterns are assumed to be generally present in birds.

Aging↗
PubMedDate not supplied

Allometric relationship of postmolt net ion uptake, ventilation, and circulation in the freshwater crayfish Procambarus clarkii: intraspecific scaling.

There are few intraspecific studies relating physiological parameters to body mass. This study relates scaling of ionic regulation and respiratory parameters with body mass in crayfish (Procambarus clarkii). These animals were chosen because of their direct development, spanning four orders of magnitude in body mass. Usually, these animals are hyperregulators and must maintain hemolymph electrolyte levels above those in the ambient freshwater. This is especially important in the postmolt, when ion imbalance can occur. Maintaining hemolymph ion levels above ambient involves active processes that are independently related to metabolic rate, ventilation, and circulation. Therefore, this study investigates relationships among size and ionic regulation, heart rate, and ventilation in crayfish, spanning a size range of 0.003-24 g. Postmolt net ion uptake of Ca, titratable base, Na, Cl, and NH4 increase with body mass (positive allometry) with slopes of 0.92, 0.79, 0.90, 0.84, and 0.87, respectively. Between 72% and 97% of variation in ionic regulation was related to body mass. The slopes differed from each other for Ca and titratable base but not for Na, Cl, and NH4. For heart rate and ventilation rate, different relationships were derived for animals smaller and larger than 0.01 g (between first and third instar). Animals larger than 0.01 g show a negative allometric relationship between heart rate and body size ([body mass](0.15)), while smaller animals show positive allometry with body size, but only 29% of variation in heart rate is explained by body size alone. For ventilation rates, the negative allometry with body size for animals larger than 0.01 g is present, but less than 15% of variation in ventilation rate is explained by size, while for smaller animals the size dependency disappears. Based on these results, predictions of physiological parameters such as ionic regulation based on body size are useful in crayfish, but estimates of respiratory parameters and body size should be used with caution.

Analysis of Variance↗
PubMed2003

Size-dependent growth and the development of inequality in maize, sunflower and soybean.

Links were investigated between allometry of plant growth and dynamics of size structure of well-fertilized, irrigated crops of soybean (Glycine max L.), sunflower (Helianthus annuus L.) and maize (Zea mays L.) grown at standard plant-population densities (D), as in commercial crops (D = 30, 6 and 8.5 plants m-2, respectively), and at high densities (2D). Patterns of size-dependent growth of shoot and seed mass accumulation were distinctly different among species. In soybean and sunflower, non-linear relationships between size and subsequent growth led to strong hierarchical populations in terms of both shoot and seed biomass. Curvilinear (soybean) and sigmoid (sunflower) size-dependent growth determined strongly asymmetrical (soybean) and bimodal (sunflower) frequency distributions of shoot biomass indicating predominantly size asymmetrical competition among individuals. In comparison, a lower plant-to-plant variation coupled with a typical linear allometry of growth to plant size indicated symmetrical two-sided plant interference in maize. Despite the weak development of hierarchies in shoot biomass, a strong inequality in reproductive output developed in crowded populations of maize indicating an apparent breakage of reproductive allometry.

Biomass↗
PubMed2006

Responses of crown development to canopy openings by saplings of eight tropical submontane forest tree species in Indonesia: a comparison with cool-temperate trees.

BACKGROUND AND AIMS: Growth in trunk height in canopy openings is important for saplings. How saplings increase height growth in canopy openings may relate to crown architectural constraints. Responses of crown development to canopy openings in relation to trunk height growth were studied for saplings (0.2-2.5 m tall) of eight tropical submontane forest tree species in Indonesia. The results of this study were also compared with those of temperate trees in northern Japan. METHODS: The crown architecture differed among the eight tropical species, i.e. they had sparsely to highly developed branching structures. Crown allometry was compared among the eight species in each canopy condition (closed canopy or canopy openings), and between closed canopy and canopy openings within a species. A general linear regression model was used to analyse how each species increases height growth rate in canopy openings. Crown allometry and its plasticity were compared between tropical and temperate trees by a nested analysis of covariance. KEY RESULTS: Tropical submontane trees had responses similar to cool-temperate trees, showing an increase in height in canopy openings, i.e. taller saplings of sparsely branched species increase height growth rates by increasing the sapling leaf area. Cool-temperate trees have a wider crown projection area and a smaller leaf area per crown projection area to avoid self-shading within a crown compared with tropical submontane trees. Plasticity of the crown projection area is greater in cool-temperate trees than in tropical submontane trees, probably because of the difference in leaf longevity. CONCLUSIONS: This study concluded that interspecific variation in the responses of crown development to canopy openings in regard to increasing height related to the species' branching structure, and that different life-forms, such as evergreen and deciduous trees, had different crown allometry and plasticity.

Indonesia↗
PubMed1991

A multivariate analysis of cardiac growth in human embryos: endocardial cushions and ventricular myocardium.

STUDY OBJECTIVE: In view of the controversy about the morphological significance of the endocardial cushion tissue and ventricular myocardium during cardiac development, the aim was to carry out quantitative studies of these structures. DESIGN: Endocardial cushion tissue and ventricular myocardium were quantified by point count planimetry. The relative growth of the volume of these structures, and also the embryonic crown-rump length, was studied by multivariate allometry (principal components analysis) with the covariance matrix calculated from natural logarithms of the data. EXPERIMENTAL MATERIAL: 27 serially sectioned human embryos were studied, ranging from stage 15 to stage 23 (Paris collection). MEASUREMENTS AND MAIN RESULTS: The relative growth of endocardial cushion tissue, ventricular myocardium, and crown-rump length was discontinuous during the postsomitic period. The first component in principal components analysis measures overall size and, in the present analysis, accounts for 88.6% of the total variance. The growth vector isometry hypothesis was checked with the chi 2 test. This showed that differences in growth between cardiac structures and crown-rump length were allometric (p less than 0.01). Endocardial cushion tissue volume and crown-rump length grew with negative allometry during the second month of gestation, while ventricular myocardium volume grew with positive allometry. CONCLUSIONS: The results agree with those researchers who consider that endocardial cushion tissue functions only in causing initial cardiac fusion and partitioning, with little influence on the formation of definitive cardiac structures.

Heart↗
PubMed2003

Soft tissue changes in patients with Class II Division 1 malocclusions treated using Twin Block appliances: finite-element scaling analysis.

To determine changes in soft tissue profile in patients with Class II division 1 malocclusions treated with Twin Block appliances (TBA), 99 pairs of lateral cephalographs were traced and 25 soft tissue landmarks digitized. Procrustes superimposition was used to generate average soft tissue profiles scaled to an equivalent size. Statistical differences between prepubertal, pre- and post-treatment profiles were found using ANOVA (P < 0.001). Similarly, significant differences were found between adolescent, pre- and post-treatment profiles (P < 0.001). Using a colour-coded finite element scaling analysis (FESA) programme to localize size change, male prepubertal post-treatment configurations revealed local increases in size at the labiomental groove (approximately 25%) with negative allometry (size-related form change approximately 5%) in the labial and symphyseal regions. For the female prepubertal post-treatment configuration, local increases in size were conspicuous also at the labiomental groove (approximately 6%). Male adolescent post-treatment configurations revealed increases in size in the nasal, mental, and labiomental groove regions (approximately 18%) with negative allometries associated with the upper and lower lips (approximately 20%). For the female adolescent post-treatment configuration, the labial fissure showed an increase in size (approximately 17%), whereas the upper and lower lips and symphyseal region exhibited negative allometries (approximately 5-15%). For shape change, all soft tissue post-treatment configurations were highly isotropic (uniform shape change) over the entire facial nodal mesh except in the areas of the labiomental region and the labial fissure. Thus, in children and adolescents treated for Class II malocclusions a less pronounced labiomental groove is associated with using TBAs, which may provide a more effective anterior lip seal.

Adolescent↗
PubMed2005

Power laws of complex systems from extreme physical information.

Many complex systems obey allometric, or power, laws y=Y x(a) . Here y > or = 0 is the measured value of some system attribute a , Y> or =0 is a constant, and x is a stochastic variable. Remarkably, for many living systems the exponent a is limited to values n/4 , n=0, +/-1, +/-2.... Here x is the mass of a randomly selected creature in the population. These quarter-power laws hold for many attributes, such as pulse rate (n=-1) . Allometry has, in the past, been theoretically justified on a case-by-case basis. An ultimate goal is to find a common cause for allometry of all types and for both living and nonliving systems. The principle I-J=extremum of extreme physical information is found to provide such a cause. It describes the flow of Fisher information J-->I from an attribute value a on the cell level to its exterior observation y . Data y are formed via a system channel function y identical to f (x,a) , with f (x,a) to be found. Extremizing the difference I-J through variation of f (x,a) results in a general allometric law f (x,a) identical to y=Y x(a) . Darwinian evolution is presumed to cause a second extremization of I-J , now with respect to the choice of a . The solution is a=n/4 , n=0,+/-1,+/-2..., defining the particular powers of biological allometry. Under special circumstances, the model predicts that such biological systems are controlled by only two distinct intracellular information sources. These sources are conjectured to be cellular DNA and cellular transmembrane ion gradients.

Algorithms↗
PubMed2006

Interspecies allometric scaling. Part I: prediction of clearance in large animals.

Interspecies scaling is a useful tool for the prediction of pharmacokinetic parameters from animals to humans, and it is often used for estimating a first-time in human dose. The knowledge of pharmacokinetics in veterinary species is important for dosage selection, particularly in the treatment of large zoo animal species, such as elephants, giant cats and camels, for which pharmacokinetic data are scant. Therefore, the accuracy in clearance predictions in large animal species, with and without the use of correction factors (rule of exponents), and the impact of species selection in the prediction of clearance in large animal species was examined. Based upon this analysis, it was determined that there is a much larger risk of inaccuracies in the clearance estimates in large animal species when compared with that observed for humans. Unlike in humans, for large animal species, correction factors could not be applied because there was no trend between the exponents of simple allometry and the appropriate correction factor for improving our predictions. Nevertheless, we did see an indication that the exponents of simple allometry may alert us as to when the predicted clearance in the large animal may be underestimated or overpredicted. For example, if a large animal is included in the scaling, the predicted clearance in a large animal should be considered overestimated if the exponent of simple allometry is >1.3. Despite the potential for extrapolation error, the reality is that allometric scaling is needed across many veterinary practice situations, and therefore will be used. For this reason, it is important to consider mechanisms for reducing the risk of extrapolation errors that can seriously affect target animal safety, therapeutic response, or the accuracy of withdrawal time predictions.

Animals↗
PubMed1974

Size and scaling in human evolution.

Our general conclusion is simply stated: many lineages display phyletic size increase; allometric changes almost always accompany increase in body size. We cannot judge adaptation until we separate such changes into those required by increasing size and those serving as special adaptations to changing environments. In our view, the three australopithecines are, in a number of features, scaled variants of the "same" animal. In these characters, A. africanus is no more "advanced" than the larger, more robust forms. The one early hominid to show a significant departure from this adaptive pattern toward later hominids-cranially, dentally, and postcranially-is H. habilis from East Africa. The australopithecines, one of which was probably a precursor of the Homolineage, were apparently a successful group of basically vegetarian hominids, more advanced behaviorally than apes (87), but not hunter-gatherers. The fossil hominids of Africa fall into two major groupings. One probable lineage, the australopithecines, apparently became extinct without issue; the other evolved to modern man. Both groups displayed steady increase in body size. We consider quantitatively two key characters of the hominid skull: cranial capacity and cheek tooth size. The variables are allometrically related to body size in both lineages. In australopithecines, the manner of relative growth neatly meets the predictions for functional equivalence over a wide range of sizes (negative allometry of cranial capacity with a slope against body weight of 0.2 to 0.4 and positive allometry of postcanine area with a slope near 0.75). In the A. africanus to H. sapiens lineage, cranial capacity increases with positive allometry (slope 1.73) while cheek teeth decrease absolutely (slope - 0.725). Clearly, these are special adaptations unrelated to the physical requirements of increasing body size. We examined qualitatively other features, which also seem to vary allometrically. Of course, many characters should be studied quantitatively, but we think that the scheme outlined here should be treated as the null hypothesis to be disproved.

Animals↗