Body Shape Variation Research Articles

Disentangling the importance of body size, shape and phylogenetic variation in community assembly: the case of Neotropical treefrogs communities

Disentangling the importance of body size, shape and phylogenetic variation in community assembly: the case of Neotropical treefrogs communities

The impact of Manjil and Tarik dams (Sefidroud River, southern Caspian Sea basin) on morphological traits of Siah Mahi Capoeta gracilis (Pisces: Cyprinidae)

It has been postulated that the building of the Manjil and Tarik dams on Sefidroud River has led to the body shape variation of Capoeta gracilis in up- and downstream populations due to the isolation. In this study, Geometric morphometric approach was used to explore body shape variations of Capoeta gracilis populations in up- and downstream Manjil and Tarik dams in Sefidroud River from south of the Caspian Sea basin. The shape of 90 individuals from three sampling sites was extracted by recording the 2-D coordinates of 13 landmark points. PCA, CVA, DFA and CA analysis were used to examine shape differences among the populations. The significant differences were found among the shape of the populations and these differences were observed in the snout, the caudal peduncle and head. The present study indicated the body shape differences in the populations of Capoeta gracilis in the Sefidroud River across the Manjil and Tarik dams, probably due to the dam construction showing anthropogenic transformation of rivers influences body shape in an aquatic organism.

Morphological differentiation among populations of Rhinella marina (Amphibia: Anura) in western Mexico

Conspecific populations inhabiting different environments may exhibit mor- phological differences, potentially reflecting differential local adaptation. In anuran amphibians, morphology of the pelvis and hindlimbs may often experience strong selection due to effects on locomotion. In this study, we used the cane toad Rhinella marina to test the hypothesis that populations experiencing a higher abundance of predators should suffer higher mortality rates and exhibit morphological traits associated with enhanced locomotor performance (narrower pelvis and head, longer pelvis and hindlimbs, shorter presacral vertebral column). We investigated inter-population variation in survival rate, abundance of predators, and body shape across five populations in rivers in western Mexico. We conducted (1) mark-recapture experiments to calculate survival rates, (2) linear transects with point counts to estimate abundance of predatory spiders, snakes, and birds, and (3) geometric morphometric analyses to investigate body shape variation. We found signifi- cant differences among populations in survival rates, abundance of predators, and body shape. However, these three variables were not necessarily inter-related. Increased predator abundance did not result in decreased survival rates, suggesting other causes of mortality affect these populations. While some morphological differences supported our predictions (trend for longer pelvis, shorter presacral vertebral column, and narrower head in sites with increased abundance of spiders and snakes), other aspects of morphology did not. We discuss alternative explanations for the lack of clear associations between predation, sur- vival, and morphology.

Fast Human Detection Using Dynamic Contour and Histograms of Oriented Gradients

Human detection is a challenging problem, owing to variations in pose, body shape, appearance, clothing, illumination, and background clutter, in addition, the cameras or backgrounds make it even harder. But even so, it has many potential applications including net-meeting, security, human-computer interaction, gaming, and even health-care. Various new approaches have been proposed to solve this problem. We have studied and implemented a method by using dynamic contour [ and Histograms of Oriented Gradients [ to detecting human body fast and accurately in static images.

Intraspecific variation in body size and shape in an Andean highland anole species, <i>Anolis ventrimaculatus</i> (Squamata: Dactyloidae)

Variation in body characteristics related to lizard locomotion has been poorly studied at the intraspecific level in Anolis species. Local adaptation due to habitat heterogeneity has been reported in some island species. However, studies of mainland species are particularly scarce and suggest different patterns: high variability among highland lizards and poorly differentiated populations in one Amazonian species. We characterized inter population variation of body size and shape in the highland Andean Anolis ventrimaculatus, an endemic species from Western Colombia. A total of 15 morphometric variables were measured in specimens from the reptile collection of the Instituto de Ciencias Naturales, Universidad Nacional, Colombia. The study included individuals from seven different highland localities. We found size and shape sexual dimorphism, both of which varied among localities. Patterns of variation in body proportions among populations were different in both males and females, suggesting that either sexual or natural selective factors are different in each locality and between sexes. Since this species exhibits a fragmented distribution in highlands, genetic divergence may also be a causal factor of the observed variation. Ecological, behavioral, additional morphological as well as phylogenetic data, may help to understand the evolutionary processes behind the geographic patterns found in this species.

Sexual and seasonal dimorphism in adult adfluvial bull trout (Salvelinus confluentus)

Sexual dimorphism in fishes may be obvious during the reproductive period and less clear during the nonreproductive periods. Despite being difficult to discern during the nonreproductive period, sex-related differences in body condition and shape can yield important insights into a species’ behaviour and ecology. The purpose of this study was to test hypotheses about body condition and shape variation related to sex and season (nonreproductive and reproductive periods) in a population of adult adfluvial bull trout (Salvelinus confluentus (Suckley, 1859)), which is a poorly understood and imperiled species across much of its range. Geometric morphometric samples were collected by angling in the spring and late summer in a reservoir in British Columbia. Principal components analysis identified two principal components (PC) that were related to body condition and that varied according to season and sex. Spring-caught females were in better body condition than spring-caught males. There was a significant sex × season interaction on body condition such that late-summer males were not different from late-summer females. Spawning bull trout exhibited a decline in body condition during the summer season. An additional PC that described head size was found to vary significantly between sexes; however, an assignment test showed that it failed to reliably distinguish between the sexes. We hypothesized that the ecology of these animals, including sex-specific behaviour, is responsible for sexual and seasonal differences in bull trout body condition and morphology. This study offers new insight into the ecology of bull trout and shows that shape data for fishes can be obtained nonlethally, which is particularly important for species that are imperiled.

DXA-based Model for Advanced Analysis of Body Shape Variation

The aim of this study was to measure the effective dose on an anthropomorphic phantom undergoing lumbar and femoral dual energy X-ray absorption (DXA) examinations, using 3 different scan modalities (fast-array [FA], array [A], high-definition [HD]), and assess the differences in the lifetime attributable risk (LAR) of cancer due to radiation. An anthropomorphic phantom was used. Thermoluminescent dosimeters were placed over 12 anatomic phantom regions and outside the room (to measure background radiation). Fifty scans on the femur and spine were performed for each mode. The dose relative to a single DXA scan for each dosimeter was measured (mean over the 50 scans) and the background radiation was then subtracted. The equivalent dose per organ was obtained. The total body effective dose was calculated by adding the equivalent doses. We estimated the lifetime dose absorption and LAR for cancer for a male and a female patient undergoing 36 DXA studies (18 lumbar, 18 femoral) every 21 months for 32 years. The effective dose for lumbar scans was FA = 17.79 μSv, A = 32.88 μSv, HD = 31.08 μSv; for femoral scans, FA = 5.29 μSv, A = 9.55 μSv, HD = 7.54 μSv. LAR estimation showed a minimal increase in cancer risk (range 4.55 × 10−4% [FA, femoral, male] to 4.02 × 10−3% [A, lumbar, female]). The lifetime dose absorption and LAR for cancer for a male and a female patient undergoing 36 DXA studies (18 lumbar, 18 femoral) every 21 months for 32 years were 0.756 mSv, 3.82 × 10−3% and 0.756 mSv, 5.11 × 10−3%, respectively. DXA examinations cause radiation levels that are comparable to the background radiation. Regardless of the scan modality or the anatomic site, a patient undergoing DXA scans for a lifetime has a negligible increased risk of developing cancer.

Variation in Body Shape across Species and Populations in a Radiation of Diaptomid Copepods

Inter and intra-population variation in morphological traits, such as body size and shape, provides important insights into the ecological importance of individual natural populations. The radiation of Diaptomid species (~400 species) has apparently produced little morphological differentiation other than those in secondary sexual characteristics, suggesting sexual, rather than ecological, selection has driven speciation. This evolutionary history suggests that species, and conspecific populations, would be ecologically redundant but recent work found contrasting ecosystem effects among both species and populations. This study provides the first quantification of shape variation among species, populations, and/or sexes (beyond taxonomic illustrations and body size measurements) to gain insight into the ecological differentiation of Diaptomids. Here we quantify the shape of five Diaptomid species (family Diaptomidae) from four populations each, using morphometric landmarks on the prosome, urosome, and antennae. We partition morphological variation among species, populations, and sexes, and test for phenotype-by-environment correlations to reveal possible functional consequences of shape variation. We found that intraspecific variation was 18-35% as large as interspecific variation across all measured traits. Interspecific variation in body size and relative antennae length, the two traits showing significant sexual dimorphism, were correlated with lake size and geographic location suggesting some niche differentiation between species. Observed relationships between intraspecific morphological variation and the environment suggest that divergent selection in contrasting lakes might contribute to shape differences among local populations, but confirming this requires further analyses. Our results show that although Diaptomid species differ in their reproductive traits, they also differ in other morphological traits that might indicate ecological differences among species and populations.

A revised metric for quantifying body shape in vertebrates

Vertebrates exhibit tremendous diversity in body shape, though quantifying this variation has been challenging. In the past, researchers have used simplified metrics that either describe overall shape but reveal little about its anatomical basis or that characterize only a subset of the morphological features that contribute to shape variation. Here, we present a revised metric of body shape, the vertebrate shape index (VSI), which combines the four primary morphological components that lead to shape diversity in vertebrates: head shape, length of the second major body axis (depth or width), and shape of the precaudal and caudal regions of the vertebral column. We illustrate the usefulness of VSI on a data set of 194 species, primarily representing five major vertebrate clades: Actinopterygii, Lissamphibia, Squamata, Aves, and Mammalia. We quantify VSI diversity within each of these clades and, in the course of doing so, show how measurements of the morphological components of VSI can be obtained from radiographs, articulated skeletons, and cleared and stained specimens. We also demonstrate that head shape, secondary body axis, and vertebral characteristics are important independent contributors to body shape diversity, though their importance varies across vertebrate groups. Finally, we present a functional application of VSI to test a hypothesized relationship between body shape and the degree of axial bending associated with locomotor modes in ray-finned fishes. Altogether, our study highlights the promise VSI holds for identifying the morphological variation underlying body shape diversity as well as the selective factors driving shape evolution.

Recent parallel divergence in body shape and diet source of alewife life history forms

Recent work suggests that juvenile alewives (Alosa pseudoharengus) share similar phenotypes among independently derived landlocked (freshwater resident) populations. Based on this observation, it is possible that the alewife life history forms represent a case of parallel adaptive divergence. To further evaluate this hypothesis, we describe patterns of body shape divergence between anadromous and landlocked alewife life history forms using geometric morphometrics. Our results suggest that body shape differs significantly between juveniles of the alewife forms: anadromous fish were more robust, with larger heads and deeper caudal peduncles, while landlocked fish from three independently isolated populations were more fusiform with thinner caudal peduncles and smaller heads. These differences matched population level dietary patterns, which suggest that anadromous fish consumed more littoral resources than landlocked fish. Finding consistent differences across populations of the same form supports the notion that landlocked alewives have diverged from their anadromous ancestors in a parallel manner, in response to pressures associated with being isolated in freshwater lakes. Comparing alewife phenotypes to expectations from the literature suggests that neither migration distance of the population, nor the relative availability of habitats in each lake, are likely drivers of the pattern we report. Instead, the pattern is consistent with the hypothesis that divergence between alewife forms results from the distinct effects of each form on its zooplankton prey.

Habitat-associated morphological divergence in four Shemaya, Alburnus chalcoides (Actinopterygii: Cyprinidae) populations in the southern Caspian Sea using geometric morphometrics analysis

In this study, Geometric morphometrics approach was used to explore body shape variations and growth trajectory among four population of Shemaya (Alburnus chalcoides). The shape of 114 individuals from three rivers (Lisar, Shiroud and Babolroud) and one lagoon (Anzali) from the south of Caspian Sea was extracted by recording the 2-D coordinates of 16 landmark points. We applied a GPA analysis to eliminate non-shape variations. PCA, CVA, MANOVA and DFA analysis were used to examine shape differences among populations. The significant differences found among the shape of populations. Since Shemaya is an anaderemus fish and all their populations have a common origin, we concluded that differences between habitat features might create selective pressures resulting morphological divergence among conspecific populations. We suggest that high level of plasticity, particularly in the depth of body, head and caudal peduncle shape may reflect low costs of maintaining the plastic response even in relatively isolated populations.

Evolutionary history of elongation and maximum body length in moray eels (Anguilliformes: Muraenidae)

Body shape and size are important axes of organismal diversification. The elongate body form has evolved repeatedly in disparate vertebrate clades, and is associated with a variety of maximum body lengths. We used a time-calibrated phylogeny for 40 species of moray eels to analyse the evolution of elongation and the morphological mechanisms underlying variation in body shape and maximum body length. We find that body elongation in morays evolves independently of elongation of the vertebral column. In contrast, maximum body length evolves by a different mechanism: through region-specific increases in vertebral number, elongation of individual vertebral centra, and postembryonic somatic growth. We reconstruct an ancestral moray eel and provide evidence for accelerated morphological evolution in three highly elongate species that are associated with a burrowing lifestyle. We compare these patterns with those described for other vertebrates, and show that body shape and body length may evolve independently of each other and (in the case of shape) of the vertebral column. © 2013 The Linnean Society of London, Biological Journal of the Linnean Society, 2013, ••, ••‐••. ADDITIONAL KEYWORDS: axial skeleton ‐ morphological evolution ‐ pleomerism ‐ size ‐ vertebrae ‐ vertebral aspect ratio.

Sympatric Polymorphism in Lake Trout: The Coexistence of Multiple Shallow‐Water Morphotypes in Great Bear Lake

AbstractPolymorphism in northern fishes is common, but the extent to which polymorphism occurs in Lake Trout Salvelinus namaycush, a species generally associated with low intraspecific variation, is not well known. This study examined the polymorphism of Lake Trout inhabiting the shallow‐water zones (≤30 m) of Great Bear Lake, Northwest Territories. We combined an analysis of classical morphometric and traditional linear measures with shape analysis (geometric morphometrics) to quantify morphological differences in body shape, head shape, and fin and body length measurements among 558 adult and 55 juvenile shallow‐water Lake Trout from Great Bear Lake. A UPGMA cluster analysis on adult Lake Trout distinguished three different morphs that coexist in the shallow‐water habitat. The most important differences among adult morphotypes were associated with head and fin measurements, whereas body shape variation was less distinct. A fourth, albeit rarer, morph was supported by a multivariate ANOVA that indicated significant differences in head and fin characteristics among the four groups. The divergent morphologies among the shallow‐water Lake Trout of Great Bear Lake are consistent with traits generally associated with feeding and swimming. In contrast to adult trout, no consistent patterns were found for juveniles, suggesting that phenotypic differences develop at a later stage. This unusual level of endemic diversity in the shallow‐water habitat expands our knowledge of Lake Trout diversity beyond the predominant focus on shallow‐ versus deepwater forms.

Body shape analyses of large persons in South Korea

Despite the prevalence of obesity and overweight, anthropometric characteristics of large individuals have not been extensively studied. This study investigated body shapes of large persons (Broca index ≥ 20, BMI ≥ 25 or WHR>1.0) using stature-normalised body dimensions data from the latest South Korean anthropometric survey. For each sex, a factor analysis was performed on the anthropometric data set to identify the key factors that explain the shape variability; and then, a cluster analysis was conducted on the factor scores data to determine a set of representative body types. The body types were labelled in terms of their distinct shape characteristics and their relative frequencies were computed for each of the four age groups considered: the 10s, 20s–30s, 40s–50s and 60s. The study findings may facilitate creating artefacts that anthropometrically accommodate large individuals, developing digital human models of large persons and designing future ergonomics studies on largeness. Practitioner Summary: This study investigated body shapes of large persons using anthropometric data from South Korea. For each sex, multivariate statistical analyses were conducted to identify the key factors of the body shape variability and determine the representative body types. The study findings may facilitate designing artefacts that anthropometrically accommodate large persons.

Distribution Pattern of Seahorse species (Genus: Hippocampus) in Tamilnadu and Kerala Coasts of India

The survey along the Tamilnadu and Kerala coats of India reveled that six species of seahors (Hippocampus fuscus, H. kelloggi, H. kuda, H. histrix H. mohnikei and H. trimaculatus) were distributed with different density. Out of the six species, H. fuscus, H. kuda and H. trimaculatus, were the commonly available species in all the observed areas. In Palk Bay, H. kuda was the dominant species constituting 49.10% of the total seahorses encountered. Hippocampus trimaculatus was the second dominant species which accounting 39.28%. The Gulf of Mannar region also most abounded with H. kuda (68.98%) followed by H. trimaculatus (20.80%), H. fuscus (9.80%), H. kelloggi (2.23%) and H. histrix (0.37%). In Kerala coast, H. trimaculatus was the dominant species (79.68%) followed by H. kuda (9.89%), H. kelloggi (8.33%) and H. fuscus (2.08%). To infer the variation of six seahorse species the morphometric and meristic characters were analysed. The important morphometric and meristic characters are trunk rings, tail rings, pectoral and dorsal fin rays, trunk length, tail length, coronet height, head length, snout length, snout depth and head depth. Variation in overall body shape, relative snout length, coronet height, number of tail ring was sufficient to separate the specimens to Hippocampus fuscus, H. kelloggi, H. kuda, H. histrix H. mohnikei and H.trimaculatus. The species density and diversity depends on the habitat and biogeography of those areas. Majority of seahorse fishing in Tamilnadu was by shrimp trawl, by-catch and very few target catch by divers also seen in some villages of Palk Bay and Gulf of Mannar region. The shrimp trawl by-catch only bringing more H. trimaculatus than the other species in Kerala coasts.

Shared and unique morphological responses of stream fishes to anthropogenic habitat alteration.

Understanding population-level responses to novel selective pressures can elucidate evolutionary consequences of human-altered habitats. Stream impoundments (reservoirs) alter riverine ecosystems worldwide, exposing stream fishes to uncommon selective pressures. Assessing phenotypic trait divergence in reservoir habitats will be a first step in identifying the potential evolutionary and ecological consequences of stream impoundments. We tested for body shape divergence in four stream-adapted fishes found in both habitats within three separate basins. Shape variation among fishes was partitioned into shared (exhibited by all species) and unique (species-specific) responses to reservoir habitats. All fishes demonstrated consistent significant shared and unique morphological responses to reservoir habitats. Shared responses were linked to fin positioning, decreased body depths and larger caudal areas; traits likely related to locomotion. Unique responses were linked to head shape, suggesting species-specific responses to abiotic conditions or changes to their trophic ecology in reservoirs. Our results highlight how human-altered habitats can simultaneously drive similar and unique trait divergence in native populations.

Body shape evolution of Chromis and Azurina species (Percifomes, Pomacentridae) of the eastern Pacific

Chromis is a circumglobal tropical and temperate genus with over 84 species of damselfishes. Studies based in osteological and molecular data have cited the relationship between Azurina and Chromis in the eastern Pacific. The main objectives of the study are: (1) to characterize size and shape in all Chromis and Azurina species of the eastern Pacific, (2) explore the phylogenetic signal of external morphology, and (3) present a hypothesis of the diversification process of this group. According to the results, there is no significant relationship between size and shape. The variation in body shape among all species is related to the height of the trunk, position of the snout and eye, and length of the caudal peduncle. The main morphologic variation between Azurina and Chromis is the degree of elongation of the body. Both Azurina species are closely related to C. punctipinnis and C. atrilobata. The morphological pattern of Azurina integrated it into Chromis. The phylogenetic pattern found by geometric morphometric analyses presented a high similarity with previous results based on molecular data. Phylogeny recovered two main clades, slender-bodied and deep-bodied species. This pattern of morphometric variation is closely related to exploitation of two different reef environments.

Biomedical Anthropology and Climate: Exploring Physiological Adaptations as Causes of Ethnic Variation in Metabolic Diseases

It is well known that climate is a significant contributor to extant human biological variation. Since the mid-1950’s, several authors have demonstrated that Bergman’s and Allen’s rules regarding body surface area and mass and mean annual temperature in mammals seem to hold for humans as a species, providing a basis for the understanding of body size and shape variation among indigenous human groups [1]. Studies in human population biology have also found that other climate related aspects such as the gradation of decreasing ultraviolet radiation intensity from the equator to the poles and the decrease in atmospheric oxygen as the altitude of terrestrial habitats increases has modified the biology of humans

Optimization and Soft Constraints for Human Shape and Pose Estimation Based on a 3D Morphable Model

We propose an approach about multiview markerless motion capture based on a 3D morphable human model. This morphable model was learned from a database of registered 3D body scans in different shapes and poses. We implement pose variation of body shape by the defined underlying skeleton. At the initialization step, we adapt the 3D morphable model to the multi-view images by changing its shape and pose parameters. Then, for the tracking step, we implement a method of combining the local and global algorithm to do the pose estimation and surface tracking. And we add the human pose prior information as a soft constraint to the energy of a particle. When it meets an error after the local algorithm, we can fix the error using less particles and iterations. We demonstrate the improvements with estimating result from a multi-view image sequence.

A model for estimating body shape biological age based on clinical parameters associated with body composition.

BackgroundTo date, no studies have attempted to estimate body shape biological age using clinical parameters associated with body composition for the purposes of examining a person’s body shape based on their age.ObjectiveWe examined the relations between clinical parameters associated with body composition and chronological age, and proposed a model for estimating the body shape biological age.MethodsThe study was conducted in 243,778 subjects aged between 20 and 90 years who received a general medical checkup at health promotion centers at university and community hospitals in Korea from 2004 to 2011.ResultsIn men, the clinical parameters with the highest correlation to age included the waist- to-hip ratio (r = 0.786, P < 0.001), hip circumference (r = −0.448, P < 0.001), and height (r = −0.377, P < 0.001). In women, the clinical parameters with the highest correlation to age include the waist-to-hip ratio (r = 0.859, P < 0.001), waist circumference (r = 0.580, P < 0.001), and hip circumference (r = 0.520, P < 0.001). To estimate the optimal body shape biological age based on clinical parameters associated with body composition, we performed a multiple regression analysis. In a model estimating the body shape biological age, the coefficient of determination (R2) was 0.71 in men and 0.76 in women.ConclusionOur model for estimating body shape biological age might be a novel approach to variation in body shape that is due to aging. We assume that our estimation model would be used as an adjunctive measure in easily predicting differences in body shape with the use of clinical parameters that are commonly used to assess the status of obesity in a clinical setting.