Body Shape Variation Research Articles

Effects of hydroperiod on morphology of tadpoles from highland ponds

Hydroperiod length has been identified as a major driver in community assembly in freshwater systems. Yet we generally lack an understanding of how morphological traits respond to water level decrease under natural conditions. Here, we studied variation in body size and shape in lateral view in tadpoles of Scinax squalirostris and Odontophrynus americanus inhabiting ponds in superhumid highland plateau in southern Brazil. Hydroperiod did not affect tadpole size in either species. In relation to body shape, S. squalirostris tadpoles from long hydroperiod ponds had shorter tails and deeper tail fins than tadpoles from other hydroperiods. Predator presence was positively associated with hydroperiod, restricting our ability to separate their effects on tadpoles morphology. For O. americanus, tadpole shape was not affected by pond hydroperiod. We demonstrated that, in natural environment, the influence of hydroperiod on tadpole morphology might depend on species-specific characteristics, such as behavior and life-history traits. Our results indicate that local context may lead to different effects of hydroperiod, and hydroperiod alone can only partly explain the variation on tadpole shape.

Heteroquely, laterality, maturity body size and shape variation of males and females of the endemic South American anomuran Aegla quilombola Moraes, Tavares & Bueno, 2017

ABSTRACT Aegla quilombola is an anomuran crab endemic to São Paulo State, Brazil. The present manuscript aims to provide information about sexual dimorphism using geometric morphometrics, as well as information about heterochely, laterality and sexual maturity. The specimens were sampled in Intervales State Park. The carapace and chelipeds of all animals were photographed and landmarks digitalized. In the analyses, the propodus of the first pair of pereopods (chelipeds) were used. The same structures were measured for morphometric sexual maturity, analysing the relationships between carapace length (CL) x propodus height for males, and CL x abdomen length (ABL) for females. For heterochely and laterality, the height of male and female chelipeds were evaluated. Morphological differences were found in the shape of the posterior margin of the carapace and in the chelipeds’ palmar region. Males reached morphometric maturity at smaller sizes and showed heterochely and laterality, usually having a larger left cheliped. These differences are probably related to differential energy use by males and females in fulfiling specific ecological roles. Females had larger abdominal margins to invest in reproduction and males invested energy in chelipeds that were more robust and larger than females, as chelipeds are often used in agonistic interactions and to obtain better resources.

Morphometric Variation of Hybridizing Species and Gynogenetic Biotypes of Spined Loaches (Cobitidae, Cobitis) in River Systems of Ukraine

To test the possibility of identifying the species and biotypes of spined loaches of the complex Cobitis elongatoides – taenia – tanaitica using body morphometric characteristics, we considered a pool of specimens from different river systems of Ukraine. The sample included three parental species and seven hybrid biotypes with various genome combinations, and the morphometry was based on 23 body parameters and 26 derivative indices. The variability was analyzed by standard and multivariate statistics. Neither any one measurement, nor their combination allowed identifying the specimens with 95-100% probability. Pooled, samples had no internal logic of morphological remoteness of hybrid biotypes and parental species in regards to their genetic similarity. Morphometry’s low resolution in case of pooled samples is linked to the specifics of body shape and significant geographic variability which partially evens out the between-group differences, while within samples the resolution was higher without reaching even 95% diagnostical certainty. All in all, the resolutions obtained for morphometric parameters are within results obtained in similar studies for other hybrid fishes.

Determination of body shape and meristic characters variations in wild and cultured populations of cichlid fish, Oreochromis niloticus, from the Republic of Benin, West of Africa

Abstract This study was designed to assess morphological changes between cultured and wild tilapia, Oreochromis niloticus (L.). Wild fish samples were obtained from fishermen operating in the waters of the vicinity of the province Parakou, Benin in November 2014, while the cultured samples were obtained from a fish farm in the municipality of Sô-Ava in the Atlantic region of the southern part of the Republic of Benin. Significant differences were observed in all nine morphometric traits measured. Discriminant analysis of morphometric parameters showed high divergence between the populations. The meristic count, however, overlapped broadly showing no divergence between the populations. The morphometric differences between the cultured and wild tilapia, O. niloticus, could have been linked to genetic differences or environmental factors or a combination of these.

Utility of specific bioelectrical impedance vector analysis for the assessment of body composition in children

SummaryBackground & aimsBioelectrical impedance analysis (BIA) is widely considered a body composition technique suitable for routine application. However, its utility in sick or malnourished children is complicated by variability in hydration. A BIA variant termed vector analysis (BIVA) aims to resolve this, by differentiating hydration from cell mass. However, the model was only partially supported by children's data. To improve accuracy, further adjustment for body shape variability has been proposed, known as specific BIVA (BIVAspecific).MethodsWe re-analysed body composition data from 281 children and adolescents (46% male) aged 4–20 years of European ancestry. Measurements included anthropometry, conventional BIA, BIVA outcomes adjusted either for height (BIVAconventional), or for height and body cross-sectional area (BIVAspecific), and fat-free mass (FFM) and fat mass (FM) by the criterion 4-component model. Graphic analysis and regression analysis were used to evaluate different BIA models for predicting FFM and FM.ResultsAge was strongly correlated with BIVAconventional parameters, but weakly with BIVAspecific parameters. FFM correlated more strongly with BIVAconventional than with BIVAspecific parameters, whereas the opposite pattern was found for FM. In multiple regression analyses, the best prediction models combined conventional BIA with BIVAspecific parameters, explaining 97.0% and 89.8% of the variance in FFM and FM respectively. These models could be further improved by incorporating body weight.ConclusionsThe prediction of body composition can be improved by combining two different theoretical models, each of which appears to provide different information about the two components FFM and FM. Further work should test the utility of this approach in pediatric patients.

Evolutionary trends of the conserved neurocranium shape in angel sharks (Squatiniformes, Elasmobranchii)

Elasmobranchii (i.e., sharks, skates, and rays) forms one of the most diverse groups of marine predators. With a fossil record extending back into the Devonian, several modifications in their body plan illustrate their body shape diversity through time. The angel sharks, whose fossil record dates back to the Late Jurassic, some 160 Ma, have a dorsoventrally flattened body, similar to skates and rays. Fossil skeletons of this group show that the overall morphology was well established earlier in its history. By examining the skull shape of well-preserved fossil material compared to extant angel sharks using geometric morphometric methods, within a phylogenetic framework, we were able to determine the conservative skull shape among angel sharks with a high degree of integration. The morphospace occupation of extant angel sharks is rather restricted, with extensive overlap. Most of the differences in skull shape are related to their geographic distribution patterns. We found higher levels of disparity in extinct forms, but lower ones in extant species. Since angel sharks display a highly specialized prey capture behaviour, we suggest that the morphological integration and biogeographic processes are the main drivers of their diversity, which might limit their capacity to display higher disparities since their origin.

Shape diversity of the fish genus Astyanax Baird & Girard, 1854 (Teleostei, Characidae) in adjacent basins

The Neotropical region is highly diverse in fresh water teleost fishes and extends through vast regions of South America. The genus Astyanax comprises small fish found in the tributaries and ditches of the great Brazilian basins, such as the Parana and Sao Francisco Rivers. This group has been ostensibly studied from a chromosomal and molecular point of view but is still involved in problems of phylogenetic location, justifying its position incertae sedis, while having a wide diversity of forms and habitats. Our study counted on the analysis of body shape variations in seven species of the genus Astyanax and in the bimaculatus, fasciatus, and scabripinnis complexes using geometric morphometrics. We obtained images of individuals from different localities in the Parana and Sao Francisco River basins, delineated two-dimensional anatomical landmarks that we then subjected to the generalized Procrustes analysis, and subsequent ordination by principal component analysis and canonical variate analysis. The results showed variation between two large groups, related mainly to variations in body height, indicating the probable existence of different evolutionarily significant units morphologically shaped by the pressure of the environment with what may be incipient speciation.

Body shape diversification along the benthic-pelagic axis in marine fishes.

Colonization of novel habitats can result in marked phenotypic responses to the new environment that include changes in body shape and opportunities for further morphological diversification. Fishes have repeatedly transitioned along the benthic-pelagic axis, with varying degrees of association with the substrate. Previous work focusing on individual lineages shows that these transitions are accompanied by highly predictable changes in body form. Here, we generalize expectations drawn from this literature to study the effects of habitat on body shape diversification across 3344 marine teleost fishes. We compare rates and patterns of evolution in eight linear measurements of body shape among fishes that live in pelagic, demersal and benthic habitats. While average body shape differs between habitats, these differences are subtle compared with the high diversity of shapes found within each habitat. Benthic living increases the rate of body shape evolution and has led to numerous lineages evolving extreme body shapes, including both exceptionally wide bodies and highly elongate, eel-like forms. By contrast, we find that benthic living is associated with the slowest diversification of structures associated with feeding. Though we find that habitat can serve as an impetus for predictable trait changes, we also highlight the diversity of responses in marine teleosts to opportunities presented by major habitats.

Integrating morphological and genetic data at different spatial scales in a cosmopolitan marine turtle species: challenges for management and conservation

AbstractPatterns of genetic structure in highly mobile marine vertebrates may be accompanied by phenotypic variation. Most studies in marine turtles focused on population genetic structure have been performed at rookeries. We studied whether genetic and morphological variation of the endangered green turtle (Chelonia mydas) is consistent geographically, focusing on foraging grounds. An association between population genetic structure and body shape variation at broad (inter-lineage) and fine (foraging grounds) scales was predicted and analysed using mitochondrial DNA and geometric morphometrics. Although genetic and phenotypic differentiation patterns were congruent between lineages, no fine-scale association was found, suggesting adaptive divergence. Connectivity among Pacific foraging grounds found here suggests that temperatures of ocean surface currents may influence the genetic structure of C. mydas on a broad scale. Our results suggest that vicariance, dispersal, life-history traits and ecological conditions operating in foraging grounds have shaped the intraspecific morphology and genetic diversity of this species. Considering a range of geographic and temporal scales is useful when management strategies are required for cosmopolitan species. Integrating morphological and genetic tools at different spatial scales, conservation management is proposed based on protection of neutral and adaptive diversity. This approach opens new questions and challenges, especially regarding conservation genetics in cosmopolitan species.

Landmark-based geometric morphometrics analysis of body shape variation among populations of the blue jack mackerel, Trachurus picturatus, from the North-East Atlantic

Phenotypic variation in fish can indicate exposure to different environmental conditions, affecting species growth and maturation rates and/or be a consequence of genetic factors that allow fish adaptation to different environments. Understanding population structure and dynamics is extremely important for the establishment of sustainable fisheries. The blue jack mackerel, Trachurus picturatus, is an important fishery resource of the North-East (NE) Atlantic. Fish were captured in six sampling locations in the NE Atlantic - Azores, Madeira, Canaries and Portugal mainland - Matosinhos, Peniche and Portimão. The phenotypic diversity of the species was studied using body landmark-based geometric morphometrics. A truss box method was followed and 30 distance variables were extracted from digital images. Additionally, the temporal stability of the morphological characters was investigated by comparing samples from two different years: 2016 and 2019. The transformed distances were analysed by univariate and multivariate statistics. The Macaronesia region – Azores, Madeira and Canaries – and Portugal mainland displayed a clear phenotypic pattern. Distances related to the body width and caudal peduncle were the most significant variables explaining the observed phenotypic heterogeneity. Furthermore, this study also showed that T. picturatus can exhibit fast phenotypic adaptations to the surrounding environment, observed by the discrimination of Peniche in 2019. Nevertheless, the high overall allocation of individuals to the original location observed for both years (78% in 2016 and 83% in 2019) suggests that the population of T. picturatus in the NE Atlantic is phenotypic heterogeneous. These findings corroborate previous studies and have implications for fishery management.

Morphological and trophic divergence of lake and stream minnows (Phoxinus phoxinus).

Phenotypic divergence in response to divergent natural selection between environments is a common phenomenon in species of freshwater fishes. Intraspecific differentiation is often pronounced between individuals inhabiting lakes versus stream habitats. The different hydrodynamic regimes in the contrasting habitats may promote a variation of body shape, but this could be intertwined with morphological adaptations to a specific foraging mode.Herein, I studied the divergence pattern of the European minnow (Phoxinus phoxinus), a common freshwater fish that has received little attention despite its large distribution. In many Scandinavian mountain lakes, European minnows are considered as being invasive and were found to pose threats to the native fish populations due to resource competition. Minnows were recently found to show phenotypic adaptations in lake versus stream habitats, but the question remained if this divergence pattern is related to differences in resource use. I therefore studied the patterns of minnow divergence in morphology (i.e., using geometric morphometrics) and trophic niches (i.e., using stomach content analyses) in the lake Ånnsjön and its tributaries to link the changes in body morphology to the feeding on specific resources. Lake minnows showed a strong reliance on benthic Cladocera and a more streamlined body shape with a more upward facing snout, whereas stream minnows fed on macroinvertebrates (larvae and adults) to a higher degree and had a deeper body with a snout that was pointed down. Correlations showed a significant relationship of the proportion of macroinvertebrates in the gut and morphological features present in the stream minnows. The results of this study highlight the habitat‐specific divergence pattern in morphology and resource use in this ubiquitous freshwater fish. Consequently, interspecific interactions of invasive minnows and the native fish population could differ in the respective food webs and resource competition could target different native fish species in the contrasting habitats.

Comparison of the body shape of Aphanius vladykovi populations (Teleostei: Aphaniidae) using geometric morphometric method

The main purpose of this study was to investigate the morphological changes and body shape variations of the Zagros Tooth-carp Aphanius vladykovi populations in six water bodies located in Chaharmahal and Bakhtiari province, Iran. For this purpose, 240 specimens were collected from the Choghakhor and Gandoman wetlands, the Shalamzar, Balagholi, and Brovi springs, and the Beheshtabad River. Twelve landmark points were digitized on the right side of the fish. Statistical analyses including Principal Component Analysis (PCA), Discriminant Function Analysis (DFA), and Cluster Analysis (CA) were performed using TPS package, SYSTAT 9, and PAST Software. Discriminant function analysis revealed that female fish in different localities show more pronounced body shape differences compared to males from different localities (p <0.001). In addition, in clustering analysis performed among males and among females, two clusters were resolved, which were fairly similar for males and females. These differences might be attributed to the morphological adaptation of the Zagros Tooth-carp to their habitats but a clear inference on the observed morphological divergence will be possible with more genetic, ecological, and experimental evidence.

Ecological Drivers and Sex-Based Variation in Body Size and Shape in the Queensland Fruit Fly, Bactrocera tryoni (Diptera: Tephritidae).

The Queensland fruit fly (Bactrocera tryoni; Q-fly) is an Australian endemic horticultural pest species, which has caused enormous economic losses. It has the potential to expand its range to currently Q-fly-free areas and poses a serious threat to the Australian horticultural industry. A large number of studies have investigated the correlation between environmental factors and Q-fly development, reproduction, and expansion. However, it is still not clear how Q-fly morphological traits vary with the environment. Our study focused on three morphological traits (body size, wing shape, and fluctuating asymmetry) in Q-fly samples collected from 1955 to 1965. We assessed how these traits vary by sex, and in response to latitude, environmental variables, and geographic distance. First, we found sexual dimorphism in body size and wing shape, but not in fluctuating asymmetry. Females had a larger body size but shorter and wider wings than males, which may be due to reproductive and/or locomotion differences between females and males. Secondly, the body size of Q-flies varied with latitude, which conforms to Bergmann’s rule. Finally, we found Q-fly wing shape was more closely related to temperature rather than aridity, and low temperature and high aridity may lead to high asymmetry in Q-fly populations.

Biometric and sexual dimorphism variation of &lt;em&gt;Hydromedusa tectifera&lt;/em&gt; in Brazil

Body size has a strong influence on the ecology and evolution of organisms’ life history. Turtle species can exhibit variation in body size and shape between populations of conspecifics through usually broad geographical scales. This prediction is timely to be tested in this study with the species Hydromedusa tectifera. We aimed to evaluate the variation in body size between and sexual dimorphism within populations of H. tectifera in two areas in Brazil. Sampling occurred in Minas Gerais and Rio Grande do Sul states in order to obtain morphometric measures of carapace and plastron of the individuals. We observed sexual dimorphism within populations. In Rio Grande do Sul state, females were larger than males in most of the carapace and plastron measures. In Minas Gerais state, males were larger than females regarding maximum carapace width. Overall, individuals from Rio Grande do Sul state were larger than those from Minas Gerais state. We discuss possible factors that might cause variation in morphology within and between populations of conspecifics. Research on morphology is encouraged to facilitate comparisons among populations in geographically broad areas.

Measuring the Inter and Intraspecific Sexual Shape Dimorphism and Body Shape Variation in Generalist Ground Beetles in Russia.

Ground beetles in multiple species vary greatly in the expression of the shape on sexual traits, resulting in a sexual shape dimorphism as a consequence of sexual selection differences. The present research focuses on the study of inter and intrasexual sexual shape dimorphism of two generalist genera of ground beetles Pterostichus and Carabus. Geometric morphometric methods were applied to five generalist species of ground beetles Carabus exaratus, C. granulatus, Pterostichus melanarius, P. niger, and P. oblongopunctatus and several multivariate analyses were applied for two different traits, abdomen and elytra. Three of the five species analyzed showed high levels of sex-based shape dimorphism. However, the most generalist species, P. melanarius and P. oblongopunctatus, did not evidence shape-based sexual dimorphism differentiation in both of the analyzed traits, as statistically confirmed based on the permutation of pairwise comparison of the Mahalanobis distances of a sex–species classifier. It is generally known that environmental stress in natural populations can affect the fitness expression, principally related to sexual fecundity, being that this pattern is more evident in non-generalist species. In our results, the contrary pattern was found, with the absence of sexual shape dimorphism for two of the three generalist species analyzed. On the other hand, the interspecies shape variation was clearly identified using principal component analysis of both of the analyzed traits. Finally, this research is the first to analyze the relationship between sexual shape dimorphism in Russian ground beetles, evidencing the lack of understanding of the mechanism underlying the sexual dimorphism, especially in species living in extreme environments.

Shape variation of the prawn Macrobrachium jelskii (Palaemonidae: Decapoda) in the Neotropical semiarid drainages: an intra- and inter-basin investigation

The present study aims to show the intra- and inter-basin body-shape variations of the freshwater prawn Macrobrachium jelskii (Miers, 1877) in Brazilian Neotropical semiarid basins, quantifying relations to address if its occurrence is old and natural or recent and artificial (anthropic). We used a geometric-morphometric tool to explore patterns of shape variation of the cephalothorax, abdomen and cheliped regarding eco-evolutionary traces (sexual dimorphism, hydrodynamism and geographical isolation) among the drainages. The sexual shape dimorphism was observed in cephalothorax and abdomen of females, which presented more horizontally stretched than in males, possibly favouring gonadal development, vitellogenesis and egg attachment. No apparent hydrodynamic trend was observed in the morpho-space. Moreover, no consensus was shown in the morpho-space about the geographic isolation in semiarid basins regarding the three body-structure planes. However, the abdominal plane indicates a low population/basin structure, which can be an indirect reflection of variations of vitellogenesis in eggs modulated by environmental factors. Furthermore, morphometric variations show low phenotypic plasticity, which is supported by the literature, indicating a scenario of non-natural distribution.

The complete mitochondrial genome of Liparis tessellatus and its phylogenetic analysis

Liparis tessellatus is a cubed snailfish that inhabits the northwestern region of the Pacific Ocean. The family Liparidae is difficult to distinguish morphologically due to the typical body color and shape variation, which are used interchangeably due to the differences in local dialects. Therefore, we determined the complete mitochondrial genome sequence of L. tesellatus. The mitochondrial genome length of L. tesellatus was determined as 17,221 bp, which consisted of 22 tRNA genes, two rRNA genes, 13 protein-coding genes (PCGs), and a control region (D-loop). The base composition was as follows: 28.6% of A, 29.5% of T, 26.5% of C, and 15.4% of G. The phylogenetic analysis revealed that L. tesellatus clustered together with different species of the genus Liparis. Thus, the complete mitochondrial genome sequence provided herein would further help in understanding the evolution of Liparis species.

Fat Distribution in Women Is Associated With Depot-Specific Transcriptomic Signatures and Chromatin Structure.

BackgroundPreferential accumulation of fat in the upper body (apple shape) is associated with higher risk of developing metabolic syndrome relative to lower body fat (pear shape). We previously discovered that chromatin openness partially defined the transcriptome of preadipocytes isolated from abdominal and gluteofemoral fat. However, the molecular mechanisms underlying interindividual variation in body shape are unknown.MethodsAdipocyte fraction was isolated from abdominal and gluteofemoral fat biopsies of premenopausal women (age and body mass index matched) segregated initially only by their waist-to-hip ratio. We evaluated transcriptomic and chromatin accessibility using RNA sequencing and assay for transposase-accessible chromatin using sequencing (ATAC-seq) along with key clinical parameters.ResultsOur data showed that higher lower body fat mass was associated with better lipid profile and free fatty acid decrease after glucose administration. Lipid and glucose metabolic pathways genes were expressed at higher levels in gluteofemoral adipocyte fraction in pears, whereas genes associated with inflammation were higher both in abdominal and gluteofemoral apple adipocyte fraction. Gluteofemoral adipocyte chromatin from pear-shaped women contained a significantly higher number of differentially open ATAC-seq peaks relative to chromatin from the apple-shaped gluteofemoral adipocytes. In contrast, abdominal adipocyte chromatin openness showed few differences between apple- and pear-shaped women. We revealed a correlation between gene transcription and open chromatin at the proximity of the transcriptional start site of some of the differentially expressed genes.ConclusionsIntegration of data from all 3 approaches suggests that chromatin openness partially governs the transcriptome of gluteofemoral adipocytes and may be involved in the early metabolic syndrome predisposition associated with body shape.

Inconspicuous genetic and morphological patterns challenge the taxonomic status of endemic species Bodianus insularis (Labridae)

Bodianus constitutes a marine fish group of particular interest due to its trophic interactions with reef environments. Knowledge of phylogenetic relationships of this genus have been improved by shared advances of classical and genetic approaches. However, some of its species have yet to be compared regarding its genetic patterns. Morphological variations in body shape and color patterns during the course of ontogenetic development, in addition to recurring sex reversal in species of this genus, make its taxonomy challenging. In the Atlantic Ocean five species have been described: Bodianus scrofa and Bodianus speciosus (Eastern Atlantic), Bodianus rufus (Western Atlantic), Bodianus pulchellus (Western Atlantic and Eastern Atlantic Islands) and Bodianus insularis (Mid-Atlantic islands). The phylogenetic relationships of the last species could not be resolved using genetic analyses. With a very restrict geographic distribution, B. insularis deserves high attention regarding its taxonomic and evolutionary aspects. Here, we use mitochondrial DNA sequences (COI and 16S rRNA) and nuclear analyses (rhodopsin) to assess the genetic divergence of B. insularis in relation to other Atlantic species and clarify its phylogenetic relationships. Bodianus pulchellus and B. insularis were not genetically distinct and are grouped with B. rufus, forming a sister clade of B. speciosus, while B. scrofa is more related to Pacific species. DNA-based and morphological traits are very similar between B. insularis and B. pulchellus, whose most obvious difference is their color pattern. The actual reinterpretation of ecological and biogeographic contexts allows to suggest that B. insularis is most likely a synonym of B. pulchellus, constituting a population enclave of this species.

Genetic and morphological variation of metacercariae of Microphallus piriformes (Trematoda, Microphallidae): Effects of paraxenia and geographic location.

Host organism offers an environment for a parasite, and this environment is heterogenous within the host, variable among individual as well as between the hosts, and changing during the host's lifetime. This heterogeneity may act as a prerequisite for parasite species divergence. Intraspecific variability related to a certain type of heterogeneity may indicate an initial stage of speciation, and thus poses an evolutionary importance. Here we analyzed genetic and morphologic variation of trematode metacercariae of Microphallus piriformes (Trematoda, Microphallidae). Genetic variability of trematodes was assessed from sequences of cytochrome c oxidase subunit 1 (COI) and internal transcribed spacer region (ITS-1). Morphological variation of metacercarial body shape was for the first time analyzed using geometric morphometrics. Parasites from the White Sea and the Barents Sea coasts demonstrated partial genetic divergence (according to COI sequence analysis) and had significantly different body shape. Neither genetic nor morphological variation of metacercariae was related to intermediate host species. We discuss possible causes of the observed genetic divergence of parasite populations in different geographic regions.