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

2013 ◽  
Vol 63 (2) ◽  
pp. 217-232 ◽  
Author(s):  
Rosalía Aguilar-Medrano

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.

Mammalia ◽  
2017 ◽  
Vol 81 (2) ◽  
Author(s):  
Luíza Z. Magnus ◽  
Nilton Cáceres

AbstractTribosphenic molars are considered great innovations in mammals and are related to several structures and variables that can explain adaptation. The aim of this study was to investigate the importance of body size and habitat relation, using a phylogenetic approach, in the first lower molar shape in didelphid marsupials. Geometric morphometric analyses of the lower molar’s shape were performed on 261 specimens, 130 females and 131 males, covering 14 genera and 37 species of the Didelphidae family. The molar conformation showed a larger talonid in relation to the trigonid in more arboreal genera, and narrower and longer molars in genera with a larger body size. Phylogeny was the variable with the highest explanation for both females and males (16.17% and 9.02%, respectively). The body size was significant in males, presenting an important influence on molar shape, while the body size in females was not significant when phylogenetic relationship was controlled for. In both sexes, habitat presents a strong effect of phylogeny, with no direct effect on molar shape. Didelphid molar shape is another result of its phylogenetic history and does not respond very much to environmental pressures. Male body size influences molar shape in didelphids, even in the presence of a strong phylogenetic signal.


2021 ◽  
Vol 51 (4) ◽  
pp. 403-412
Author(s):  
Yanet Elizabeth Aguilar-Contreras ◽  
Alfonso A. González-Díaz ◽  
Omar Mejía ◽  
Rocío Rodiles-Hernández

This study assesses the patterns of variation in body shape, and relations of morphological similarity among species of the Theraps–Paraneetroplus clade in order to determine whether body shape may be a trait in phylogenetic relations. A total of 208 specimens belonging to 10 species of the Theraps–Paraneetroplus clade were examined. The left side of each specimen was photographed; in each photograph, 27 fixed landmarks were placed to identify patterns in body shape variation. Images were processed by using geometric morphometrics, followed by a phylogenetic principal component analysis. The phylogenetic signal for body shape was then calculated. To determine the relations in morphological similarity, a dendrogram was created using the unweighted pair group method and arithmetic mean values, while a Procrustes ANOVA and post-hoc test were used to evaluate significant differences between species and habitats. We found three morphological groups that differed in body length and depth, head size, and the position of the mouth and eyes. The body shape analysis recovered the morphotypes of seven species, and statistical differences were demonstrated in eight species. Based on traits associated with cranial morphology, Wajpamheros nourissati (Allgayer, 1989) differed the most among the species examined. No phylogenetic signal was found for body shape; this trait shows independence from ancestral relatedness, indicating that there is little congruence between morphological and genetic interspecific patterns. As evidenced by the consistently convergent morphology of the species in the Theraps–Paraneetroplus clade, the diversification of the group is related to an ecological opportunity for habitat use and the exploitation of food resources. Although no phylogenetic signal was detected for body shape, there appears to be an order associated with cranial morphology-based phylogeny. However, it is important to evaluate the intraspecific morphologic plasticity produced by ecological segregation or partitioning of resources. Therefore, future morphological evolutionary studies should consider cranial structures related to the capture and processing of food.


2019 ◽  
Vol 2019 ◽  
pp. 1-8 ◽  
Author(s):  
Renan Rodrigues Rocha ◽  
Rosana de Mesquita Alves ◽  
Rubens Pasa ◽  
Karine Frehner Kavalco

The Astyanax scabripinnis complex is composed of a large number of almost morphological indistinguishable species, including Astyanax paranae and Astyanax rivularis, which exist in the Paraná and São Francisco Basins, respectively, and sometimes are considered subspecies of the A. scabripinnis group or even are cited just as A. scabripinnis. The two river basins are separated by the Upper Paranaíba Arc, likely the main cause of the isolation of these species. We used geometric morphometric tools and DNA analyses of populations of both species to identify the differences between them. Geometric morphometrics separated the two species into distinct groups, whose main difference was the body depth. This is generally related to the speed of the water flow in the river basins. The maximum likelihood phylogram based on mitochondrial DNA sequences formed two main clades: one composed of the population of A. rivularis and the other, of A. paranae. In the haplotype network, the species were similarly separated into two groups from the same ancestral haplotype, with A. rivularis dispersing into two lineages in the São Francisco River Basin. The distribution of A. paranae is a consequence of a secondary dispersion event in the Paraná River Basin. It forms two lineages from a haplotype derived from the ancestor. The vicariant effect of separate basins, through the elevation of the Upper Paranaíba Arc, led to the allopatric speciation of the populations originating the present species. The results of geometric morphometrics and molecular data of the fish show the importance of this geological event in the biogeography and evolutionary history of the ichthyofauna of the region and indicate that the isolation of these species seems to be effective.


2019 ◽  
Vol 128 (1) ◽  
pp. 107-121 ◽  
Author(s):  
Katherine E Dale ◽  
M Timothy Tinker ◽  
Rita S Mehta

Abstract The geographical range of many marine species is strongly influenced by the dispersal potential of propagules such as eggs and larvae. Here, we investigate morphological diversity and the effect of body shape on geographical range of leptocephali, the unique, laterally compressed larvae of eels (order Anguilliformes). We used phylogenetically informed analyses to examine the morphological variation of larvae for 17 Eastern Pacific eel species from three adult habitats. We also investigated whether morphological traits of leptocephali could predict larval latitudinal range, hypothesizing that body shape may influence passive dispersal via currents. We found that no two species shared the same multivariate growth trajectories, with the size and scaling of pectoral fin length and snout-to-anus length being particularly variable. Larvae with longer relative predorsal and snout-to-anus lengths at median sizes exhibited wider larval geographical ranges. Body aspect ratio and maximum body length at metamorphosis, two traits we hypothesized to be important for passive transport, were not significant predictors of maximal larval range. We discovered an increase in phylogenetic signal over larval development as eels approach metamorphosis, potentially due to similar selective pressures between related species (such as juvenile habitat or adult morphology). Lastly, we conclude that larval body shape is probably influenced by adult habitat and adult morphology.


2019 ◽  
Vol 31 (6) ◽  
pp. 755-776
Author(s):  
Heekyung Jang ◽  
Jianhui Chen

Purpose The purpose of this paper is to use body shape analysis and develop a 3D virtual body formation and deformation model that can accurately express size and shape. Design/methodology/approach In this paper, 1,882 sets of direct measurement data of Korean women in their 20s (19–29 years) were analyzed. These data sets were sourced from the sixth and seventh “Size Korea” anthropometric survey data. Through body shape analysis, the authors classified them into seven body types and selected their representative bodies. A 2D image based on the height, breadth, depth and length was first formed, and the representative virtual body was modeled using the polygon technique. The authors calculated the grading ratios for each body type according to the clothing sizing system, and modified the virtual body size type by morphing technique. Findings In order to accurately evaluate the fit in a virtual fitting system, it is necessary to study the body size and shape of the target age; this makes it possible to form virtual body reflecting the size and shape. Originality/value In this paper, the authors propose a new 3D virtual body formation method that is more accurate in shape and size compared to the present system. Through this, it will be possible to grasp the accurate simulation state in the virtual fitting system, and thereby evaluate the accurate fit.


2001 ◽  
Vol 204 (9) ◽  
pp. 1547-1557 ◽  
Author(s):  
J. Lovvorn ◽  
G.A. Liggins ◽  
M.H. Borstad ◽  
S.M. Calisal ◽  
J. Mikkelsen

For birds diving to depths where pressure has mostly reduced the buoyancy of air spaces, hydrodynamic drag is the main mechanical cost of steady swimming. Drag is strongly affected by body size and shape, so such differences among species should affect energy costs. Because flow around the body is complicated by the roughness and vibration of feathers, feathers must be considered in evaluating the effects of size and shape on drag. We investigated the effects of size, shape and feathers on the drag of avian divers ranging from wing-propelled auklets weighing 75 g to foot-propelled eiders weighing up to 2060 g. Laser scanning of body surfaces yielded digitized shapes that were averaged over several specimens per species and then used by a milling machine to cut foam models. These models were fitted with casts of the bill area, and their drag was compared with that of frozen specimens. Because of the roughness and vibration of the feathers, the drag of the frozen birds was 2–6 times that of the models. Plots of drag coefficient (C(D)) versus Reynolds number (Re) differed between the model and the frozen birds, with the pattern of difference varying with body shape. Thus, the drag of cast models or similar featherless shapes can differ both quantitatively and qualitatively from that of real birds. On the basis of a new towing method with no posts or stings that alter flow or angles of attack, the dimensionless C(D)/Re curves differed among a size gradient of five auklet species (75–100g) with similar shapes. Thus, extrapolation of C(D)/Re curves among related species must be performed with caution. At lower speeds, the C(D) at a given Re was generally higher for long-necked birds that swim with their neck extended (cormorants, grebes, some ducks) than for birds that swim with their head retracted (penguins, alcids), but this trend was reversed at high speeds. Because swimming birds actually travel at a range of instantaneous speeds during oscillatory strokes, species variations in drag at different speeds must be considered in the context of accelerational stroking.


2013 ◽  
Vol 26 (1) ◽  
pp. 13 ◽  
Author(s):  
Matt A. M. Renner ◽  
Elizabeth A. Brown ◽  
Glenda M. Wardle

Molecular data have revealed many morphologically cryptic species. More surprising than lack of difference, however, is that morphological variation and complex patterns of overlapping features can mask cryptic species. We employ geometric morphometric methods (GMM) to explore patterns of variation within four liverwort species, three of which were previously attributed to Lejeunea tumida Mitt. Each species exhibited considerable variation within, and overlap among, species in size and shape, independent of degree of relatedness. Most variation was expressed within individuals, suggesting that the observed breadth of variation was within the developmental capacity of single genotypes. Size and shape variation within, and consequently overlap among, individuals resulted primarily from variance in growth of shoots. Inter-specific differences were swamped by intra- and inter-individual variation. We coupled GMM with multivariate methods for outlier removal, and simple averaging of individuals to explore whether intra-individual variation could be reconciled to maximise the inter-species difference, facilitating resolution of cryptic species despite extensive morphological continuity and overlap. Unfortunately, outlier removal did not achieve separation among species, because removing extremes failed to eliminate overlap resulting from within-species variation. Individual averaging was partially successful in extracting L. tumida as a discrete entity but did not segregate the remaining three species. Although the challenges for morphology-based identification of cryptic species are significant, GMM provide one of the best sets of methods for identifying and communicating any subtle morphological differences that may exist.


Author(s):  
Nadia Maalin ◽  
Sophie Mohamed ◽  
Robin S. S. Kramer ◽  
Piers L. Cornelissen ◽  
Daniel Martin ◽  
...  

Abstract Accurate self-assessment of body shape and size plays a key role in the prevention, diagnosis, and treatment of both obesity and eating disorders. These chronic conditions cause significant health problems, reduced quality of life, and represent a major problem for health services. Variation in body shape depends on two aspects of composition: adiposity and muscularity. However, most self-assessment tools are unidimensional. They depict variation in adiposity only, typically quantified by the body mass index. This can lead to substantial, and clinically meaningful, errors in estimates of body shape and size. To solve this problem, we detail a method of creating biometrically valid body stimuli. We obtained high-resolution 3D body shape scans and composition measures from 397 volunteers (aged 18–45 years) and produced a statistical mapping between the two. This allowed us to create 3D computer-generated models of bodies, correctly calibrated for body composition (i.e., muscularity and adiposity). We show how these stimuli, whose shape changes are based on change in composition in two dimensions, can be used to match the body size and shape participants believe themselves to have, to the stimulus they see. We also show how multivariate multiple regression can be used to model shape change predicted by these 2D outcomes, so that participants’ choices can be explained by their measured body composition together with other psychometric variables. Together, this approach should substantially improve the accuracy and precision with which self-assessments of body size and shape can be made in obese individuals and those suffering from eating disorders.


2017 ◽  
Vol 65 (2) ◽  
Author(s):  
Caleb D. McMahan ◽  
Justin Kutz ◽  
Christopher Murray ◽  
Prosanta Chakrabarty ◽  
Aaron Geheber ◽  
...  

Vieja melanura is a Neotropical cichlid occurring in the Petén-lake district systems of Guatemala, as well as the Río Grijalva-Usumacinta basin, and other systems in Southern México, Belize, and Guatemala. A caudal stripe, extending forward from the caudal peduncle, is characteristic of this species. This stripe is sloped downward in nearly all individuals of V. melanura, but the degree of the slope is highly variable throughout its range. The slope and shape of the stripe has previously been used in diagnosing and differentiating between species of Vieja. The purpose of this study was to use objective methods to investigate morphological variation in the caudal stripe and body shape throughout the range of V. melanura. We studied geometric morphometric analyses of body shape and empirical measurements of the slope of the caudal stripe in 215 specimens of V. melanura. We also used the mitochondrial cytochrome b marker to study population level patterns within V. melanura. Results from our analyses showed significant geographic variation in body shape and patterns of coloration with little mitochondrial phylogeographic structure. These patterns likely correspond to differences in riverine habitats throughout the species’ distribution. In conclusion, these results can be used to inform other studies of color and shape variation as it applies to taxonomy and systematics.


Zootaxa ◽  
2011 ◽  
Vol 2775 (1) ◽  
pp. 1 ◽  
Author(s):  
STANISŁAW SENICZAK ◽  
ANNA SENICZAK

Morphology of juvenile stages and ontogeny of Damaeus onustus C. L. Koch, 1844, Damaeus clavipes (Hermann, 1804) and Kunstidamaeus tecticola (Michael, 1888) was investigated. The juveniles of these species differ mainly in body shape and size, and shape of some setae on the gastronotum and legs. The nymphs of all species lose centrodorsal setae of the d-series, and carry the exuviae of previous instars, but D. onustus carries also compact humus mass adhering to exuviae, D. clavipes a lot of loose debris, while K. tecticola usually only exuviae. The kind of camouflage is partly determined by the shape of gastronotal setae; in D. onustus these setae are curved ventrally, in D. clavipes are raised, while in K. tecticola are raised, and strongly curved medial. The nymphs of these species, as the nymphs of all other known Damaeidae, have gastronotal cornicle, which connects the exuviae of previous instars to the gastronotum. The cornicle of particular species differs in shape and location on the gastronotum; in some species is located anteromedial to setae la, in the other between setae lm, and in the other yet between setae lp or h 3 . The adults of these species differ mainly in body size, presence and shape of cuticular apophyses on the body, length of some setae on the prodorsum and notogaster, and the number of setae on legs, including dorsal seta d on genua I–III and tibiae I–IV.


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