scholarly journals Sexual Dimorphism in Bite Performance Drives Morphological Variation in Chameleons

PLoS ONE ◽  
2014 ◽  
Vol 9 (1) ◽  
pp. e86846 ◽  
Author(s):  
Jessica M. da Silva ◽  
Anthony Herrel ◽  
G. John Measey ◽  
Krystal A. Tolley
Keyword(s):  
Sexual Dimorphism ◽  
Morphological Variation

scholarly journals Habitat, Sexual and Allometric Influences on Morphological Traits of Intertidal Crabs

2020 ◽  
Author(s):  
P. Vermeiren ◽  
C. Lennard ◽  
C. Trave
Keyword(s):  
Sexual Selection ◽  
Sexual Dimorphism ◽  
Morphological Variation ◽  
Morphological Traits ◽  
Low Cost ◽  
Habitat Preferences ◽  
Mangrove Crab ◽  
Habitat Factors ◽  
Specific Factors ◽  
Claw Shape

Abstract Intertidal crabs display distinct morphological traits that allow differential interactions with biotic and abiotic features of the intertidal landscape, but are also influenced by allometry and sexual selection. This study aimed to explore the influence of sexual, allometric and habitat factors on morphological variation in the intertidal mangrove crab assemblage. A standardized photographic protocol was developed using readily available, low-cost technology to capture the morphology of carapaces and claws as sets of Cartesian landmarks. Digitization errors were 1 to 2 orders of magnitude smaller than the variation among individuals. In Tubuca seismella and Tubuca signata (superfamily Ocypodoidea), species that have traditionally been studied for sexual dimorphism, standardized major claw sizes were 2.8 and 3.7, respectively, times larger for males than females. Sexual dimorphism in claw size was also observed for Metopograpsus frontalis and Parasesarma longicristatum (superfamily Grapsoidea), with the largest claw in males being 15% and 33%, respectively, larger than in females. In contrast to size, claw shape did not relate to sex, except for T. seismella. Carapace shape, although variable among individuals and displaying asymmetry, was unrelated to sex. Claw and carapace shapes displayed high correlations, with values around 0.78. Carapace shapes grouped into taxonomic families and linked to habitat preferences, while claw shapes varied along a taxonomic gradient. These results complement studies on crab morphology that focus on specific factors or species, and stress the importance of multiple, interacting factors including sexual, allometric and habitat influences as drivers of morphological trait variability.

Morphological variation and sexual dimorphism in the Aspidoscelis gularis complex (Squamata: Teiidae) from Mexico

2020 ◽  
Author(s):  
Anahí Esquivel‐Ramírez ◽  
Claudia T. Hornung‐Leoni ◽  
Norma L. Manríquez‐Morán
Keyword(s):  
Sexual Dimorphism ◽  
Morphological Variation

Morphological variation in a conservative structure: the scapulocoracoids in Sympterygia acuta Garman, 1837 and Sympterygia bonapartii Müller & Henle, 1841 (Chondrichthyes: Rajidae)

Zootaxa ◽  
2017 ◽  
Vol 4318 (1) ◽  
pp. 157 ◽  
Author(s):  
CARLOS D. JURADO ◽  
EZEQUIEL MABRAGAÑA ◽  
JUAN MARTÍN DÍAZ DE ASTARLOA
Keyword(s):  
New Species ◽  
Sexual Dimorphism ◽  
Morphological Variation ◽  
Coastal Waters ◽  
Slight Variation ◽  
Morphometric Variation ◽  
Phylogenetic Studies ◽  
Morphologic Variation ◽  
Broad Variation ◽  
Males And Females

Scapulocoracoid variation in Sympterygia acuta and S. bonapartii was analyzed inter- and intraspecifically, and the utility of this structure as a diagnostic character in skates was evaluated. Skeletal pieces were obtained from a total of 85 specimens collected in coastal waters of northern Argentina in 2011 and 2012. Morphometric variation was analyzed using non parametric tests. Morphologic variation was qualitatively and quantitatively evaluated by comparing number, shape and arrangement of posterior fenestrae. Scapulocoracoids of both species are rectangular in shape and expanded anteroposteriorly, but those of S. bonapartii were more expanded. Differences in shape, both in males and females, were reflected in the ANOSIM test. Greatest Height and Height of Rear Corner were the variables that most contributed to the differences found between both species. These differences in morphology agree with previous descriptions. No sexual dimorphism was observed regarding scapulocoracoids in S. acuta, and only a slight variation between males and females of S. bonapartii was found. Number of postdorsal and postventral fenestrae was highly variable. At least five scapulocoracoid morphotypes for S. acuta (with two to six fenestrae) and seven scapulocoracoid morphotypes for S. bonapartii (with three up to nine fenestrae) were identified. However, patterns of fenestrae arrangement were also very diverse in both species. Therefore, a broad variation in fenestrae number and pattern, especially postdorsal ones, was shown in both species. These results indicate that caution needs to be taken when using the scapulocoracoids not only in phylogenetic studies but also in descriptions of new species. 

scholarly journals Intraspecific Morphological Variation in Two Common Marine Fish Species from South Africa

2013 ◽  
Vol 6 (1) ◽  
pp. 87-91 ◽  
Author(s):  
Eric Mattson ◽  
Mark C. Belk
Keyword(s):  
Sexual Dimorphism ◽  
Marine Fish ◽  
Fish Species ◽  
Morphological Variation ◽  
Environmental Gradients ◽  
Human Consumption ◽  
Shape Variation ◽  
Geometric Morphometric ◽  
Feeding Niche ◽  
Intraspecific Morphological Variation

Intraspecific morphological variation in fish is typically associated with sexual dimorphism, or one of three common environmental gradients: variation in intensity of predation, variation in water velocity, or variation in feeding niche. The preponderance of examples of environment-associated morphological variation within fish species has been documented in freshwater systems. It is not clear whether environment-associated intraspecific morphological variation is less common in marine fishes or whether there has just been a lack of investigation. We used geometric morphometric analysis to quantify shape variation in two species of South African marine fish commonly harvested for human consumption, Pterogymnus laniarius (panga), and Argyrosomus inodorus (silver kob). Neither species exhibited significant sexual dimorphism, but both species exhibited significant intraspecific morphological variation. This variation appears consistent with patterns expected from variation along the benthic-pelagic feeding niche continuum.

Morphological variation in bony structures of Hylaeamys seuanezi (Rodentia, Cricetidae, Sigmodontinae) in Southern Bahia, Brazil

Mammalia ◽  
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Franger J. García ◽  
Martín Roberto del Valle Alvarez
Keyword(s):  
Sexual Dimorphism ◽  
Morphological Variation ◽  
Climatic Factors ◽  
Geometric Morphometric ◽  
Average Shape ◽  
Southern Bahia ◽  
Morphological Diagnosis ◽  
Males And Females ◽  
Negative Pressures ◽  
First Time

Abstract Rodents of the genus Hylaeamys, are a group of cryptic species previously included in the Oryzomys capito complex. In Brazil are represented by six species, distributed in different biomes. However, the limits of their geographic distributions and taxonomy have not yet been well defined. In particular, the taxonomy for Hylaeamys seuanezi is unstable. Based on the analysis of bony structures and supported with geometric morphometric techniques, we characterize and compare the average shape from populations in four localities from Southern Bahia, Brazil. We review 145 individuals and we create morphological landmarks in skulls, mandibles, scapulae, and pelvis. In all the structures there were statistically significant differences between populations, in which the average shape from the Igrapiúna population was the most differentiated. Our results also showed differences between the pelvis of males and females, reporting for the first time sexual dimorphism for H. seuanezi. Finally, we provide a morphological diagnosis between the populations and postulate that such differences may be correlated with environmental and climatic factors that could be exerting negative pressures on H. seuanezi; as has been evidenced with other species of rodents and other mammals.

Skull morphological variation in a British stranded population of false killer whale (Pseudorca crassidens): a three-dimensional geometric morphometric approach

2022 ◽  
pp. 119-132
Author(s):  
Deborah Vicari ◽  
Richard C. Sabin ◽  
Richard P. Brown ◽  
Olivier Lambert ◽  
Giovanni Bianucci ◽  
...  
Keyword(s):  
Sexual Dimorphism ◽  
Morphological Variation ◽  
Killer Whale ◽  
Three Dimensional ◽  
Anatomical Landmarks ◽  
Geometric Morphometric ◽  
False Killer Whale ◽  
Sexual Shape Dimorphism ◽  
Males And Females ◽  
Pseudorca Crassidens

The false killer whale (Pseudorca crassidens (Owen, 1846)) is a globally distributed delphinid that shows geographical differentiation in its skull morphology. We explored cranial morphological variation in a sample of 85 skulls belonging to a mixed sex population stranded in the Moray Firth, Scotland, in 1927. A three-dimensional digitizer (Microscribe 2GX) was used to record 37 anatomical landmarks on the cranium and 25 on the mandible to investigate size and shape variation and to explore sexual dimorphism using geometric morphometric. Males showed greater overall skull size than females, whereas no sexual dimorphism could be identified in cranial and mandibular shape. Allometric skull changes occurred in parallel for both males and females, supporting the lack of sexual shape dimorphism for this particular sample. Also, fluctuating asymmetry did not differ between crania of males and females. This study confirms the absence of sexual shape dimorphism and the presence of a sexual size dimorphism in this false killer whale population.

Intraspecific variation in morphology and sexual dimorphism in Liolaemus tenuis (Tropiduridae)

2005 ◽  
Vol 26 (3) ◽  
pp. 343-351 ◽  
Author(s):  
Madeleine Lamborot ◽  
Marcela Vidal ◽  
Claudio Ramírez ◽  
Juan Carlos Ortiz
Keyword(s):  
Sexual Dimorphism ◽  
Morphological Variation ◽  
Latitudinal Gradient ◽  
Geometric Approach ◽  
Climatic Conditions ◽  
Territorial Defense ◽  
Lizard Species ◽  
Distribution Ranges ◽  
Morphological Variables ◽  
Wide Geographic Distribution

AbstractLiolaemus tenuis is a widely distributed arboreal lizard species in central-southern Chile. Although two subspecies, L. t. tenuis and L. t. punctatissimus, have been described based on sexual dimorphism, their characteristic have not been accurately demarcated. Therefore, both traditional and geometric morphometrics were used to study the morphological variation of L. tenuis. Four specific questions were addressed: (1) Does population morphological variation occur along a latitudinal gradient, given its wide geographic distribution in a climactic gradient? (2) Does L. tenuis present sexual dimorphism? (3) In the case of dimorphism, what is the variation along a latitudinal gradient? (4) Are these subspecies morphologically distinguishable? The study was performed in a variety of locations, including the following six bioclimatic regions of Chile: arid mediterranean, semi-arid mediterranean, sub-humid mediterranean, humid mediterranean, per-humid mediterranean, and oceanic with mediterranean influence. Male and female individuals were measured and photographed. Our results suggest sexual dimorphism for all morphological variables analyzed. Geometric data indicate that the eye orbits of the males are more extended than those of the females; this is probably related to territorial defense and/or polygynic mating system. The traditional morphometric approach revealed a difference in individuals from the arid region, whereas the geometric approach revealed a difference in individuals from the oceanic region. Differences in the limits of their distribution ranges seem be related to local factors, such as topography and climatic conditions. Finally, is not possible to recognize distinct subspecies within L. tenuis, and our research concludes that the species consists of one homogenous identity.

scholarly journals Morphological variation and a remarkable new sexual dimorphism in the Pseudocyclops xiphophorus population of Lake Faro in northeastern Sicily

2009 ◽  
Vol 73 (2) ◽  
pp. 347-355 ◽  
Author(s):  
Cinzia Brugnano ◽  
Geoffrey A. Boxshall ◽  
Giuseppe Costanzo ◽  
Giacomo Zagami
Keyword(s):  
Sexual Dimorphism ◽  
Morphological Variation ◽  
Northeastern Sicily

A new species of Paratagalis Monte from Brazil with taxonomical notes and a key to New World genera of Saicinae (Hemiptera: Heteroptera: Reduviidae: Saicinae)

Zootaxa ◽  
2009 ◽  
Vol 2197 (1) ◽  
pp. 20-30 ◽  
Author(s):  
HÉLCIO R. GIL-SANTANA ◽  
LUIZ A. A. COSTA
Keyword(s):  
New Species ◽  
Sexual Dimorphism ◽  
Morphological Variation ◽  
New World ◽  
First Time ◽  
A New Species

Paratagalis zikani sp. nov. from Brazil is described. A revised diagnosis of Paratagalis Monte, 1943, is provided. Morphological variation and sexual dimorphism of Paratagalis spinosus Monte, 1943, are described for the first time. A key to the Saicinae genera of the New World is provided.

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