scholarly journals Morphological distinction and sexual dimorphism in divergent clades of Neurergus kaiseri (Amphibia: Salamandridae)

2018 ◽  
Vol 32 ◽  
pp. 5-17
Author(s):  
Hadi Khoshnamvand ◽  
Mansoureh Malekian ◽  
Yazdan Keivany
Keyword(s):  
Sexual Selection ◽  
Body Size ◽  
Sexual Dimorphism ◽  
Principle Component Analysis ◽  
Morphological Differentiation ◽  
Taxonomic Revision ◽  
Morphological Characters ◽  
Head Width ◽  
Morphological Distinction ◽  
Ecological Differences

Morphological differentiation and sexual dimorphism in the two genetically distinct clades (Northern and Southern clades) of the Lorestan newt, Neurergus kaiseri, was evaluated for 72 live specimens, using five body- and nine head-related characters and eight calculated ratios. Principle component analysis of morphological characters confirmed that the Lorestan newt populations are well separated into two distinct groups, suggesting that a taxonomic revision in N. kaiseri may be required because of significant molecular, morphological and ecological differences between these clades. Sexual dimorphism in N. kaiseri includes body size and shape. Females were clearly larger than males in most body- and head-related variables and males had relatively greater head width and eye length. Sexual dimorphism in this species may be linked to sexual selection and ecological differences between sexes. However, many aspects of the ecology and reproductive biology of this species remain unknown.

Taxonomic revision of the genus Lycenchelys (Osteichthyes: Zoarcidae) in Japanese waters

Zootaxa ◽  
2020 ◽  
Vol 4762 (1) ◽  
pp. 1-66
Author(s):  
SHUMPEI KAWARADA ◽  
HISASHI IMAMURA ◽  
YOJI NARIMATSU ◽  
GENTO SHINOHARA
Keyword(s):  
Sexual Dimorphism ◽  
Taxonomic Revision ◽  
Head Length ◽  
Head Width ◽  
Type Specimens ◽  
Snout Length ◽  
Lower Jaw ◽  
Eye Diameter ◽  
Japanese Waters

Eelpout species of the genus Lycenchelys Gill, 1884 recorded from Japanese waters are taxonomically revised. This study recognizes the following 11 species from Japanese waters as valid: Lycenchelys albomaculata Toyoshima, 1983, Lycenchelys aurantiaca Shinohara & Matsuura, 1998, Lycenchelys hippopotamus Schmidt, 1950, Lycenchelys maculata Toyoshima, 1985, Lycenchelys makushok Fedorov & Andriashev, 1993, Lycenchelys melanostomias Toyoshima, 1983, Lycenchelys rassi Andriashev, 1955, Lycenchelys remissaria Fedorov, 1995, Lycenchelys ryukyuensis Shinohara & Anderson, 2007, Lycenchelys squamosa Toyoshima, 1983 and Lycenchelys tohokuensis Anderson & Imamura, 2002. We redescribe species in detail based on type specimens as well as additional specimens in many cases. The synonymy of Lycenchelys brevimaxillaris Toyoshima, 1985 with L. melanostomias is supported in this study. Sexual dimorphism and changes with growth are revealed in L. albomaculata, L. aurantiaca, L. hippopotamus, L. makushok, L. melanostomias and L. rassi, all based on 10 or more specimens, for relative head length, head width, and upper and lower jaw lengths. In addition, we also found that the sizes at which sexual dimorphism can be recognized, and the tendencies for change with growth, differ among species. Furthermore, the dimorphism in head length is influenced by the snout length, eye diameter and/or postorbital length in L. albomaculata and L. aurantiaca. 

scholarly journals Body size, female reproduction and sexual dimorphism in the lizard Ameiva ameiva (Teiidae) in a restinga of southeastern Brazil

2008 ◽  
Vol 25 (2) ◽  
pp. 370-372 ◽  
Author(s):  
Carlos Frederico Duarte Rocha
Keyword(s):  
Body Size ◽  
Sexual Dimorphism ◽  
Clutch Size ◽  
Reproductive Period ◽  
Southeastern Brazil ◽  
Head Width ◽  
Sexually Dimorphic ◽  
Female Reproduction ◽  
Female Body Size ◽  
Reproductive Body

In this study 57 specimens of the lizard Ameiva ameiva (Linnaeus, 1758) collected in the restinga at Barra de Maricá, in the state of Rio de Janeiro, southeastern Brazil, were analyzed to investigate size relations and reproduction (in females) and sexual dimorphism of this population. We answered the following questions: 1) what is the minimum reproductive body size in females? 2) what is the average clutch size and 3) how is clutch size related to body size? 4) Are body and head sizes sexually dimorphic? Mean clutch size was 6.7 ± 2.1 eggs and was positively correlated with female body size. Sexual dimorphism favoring males was found: adult mean snout-vent length was great in males (124.2 ± 17.8 mm) than females (96.5 ± 23.1 mm SVL), and males were larger with respect to head width and length, and body mass. Thus, despite the marked seasonality at Barra de Maricá, A. ameiva has an extended reproductive period. Also, intrasexual selection may have acted on females to produce larger clutches, and on males, favoring larger males.

Factors driving sexual dimorphism and colour variability in the Achala Copper Lizard (Pristidactylus achalensis), an endemic species to the highland mountains in central Argentina

2020 ◽  
Vol 98 (6) ◽  
pp. 377-389
Author(s):  
S. Naretto ◽  
M. Chiaraviglio
Keyword(s):  
Sex Differences ◽  
Spatial Distribution ◽  
Body Size ◽  
Sexual Dimorphism ◽  
Endemic Species ◽  
Morphological Changes ◽  
Head Size ◽  
Head Width ◽  
Temporal And Spatial Distribution ◽  
Central Argentina

The intensity of mating competition varies according to the temporal and spatial distribution of individuals. Measuring sexual dimorphism over time and interpreting the association between individuals is therefore important if we aim to understand how sexual traits are influenced. We examined sex differences in the Achala Copper Lizard (Pristidactylus achalensis (Gallardo, 1964)), an endemic species from the highest part of mountains of central Argentina. Over 4 years, we explored sex-specific variation in body size, head size, interlimb length, and body colouration. Furthermore, we evaluated how these traits varied temporally, and we also explored whether the spatial distribution of individuals is explained by variation in these traits. We found that P. achalensis is a species with sexual dimorphism in multiple characters, including body size, head size, and colouration. Interestingly, some traits related to mating, such as head width, show a temporal variability in both sexes, whereas other traits, such as colouration, varies seasonally only in males. Our results underline the intriguing possibility of seasonal morphological changes related to mating, and more broadly that sex differences are influenced by sexual selection pressures mediated by temporal variation in mate competition.

Heads or tails? Sexual dimorphism in helodermatid lizards

2007 ◽  
Vol 85 (1) ◽  
pp. 92-98 ◽  
Author(s):  
C.M. Gienger ◽  
Daniel D. Beck
Keyword(s):  
Sexual Selection ◽  
Body Size ◽  
Sexual Dimorphism ◽  
Morphological Traits ◽  
Tail Length ◽  
Repeated Sequences ◽  
Analysis Of Covariance ◽  
Head Size ◽  
Heloderma Suspectum

We tested the hypothesis that helodermatid lizards (Gila monsters, Heloderma suspectum Cope, 1869, and beaded lizards, H. horridum (Wiegmann, 1829)) show sexual dimorphism in morphological traits related to male–male agonistic behaviors. Male–male combat in helodermatid lizards involves repeated sequences of ritualized grappling. Male Gila monsters use their heads in attempts to gain or maintain a superior position during repeated combat bouts that may last for hours. Pairs of fighting male beaded lizards form spectacular body arches, with abdomens adpressed and snouts, forelimbs, and tail tips contacting the ground. We measured body size, head size, and tail length in 208 preserved H. suspectum, and body size and tail length (but not head size) in 79 live H. horridum, then tested for sexual dimorphism using analysis of covariance. Male Gila monsters had proportionately larger heads than females but did not differ in tail length or body size. Male beaded lizards had proportionately longer tails than females and were larger in body size only when the largest individuals were included in the analysis. Differences in head dimensions (in H. suspectum) and tail length (in H. horridum) are likely the result of sexual selection acting through male–male agonistic behaviors in this unique lizard taxon.

scholarly journals Morphometric differentiation and sexual dimorphism in Limnomedusa macroglossa (Duméril & Bibron, 1841) (Anura: Alsodidae) from Uruguay

2021 ◽  
Vol 16 (1) ◽  
pp. 11-25
Author(s):  
Valeria De Olivera-López ◽  
Arley Camargo ◽  
Raúl Maneyro
Keyword(s):  
Sexual Selection ◽  
Body Size ◽  
Sexual Dimorphism ◽  
Phenotypic Plasticity ◽  
Life History Strategies ◽  
Clinal Variation ◽  
Size And Shape ◽  
Secondary Sexual Characteristics ◽  
Sexual Characteristics ◽  
Morphological Differences

Intersexual morphological differences within a species occur in many traits, including body size and shape. Many processes that cause geographic variability in morphology have been proposed: population structure, phenotypic plasticity (environmental effects on development), and natural and/or sexual selection. Several hypotheses can explain patterns of sexual dimorphism in anurans, including natural or intra/inter-sexual selection, and differences in life history strategies between sexes. Limnomedusa macroglossa is considered a habitat specialist restricted to rocky outcrops in Brazil, Argentina, Paraguay, and Uruguay. We evaluated the extent of sexual (size and shape) dimorphism in L. macroglossa from Uruguay based on morphometrics and secondary sexual characteristics, while taking into account geographic variation. Sexual dimorphism in body size of adults was found, but multivariate analyses did not demonstrate the existence of significant differences in shape. There were also significant differences in body size and hind leg measurements among six hydrographic basins as a result from the phenotypic plasticity correlated with local temperature, representing a clinal variation along the latitudinal gradient of Uruguay. The sexual dimorphism found in body size is probably the consequence of higher growth rates and/or late sexual maturity in females, which favors larger body size for accommodating larger ovaries, and thus, higher reproductive output. 

scholarly journals Cave shrimps Troglocaris s. str. (Dormitzer, 1853), taxonomic revision and description of new taxa after phylogenetic and morphometric studies

Zootaxa ◽  
2012 ◽  
Vol 3421 (1) ◽  
pp. 1 ◽  
Author(s):  
JURE JUGOVIC ◽  
BRANKO JALŽIĆ ◽  
SIMONA PREVORČNIK ◽  
BORIS SKET
Keyword(s):  
Type Species ◽  
Morphological Variability ◽  
Taxonomic Revision ◽  
Morphological Characters ◽  
Molecular Data ◽  
Coi Gene ◽  
Distribution Area ◽  
Molecular Analyses ◽  
Morphometric Analyses ◽  
Morphological Distinction

Within the Dinaric genus Troglocaris cave shrimps from the subgenus Troglocaris s. str. (Dormitzer, 1853) (Crustacea:Decapoda: Atyidae), have the widest distribution area. The recent molecular analyses have revealed significant, crypticdiversity in the subgenus. The aim of the subsequent detailed morphometric analyses was the provision of the appropriatediagnosable characters for the discovered lineages, i.e. taking care of their taxonomical visibility. We herein designate aneotype and provide a detailed description for the polytipic type species of the genus T. (T.) anophthalmus (Kollar, 1848), toenable its morphological distinction from the erroneously described T. (T.) planinensis Birštejn, 1948. Considering acombination of morphological, geographical and molecular data, we describe four new subspecies: T. (T.) a. ocellata ssp. nov.,T. (T.) a. periadriatica ssp. nov., T. (T.) a. legovici ssp. nov. and T. (T.) a. sontica ssp. nov., apart from the extant T. (T.) a.intermedia Babić, 1922. Due to a considerable morphological variability and no easily observable diagnostic morphological characters, the GenBank accession numbers for the COI gene are added in all mentioned taxa.

Sexual Dimorphism in Head Shape, Relative Head Width, and Body Size ofEurycea aquaticaandEurycea cirrigera

2013 ◽  
Vol 47 (2) ◽  
pp. 321-327 ◽  
Author(s):  
Michael A. Alcorn ◽  
Jennifer Deitloff ◽  
Sean P. Graham ◽  
Elizabeth K. Timpe
Keyword(s):  
Body Size ◽  
Sexual Dimorphism ◽  
Head Width ◽  
Head Shape

scholarly journals Sexual dimorphism in Apfelbeckia insculpta (L. Koch, 1867) (Myriapoda: Diplopoda: Callipodida)

2017 ◽  
Vol 69 (1) ◽  
pp. 23-33 ◽  
Author(s):  
Bojan Ilic ◽  
Bojan Mitic ◽  
Slobodan Makarov
Keyword(s):  
Sexual Selection ◽  
Body Size ◽  
Sexual Dimorphism ◽  
Endemic Species ◽  
Balkan Peninsula ◽  
Body Plan ◽  
Body Proportions ◽  
Adult Body ◽  
Copulation Behavior

Apfelbeckia insculpta (L. Koch, 1867) is one of the largest European millipedes and an endemic species of the Balkan Peninsula. We present data on sexual dimorphism in size and body proportions obtained from 179 adult specimens of this species from four caves in Serbia and one in Montenegro using univariate and multivariate morphometric techniques. Sexual dimorphism was apparent and female-biased for all measured characters, except for lengths of the antennae and the 24th leg pair (which were larger in males) and lengths of the first, second and fourth leg pairs, which exhibited small differences between sexes. Generally, females had significantly greater body size than males, while males expressed significantly greater values in traits that can be associated with mobility and copulation behavior. Also, we found significant variations in sexual size and body proportions dimorphism among analyzed populations. The influences of fecundity and sexual selection on the adult body plan in A. insculpta are discussed.

A new wide-headed Fanged Frog of the Limnonectes kuhlii group (Anura: Dicroglossidae) from western Borneo with a redescription of Rana conspicillata Günther, 1872

Zootaxa ◽  
2017 ◽  
Vol 4317 (2) ◽  
pp. 291 ◽  
Author(s):  
J. MAXIMILIAN DEHLING ◽  
D. MATTHIAS DEHLING
Keyword(s):  
New Species ◽  
Body Size ◽  
Genetic Information ◽  
Taxonomic Revision ◽  
Distinct Species ◽  
Morphological Characters ◽  
Head Size ◽  
Type Series

We re-examined the type series of Rana conspicillata Günther, 1872 from Matang in western Sarawak, Borneo and found it to consist of specimens of three distinct species that can be separated by qualitative morphological characters and morphometrics. We re-allocate one paralectotype to Limnonectes hikidai and another to a large-sized species from western Borneo that we describe as new. The new species is morphologically distinguished from all described species of the L. kuhlii group from the Sunda region by body size, extent of toe webbing, head size and odontoid shape. It differs genetically from all described species for which genetic information is available. In order to facilitate the further taxonomic revision of the L. kuhlii group on Borneo, we provide a detailed morphological redescription of the holotype of Rana conspicillata. 

Sexual dimorphism in thick-billed murres, Uria lomvia

1993 ◽  
Vol 71 (2) ◽  
pp. 346-351 ◽  
Author(s):  
Donald T. Stewart
Keyword(s):  
Sexual Selection ◽  
Body Size ◽  
Sexual Dimorphism ◽  
Discriminant Analysis ◽  
Driving Force ◽  
Mate Guarding ◽  
Canonical Discriminant Analysis ◽  
Uria Lomvia ◽  
Breeding Sites ◽  
Univariate Statistics

The pattern of sexual dimorphism in thick-billed murres, Uria lomvia, from the Lancaster Sound – Jones Sound region, Northwest Territories, was examined for weight and 21 skeletal characters. Univariate statistics (Bonferroni-corrected t-tests) indicated that males were significantly larger than females in 6 bill and skull characters. Multivariate statistics also indicated that males had larger bills and skulls than females (based on canonical discriminant analysis), but males were not larger than females in overall body size (as defined by the first principal-components axis). The direction and magnitude of dimorphism were consistent with a hypothesis based on sexual selection as the driving force. In particular, large bill and skull sizes in males are consistent with agonistic behaviours associated with male–male competition for breeding sites and mate guarding.

Sign in / Sign up

Export Citation Format

Share Document