we collected 60 adult males and 85 adult females of trapelus lessonae de filippi, 1863 in early may 2008 from central iranian plateau to study sexual dimorphism in morphological traits as well as female reproductive traits. size-related sexual dimorphism occurred in all the compared body dimensions. the largest female was 83.88 mm in snout-vent length, and the largest male was 73.12 mm. as well...

Theory suggests that the net benefit of allocating resources to a sexual trait depends both on the strength of sexual selection on that trait and on individual condition. This predicts a tight coevolution between sexual dimorphism and condition dependence and suggests that these patterns of within-sex and between-sex variation may share a common genetic and developmental basis. Although conditi...

introduction: the existence of sexual dimorphism in human skeletons especially skull and its medico-legal importance had long been studied [3] [2,1]. this study has investigated the existence of sexual dimorphism in cranial dimensions of nigerian population. methods: a total of 100 adult dry skulls, (78 males, 22 females) free from damage and deformity fully ossified from departments of anatomy...

background and aims. the aim of this study was to determine whether variations in the mesiodistal dimensions of mandibular canines had any role in sex determination. materials and methods. the study comprised of patients in the 19‒24-year age group (20 males and 20 females). mesiodistal dimensions of mandibular canines was measured at the maximum mesiodistal width, first intraorally, then on pl...

there is little chance for species with competitor to develop intraspecific variability such as sexual dimorphism. sitta tephronota is a well-known rock-dwelling bird species in iran, which occurs in zagros mountains in strong ecological competition with sitta neumayer. thus, no sexual dimorphism is expected for sitta tephronota in this area. despite the role of this species in the rise of the ...

Sexual dimorphism, i.e. the distinct recognition of only two sexes per species, is the phenotypic expression of a multi-stage procedure at chromosomal, gonadal, hormonal and behavioral level. Chromosomal--genetic sexual dimorphism refers to the presence of two identical (XX) or two different (XY) gonosomes in females and males, respectively. This is due to the distinct content of the X and Y-ch...

Sexual dimorphism accounts for a large fraction of intraspecific diversity. However, not all traits are equally sexually dimorphic; instead, individuals are mosaics of tissues that vary in their ability to exhibit dimorphism. Furthermore, the degree of a trait's sexual dimorphism is frequently environment-dependent, with elaborate sexual dimorphism commonly being restricted to high nutritional ...

Sexual size dimorphism is widespread among animals; males are larger than females in most birds and mammals whereas the opposite is true among invertebrates, amphibians and reptiles (Andersson 1994, Fairbairn 1997). These taxonomic differences have influenced the terminology and prevailing hypotheses for dimorphism. Although sexual size dimorphism is often described as “normal-” or “reversed-” ...