Sexual dimorphism in the size and shape of the raptorial pedipalps of Giant Whip Spiders (Arachnida: Amblypygi)

Members of the tubicolous polychaete family Serpulidae constitute one of the most important groups of marine fouling biota. This paper describes a new species of the serpulid genusHydroidesfrom dock fouling at Mazatlán (southern Gulf of California), providing information about live colouration and reproductive features.Hydroides dolabrussp. nov. belongs to a subgroup of species in which verticil spines are equal in size and shape, lack both external and lateral spinules, but have various modifications to their tips. However,Hydroides dolabrussp. nov. is distinct in having tips of verticil spines pickaxe-shaped, with asymmetrical triangular radially orientated projections: the internal projections are short and point inward the verticil centre, while longer external projections point outward the verticil centre. Like all species of the genus,H. dolabrussp. nov. is a gonochoristic broadcast spawner lacking sexual dimorphism. A phylogenetic analysis of Hydroides based on COI, 18S and cytbsequence data reveals thatH. dolabrussp. nov. is genetically distinct from other species ofHydroidesfor which sequence data are available. The new species is the 11th in the genus described from Mexican waters.

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Age, Body Size, and Sexual Dimorphism in Size and Shape in Salamandrella keyserlingii (Caudata: Hynobiidae)

Evolutionary Biology ◽

10.1007/s11692-010-9080-9 ◽

2010 ◽

Vol 37 (1) ◽

pp. 38-48 ◽

Cited By ~ 28

Author(s):

Masato Hasumi

Keyword(s):

Body Size ◽

Sexual Dimorphism ◽

Size And Shape

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Nasal index among Students of People’s Dental College and Hospital

Europasian Journal of Medical Sciences ◽

10.46405/ejms.v1i1.11 ◽

2019 ◽

Vol 1 (1) ◽

pp. 21-27

Author(s):

Mangesh Bajracharya ◽

Samjhana Sharma

Keyword(s):

Ethnic Identity ◽

Sexual Dimorphism ◽

Female Students ◽

Baseline Data ◽

Craniofacial Surgery ◽

Male And Female ◽

Size And Shape ◽

Gender Differentiation ◽

Significant Difference ◽

The Mean

Introduction: Nasal anthropometry is a study that deals with the measurements of the proportion, size, and shape of the nose. The nasal index is considered as one of the major landmarks for craniofacial surgery, gender differentiation, and ethnic identity. This study is aimed to provide baseline data of the nasal index of Nepalese people and to assess the gender variation which will be of clinical, surgical interest in rhinology and craniofacial prosthetic purpose. Methods: BDS students from 17 to 25 years with various ethnicity were included in the study. A total of 160 students with an equal number of male and female students was included. Nasal parameters were measured and the nasal index was calculated for each student. Result: The mean nasal index was 78.03±7.07 suggesting Mesorrhine type of nose. The nasal width and height show statistically significant differences whereas there was no significant difference found between the nasal indices of male and female students. Hill Janajati showed the highest nasal index followed by Newar, Brahmin and Chettri; and Others. Conclusion: The study concludes the type of nose has an effect on gender when compared between the sex but the nasal index calculated to have a little contribution to sexual dimorphism. Mesorrhine nose was found to be most frequent. Among the population, Hill Janajati showed the highest nasal index. We recommend further study to compare the nasal index of various ethnical groups of the Nepalese population. Keywords: Anthropometry, Mesorrhine, Nasal Index

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

Acta Herpetologica ◽

10.36253/a_h-8955 ◽

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.

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Size and shape sexual dimorphism in the skull of the South American fur seal, Arctocephalus australis (Zimmermann, 1783) (Carnivora: Otariidae)

Latin American Journal of Aquatic Mammals ◽

10.5597/lajam00067 ◽

2005 ◽

Vol 4 (1) ◽

Cited By ~ 11

Author(s):

L. R. Oliveira ◽

E. Hingst-Zaher ◽

J. S. Morgante

Keyword(s):

Sexual Dimorphism ◽

South American ◽

The South ◽

Size And Shape ◽

Fur Seal

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No functional sexual dimorphism in Minorcan horse assessed by geometric morphometric methods

Animal Genetic Resources/Ressources génétiques animales/Recursos genéticos animales ◽

10.1017/s2078633614000514 ◽

2015 ◽

Vol 56 ◽

pp. 91-95 ◽

Cited By ~ 3

Author(s):

Pere M. Parés-Casanova ◽

C. Allés

Keyword(s):

Sexual Dimorphism ◽

Lateral View ◽

Geometric Morphometric ◽

Male And Female ◽

Size And Shape ◽

Morphometric Methods ◽

Nw Mediterranean ◽

Nw Mediterranean Sea ◽

Age Range ◽

Shape And Size

SummaryThe existence of sexual dimorphism in the Minorcan horse, an autochthonous breed from Minorca Island in the Balearic archipelago (NW Mediterranean Sea), is established in the official standard, with females being shorter and longer than males as well as having slenderer necks and a squarer croup. However, no study so far has explored the size and shape components of this dimorphism separately. The aim of this study was to analyse the morphology of this breed using geometric morphometric methods in order to find size and shape differences between sire lines. The analysis was based on landmarks digitized in lateral view from 38 registered adult Minorcan horses (20 males and 18 females) within an age range of 3–14 years (average 7 years) with different performance goals. The analyses did not reveal any significant differences between the “shape” and “size” of male and female animals, for the landmarks studied, so the sexes are functionally similar.

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