Sexual dimorphism of crania in a Romanian population: Discriminant function analysis approach for sex estimation

Sexual dimorphism is a common phenomenon in the animal kingdom. To test the consistency of sexual dimorphism patterns among sympatric species of the same genus, ten morphometric characteristics of mud crabs Scylla olivacea, S. tranquebarica and S. paramamosain were measured and compared using Discriminant Function Analysis (DFA). The descriptive analysis revealed that in all three species, body size dimensions and cheliped dimensions were significantly larger in males whereas the abdomen width was female-biased. Also, we described a morphological variation (carapace width, CW ≤ CW at spine 8, 8CW) that is unique to S. olivacea. Discriminant function analysis revealed that all nine morphometric characteristics were sexually dimorphic in S. olivacea, S. tranquebarica (except right cheliped’s merus length, ML) and S. paramamosain (except 8CW). The obtained discriminant functions based on the morphometric ratios (with CW as divisor) correctly classified 100% of adults of known sex of all three species. Further, based on the selected body traits, DFA was able to almost completely distinguish males (94%), but not females (74%), among the three Scylla species. This study highlights that congeneric species of portunids (e.g., Scylla spp.) show similar sexually dimorphic characteristics (body size and secondary sexual characteristics).

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Best parameters for sexual dimorphism in the facial thickness tissue with ultrasonic assessment

Saúde Ética & Justiça ◽

10.11606/issn.2317-2770.v13i2p60-64 ◽

2008 ◽

Vol 13 (2) ◽

pp. 60 ◽

Cited By ~ 3

Author(s):

Iván Claudio Suazo Galdames ◽

Guillermo Enrique Salgado Alarcón ◽

Daniela Alejandra Zavando Matamala

Keyword(s):

Sexual Dimorphism ◽

Discriminant Function ◽

Discriminant Function Analysis ◽

Function Analysis ◽

Tissue Thickness ◽

Significance Level ◽

Ultrasound Measurements ◽

Males And Females ◽

Ultrasonic Assessment ◽

Best Parameters

<p>Knowledge of facial tissue thickness is crucial to facial reconstruction procedures in forensic sculpture. The literature still brings some controversy on the validity of data obtained for different population groups. The purpose of this study was to investigate sexual dimorphism in the thickness of the facial tissues. The study sample consisted of 43 volunteers, between 24 and 48 years of age, and of normal body mass. Ultrasound measurements of facial tissue thickness were obtained at 14 median and paramedian landmarks. A T test was used to compare measurements from males and females, with a significance level of at least 0.05. Discriminant function analysis was used to determine the points that showed most distinction between the sexes. Measurements at paramedian landmarks were greater in males, while those at median landmarks were greater in female subjects, except for Down’s A and B points. We conclude that sexual dimorphism in facial thickness justifies the pre-assignment of sex in reconstruction procedures in forensic sculpture</p>

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Sex estimation from the femur using discriminant function analysis in a Central Indian population

Medicine Science and the Law ◽

10.1177/0025802419900576 ◽

2020 ◽

Vol 60 (2) ◽

pp. 112-121

Author(s):

Preetika M Chatterjee ◽

Kewal Krishan ◽

RK Singh ◽

Tanuj Kanchan

Keyword(s):

Discriminant Function ◽

Discriminant Function Analysis ◽

Function Analysis ◽

Central India ◽

Growth Patterns ◽

Personal Identification ◽

Sex Estimation ◽

Biological Profile ◽

Head Diameter ◽

Major Factors

Sexual dimorphism is one of the major factors responsible for apparent variations in human skeletal anatomy. Establishing the biological profile of the deceased is essential for personal identification in forensic and archaeological casework. To develop a reliable biological profile, sex allocation is an integral step required to determine age, race/ancestry and stature, given observable differences in aging and growth patterns and variations in morphological traits relating to ancestry. Sex estimation from long bones by visual examination is very difficult. However, metric observations are more objective and effective. This osteometric analysis focused on sex estimation from the femur using discriminant function analysis. Fourteen measurements were taken directly on 175 dry femora (117 males and 58 females), aged 20–60 years, from the Chhattisgarh region of Central India. Student’s t-test was applied to assess significant sex and size differences. Direct and stepwise discriminant function analyses were applied to derive discriminant function models for sex estimation. The three parameters that were selected for the discriminant function analysis included: transverse head diameter, bi-trochanteric distance and maximum shaft diameter. Males were more accurately classified than females. An overall accuracy of 80.6% was reported with direct discriminant function analysis and 76% with stepwise discriminant function analysis upon cross-validation. The transverse head diameter emerged to be the best predictor of sex. This study provides a database and standards for sex estimation from skeletal remains of an unknown nature based on discriminant function equations. This is one of the few studies conducted in India on dry bones, and we anticipate that it will guide forensic specialists in the identification of unknown skeletons from this region.

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