scholarly journals Morphological descriptions and morphometric discriminant function analysis reveal an additional four groups of Scylla spp

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e8066 ◽  
Author(s):  
Hanafiah Fazhan ◽  
Khor Waiho ◽  
Emilia Quinitio ◽  
Juliana C. Baylon ◽  
Yushinta Fujaya ◽  
...  
Keyword(s):  
Discriminant Function ◽  
Discriminant Function Analysis ◽  
Function Analysis ◽  
Carapace Width ◽  
Morphological Characters ◽  
Equatorial Region ◽  
Natural Occurrence ◽  
Pure Species ◽  
Sulu Sea ◽  
Males And Females

There are four species of mud crabs within the genus Scylla, and most of them live sympatrically in the equatorial region. Apart from a report in Japan about the finding of a natural Scylla hybrid more than a decade ago after the division of genus Scylla into four species by Keenan, Davie & Mann (1998), no subsequent sighting was found. Thus, this study investigates the possible natural occurrence of potential hybridization among Scylla species in the wild. A total of 76,211 individuals from mud crab landing sites around the Malacca Straits, South China Sea and Sulu Sea were screened. In addition to the four-purebred species, four groups (SH 1, n = 2, 627; SH 2, n = 136; SH 3, n = 1; SH 4, n = 2) with intermediate characteristics were found, mostly at Sulu Sea. Discriminant Function Analysis revealed that all Scylla species, including SH 1 - 4, are distinguishable via their morphometric ratios. The most powerful discriminant ratios for each character and the top five discriminant ratios of males and females were suggested. The carapace width of SH 1 males and females were significantly smaller than pure species. Based on the discriminant ratios and the description of morphological characters, we hypothesize that the additional four groups of Scylla with intermediate characteristics could be presumed hybrids. Future work at the molecular level is urgently needed to validate this postulate.

scholarly journals Sexual dimorphism in mud crabs: a tale of three sympatric Scylla species

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e10936
Author(s):  
Hanafiah Fazhan ◽  
Khor Waiho ◽  
Yushinta Fujaya ◽  
Nita Rukminasari ◽  
Hongyu Ma ◽  
...  
Keyword(s):  
Body Size ◽  
Sexual Dimorphism ◽  
Discriminant Function ◽  
Discriminant Function Analysis ◽  
Function Analysis ◽  
Carapace Width ◽  
Sympatric Species ◽  
Sexually Dimorphic ◽  
Morphometric Characteristics ◽  
Mud Crabs

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).

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

2008 ◽  
Vol 13 (2) ◽  
pp. 60 ◽  
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>

scholarly journals Cohort effect on discriminant rate: the case of greater flamingo (<i>Phœnicopterus roseus</i>) chicks sexed with morphological characters

Web Ecology ◽  
2020 ◽  
Vol 20 (2) ◽  
pp. 153-159
Author(s):  
Abdennour Boucheker ◽  
Riad Nedjah ◽  
Roger Prodon ◽  
Mark Gillingham ◽  
François-Xavier Dechaume-Moncharmont ◽  
...  
Keyword(s):  
Discriminant Function ◽  
Discriminant Function Analysis ◽  
Function Analysis ◽  
Cohort Effect ◽  
Morphological Characters ◽  
Genetic Determination ◽  
One Year ◽  
Breeding Seasons ◽  
Number Of Individuals

Abstract. We used a large dataset of greater flamingo chicks banded and measured at Camargue, France, to verify the applicability of discriminant function analysis to sex this species. Males and females sexed genetically differed significantly in all of the morphological characters measured (body mass, tarsus and wing length), with males being significantly larger than females. Although the discriminant rate varied substantially from one year to another, we found that it increased with the sample size of genetically sexed individuals. Our results suggest that discriminant function analysis (DFA) does not provide an efficient tool to sex greater flamingo chicks as these relationship are highly variable across years, requiring the genetic determination of sex on a large number of individuals every year for calibrating the DFA and still providing an overall low accuracy in sex determination. Indeed, conditions at breeding seasons can vary between years and can be considered proximate causes affecting the correct discriminant rate. Like previous studies, we recommend caution in dealing with discriminant equations computed from small datasets, and our simulation suggests that 325 genetically sexed individuals are needed to obtain 80 % correctly classified greater flamingo chicks.

Morphometric differentiation of five biotypes of Lysiphlebus fabarum (Marshall) (Hymenoptera: Braconidae: Aphidiinae) in Iran

Zootaxa ◽  
2011 ◽  
Vol 2745 (1) ◽  
pp. 43 ◽  
Author(s):  
HOSSEIN BARAHOEI ◽  
SEYED MASSOUD MADJDZADEH ◽  
MOHSEN MEHRPARVAR
Keyword(s):  
Cluster Analysis ◽  
Discriminant Function ◽  
Discriminant Function Analysis ◽  
Function Analysis ◽  
Aphis Gossypii ◽  
Size Variation ◽  
Morphological Characters ◽  
Aphis Fabae ◽  
Group Method ◽  
Melanaphis Sacchari

Morphometric analyses were carried out on five biotypes of Lysiphlebus fabarum (Marshall) (Hymenoptera: Braconidae: Aphidiinae) associated with five host aphid species, Aphis craccivora Koch, Aphis fabae Scopoli, Aphis gossypii Glover, Brachyunguis zygophylli (Nevsky) and Melanaphis sacchari (Zehntner). Sixteen morphological characters were measured on female specimens of L. fabarum. Two multivariate discriminant analyses, discriminant function analysis and Unweighted Pair Group Method with Arithmetic mean cluster analysis, were employed to discriminate among L. fabarum biotypes on a morphological basis. Both discriminant function analysis and cluster analysis revealed significant morphological differences. Specimens of L. fabarum reared on Melanaphis sacchari/ Sorghum halepense association showed clear differentiation from other L. fabarum biotypes. A stepwise discriminant function analysis selected Distance between R1-R2 junction and outer margin of wing, Metacarpus length, Width of first tergit, Basal vein length and Femur length that showed the highest contribution to the separation of host-adapted biotypes. A dendrogram of the cluster analysis based on data of squared Euclidean distances classified biotypes in different groups. This study demonstrates that morphometric analysis of morphological characters can efficiently discriminate among host-associated groups based on size variation and clearly separate biotypes of L. fabarum. We concluded that L. fabarum biotypes are not homogeneous morphological entities, and represent different host-associated forms.

Diagnoses Generated by Numerical Taxonomic Methods Applied to Standard Blood Variables

1980 ◽  
Vol 19 (04) ◽  
pp. 205-209
Author(s):  
L. A. Abbott ◽  
J. B. Mitton
Keyword(s):  
Liver Cirrhosis ◽  
Renal Disease ◽  
Principal Components Analysis ◽  
Discriminant Function ◽  
Principal Components ◽  
Discriminant Function Analysis ◽  
Chronic Renal Disease ◽  
Function Analysis ◽  
Infectious Hepatitis ◽  
Components Analysis

Data taken from the blood of 262 patients diagnosed for malabsorption, elective cholecystectomy, acute cholecystitis, infectious hepatitis, liver cirrhosis, or chronic renal disease were analyzed with three numerical taxonomy (NT) methods : cluster analysis, principal components analysis, and discriminant function analysis. Principal components analysis revealed discrete clusters of patients suffering from chronic renal disease, liver cirrhosis, and infectious hepatitis, which could be displayed by NT clustering as well as by plotting, but other disease groups were poorly defined. Sharper resolution of the same disease groups was attained by discriminant function analysis.

scholarly journals Description of Echolocation Call Parameters for Urban Bats in Vietnam as a Step Towards a More Integrated Acoustic Monitoring of Urban Wildlife in Southeast Asia

Diversity ◽  
2021 ◽  
Vol 13 (1) ◽  
pp. 18
Author(s):  
Long Kim Pham ◽  
Bang Van Tran ◽  
Quy Tan Le ◽  
Trung Thanh Nguyen ◽  
Christian C. Voigt
Keyword(s):  
Discriminant Function ◽  
Discriminant Function Analysis ◽  
Function Analysis ◽  
Quantitative Description ◽  
Southeast Asian ◽  
Asian Countries ◽  
Echolocation Call ◽  
Echolocation Calls ◽  
Pilot Work ◽  
Southeast Asian Countries

This study is the first step towards more systematic monitoring of urban bat fauna in Vietnam and other Southeast Asian countries by collecting bat echolocation call parameters in Ho Chi Minh and Tra Vinh cities. We captured urban bats and then recorded echolocation calls after releasing in a tent. Additional bat’s echolocation calls from the free-flying bats were recorded at the site where we captured bat. We used the obtained echolocation call parameters for a discriminant function analysis to test the accuracy of classifying these species based on their echolocation call parameters. Data from this pilot work revealed a low level of diversity for the studied bat assemblages. Additionally, the discriminant function analysis successfully classified bats to four bat species with an accuracy of >87.4%. On average, species assignments were correct for all calls from Taphozous melanopogon (100% success rate), for 70% of calls from Pipistrellus javanicus, for 80.8% of calls from Myotis hasseltii and 67.3% of calls from Scotophilus kuhlii. Our study comprises the first quantitative description of echolocation call parameters for urban bats of Vietnam. The success in classifying urban bats based on their echolocation call parameters provides a promising baseline for monitoring the effect of urbanization on bat assemblages in Vietnam and potentially also other Southeast Asian countries.

Predictors of hyoid fracture in hanging: Discriminant function analysis of morphometric variables

2010 ◽  
Vol 12 (3) ◽  
pp. 113-116 ◽  
Author(s):  
Partha Pratim Mukhopadhyay
Keyword(s):  
Discriminant Function ◽  
Discriminant Function Analysis ◽  
Function Analysis

Mineralogy of Egyptian Bentonitic Clays I: Discriminant Function Analysis

2012 ◽  
Vol 60 (4) ◽  
pp. 387-404 ◽  
Author(s):  
Mohamed Agha ◽  
Ray E. Ferrell ◽  
George F. Hart
Keyword(s):  
Discriminant Function ◽  
Discriminant Function Analysis ◽  
Function Analysis
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