Skull morphological variation in a British stranded population of false killer whale (Pseudorca crassidens): a three-dimensional geometric morphometric approach

2022 ◽  
pp. 119-132
Author(s):  
Deborah Vicari ◽  
Richard C. Sabin ◽  
Richard P. Brown ◽  
Olivier Lambert ◽  
Giovanni Bianucci ◽  
...  
Keyword(s):  
Sexual Dimorphism ◽  
Morphological Variation ◽  
Killer Whale ◽  
Three Dimensional ◽  
Anatomical Landmarks ◽  
Geometric Morphometric ◽  
False Killer Whale ◽  
Sexual Shape Dimorphism ◽  
Males And Females ◽  
Pseudorca Crassidens

The false killer whale (Pseudorca crassidens (Owen, 1846)) is a globally distributed delphinid that shows geographical differentiation in its skull morphology. We explored cranial morphological variation in a sample of 85 skulls belonging to a mixed sex population stranded in the Moray Firth, Scotland, in 1927. A three-dimensional digitizer (Microscribe 2GX) was used to record 37 anatomical landmarks on the cranium and 25 on the mandible to investigate size and shape variation and to explore sexual dimorphism using geometric morphometric. Males showed greater overall skull size than females, whereas no sexual dimorphism could be identified in cranial and mandibular shape. Allometric skull changes occurred in parallel for both males and females, supporting the lack of sexual shape dimorphism for this particular sample. Also, fluctuating asymmetry did not differ between crania of males and females. This study confirms the absence of sexual shape dimorphism and the presence of a sexual size dimorphism in this false killer whale population.

Morphological variation in bony structures of Hylaeamys seuanezi (Rodentia, Cricetidae, Sigmodontinae) in Southern Bahia, Brazil

Mammalia ◽  
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Franger J. García ◽  
Martín Roberto del Valle Alvarez
Keyword(s):  
Sexual Dimorphism ◽  
Morphological Variation ◽  
Climatic Factors ◽  
Geometric Morphometric ◽  
Average Shape ◽  
Southern Bahia ◽  
Morphological Diagnosis ◽  
Males And Females ◽  
Negative Pressures ◽  
First Time

Abstract Rodents of the genus Hylaeamys, are a group of cryptic species previously included in the Oryzomys capito complex. In Brazil are represented by six species, distributed in different biomes. However, the limits of their geographic distributions and taxonomy have not yet been well defined. In particular, the taxonomy for Hylaeamys seuanezi is unstable. Based on the analysis of bony structures and supported with geometric morphometric techniques, we characterize and compare the average shape from populations in four localities from Southern Bahia, Brazil. We review 145 individuals and we create morphological landmarks in skulls, mandibles, scapulae, and pelvis. In all the structures there were statistically significant differences between populations, in which the average shape from the Igrapiúna population was the most differentiated. Our results also showed differences between the pelvis of males and females, reporting for the first time sexual dimorphism for H. seuanezi. Finally, we provide a morphological diagnosis between the populations and postulate that such differences may be correlated with environmental and climatic factors that could be exerting negative pressures on H. seuanezi; as has been evidenced with other species of rodents and other mammals.

scholarly journals A Case of Chronic Purulent Pneumonia in False Killer Whale (Pseudorca crassidens)

2005 ◽  
Vol 10 (2) ◽  
pp. 117-122 ◽  
Author(s):  
Fumio TERASAWA ◽  
Kimimasa TAKAHASHI ◽  
Isao OHSHITA ◽  
Masakazu KITAMURA
Keyword(s):  
Killer Whale ◽  
False Killer Whale ◽  
Pseudorca Crassidens

Sexual dimorphism in the carapace shape and length of the freshwater palaemonid shrimp Macrobrachium potiuna (Müller, 1880) (Decapoda: Caridea: Palaemonidae): geometric and traditional morphometric approaches

2017 ◽  
Vol 67 (2) ◽  
pp. 93-103 ◽  
Author(s):  
Madson Silveira de Melo ◽  
Setuko Masunari
Keyword(s):  
Body Weight ◽  
Sexual Dimorphism ◽  
Behavioral Differences ◽  
Geometric Morphometric ◽  
Freshwater Shrimps ◽  
Morphometric Analyses ◽  
Males And Females ◽  
Morphological Differences ◽  
Three Rivers ◽  
Coastal Basin

Sexual dimorphism is characterized by morphological, physiological, or behavioral differences between males and females. The genus Macrobrachium is a diverse group of freshwater shrimps distributed throughout tropical and subtropical regions. They have a great intra- and interspecific morphological variation, with some species showing sexual dimorphism. We investigated the sexual dimorphism of the size and shape of the carapace and body weight of Macrobrachium potiuna (Müller, 1880) in three populations of the State of Paraná through traditional and geometric morphometric techniques. The populations were sampled from three rivers: the Pombas River, Coastal Basin, the Piraquara River, First Plateau, and the Guabiroba River, Second Plateau. Morphometric analyses indicated that male shrimps showed differences in carapace length and body weight: the higher the distance from the sea, the smaller and lighter the shrimps. Carapace shape also differed significantly between the sexes in all three populations, with males having a less robust carapace, but a more elongated rostrum than females. The morphological differences between the genders seem to reflect the reproductive roles of males and females in this environment.

Morphological variation in a conservative structure: the scapulocoracoids in Sympterygia acuta Garman, 1837 and Sympterygia bonapartii Müller & Henle, 1841 (Chondrichthyes: Rajidae)

Zootaxa ◽  
2017 ◽  
Vol 4318 (1) ◽  
pp. 157 ◽  
Author(s):  
CARLOS D. JURADO ◽  
EZEQUIEL MABRAGAÑA ◽  
JUAN MARTÍN DÍAZ DE ASTARLOA
Keyword(s):  
New Species ◽  
Sexual Dimorphism ◽  
Morphological Variation ◽  
Coastal Waters ◽  
Slight Variation ◽  
Morphometric Variation ◽  
Phylogenetic Studies ◽  
Morphologic Variation ◽  
Broad Variation ◽  
Males And Females

Scapulocoracoid variation in Sympterygia acuta and S. bonapartii was analyzed inter- and intraspecifically, and the utility of this structure as a diagnostic character in skates was evaluated. Skeletal pieces were obtained from a total of 85 specimens collected in coastal waters of northern Argentina in 2011 and 2012. Morphometric variation was analyzed using non parametric tests. Morphologic variation was qualitatively and quantitatively evaluated by comparing number, shape and arrangement of posterior fenestrae. Scapulocoracoids of both species are rectangular in shape and expanded anteroposteriorly, but those of S. bonapartii were more expanded. Differences in shape, both in males and females, were reflected in the ANOSIM test. Greatest Height and Height of Rear Corner were the variables that most contributed to the differences found between both species. These differences in morphology agree with previous descriptions. No sexual dimorphism was observed regarding scapulocoracoids in S. acuta, and only a slight variation between males and females of S. bonapartii was found. Number of postdorsal and postventral fenestrae was highly variable. At least five scapulocoracoid morphotypes for S. acuta (with two to six fenestrae) and seven scapulocoracoid morphotypes for S. bonapartii (with three up to nine fenestrae) were identified. However, patterns of fenestrae arrangement were also very diverse in both species. Therefore, a broad variation in fenestrae number and pattern, especially postdorsal ones, was shown in both species. These results indicate that caution needs to be taken when using the scapulocoracoids not only in phylogenetic studies but also in descriptions of new species. 

scholarly journals Active echolocation beam focusing in the false killer whale, Pseudorca crassidens

2012 ◽  
Vol 215 (8) ◽  
pp. 1306-1312 ◽  
Author(s):  
L. N. Kloepper ◽  
P. E. Nachtigall ◽  
M. J. Donahue ◽  
M. Breese
Keyword(s):  
Killer Whale ◽  
Beam Focusing ◽  
False Killer Whale ◽  
Pseudorca Crassidens

scholarly journals Evolutionary characterization of a highly repetitive sequence identified from the false killer whale (Pseudorca crassidens)

2009 ◽  
Vol 84 (2) ◽  
pp. 185-189
Author(s):  
Dae-Won Kim ◽  
Aram Kang ◽  
Sang-Haeng Choi ◽  
Zang Geun Kim ◽  
Woo-Jin Kim ◽  
...  
Keyword(s):  
Repetitive Sequence ◽  
Killer Whale ◽  
False Killer Whale ◽  
Pseudorca Crassidens
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