Cranial Osteology of the Armadillo Chaetophractus villosus (Mammalia, Xenarthra, Dasypodidae)

Squarcia, Silvia M; Sidorkewicj, Nora Silvia; Casanave, Emma Beatriz

doi:10.4067/s0717-95022006000500004

Cited by 11 publications

(13 citation statements)

References 7 publications

(7 reference statements)

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“…Variables were Squarcia et al, 2006), physiology (Casanave et al, 2005(Casanave et al, , 2006, evolutionary history and phylogenetic affinities (Delsuc et al, 2001;Gaudin, 2003).…”

Section: Sexual Dimorphism In the Mandible Of The Armadillomentioning

confidence: 99%

Sexual dimorphism in the mandible of the armadillo Chaetophractus villosus (Desmarest, 1804) (Dasypodidae) from northern Patagonia, Argentina

et al. 2009

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The aim of this study was to study the sexual dimorphism in adult Chaetophractus villosus (Desmarest, 1804), from northern Patagonia, Argentina. Eight mandibular traits were measured in 37 males and 34 females. Univariate and multivariate morphometric analysis were applied to the data set. Results showed that C. villosus was sexually dimorphic, with higher absolute values corresponding to females. The total length of the mandible was the most important variable to discriminate sexes, followed by the height at the level of the last tooth and body length. The percentages of sex discrimination were high, as they were when a new sample (17 males, 13 females) was tested. Females have larger mandibles than males independently of their larger cranial size. They also showed a higher degree of correlation between variables, suggesting a more stable shape for the mandible than in males.Keywords: Xenarthra, gender differences, jaw, morphometry, discriminant analysis. Dimorfismo sexual da mandíbula do tatu Chaetophractus villosus (Desmarest, 1804) (Dasypodidae) do norte da Patagônia ArgentinaResumo O presente estudo examinou o dimorfismo sexual dos adultos de Chaetophractus villosus (Desmarest, 1804) do norte da Patagônia Argentina. Oito parâmetros mandibulares foram medidos em 37 machos e 34 fêmeas. Análises morfométricas univariada e multivariada foram aplicadas à série de dados. Os resultados mostraram que C. villosus apresenta dimorfismo sexual, com todos os valores absolutos mais elevados nas fêmeas. O comprimento total da mandíbula foi a variável mais importante para discriminar os sexos, seguidos pela altura no nível dos últimos dentes e pelo comprimento do corpo da mandíbula. As porcentagens de discriminação dos sexos foram elevadas, quando uma amostra nova (17 machos, 13 fêmeas) foi testada. As fêmeas têm as mandíbulas maiores que os machos, independentemente de seu tamanho cranial maior. Mostraram também um grau mais elevado de correlação entre variáveis, sugerindo uma forma mais estável para a mandíbula que nos machos.Palavras-chave: Xenarthra, diferenças do sexo, mandíbula, morfometria, análise discriminante.

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“…Variables were Squarcia et al, 2006), physiology (Casanave et al, 2005(Casanave et al, , 2006, evolutionary history and phylogenetic affinities (Delsuc et al, 2001;Gaudin, 2003).…”

Section: Sexual Dimorphism In the Mandible Of The Armadillomentioning

confidence: 99%

Sexual dimorphism in the mandible of the armadillo Chaetophractus villosus (Desmarest, 1804) (Dasypodidae) from northern Patagonia, Argentina

et al. 2009

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“…According to Ralls (1977), the Edentata (at present Xenarthra) are a group with a small to moderate degree of sexual dimorphism, with males generally larger than females. Results of Squarcia et al (1993Squarcia et al ( , 1994Squarcia et al ( , 1999Squarcia et al ( , 2009) demonstrated for C. villosus a clear-cut sexual size dimorphism in the skull and mandible but, contrarily to the vision of Ralls (1977), females were larger than males for both structures. This does not seem to be the general trend for the whole skeletal system of the species, since the morphometric analysis in this work showed the absence of size differences in appendicular elements between sexes.…”

Section: Discussionmentioning

confidence: 98%

A geometric morphometric study of sex differences in the scapula, humerus and ulna of Chaetophractus villosus (Xenarthra, Dasypodidae)

Acuña

Sidorkewicj

Popp

et al. 2017

Iheringia, Sér. Zool.

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ABSTRACT. Sexual diff erences in some of the components of the pectoral girdle and forelimb of Chaetophractus villosus (Desmarest, 1804) were investigated by means of geometric morphometrics. A total of 15 scapulae (7 males, 8 females) and 50 humeri-ulnae complexes (24 males, 26 females) were examined. No size diff erences were detected between sexes for any of the bones, but shape diff erences were found for the humerus and the ulna that enhance the in-forces or the related in-levers. Females had a more robust humerus, with an enlarged deltoid tuberosity, a more spherical head, higher tubercular and epicondylar widths, and more developed supracondylar crests. The ulna of the females was characterised by a more pronounced curvature along its main axis, a caudal displacement of the lateral fossa, a longer olecranon, and a deeper trochlear notch. For both bones, the discriminant analysis classifi ed correctly all the specimens according to their sex. A small percentage of the variance (5.2% for the humerus; 6.8% for the ulna) was explained by allometry. The morphological traits found for the humerus and ulna of the females suggest an increased structural strength that could result in powerful digging strokes while keeping shoulder and elbow stabilisation, suggesting a fossorial advantage over males.KEYWORDS. Large hairy armadillo, fossorial mammals, shape-based dimorphism, appendicular skeleton.RESUMEN. Estudio del dimorfi smo sexual en la escápula, húmero y ulna de Chaetophractus villosus (Xenarthra, Dasypodidae) mediante técnicas de morfometría geométrica. Se investigaron las diferencias sexuales en algunos de los elementos de la cintura escapular y del miembro anterior de Chaetophractus villosus (Desmarest, 1804) utilizando técnicas de morfometría geométrica. La muestra estuvo constituida por 15 escápulas (7 machos, 8 hembras) y 50 complejos húmero-ulna (24 machos, 26 hembras). No se detectaron diferencias de tamaño entre sexos para ninguno de los tres huesos. Sin embargo, se observaron diferencias de forma para el húmero y la ulna, con mayor desarrollo en las hembras de estructuras que favorecen el incremento de fuerzas internas o de las palancas internas relacionadas. En ellas, el húmero se caracterizó por una morfología general más robusta, con mayor desarrollo de la tuberosidad deltoidea, cabeza más esférica, mayores anchos intertubercular y epicondilar, y mayor desarrollo de las crestas supracondilares. Para la ulna se observó una curvatura más pronunciada a lo largo de su eje mayor, desplazamiento de la fosa lateral hacia caudal, olecranon de mayor desarrollo, e incisura troclear más profunda. Para ambos huesos, el análisis discriminante clasifi có correctamente al total de los ejemplares de acuerdo al sexo. Un pequeño porcentaje de la varianza (5,2% para el húmero; 6,8% para la ulna) se debió a efectos alométricos. Las características morfológicas del húmero y la ulna de las hembras sugieren una ventaja fosorial sobre los machos, debido a una mayor fuerza estructural durante los movimientos involucrados...

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“…La terminología anatómica utilizada proviene principalmente de las contribuciones realizadas por Ameghino (1875), Wible & Gaudin (2004) y Squarcia et al (2006). La sistemática se basa en el arreglo propuesto por McKenna & Bell (1997).…”

Section: Rodriguez-bualó Et Al -Chaetophractus Tarijensis ¿Un Endemiunclassified

Chaetophractus tarijensis (Xenarthra, Dasypodidae) ¿Un endemismo del Valle de Tarija (Bolivia)? Implicancias paleobiogeográficas

Rodriguez-Bualó¹,

Soibelzon²,

Scarano³

et al. 2014

Rev. bras. paleontol.

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Cranial Osteology of the Armadillo Chaetophractus villosus (Mammalia, Xenarthra, Dasypodidae)

Cited by 11 publications

References 7 publications

Sexual dimorphism in the mandible of the armadillo Chaetophractus villosus (Desmarest, 1804) (Dasypodidae) from northern Patagonia, Argentina

Sexual dimorphism in the mandible of the armadillo Chaetophractus villosus (Desmarest, 1804) (Dasypodidae) from northern Patagonia, Argentina

A geometric morphometric study of sex differences in the scapula, humerus and ulna of Chaetophractus villosus (Xenarthra, Dasypodidae)

Chaetophractus tarijensis (Xenarthra, Dasypodidae) ¿Un endemismo del Valle de Tarija (Bolivia)? Implicancias paleobiogeográficas

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