Resumo

HERNANDEZ, María Laura  e  ACOSTA, Luis E.. Characterization of sexual dimorphism and recognition of dimorphic males in the Discocyrtus prospicuus complex (Arachnida: Opiliones: Gonyleptidae): a geometric morphometrics approach. Rev. Mex. Biodiv. [online]. 2021, vol.92, e923545.  Epub 25-Out-2021. ISSN 2007-8706.  https://doi.org/10.22201/ib.20078706e.2021.92.3545.

The remarkable sexual dimorphism, characteristic of the family Gonyleptidae (Opiliones), as well as the occurrence of discrete morphotypes in males with respect to body size and weaponry, have merited several analyses, by several authors, using linear morphometrics. In this work, we propose the application of geometric morphometrics techniques to analyze the morphometric variability in centroid size and shape of dorsal scutum and coxa IV of males of the Discocyrtus prospicuus complex (Gonyleptidae), in order to evaluate the existence of discrete morphotypes and the influence of the geographic factor on morphometric variability. Likewise, it is aimed to characterize the sexual dimorphism based on the same characters. One hundred-thirteen individuals (58 males and 55 females), from 11 localities in 3 Argentine provinces, were analyzed. Results show that sexual dimorphism affects both the size and the conformation of the 2 measured structures, although in a different direction in coxae and dorsal scutum. Meanwhile, males showed 2 separate subgroups with respect to the centroid size of coxae and scutum, although with slight differences depending on geographic origin. The occurrence of subgroups related to centroid size is also described for the first time for females. These results constitute an advance in the understanding of the occurrence of dimorphisms and the geographic variations associated with this variation.

Palavras-chave : Morphotypes; Poecilandry; Centroid size; Shape; Dorsal scutum; Coxa IV.

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