Sexual dimorphism of Baikalian amphipoda Gmelinoides fasciatus (Crustacea, Amphipoda)

Abstract

The degree of morphological variability in different groups of Baikal amphipods is different; sexual dimorphism among Baikal amphipods is described in approximately 30% of species by a limited number of morphological characters. There are very few works based on a large number of specimens and many morphological characters. The widespread species Gmelinoides fasciatus (Stebbing, 1899) is known from its morphological heterogeneity, but no detailed studies have been carried out. Study of sexual dimorphism of the species G. fasciatus is based on a large number of quantitative characters. The purpose of this work is to investigate sexual dimorphism and identify the most significant features. The study revealed the variability of the morphological features of G. fasciatus and pronounced sexual dimorphism, as well as the features that characterize it. Comparative analysis of morphological characters showed that in the study of sexual dimorphism it is necessary to use a greater number of characters than previously used.