Morphological variability and evaluation of taxonomic characters in the genus Erythemis Hagen, 1861 (Odonata: Libellulidae: Sympetrinae).

Abstract

Erythemis Hagen, 1861 (Odonata: Libellulidae: Sympetrinae) is a Neotropical genus with ten species in which morphological characters vary widely. The aim of this paper is to study the taxonomic diversity of the genus Erythemis and to test the diagnostic value of morphological characters used to discriminate species. The diagnostic value of the morphometric characters is tested using discriminant function analysis, principal component analysis, and graphical exploration of the data. A total of 134 characters were studied; of those, 53 are recoded and 81 are proposed in this work. Discrete characters such as color, genitalia, ventral teeth of male cercus, extension of dark basal area in hind wing, and morphometric characters of abdominal carinae and antenodal wing venation are the most useful for species determination. In contrast, abdomen length/HW length ratio, vulvar lamina length, and spines of femoral structure are highly variable. A lectotype is designated for Diplax credula Hagen, 1861. Taxonomic keys for males and females are included, and variation in several characters is presented.