Taxonomic notes on the genus Heliogomphus Laidlaw, 1922 (Odonata: Gomphidae), with a redescription of H. kalarensis Fraser, 1934 from southern India

Abstract

The taxonomy and distribution of dragonflies of the genus Heliogomphus from the Western Ghats of southern India are discussed. A morphological study of fresh male specimens from the field, as well as holotypes and lectotypes from repositories was undertaken. Contradictiing statements in scientific literature, we found that the markings on the occiput and thorax are not dependable features in distinguishing sympatric Heliogomphus promelas (Selys, 1873) and H. kalarensis Fraser, 1934. The structure of the epiprocts and the male genitalia were key features for differentiating them. Heliogomphus pruinans, Fraser, 1922 is removed from the synonymy of H. promelas and is synonymized with H. kalarensis instead based on the analysis of the structure of its epiproct. In accordance with the provisions of ICZN Article 23.9.1.2, in suppression of the unused senior synonym, the taxon name H. kalarensis is retained as a nomen protectum. Heliogomphus unifasciatus is treated as nomen nudum. Taxonomic notes and updated distribution summaries of the two species from the Western Ghats with an identification key to the males are provided. Heliogomphus kalarensis is redescribed from fresh field-collected specimens, including details of the male genitalia and anal appendages. Fieldwork in the Western Ghats revealed that H. kalarensis is the most common of the two Heliogomphus species in Kerala state. The published records of H. promelas and H. kalarensis from this region need to be revisited in light of the facts presented here.