The flightless marine midge Pontomyia (Diptera: Chironomidae): ecology, distribution, and molecular phylogeny

Abstract

Pontomyia Edwards, 1926 (Diptera: Chironomidae) is a genus of exclusively marine flightless midges. There are four described species from the Indo-Pacific, and one undescribed species known only from females, pupal skins, and larvae from the Atlantic/Caribbean. They are poorly known owing to their small size (∼1.0mm), extremely short adult life (<3h), and unusual habitat for an insect (coastal lagoons, bays, or rock pools). We reviewed scattered literature on their biology and systematics, presented photomicrographs of the male hypogium, and updated the geographic distribution of each species. We carried out the first molecular study to elucidate relationships among and within three of the species. Results from our four-gene phylogenetic reconstruction using combined gene tree and species tree approaches showed that Pontomyia natans, Pontomyia oceana, and Pontomyia pacifica are each well-supported clades, with P. natans as sister to P. oceana+P. pacifica. Genetic distances based on mitochondrial cytochrome oxidase I are extraordinarily large within P. natans and P. pacifica, which suggests that they may be cryptic species complexes. © 2011 The Linnean Society of London.