Phylogeographic Analysis Elucidates the Influence of the Ice Ages on the Disjunct Distribution of Relict Dragonflies in Asia

Abstract

Unusual biogeographic patterns of closely related groups reflect events in the past, and molecular analyses can help to elucidate these events. While ample research on the origin of disjunct distributions of different organism groups in the Western Paleartic has been conducted, such studies are rare for Eastern Palearctic organisms. In this paper we present a phylogeographic analysis of the disjunct distribution pattern of the extant species of the strongly cool-adapted Epiophlebia dragonflies from Asia. We investigated sequences of the usually more conserved 18 S rDNA and 28 S rDNA genes and the more variable sequences of ITS1, ITS2 and CO2 of all three currently recognised Epiophlebia species and of a sample of other odonatan species. In all genes investigated the degrees of similarity between species of Epiophlebia are very high and resemble those otherwise found between different populations of the same species in Odonata. This indicates that substantial gene transfer between these populations occurred in the comparatively recent past. Our analyses imply a wide distribution of the ancestor of extant Epiophlebia in Southeast Asia during the last ice age, when suitable habitats were more common. During the following warming phase, its range contracted, resulting in the current disjunct distribution. Given the strong sensitivity of these species to climatic parameters, the current trend to increasing global temperatures will further reduce acceptable habitats and seriously threaten the existences of these last representatives of an ancient group of Odonata.

Homologization of the Flight Musculature of Zygoptera (Insecta: Odonata) and Neoptera (Insecta)

“…For establishing our homology hypotheses we supplemented our data with information from the literature [7], [10], [14], [17], focusing on Asahina’s comprehencive study of Epiophlebia superstes [7], which represents a conspicuous mixture of anisopteran and zygopteran characters [4], [7], [20], [21]. Furthermore, in many aspects Epiophlebia seems to have the most ancestral character distribution within the Odonata (e.g.…”

<span lang="EN-US"><span style="font-family: 'Times New Roman'; font-size: small;">The classification and diversity of dragonflies and damselflies (Odonata). In: Zhang, Z.-Q. (Ed.) Animal Biodiversity: An Outline of Higher-level Classification and Survey of Taxonomic Richness (Addenda 2013) </span></span>

“…29. A third and fourth species of Epiophlebia were described recently from China based on limited evidence (Carle 2012;Li et al 2012), especially in the light of negligible genetic variation found in three of the species (Büsse et al 2012). 30.…”

The thorax morphology of Epiophlebia (Insecta: Odonata) nymphs – including remarks on ontogenesis and evolution

“…Almost all known recent Odonata can be assigned to one of two groups: either to the Anisoptera (dragonflies) or to the Zygoptera (damselflies). A conspicuous exception are the few species of Epiophlebia , which combine characteristics of both groups 1 2 . Epiophlebia nymphs resemble those of the Anisoptera, respiring through a rectal chamber, while lacking the paddle shaped gills that arise from the tip of the abdomen 1 and are characteristic of Zygoptera.…”