Systematics and natural history of the Australian genus Metoligotoma Davis (Embioptera:Australembiidae)

Abstract

Members of the order Embioptera (webspinners) are among the least known groups of insects, but have a relatively well-developed, phylogenetically unique, and biologically interesting fauna in portions of Australia. The genus Metoligotoma Davis (Australembiidae) is a well-defined group occurring in south-eastern Australia where species are especially distinctive in that they occupy extremely small endemic areas. Additionally, both males and females are wingless, thereby severely limiting opportunities for dispersal. Hypotheses of relationships among these species are not available in a modern phylogenetic context and little is known of their natural history and biogeography. A new species of Embioptera, Metoligotoma rooksi Miller & Edgerly, sp. nov. is described from a male specimen from near Bombala, New South Wales, Australia. A phylogenetic analysis of the genus (including 10 of the 16 known species of Metoligotoma) was conducted using morphological and molecular data from 16S, 28S, COI+COII and H3. The new species is most closely related to M. begae, from which it is geographically separated by the high coastal mountains. The natural history of the genus is reviewed, including descriptions of the silk galleries, habitats and eggs. The biogeography of the genus is examined in light of the phylogeny. No obvious vicariance model supports the current distribution and small endemic areas exhibited by members of the genus. Instead, it is speculated that periodic, rare dispersal events from north to south, and inland over the coastal mountains, resulted in the current distribution of the species. This is the first modern phylogenetic analysis of the Australembiidae, and the first extensive analysis of any group of Embioptera to include molecular data.