Landcare Research - Manaaki Whenua

Landcare-Research -Manaaki Whenua

FNZ 68 - Simuliidae (Insecta: Diptera) - Abstract

Craig DA, Craig REG, Crosby TK 2012. Simuliidae (Insecta: Diptera). Fauna of New Zealand 68, 336 pages.
( ISSN 0111-5383 (print), ISSN 1179-7193 (online) ; no. 68. ISBN 978-0-478-34734-0 (print), ISBN 978-0-478-34735-7 (online) ). Published 29 June 2012


This revision recognises 19 species of Simuliidae as being present in the New Zealand subregion, with all species assignable to Austrosimulium (Austrosimulium) Tonnoir. Added to the 13 previously described species are 2 taxa originally described by Dumbleton as subspecies which we have elevated to species rank, plus 4 new species.

The species groupings of Dumbleton (1973) are confirmed with cladistic analysis: the australense species-group, diagnosed in large by the lack of a basal tooth on the female tarsal claws, and the ungulatum species-group, characterised mainly by presence of the basal tooth on the female tarsal claws. Further subdivision of these species-groups is also confirmed. In the australense species-group, the australense-subgroup contains Austrosimulium (A.) australense (Schiner) and A. (A.) longicorne Tonnoir; and that of the tillyardianum-subgroup contains A. (A.) albovelatum Dumbleton, A. (A.) alveolatum Dumbleton new status, A. (A.) dugdalei n. sp., A. (A.) extendorum n. sp., A. (A.) fiordense Dumbleton new status, A. (A.) laticorne Tonnoir, A. (A.) multicorne Tonnoir, A. (A.) stewartense Dum-bleton, and A. (A.) tillyardianum Dumbleton. In the ungulatum species-group, the ungulatum-subgroup contains A. (A.) campbellense Dumbleton, A. (A.) dumbletoni Crosby, A. (A.) ungulatum Tonnoir, A. (A.) vailavoense n. sp., and A. (A.) vexans (Mik); and the unicorne-subgroup contains A. (A.) bicorne Dumbleton, A. (A.) tonnoiri n. sp., and A. (A.) unicorne Dumbleton. Lectotypes are designated for A. (A.) australense and Simulium tillyardi Tonnoir, 1923 (= A. (A.) australense), and a neotype is designated for A. (A.) fiordense. Examination of specimens with the nomen nudum, caecutiens Walker, 1848, confirmed the synonymy with A. (A.) australense.

The Simuliidae of New Zealand are a segregate of species of the genus Austrosimulium endemic to Australia, Tasmania, and New Zealand. A small group of Australian species form the subgenus Novaustrosimulium Dumbleton. However, only members of subgenus Austrosimulium occur in the New Zealand subregion. The genus is well established as the sister taxon to the monospecific genus Paraustrosimulium Wygodzinsky & Coscarón in South America.

This revision is based on numerous new specimens obtained between 2006 and 2012 from over 319 localities, and 330 collections in addition to an equal number of earlier collections. Full descriptions for known stages are given for all previously described species as well as the new species. Most diagnostic characters are found in the pupal stage and involve the structure of the pupal gills, the cocoon structure, and sculpture of the thoracic cuticle. Mature final instar larvae, exhibiting dark pharate pupal gills, are also of major diagnostic value. Keys are provided to adult females and males, pupae, cocoons, final instar larvae, and larval ecological requirements. There are full illustrations of the morphological characters used.

An extensive review is provided on bionomics. For most species little is known about their biology, habitat requirements, and the factors limiting their distribution, but it appears that the requirements of the immature stages are the major determinants. A. longicorne larvae are found in smooth, markedly slow flowing water — quite unusual for a simuliid — and we propose the common name “slow flow black fly” for this species. Some high altitude species, such as A. bicorne, have quite specific habitat requirements for the immature stages. Others, such as those of A. australense, are habitat generalists, but normally use vegetation as a substrate. Details about recent collecting localities and their hydrological parameters are given. Typical habitats for species are illustrated, although all recent localities have an associated photograph that is accessible through <>.

The biogeography of species is discussed in-depth in relation to current knowledge of the geological events that have shaped New Zealand and influenced the distribution of species.

Preliminary molecular analysis (Cytochrome oxidase subunit 1 (CO1) mitochondrial DNA barcoding, 800 base pairs) is almost in full concordance with the groupings formed through morphological cladistic analysis, but the molecular analysis could not distinguish species in the tillyardianum-subgroup. Austrosimulium ungulatum, recognised from morphological evidence to be a single entity, is shown to comprise 4 haplotypes. Similarly, some other species show multiple haplotypes. Further, A. vexans of the Auckland Islands is sister to an aggregate of haplotypes previously assumed to be A. ungulatum. Austrosimulium dumbletoni and A. vailavoense, taxonomically placed in the ungulatum-subgroup because of morphological characters, are shown by molecular analysis to be in the unicorne-subgroup; and that subgroup is sister to all remaining New Zealand Austrosimulium. Further, A. australense probably comprises 2 species, one primarily North Island, the other precinctive to the South Island and Stewart Island and that cannot be distinguished on current morphological characters.

The molecular analysis indicated that New Zealand Austrosimulium originally arrived by dispersal well after the so-called Oligocene Great Inundation ca 34–23 Mya, and the concatenation of the large tillyardianumsubgroup even more strongly indicated that it is a segregate of recent origin. That the unicorne-subgroup of species require cold water, high altitude habitats in the Southern Alps, that at maximum are only some 5 million years of age, indicates that New Zealand Austrosimulium is unlikely to be older.

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