Austalis Thompson & Vockeroth

Thompson, F. Christian, 2003, Austalis, a new genus of flower flies (Diptera: Syrphidae) with revisionary notes on related genera, Zootaxa 246, pp. 1-19 : 6-7

Austalis Thompson & Vockeroth , gen. nov.

Type­species: Eristalis resolutus Walker

Head: face broadly pilose and pollinose laterally, usually shiny and bare medially, rarely entirely pollinose, straight except for medial tubercle and slight anterior production at antennal pits; tentorial pit short, extending along ventral third of eye; facial stripes indistinct; frontal prominence low, on dorsal third of head; eye bare, holoptic to broadly dichoptic in males; antenna short, about 1/4 as long as face; basoflagellomere oval, slightly longer than broad; arista variable, from bare to plumose.

Thorax: slightly longer than broad, with long pile; anterior anepisternum bare; katepisternum continuously pilose from ventral to dorsal margin; anepimeron with dorsomedial and posterior portions bare; without a postalar pile tuft; katepimeron pilose dorsally; metathoracic pleuron bare; metathoracic spiracle large, usually larger than basoflagellomere; plumula long and multibranched; scutellum without apical sulcus. Legs: simple; metafemur not swollen; metatibia without basal nor apical carina nor apical dens. Wing: usually partially microtrichose; cell R1 closed and petiolate; cell R4+5 petiolate, with petiole as long as stigmatic crossvein; stigmatic crossvein present.

Abdomen: oval to suboval.

Austalis is readily distinguished from all other eristaline syrphids by the pilosity of the pleuron ( Fig. 1 ), having the unique combination of pilose posteroventral anepimeron along with pilose katepimeron. These flies are also typically bright metallic in coloration. Ferguson (1926: 153), while recognizing a broad definition for Eristalis , did recognize that the species with metallic coloration formed a distinct group. He, however, declared that pulchellus had "no very close relationship."

Little is known of the life histories of the species of Austalis . Our only source of information is what has been recorded on specimen labels and unfortunately there is not much beyond the standard locality, date and collector data. However, there is a series of specimens of a few species which were collected by H. Roberts as part of an ecological study of Geschis Seed Orchards in Papua New Guinea. His work indicated that the adults are not uncommon pollinators of Eucalyptus .

Etymology. The name Austalis is an arbitrary combination of letters created to be similar to Eristalis and the Australasian Region where the group occurs. The name is to be treated as feminine.

Eristalis is a Latin noun of feminine gender ( Lewis & Short 1879: 657, Brown 1956: 339), however the International Commission of Zoological Nomenclature (ICZN 1993: 256) as well as various authors (Fabricius, Meigen, and others) treated the name as of masculine gender. As the Code (ICZN 1999: 34, see Art. 30.1.1) clearly states that genusgroup names based on Latin nouns take the gender accorded to them by Latin dictionaries (such as Harpers' (Lewis & Short 1879)), Eristalis is feminine regardless of the Commission's own declaration.

Austalis includes the following species, all of which represent new nomenclatural combinations: aequipars Walker (1864: 210, Eristalis ); bergi Curran (1947: 12, Eristalis ); caledonica Bigot (1884: 339, Eristalomyia ); calliphoroides Shiraki (1963: 165, Eristalis ); ciliata Meijere (1913: 355, Eristalis ); conjuncta Ferguson (1926: 155, Eristalis ); copiosa Walker (1852: 249, Eristalis ); cupreoides Goot (1964: 220, Eristalis ); erythropyga Walker (1864: 211, Eristalis ); inscripta Doleschall (1857: 407, Eristalis ); latilimbata Meijere (1913: 354, Eristalis ); lucilioides Walker (1861: 284, Eristalis ); luciliomima Hull (1944: 46, Eristalis ); muscoides Walker (1858: 96, Eristalis ); muscomima Hull (1944: 48, Eristalis ); postscripta Walker (1864: 210, Eristalis ); pulchella Macquart (1846: 255, Eristalis ); refulgens Doleschall (1858: 96, Eristalis ); resoluta Walker (1858: 95, Eristalis ; = maritima Hull, 1945: 210 , Eristalis , syn. nov.); rhynchops Bezzi (1928: 80, Eristalis ); roederi Bergroth (1894: 72, Eristalis ); smaradgi Walker (1849: 631, Eristalis ); and triseriata Meijere (1913: 353, Eristalis ). In addition, another dozen species are known from the Oriental and Australian Regions and will be described in a subsequent revision of the genus (Thompson, in preparation).

Figures

FIGURES 1 ­ 6. 1 ­ 4. Thoracic pleurae of eristaline flies. Arrows point to the critical areas, 1. Austalis rhina, sp. nov., arrow pointing to bare anterodorsal area of the posterior anepimeron, 2. Eristalinus aeneus (Scopoli), arrow pointing to pilose katepimeron, 3. Eristalis (Eoseristalis) arbustorum (Linnaeus), arrow pointing bare posterior anepimeron and meron, 4. Eristalis (E.) tenax (Linnaeus), arrow pointing to bare posterior anepimeron, but pilose katepimeron; 5. Thorax, dorsal view, Eristalinus aeneus (Scopoli), arrow pointing to postalar pile turf; 6. Male genitalia, lateral view, Austalis rhina, sp. nov. Figures 1 ­ 5 are from Thompson & Rotheray (1998).