COLLECTIONS: Known from four sites near Christchurch, South Island: 34 (type locality), 37, 43, and 45.

Trichospores ovoid, (11-)14(-15) x (6.5-)8(-9) µm, with an obvious collar narrowed where the single, fine appendage emerges, borne 1-3 per fertile branch. Zygospores (27-)32(-35) x 10-12 µm, produced following scalariform conjugation of branches, upon release bearing a collar approximately 18 x 4 µm attached about 8 µm from one end. In hindgut of Chironomidae larvae.

HOSTS: At least two unidentified species of Orthocladiinae.

Trichosporae ovales, (11-)14(-15) x (6.5-)8(-9) µm, collari manifesto ad appendiculi unici tenuis emersum attenuato, in ramo fertili singulae, binae, vel ternae. Zygosporae (27-)32(-35) x 10-12 µm, per conjugationem ramorum scalariformem partae, liberatae collate 18 x 4 µm circa 8 µm ab fine uno affixum gerentes. In proctodaeo Chronomidarum larvarum.

Some of the same species of Orthocladiinae from site 43 also harbored Stachylina minima in their hindguts, a new species described later in this paper. The only Smittium species with trichospores near the size of A. kiwiorum is S. incrassatum Y. Kobayasi with trichospores 12-14 x 7-9 µm, collar 1.15 µm long. The spores of S. incrassatum are described as finely punctate with a short collar and long appendage. The spores of A. kiwiorum lack the punctate feature, have a longer collar, and are more ovoid than those of S. incrassatum. No comparison of zygospores can be made as they were not reported for S. incrassatum; however, zygospores from known Smittium spp. do not have the median swelling found in zygospores of Austrosmittium.

HOLOTYPE: Slide ZEA-34-3 prepared from a species of Orthocladiinae larvae (Diptera, Chironomidae) collected from Wainui Stream, Banks Peninsula, South Island (site 34), 21.I.87.