Body mostly invested with gray or brown microtomentum. Three orbital setae, anterior orbital seta medioreclinate, middle and posterior setae lateroreclinate; paravertical setae present. Antennae not in deep grooves. Proboscis with prementum short and wide; labellum short. Thorax with anepisternum bare, katepisternum with 2 setae. Wing with humeral and subcostal breaks; subcostal break not deeply incised; cell cup present, veins CuA1 and A1+CuA2 present but not reaching posterior wing margin. Specimens found in coastal regions. (Brake & Mathis 2007)
Head: Frons gray with anterior margin yellowish or reddish; shape trapezoidal, narrowed anteriorly; postocellar setae parallel, each about ½ length of medial vertical seta; ocellar setae lateroproclinate; 3 orbital setae, posterior seta often slightly longer; anterior orbital seta medioreclinate, middle and posterior setae lateroreclinate; 1 inclinate setula anterior to anterior orbital seta; interfrontal setulae proclinate, scattered or more or less arranged in 2 rows, supra-antennal pair not enlarged; occiput generally gray with some brown to blackish coloration; dorsal portion concave. Ptilinal fissure well developed but short, not extended below level of upper margin of insertion area of antenna; ptilinum extremely reduced and probably non-functional, developed as a simple fold that extends no more than diameter of one mid ocellus into head capsule; surface of ptilinum covered with low scales, as in Schizophora (Buck 2006). Tentorial pit undivided and anterior tentorial arm well developed (Buck 2006). Antenna generally yellow, base of basoflagellomere usually darker; scape bearing 1 setula mediodorsally; pedicel bearing 2 dorsal setulae and some smaller setulae; arista bare, usually 3-segmented, with a trace of the basal segment, but sometimes without. Face lightly sclerotized, yellow. Eye broadly oval, oriented obliquely; with anterior ommatidia slightly larger than posterior ommatidia; densely setulose, every junction between ommatidia occupied by a setula. Gena yellow anteriorly, becoming gray posteriorly; gena bearing a conspicuous, medioclinate vibrissal seta and 3-4 larger genal setae near ventral margin, these becoming slightly shorter posteriorly; anterior genal seta anterolateroclinate, other genal setae more ventroclinate. Proboscis normally developed, not geniculate or elongate, yellow; fulcrum with stretch receptors consisting of two rows of 5 close-set setulae on each side; palpus spatulate, bearing a few setulae; stipes with ventral appendage; lacinia bare, long and acuminate, medial surface with very fine serration; prementum short and wide; labellum short, with 5 pseudotracheae, labellar lobes completely fused along middle and extended posteriorly, forming an acute angle with haustellum ventrally (Buck 2006, Brake & Mathis 2007)
Thorax: Ground color gray to brownish gray with brown to gray microtomentum. Acrostichal setulae scattered and, usually, with 1 large, prescutellar pair; 2-6 dorsocentral setae, 1 presutural and 2 postsutural supra-alar setae; 1 postalar seta; 1 postpronotal seta; 2 notopleural setae, anterior seta slightly longer; anepisternum and anepimeron bare; 1 proepimeral seta; proepisternal seta present or absent, and of variable position; katepisternum bearing 2 setae near dorsal margin, posterior seta usually slightly longer, also bearing a few small setulae; scutellum bearing 2 setae. Subscutellum moderately developed; basisternum basiliform, precoxal bridge absent. (Brake & Mathis 2007)
Wing generally hyaline, often very faintly yellowish; costa broken twice, shortly beyond humeral crossvein and at end of subcostal; costa extended to vein M1 but very weakened in last sector; row of costal spinules extended to apex of R2+3; subcosta ending in costa, not fused with vein R1 apically. From a dorsal view the subcostal vein and R1 appear to be fused apically, but from an anteriorly oblique view they are separate); R1 with slight angle on posterior margin at about 2/3 its length, broken shortly before reaching costa; discal cell separate from cell bm by crossvein bm-cu; cell cup present, veins CuA1 and A1+CuA2 present but not reaching posterior wing margin; A2 absent. (Brake & Mathis 2007)
Legs generally yellow to brown; forefemur with 1-3 posteroventral setae on apical 1/3, these becoming smaller apically; tarsomeres 2, 3, and 4 shortened. (Brake & Mathis 2007)
Male abdomen: Generally brown, subshiny, posterior margins of tergites appearing lighter in color, bearing scattered setulae. Digestive tract with cavity directly anterior to rectum and about the length of a rectal papilla and nearly twice its width; connected to rectum via a duct that is about as long as the cavity and attaches to the anterior portion of the cavity (observed in A. salicorniae female). Abdominal spiracles 1-6 within ventral margin of respective tergites (Griffiths 1972, Buck 2006); 7th spiracle absent, apparently lost; sternites very wide, especially sternites 4 and 5. Postabdomen generally asymmetrical; 6th tergite large, slightly asymmetrical (larger on right side), not reduced, as long as 5th tergite; 6th sternite asymmetrical, linked to 7th sternite on left side; 7th sternite extended onto dorsum on left side, fused dorsally and ventrally with 7th tergite (which is represented by a narrow strip of sclerotization on the right side), so that a complete ring of sclerotization is formed about the 7th abdominal segment; 8th sternite large, not fused to 7th sternite in Australimyza salicorniae (narrowly fused near mid-line in species Griffiths 1972 examined); 8th tergite absent. Sternite 6 and syntergosternite 7 bare of setae except for the usual anterior pair of sensilla trichodea; sternite 8 setulose. Male terminalia: epandrium narrow dorsally but not divided into two halves (as reported by Griffiths 1972); surstylus fused with epandrium (not in A. glandulifera); cerci fused basally; no trace of a subepandrial sclerite; inner base of surstyli contiguous with hypandrium (Buck 2006); postgonite about as large as surstylus, with 1-4 short sensory hairs, connected to base of phallapodeme medially and to pregonites laterally, movable in lateral direction to a position in a right angle to the surstylus (observed in salicorniae, mcalpinei); pregonite bearing a few setulae, developed as separate thumb-like process in victoria species group and A. glandulifera, but as a low bulge in australensis-species group; phallapodeme rod-like and forked basally, encircling base of phallus, free from hypandrium; aedeagus able to be swung through wide arc against phallapodeme (Griffiths 1972, Buck 2006); basiphallus simple, ring-shaped with small widening posteriorly in australensis-species group and U-shaped in victoria species group (we interpret this structure as the basiphallus because the distiphallus arises directly from the "U"); hypandrium with paired apodemes anteriorly (very short in A. glandulifera), length subequal to that of phallapodeme, anterior part asymmetric; posterolateral arms of hypandrium running parallel to ventral margin of epandrium, reaching base of surstyli and in victoria species group and A. glandulifera forming a hypandrial bridge above base of phallus; distiphallus membranous, long, and slender, slightly coiled or curved, supported along whole length by parameres, posterior surface of distiphallus microtrichose, these sparse and very small in australensis species group, more frequent and larger in victoria species group; ejaculatory apodeme slender, elongate. (Brake & Mathis 2007)
Female abdomen: Sternites normal in victoria species group, but sternite 4 and 5 wider in australensis species group. In A. glandulifera all sternites narrower. Ovipositor apex (segments 7 and 8) normal (similar to anterior segments) in victoria species group and australensis species group, elongate and telescopic in A. glandulifera. Cerci short. Two spermathecae, mushroom-shaped, with short individual ducts and short common duct. Exact shape of spermathecae varies within species with some spermathecae having an indentation at apex and some having one to several small appendices; also ratio between spermathecal height and distance of duct penetration into spermatheca varies (this kind of variation is also found in Drosophila, see Miller 1955). Only ratio between spermathecal height and width seems to be different between species groups. Accessory glands paired, much longer than spermathecae, including ducts, dilated apically into membranous sac, basally joining vagina close to spermathecal duct. Ventral receptacle arising from anteroventral portion of vagina (overlooked by Buck 2006), projected anteriorly, surrounded by musculature and only weakly sklerotized. Apical ½-2/5 of ventral receptacle multichambered with more chambers in A. salicorniae than in A. mcalpinei; each chamber appears to hold only 1 spermatozoon. (Brake & Mathis 2007)
Larva: Only known for Australimyza macquariensis. Slender, elongate, narrower on anterior fourth. Cephaloskeleton very weakly sclerotized and hardly visible. Intermediate sclerite with ventral apodeme, parastomal bar present. First three body segments (thoracic) dorsally with row of 6 cone-shaped tubercules; each tubercule sculptured and with a small, preapical depression or opening, except for smaller lateral tubercules of first row, which lack sculpturing and probably an opening. Segments 4-11 with only 1 lateral tubercule; anal division with a pair of dorsal tubercules. Cephalic region bilobate anterodorsally, with antenna at apex of each lobe; each lobe anteriorly further separated into a dorsal and ventral part; facial mask well-developed, bearing oral ridges on either side of preoral cavity. A well-developed facial mask seems to be associated with saprophagy according to Courtney et al. (2000). Anterior spiracle with about 6 digitiform protuberances, ventral 2 protuberances very short, barely visible. Posterior spiracle with three ramifying peristigmatal tufts. (Brake & Mathis 2007)
Length: 1.3-2.6 mm
Adults occur on or near Australasian maritime beaches between 28° and 54° S and between 115°E and 175° W. According to label data, specimens have been collected on Anisotome antipoda, A. latifolia, and A. scutifolia (Apiaceae), Casinia (Asteraceae), Senecio stewartiae and Sonchus grandiflora (Asteraceae), Lepidium oleraceum (Brassicaceae), Coprosma (Rubiaceae), Hebe elliptica (Scrophulariaceae), Cryophytum flowers (Aizoaceae), Lupinus (Fabaceae), Salicornia (Chenopodiaceae), Polystichum (Polypodiaceae), Durvillea (Durvilleaceae), Myrsine (Myrsinaceae), Carex (Cyperaceae), Chrysobactron rossi and Bulbinella sedge (Asphodelaceae), Poa astonia (Poaceae), tussock grass, decaying seaweed, kelp, on dead stingray, near sea lion wallow, around Royal Albatross nest and at light. Adults have been reared from Hebe sp. and Urtica aucklandicus nettle (Urticaceae), Stilbocarpa polaris (Araliaceae) and from kelp according to label data. These plants were probably rotting, though this is not stated on the labels, because the larvae are saprophagous (R. Meier, pers. comm.). Larvae have been found in Stilbocarpa polaris (Araliaceae), tussock grass, old kelp and sooty albatross nest material. (Brake & Mathis 2007)
There are two species groups within Australimyza, an Australian group (victoria species group) and a New Zealand group (australensis species group), plus one ungrouped species.
Although Harrison (1953) placed Australimyza in Milichiidae when he described the genus, he then recognized that it was atypical (absence of frontal setae, proboscis not elongate and geniculate) for this family. Harrison also noted that Australimyza was the sole representative of Milichiidae from New Zealand. His placement in Milichiidae was based on the presence of convergent, anterior orbital seta, the absence of anepisternal setae, and having the costa broken twice. Colless and McAlpine (1970, 1991) referred the genus to the family Carnidae where it was accorded subfamilial status in their later publication. Grimaldi (1997) followed this view and included Australimyza in his phylogenetic analysis of Carnidae. In contrast, Griffiths (1972) suggested in his study of acalyptrate phylogeny that Australimyza be accorded family (Australimyzidae) and prefamily (Australimyzoinea) status and be placed between his prefamilies Micropezoinea and Diopsinoinea. McAlpine (1989) concurred with recognizing Australimyzidae as a distinct family, but his phylogenetic placement of the family was near the Carnidae and Braulidae in the superfamily Carnoidea. Buck (2006) tentatively supported the monophyly of Carnoidea as a working hypothesis and placed Australimyzidae as the sister group of Inbiomyiidae and these together as the sister group of Carnidae. Support for the relationship between Australimyzidae+Inbiomyiidae and Carnidae, however, is not very strong (five or six pairs of pseudotracheae, subepandrial sclerite absent). Two new characters are presented in this paper. The first is the presence of a multichambered female ventral receptacle in Australimyzidae that has so far not been found in any other family of Carnoidea (the shape of the receptable in Inbiomyiidae needs elucidation) but has been observed in some families of Opomyzoidea (Kotrba and Baptista 2002), for example. The second new character set is the morphology of the larvae. Larvae, however, are not known for Inbiomyiidae, so that comparison cannot be made with this family. The larvae of Australimyza agree with larvae of Carnidae (Meoneura, Carnus) and Acartophthalmidae in having a weakly sclerotized cephaloskeleton (Engel 1930, Papp 1998, Papp & Ozerov 1998) but differ in other respects (presence of antennal papilla and tubercules, and general shape of anterior and posterior regions in Australimyza). The presence of tubercles on the thoracic body segments is also found in Braulidae, however, Braula does not have tubercles on the abdominal segments and the tubercles themselves are shaped differently. The shape of the posterior spiracle is similar to Milichiidae, Chloropidae and others, but in these families the spiracles are situated on protuberances. The morphology of the larvae has not been used previously in the phylogenetic analysis of Carnoidea or related superfamilies because knowledge about larvae is incomplete. Therefore it is difficult to evaluate the characters of Australimyza larvae. However, everal similarities between larvae of Australimyzidae and other families of Carnoidea could support placement of Australimyzidae in this superfamily. It is well possible that the relationships of Australimyza+Inbiomyia will change if larval characters and molecular data are taken into account. (Brake & Mathis 2007)
A molecular analysis by Winkler et al. (2010) found strong support for a close relationship between Australimyzidae and Xenasteidae (Inbiomyiidae were not studied), and evidence that these two families are not closely related to any "opomyzoid" families.
Australia, New Zealand and associated subantarctic islands.