Species originally described as Johnsoniodon malleri by Curran (1947). Johnsoniodon was described for a female with furcate basoflagellomere. In all other known species with furcate antennae, this condition is only found in the males. Papavero (1952: 322) treat all the groups based on furcate antennae as synonyms of Masarygus. Johnsoniodon is very similar to Schizoceratomyia only differing in the state of the arista. The arista in Johnsoniodon is distinct and about 1.5 times as long as the pedicel, but in Schizoceratomyia the arista is absent or less than 2 as long as pedicel.
Cheng and Thompson (2008) considered this difference that of species, not genus-group taxa and treated this name as a synonym of Schizoceratomyia. The name, Schizoceratomyia, was published in short paper on 12 July and the name, Johnsoniodon, was published on 14 July.
Synonyms: Johnsoniodon malleri Curran, 1947: 1
Adapted from original description (Curran 1947).
Brownish, with luteous and yellow markings on the thorax, the legs light orange, the abdomen with indications of blue black.
FEMALE.
Head: Face wider than either eye, widest above, very slightly narrowing below; front narrowing to the upper third, thence slightly widening to the vertex. Front black laterally, brown in the middle and on the upper third, the ocellar tubercle black; pile dull brassy, appressed exceptabove. There is no distinct transverse frontal depression, but there are oblique, irregular ridges on each side, these being especially noticeable just above the middle. Ocellar triangle small, slightly longer than wide, lying slightly in front of the anterior angle of the eyes. Occiput not swollen, cinereous yellow pollinose, the pile short brassy yellow. Gena scarcely projecting below the eyes. Face brown, with large, oblique lateral depressions black, and a black lateral triangle projecting downward from the front along the orbits. In profile, the face is very slightly retreating, with a gentle convexity on the upper third, the lower part strongly convex; in general, the face follows the contour of the eyes and projects only a little beyond them; pile mostly limited to the depressions, golden yellow. Antennae black, the basoflagellomere brown, considerably longer than the basal two, the pedicel broader than long. The basoflagellomere is divided into two well separated, parallel lobes, the lower about three times as wide as the upper, but appearing only about twice as wide owing to the long pubescence on the latter; while the lower lobe is conspicuously pubescent, the pubescence is long only on the inner side. Arista very short and thick, tapering apically, situated on the outer side in the concavity formed by the base of the fork. Eyes bare.
Thorax pale brown, the mesonotum with very broad, sublateral, paler vittae that taper behind and are rounded in front and semi-interrupted at the suture; postpronotum pale luteous; meron and a large macula above the metacoxae reddish yellow. Pile moderately long, subappressed, brassy yellow; black on the pleura and on the sides of the scutellum. Scutellum more than twice as wide as long, the apex gently emarginate. Legs bright orange, the coxae and apical two segments of the tarsi brown; the basal third of the tibiae pale yellowish; pile golden yellow, appressed except on the metafemora, black on meso- and metacoxae. Wings brownish gray, the veins brown; both the apical and discal cells are longest posteriorly, the apical cross vein extending obliquely forward, then obliquely outward, the angle at the middle. Calypter brown, the lower lobe mostly dull yellowish, with orange border and fringe. Halteres reddish.
Abdomen dark brown, without magnification rather bluish black. Pile black, short, on the second segment a large patch of pale brassy pile on each side and scattered pale hairs on the disc, so that in some views the pile appears to be mostly brassy; third and fourth segments each with a broad, broadly interrupted apical band of pale pile, the fifth with the apex broadly pale pilose. The pile on the lateral margins is all black. Venter shining brown, with black hair.
unless otherwise stated