Johnsonomyia Felt, 1908

Jaschhof, Mathias, 2016, A review of world Diallactiini (Diptera, Cecidomyiidae, Winnertziinae), with the description of six new genera and seventeen new species, Zootaxa 4127 (2), pp. 201-244 : 225-226

Genus Johnsonomyia Felt, 1908 stat. rest.

Johnsonomyia — Felt 1908: 417. Type species, rubra Felt , by original designation.— Mamaev 1964: 902 (as junior synonym of Chastomera Skuse ); Panelius 1965: 17 (listed as distinct from Chastomera Skuse ); Mamaev 1966: 218 (altered diagnosis, new species); Parnell 1971: 281 (review, key to Nearctic species); Gagné 1978: 517 (as junior synonym of Haplusia Karsch , discussion); Spungis 1985: 47 (discussion, diagnosis, description of Latvian species); Jaschhof & Jaschhof 2013: 59 (as junior synonym of Haplusia Karsch , discussion).

Species of Johnsonomyia :

alexanderi Felt, 1921 . Afrotropical.

funebris ( Plakidas, 2007) [ Haplusia ]. New combination. Nearctic. fusca Felt, 1908 . Nearctic.

lobata ( Yukawa, 1968) [ Wyattella ]. New combination. Oriental. palpata Mamaev, 1966 . Palearctic.

rubra Felt 1908 . Nearctic.

scabra Jaschhof sp. nov., described below. Neotropical.

serrata Jaschhof sp. nov., described below. Afrotropical.

spiculosa ( Barnes, 1927) [ Chastomera ]. Oriental.

Seventeen unnamed species from the Neotropical, Afrotropical, Oriental, and Australasian regions.

Felt (1908) introduced the genus Johnsonomyia for three Nearctic species, of which one, J. humilis , was misplaced in this genus and later ( Parnell 1971) assigned to Holoneurus Kieffer, 1894 in Porricondylinae , where it provisionally resides ( Gagné & Jaschhof 2014); the other two species, J. fusca and J. rubra , are dealt with below. Felt used solely wing characters for differentiating Johnsonomyia from the other six genera of his Epidosariae, a taxon nearly equivalent to the modern Winnertziinae and Porricondylinae combined. Two other Johnsonomyia that he described in later years ( Felt 1912, 1915) fall under my concept of Haplusia (see there). The name Johnsonomyia was taken up by Mamaev (1966) to denote Diallactiini whose eye bridge covers the entire dorsal head surface, irrespective of the fact that J. rubra , the type species, does not meet this condition. Mamaev’s redefinition of Johnsonomyia , though inappropriate, was followed by subsequent authors, such as Parnell (1971) and Spungis (1985). Gagné (1978) disputed the merit of eye bridge length for distinguishing diallactiine genera and, led by similarities in venation and general habitus, regarded Johnsonomyia as synonymous with Haplusia and Chastomera . I studied the male holotype of J. rubra and specimens of several other, similar species and came to the conclusion that Johnsonomyia should be treated as a genus distinct from Haplusia (see Diagnosis) but in a sense that differs from Mamaev (1966). The basis of my concept of Johnsonomyia is supported by characters of the type species, J. rubra .

Nevertheless, Johnsonomyia , as here understood, is no unproblematic group. Its morphology is diverse and, consequently, difficult to condense in a straightforward diagnosis. A possible explanation for this may be that the group as delimited here is not monophyletic. Indeed, among the Johnsonomyia species I have seen (which are few compared with the many species that I suppose are yet uncollected) I identified two presumably natural subgroups, each with two respectively four species, which one could regard as possible candidates for discrete genera. It is beyond the scope of this paper to treat these subgroups in detail. Even J. rubra is in some way different from other Johnsonomyia . Contributing to the problem, Johnsonomyia appears to have many species in the tropics, which in my experience feature—more often than species in temperate regions—strange characters and character combinations. This phenomenon, which I have observed also in mycophagous cecidomyiids other than Johnsonomyia , complicates the task of identification, especially when those somehow aberrant species are the only fragments known of an otherwise unexplored fauna. It is likely that my present definition of Johnsonomyia will need to be reappraised with further knowledge of the world species. I have seen specimens of unnamed Johnsonomyia from Costa Rica (7 species), South Africa (2 species), Brunei (6 species), peninsular Malaysia (1 species), and New Zealand (1 species). This renders the genus cosmopolitan in distribution.

Most of the species assigned here to Johnsonomyia were described on the basis of only one sex, usually the male. With respect to preimagines, Spungis (1985) described larvae of H. palpata and Plakidas (2007) described both larvae and pupae of H. funebris .

Diagnosis. Johnsonomyia and Haplusia , which resemble each other in many respects, are distinguished as follows. Species of Johnsonomyia lack the striking coloration of Haplusia , so have much less white and much less striking color patterns. Antennae are brownish rather than white; wings are never milky white but are brownish to grayish, often with the Rs, but never the CuA, darkened; and if legs are bicolored, then in a way that tarsi are lighter than other segments, without any banding. The eye bridge is on average shorter, typically 4–7 (in an unnamed Costa Rican species 2–3) ommatidia long dorsally; palpi, which are usually 4-segmented, have in some species always 3 segments (in even other species a varying 3 or 4 segments); the scape is usually setose, rarely unsetose; the pedicel, usually unsetose, has 1 or 2 setae in a few species; flagellomere nodes have either a whorl of setae subbasally or irregular setae intermingled with translucent sensilla, and microtrichia usually only basally but sometimes everywhere; thoracal sclerites other than scutum and scutellum are usually unsetose, but an unnamed Costa Rican species has a setose anepisternum; wing length / width is 2.6–2.9; and basitarsi, which never bear a spine, have in some species a small, subtriangular, microtrichose or glabrous lobe. As regards male genitalia, the ventral gonocoxal emargination is multiform; the ventral gonocoxal bridge may have a faint transverse suture; the gonostylus is toothed in most species but untoothed in J. funebris and an unnamed species from Brunei; and tegmina are poorly to moderately sclerotized, subtriangular to elongate-subtrapezoid, usually rounded apically, and occasionally with slightly serrate edges or granulated surfaces.