Diadelophora, Ament, 2024

Ament, Danilo César, 2024, Diadelophora, a new phorid genus from central and western Brazil (Diptera: Phoridae), Zootaxa 5415 (1), pp. 144-152 : 145-147

Diadelophora gen. nov.

urn:lsid:zoobank.org:act:B10B5E22-8A65-4F36-879F-05033C1C6F9A

Type-species: Diadelophora stilbella sp. nov. Refs: Ament 2017: Hypocerides sp. n.

Diagnosis. This genus differs from other Phorinae genera by the combination of characteristics: antennal flagellomere conical-shaped; frontal setae reduced with at least ventral fronto-orbitals lacking; costa long, apically swollen; and tibiae lacking large setae. Diadelophora also has a characteristic hypopygium with epandrial left and right posterior margins invaginated, continuous with a curved process under the hypoproct.

Genus description. Male. Frontal setae reduced, ventral fronto-orbitals absent, ventral interfrontals absent or present, supra-antennals, when present, almost imperceptible, reclinate ( Figs. 1B , 4B ). Flagellomere 1 large, conical, with several sensilla of different shapes ( Fig. 4C ), without subcutaneous pit sensilla (SPS); arista preapical ( Figs. 1A , 4D ). Palpus large, with small ventral setulae ( Figs. 1A, 1C ). Body in general robust, with large thorax and abdomen and relatively thin legs. Anepisternum furrow absent, anterior spiracle large; meron dorsally slightly convex ( Fig. 1D ). Scutellum with two pairs of setae. Tibiae without isolated large setae ( Figs. 1G–I , 4G–I ). Midtibia basal half with or without an anterodorsal and a posterodorsal subtle setal palisades. Hind femur dorso-ventrally narrow, with ventral row of elongated thin setae near base ( Figs. 1F , 4F ). Hind tibia with a dorsal palisade of setulae (sometimes subtle, hard to observe). Costa apically swollen, Sc apparently absent, M 1 and M 2 sinuous ( Figs. 1E , 4E ). Epandrial left and right posterior margins invaginated, continuous with a curved process under the hypoproct ( Fig. 2 ). Distiphallus complex; core plate extending over distiphallus; right arm curved reaching left lateral, connected to a scaled epiphallus ( Fig. 3 ).

Female. Unknown.

Etymology. Name derived from the Greek word diadelos (distinguishable, distinctive) referring to the unusual general body shape and chaetotaxy of this genus.

Phylogenetic position and justification of the proposal of a new genus.

Brown (2022b) provided a series of recommendations regarding in which cases new genera should be proposed in the Phoridae family, including ‘…if there is good evidence (i.e. one or more synapomophies) that a unknown specimen is related to a known genus, then unless differences from the known genus are truly exceptional, I would be reluctant to recognize a new genus assignment. This is because there are two possibilities for the situation: the new specimens are part of a sister-taxon to the known genus, or it is something that has diverged extensively within the genus’.

Commonly during Phoridae genera proposition, we do not have information about the phylogenetic position of the putative genus or even reliable information to compare it to closely related genera. Fortunately, in the case of Diadelophora , we have evidence supporting its sister-group relationship with Hypocerides with these genera sharing the possible synapomorphies: ventral fronto-orbitals absent, costa apically swollen, epandrial left and right posterior margins invaginated, continuous with a process under the hypoproct ( Ament 2017). Concomitantly, the differences between these genera may be considered truly exceptional. Diadelophora has a much larger and distinct body general shape, conical antenna, palpus large with small ventral setulae, long costa which is also less thickened apically, sinuous wing vein M 1, and epandrium, hypandrium, surstyli and phallus morphology substantially different from Hypocerides (as described in the previous section).

Concerning phylogenetic relationships, Hypocerides is a peculiar genus comprising eight species with almost worldwide distribution but almost no considerable morphological divergence among them ( Ament 2021b). Therefore, the monophyly of Hypocerides seems to be well supported and the proposition of Diadelophora would unlikely render it paraphyletic.

Figures

FIGURE 1. Diadelophora stilbella sp. nov., male. A, habitus (holotype); B, head in dorsal view; C, palpus in dorsal view (MEV); D, thorax in lateral view (MEV); E, wing; F, hind femur; G, foretibia; H, midtibia; I, hind tibia.

FIGURE 2. Hypopygium of Diadelophora stilbella sp. nov.. A, dorsal; B, ventral; C, left lateral; D, right lateral.Abbreviations: cerc, cercus; ep, epandrium; hyp, hypandrium; hyprct, hypoproct; prj, projection.

FIGURE 3. A, B, Phallus of Diadelophora stilbella sp. nov. in left lateral (A) and dorsal view (B); C, phallus of Diadelophora inornata sp. nov. in left lateral view. Abbreviations: bs, basiphallus; cp, core plate; epi, epiphallus; ra, right arm.

FIGURE 4. Diadelophora inornata sp. nov., male. A, habitus (holotype); B, head in dorsal view; C, microscopic details of the first flagellomere of the antenna (MEV); D, thorax in lateral view; E, wing; F, hind femur; G, foretibia; H, midtibia; I, hind tibia.