PHORIDAE, Curtis, 1833

Brown, Brian V., Amorim, Dalton De Souza & Kung, Giar-Ann, 2015, New morphological characters for classifying Phoridae (Diptera) from the structure of the thorax, Zoological Journal of the Linnean Society 173 (2), pp. 424-485 : 436-442

FAMILY PHORIDAE

This family includes Sciadocerinae , which was until recently considered a separate family (Disney, 2001), and the Euphorida ( Brown, 2007).

1. Costa extends: (0) to vein M 1, (1) to, or just past, vein R 4+5 ( Fig. 10A–F ).

Reduction of costal length has not been described in sufficient detail in the literature, although it has been used in some analyses. In the platypezids we examined, the thickened part of the costa extends to vein M 1 ( Fig. 10A ), whereas it is shortened to only slightly beyond R in Ironomyia ( Fig. 10B ). In Lonchoptera and phorids ( Fig. 10C–F ), the costa extends only to vein R 4+ 5 in most species. Cumming et al. (1995) considered the costa of Lonchoptera to extend completely around the wing, i.e. a circumambient costal vein, but examination of a microscopic slide mount shows that the costa narrows considerably after R 4+5 ( Fig. 10C ). Genus Opetia Meigen has the costal thickening ending shortly after R 4+5 ( Chandler, 2001). If the cladogram in Cumming et al. (1995) is correct, with Opetia being the sister group to other Cyclorrhapha, character state 0 is the derived one at this level, and would be a synapomorphy of Platypezidae . More recent phylogenetic studies of the Diptera , however, such as Wiegmann et al. (2011), show the Opetiidae within the Platypezoidea. This character varies greatly among more distant outgroups ( Sinclair & Cumming, 2006).

2. R 4+5: (0) connected to costa at apex, (1) not connected to costa at apex ( Fig. 11A–D ).

4+5

The apex of R 4+5 is clearly fused to C in most dipterans ( Fig. 11A ), while in the phorids there is a break just before the apex ( Fig. 11B–D ). There may be a more basal contact between R 4+5 and C (such as in some Chonocephalus ), but this is interpreted to be secondary.

3. CuA+CuP: (0) complete, (1) interrupted just distal to point of fusion of CuA and CuP ( Fig. 12A–D ).

Although many wing venation characters have been used to justify the Phoridae , this is the first time that interruption of the CuA vein has been noticed. The Platypezidae have the plesiomorphic condition seen in other cyclorrhaphan families ( Fig. 12A ). In some phorids CuA+CuP is even more strongly disconnected from its base.

4. R ending: (0) at wing tip, (1) before wing tip, (2) at most at the distal third of the wing length ( Fig. 13A–H ).

4+5

The reduction of the extension of R 4+5 is a recurrent feature among families of Diptera . In the Platypezoidea, the plesiomorphic condition is seen in the Platypezidae ( Fig. 13A ), Opetiidae , Ironomyiidae and Lonchopteridae ( Fig. 13B ). R 4+5 ending before the wing tip, within the superfamily, is a synapomorphy of Phoridae . A small reduction is seen in the Sciadocerinae genera ( Fig. 13C ), as well as in the fossil Sciadophora ( Brown, 1992) . In Chonocephalus ( Fig. 13D ), R 4+5 extends until just beyond the middle of the wing, as is also seen in some other genera ( Fig. 13E– H ), such as Latiborophaga and Trophithauma . Even more extreme reductions, which are not coded here, are seen in the Termitoxeniinae and in some metopinine genera.

5. Limit between anepisternum and katepisternum: (0) with a suture on the posterior half of the contact, both sclerites continuous anteriorly, (1) with a furrow curving anteriorly to proepimeron, (2) with a furrow almost reaching the ventral margin of the thorax ( Fig. 14A–F ).

In all platypezoid families except Phoridae , the katepisternum anterior margin is continuous with the anepisternum–proepimeron (e.g. Fig. 14A, B ). The anterior limit between katepisternum and anepisternum in all Phoridae , differing from other platypezoid families, is marked by a furrow (the suture itself ending more posteriorly). In sciadocerines and Chonocephalus ( Fig. 14C ) there is a depression between both sclerites, but in termitoxeniines and other phorids ( Fig. 14D– F ), a well-characterized furrow can be seen along the line of the anapleural suture to the anterior margin of the thorax. The metopinines and some phorines have an additional modification, the furrow curving dorsally and ending almost at the level of the insertion of the forecoxa. This produces a distinctive concavity above the forefemur. In a group of higher phorines, including thaumatoxenines and hypocerines, a suture extends to the ventral margin and the katepisternum does not extend anteriorly.

6. Hind coxa: (0) with scattered setae on ventral half, (1) setae on ventral half concentrated in anteroventral corner ( Fig. 15A–F ).

This character is associated with narrowing of the apex of the hind coxa anteroventrally. In the platypezid groundplan condition, there is setation on the ventral two-thirds of the coxa ( Fig. 15A ). In the sciadocerines and chonocephalines, there is a restriction of the hind coxa setation to its ventral half ( Fig. 15B, C ). Termitoxeniines, metopinines and phorines, however, have the setation restricted to an anteroventral projection ( Fig. 15D–F ).

7. R 1 reaching at least: (0) distal third of wing length, (1) distal half of wing length, (2) basal third of wing length ( Fig. 13A–H ).

The reduction of the radial veins has been noted by other authors, especially McAlpine & Martin (1966). Most platypezid genera we examined, as well as Opetia and Ironomyia , have the plesiomorphic condition ( Fig. 13A ). Character state 1 refers to the stage found in the Sciadocerinae ( Fig. 13C ) and the fossil Sciadophora , while character state 2 is synapomorphic for the rest of the Phoridae (= Euphorida). The Lonchopteridae have extremely short R 1 ( Fig. 13B ), an apomorphic condition apparently derived independently from that seen in the euphorids ( Fig. 13D–H ).

8. Alular setae: (0) plain, (1) feathered, (2) absent ( Fig. 16A–E ).

Feathered setae are found on the alula of sciadocerines ( Fig. 16C, D ), metopinines and phorines ( Fig. 16E ). The alula and calypteres of chonocephalines and termitoxeniines have been lost, while the alula of

442 B. V. BROWN ET AL.

Ironomyia ( Fig. 16A ) and Lonchoptera ( Fig. 16B ) show the plesiomorphic condition, with long, unfeathered setae.

Figures

Figure 10 Character 1. Costa reaching M1 (0); costa reaching, or at most extending slightly past, R4+5 (1). A, Calotarsa. B, Ironomyia. C, Lonchoptera. D, Sciadocera. E, Javanoxenia. F, Anevrina.

Figure 11 Character 2. R4+5 connected to C at apex (0); R4+5 not connected to costa at apex (1). A, Lindneromyia. B, Chonocephalus. C, Rhyncophoromyia. D, Phymatopterella.

Figure 12 Character 3. CuA+CuP complete (0); CuA+CuP interrupted just distal to point of fusion of CuA and CuP (1). A, Lindneromyia. B, Sciadocera. C, Megaselia. D, Trophithauma.

Figure 13 Characters 4 and 7. Character 4 (black arrows). R4+5 ending at wing tip (0); R4+5 ending before wing tip (1); R4+5 at most at distal one-third of wing length (2). Character 7 (grey arrows). R1 reaching at least distal third of wing (0); R1 reaching distal half of wing (1); R1 reaching basal third of wing (2). A, Lindneromyia. B, Lonchoptera. C, Sciadocera. D, Chonocephalus. E, Pseudacteon. F, Coniceromyia. G. Latiborophaga. H, Trophithauma.

Figure 14 Characters 5 and 22. Character 5 (white arrows). Katepisternum and anepisternum continuous (0); with a furrow separating anespisternum from katepisternum (1); with furrow almost reaching ventral margin of thorax (2). Character 22 (black arrows). Ventral third of anepisternum microtrichose (0); ventral third of anepisternum bare (1). A, Callomyia. B, Lonchoptera. C, Chonocephalus. D, Termitophilomyia. E, Gymnophora. F, Latiborophaga.

Figure 15 Characters 6 and 35. Character 6 (white arrows). Hind coxa with scattered setae on ventral half (0); setae on ventral half of hind coxa concentrated in anteroventral corner (1). Character 35 (black arrows). Hind coxa evenly microtrichose (0); hind coxa bare (1). A, Plesioclythia. B, Sciadocera. C, Chonocephalus. D, Termitophilomyia. E, Anevrina. F, Godavaria. Abbreviation: lu, lumen.

Figure 16 Character 8. Alular setae plain (0); alular setae feathered (1). A, Ironomyia. B, Lonchoptera. C, Archiphora. D, Sciadocera. E, Godavaria.