PHORINAE (Brown, 1994)

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 : 467-474

SUBGROUPINGS WITHIN PHORINAE

35. Hind coxa: (0) evenly, densely microtrichose, as on meron, (1) microtrichia mostly absent, replaced by fine transverse sculpturing ( Fig. 15A–F ).

In outgroups ( Figs 2–3, 15A ), Sciadocerinae ( Figs 4 , 15B ) and Chonocephalinae ( Figs 5 , 15C ), the dense microtrichia found on the meron are carried over onto the hind coxa. In most other phorids, including the Termitoxeniinae genera ( Fig. 15D ), these microtrichia are less dense to completely absent ( Fig. 15E, F ). Exceptions we examined are the phorines Conicera , Contopteryx , Darwiniphora (all of which are conicerines), Tonnoirina , Wharia and the metopinine Corynusa , all of which have dense microtrichia. Many phorines have transverse sculpturing on the hind coxa that sometimes appears like microtrichia. This feature is clear in the hypocerines, but somewhat difficult to score in some intermediary taxa.

36. Hind coxa: (0) lacking anterior carina, with rounded fold only, (1) with narrow anterior carina ( Fig. 37A–F ).

The hind coxa in platypezids is cylindrical, plesiomorphic in its shape ( Fig. 37A ). The membranous part of the coxa posteriorly, the lumen, is long, facing posteriorly. Sciadocerines have the distal end of the coxa more slender ( Fig. 37B ), in some extension similar to Chonocephalus or to Javanoxenia ( Fig. 37C ). In some phorine genera ( Fig. 37D ), there is a carina, but it is not sharp or complete as in some other genera. The derived character state ( Fig. 37E, F ) apparently is convergent in higher metopinines and some phorines. Indeed, there are many more characters available in the modification of the hind coxa shape, but they are more subtle and are monophyletic for the main clades found here.

37. Halter: (0) elongate, large, (1) relatively small ( Fig. 26A–F ).

In outgroups ( Fig. 26A ), Sciadocerinae ( Fig. 26B ), Chonocephalinae ( Fig. 26C ), Termitoxeniinae ( Fig. 26D ), basal metopinines and basal phorines, the halter is elongate and relatively large compared with the body size. In a group of genera the halter has become relatively small ( Fig. 26E, F ). This character is best defined in the most derived groups, such as hypocerines, and is somewhat intermediate in more basal groups (especially Beckerina ).

38. Limit between meron and anepimeron: (0) marked by suture (posterior arm of ‘W’), (1) without suture ( Fig. 38A–F ).

The limit of the suture between the meron (usually interpreted as the katepimeron) and the anepimeron is clear in Platypezidae , a condition preserved in the Sciadocerinae ( Fig. 38A ) and Chonocephalinae genera ( Fig. 38B ), despite the changes that already began to affect the anepimeron at this level of the evolution of the thorax in phorids. In some metopinines, such as in Ctenopleuriphora ( Fig. 38C ), the suture is present, but not strongly marked, while in other genera, such as Gymnophora or Beckerina ( Fig. 38D ), at least the ventral part of the suture is missing. In some phorine genera the suture is especially evident, as in Coniceromyia ( Fig. 38E ) or Phora , but a clade with the hypocerines and diplonevrines do not show a suture ( Fig. 38F ).

39. Surface of meron dorsally (and perhaps part of the anepimeron): (0) slightly convex or relatively flat, (1) deeply concave ( Fig. 39A–F ).

This is an interesting and useful uniquely derived character of a small group of phorines. In sciadocerines ( Fig. 39A ), Chonocephalus ( Fig. 39B ), termitoxeniines, most metopinines ( Fig. 39C ) and some phorine genera ( Fig. 39D ), the meron (and the fused katepimeron) is a relatively flat sclerite dorsally. In a group of phorines, there is a conspicuous concavity on the dorsal part of the meron ( Fig. 39E, F ). This feature defines a fairly large clade with the subfamily, including hypocerines and thaumatoxenines, but not genera such as Diplonevra , Conicera , Tonnoirina , Ceratusa , Minicosta and Chaetocnemistoptera . Because there is little indication of homoplastic origin of this feature (except in the unrelated Ctenopleuriphora ) or secondary loss, this feature becomes extremely helpful to include or exclude genera from this clade.

40. Posterior arm of anepimeron: (0) wide, (1) slender, compressed ( Fig. 40A–F ).

There is a long sequence of changes in the shape of the anepimeron within the evolution of the Phoridae , generating a complex multi-state character. There is phylogenetic signal even for small details on the shape of parts of the anepimeron, but for the time being we limited the number of characters used. In the phorid groundplan, as can be seen in Sciadocera ( Fig. 4 ), the posterodorsal projection of the katepisternum into the anepimeron is nearly non-existent. In Chonocephalus ( Fig. 5 ), termitoxeniines ( Figs 6 , 40A ) and some metopinine genera ( Figs 7 , 40C ), the posterior arm of the ‘W’ is relatively small, but not compressed, as seen in hypocerine genera of Phorinae ( Figs 8, 40F ). In some other phorine genera, such as Phora , Conicera , Coniceromyia , Burmophora and Ceratoplatus , the posterior arm of the anepimeron is notably wide and with a typical plesiomorphic shape ( Fig. 40D, E ). The compression of the posterior arm ( Fig. 40F ) is correlated with a concave meron and perhaps should not be considered an independent character.

41. Ventral half of meron: (0) microtrichose, like upper half, (1) with microtrichia reduced or absent ( Fig. 41A–F ).

This character is not clear-cut in some genera. The condition in Sciadocera , Chonocephalus ( Fig. 41A ), termitoxeniines ( Fig. 41B ) and most metopinines ( Fig. 41C ) is as in outgroups. A microtrichose meron within the phorines is found in Phora and other nonhypocerine genera. Microtrichia are absent anteroventrally on the meron of Dohrniphora ( Fig. 41D ), but are present elsewhere on the structure. Further exceptions are Hypocera ( Fig. 41E ) and Trineurocephala , both of which have some microtrichia on the meron.

42. Dense setulae of scutum: (0) restricted to dorsum, (1) extending into lateral surface of thorax, especially over the anepisternum ( Fig. 42A–F ).

The extension of the typical scutal setation onto the anepisternum is a condition found in hypocerines, Dohrniphora , possibly Diplonevra , Abaristophora ( Fig. 42E ), Neopleurophora , Aenigmatias , Chaetopleurophora , Epicnemis , Thaumatoxena , Palpiclavina , Epicnemis ( Fig. 42F ), Aenigmatistes and others. This character state refers to, in large part, the long used ‘anepisternum setulose’ (or ‘mesopleuron hairy’) character in phorid taxonomy. It is in some degree (but not strictly) coordinated with the shortened lateral parapsidal suture. The fact that in hypocerine genera the setation extends from the dorsoanterior end of the anepisternum makes it obvious that it is not homologous to the presence of setation at the posterior end of the sclerite seen, for example, in Chonocephalus ( Fig. 42A ) or Termitophilomyia ( Fig. 42B ). The plesiomorphic condition is seen in platypezids ( Fig. 2), lonchopterids ( Fig. 3) and sciadocerines ( Fig. 4 ), with no setation at all on the anepisternum. On the other hand, Coniceromyia , Rhynchomicropteron and Chaetopleurophora , which are obviously plesiomorphic for almost the entire set of apomorphic characters that define the hypocerines, show similar setation, but were treated as cases of parallel development. Their setae are not continuous with those of the scutum, as is the case with hypoocerines, and were thus not coded as having this character present in our analysis. Aenigmatias , as well, has setation over the anepisternum, but other characters do not place the genus in the hypocerine clade.

43. Anterior spiracle position: (0) below level of dorsal margin of anepisternum, (1) above level of dorsal margin of anepisternum ( Fig. 43A–F ).

This is a character traditionally used to define the Aenigmatiinae . The more plesiomorphic condition has the spiracle in a much more ventral level with the parapsidal suture, as seen in Chonocephalus ( Fig. 43A ). Most metopinine and phorine genera have the spiracle displaced in different degrees to a more dorsal position ( Fig. 43B–D ), but we did not convert that variation into additional character states. In Thaumatoxena ( Fig. 43E ), Epicnemis , Misotermes ( Fig. 43F ), Stichillus , Aenigmatistes and some other genera, the middle of the anterior spiracle is even more dorsal than the dorsal margin of the anepisternum or the parapsidal suture. The change is correlated with the acquisition of the limuloid shape, which occurred more than once in the evolution of the phorids. This apomorphic condition is absent in Hypocera , Latiborophaga , Neopleurophora and other hypocerine genera.

44. Strong postpronotal seta: (0) present, (1) reduced, (2) absent ( Fig. 44A–F ).

There is a pair of long postpronotal setae in platypezids we examined ( Fig. 44A ), whereas Lonchoptera has a single one ( Fig. 44B ). Within phorids, Sciadocera ( Fig. 44C ) has one long postpronotal seta, while in Chonocephalus the single seta is relatively delicate ( Fig. 44D ). Termitoxeniines have no distinctive stronger seta on the postpronotum ( Fig. 44E ), which is apomorphic. In the remaining phorids, there is usually a strong postpronotal seta, in addition to a number of smaller ones covering the sclerite (which is now fused to the scutum and the anepisternum). This condition is seen, for example, in metopinines, Phora , Coniceromyia , Burmophora etc., whereas Epicnemis , Hypocera , Stichillus , Chaetocnemistoptera , Neopleurophora , Gymnophora , Trineurocephala , Latiborophaga ( Fig. 44F ) and other genera have only small setae on the postpronotum.

Figures

Figure 4 SEM of thorax of Sciadocera (Phoridae, Sciadocerinae), lateral view.

Figure 5 SEM of thorax of Chonocephalus (Phoridae, Chonocephalinae), lateral view.

Figure 6 SEM of thorax of Termitophilomyia (Phoridae, Termitoxeniinae), lateral view.

Figure 7 SEM of thorax of Ctenopleuriphora (Phoridae, Metopininae), lateral view.

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 26 Characters 19 and 37. Character 19 (white arrow). Posterior spiracle (and base of halter) in a relatively ventral position in the thorax (dashed line for the anapleural suture and dotted line for the spiracle position) (0); posterior spiracle close to the wing base (1). Character 37 (black arrow). Halter large (0); halter reduced in size (1). A, Protoclythia. B, Sciadocera. C, Chonocephalus. D, Javanoxenia. E, Epicnemis. F, Godavaria.

Figure 37 Character 36. Hind coxa lacking anterior carina (0); with narrow anterior carina (1). A, Protoclythia. B, Sciadocera. C, Javanoxenia. D, Phora. E, Apocephalus. F, Borophaga.

Figure 38 Character 38. Limit between meron and anepimeron marked by a suture (0); suture between meron and anepimeron absent or largely missing (1). A, Sciadocera. B, Chonocephalus. C, Ctenopleuriphora. D, Beckerina. E, Coniceromyia. F, Misotermes.

Figure 39 Character 39. Meron dorsally slightly convex or relatively flat (0); dorsal part of meron deeply concave (1). A, Sciadocera. B, Chonocephalus. C, Apodicrania. D, Phora. E, Psyllomyia. F, Peromitra.

Figure 40 Character 40. Posterior arm of anepimeron wide (0); posterior arm of anepimeron compressed (1). A, Javanoxenia. B, Beckerina. C, Apodicrania. D, Conicera. E, Coniceromyia. F, Epicnemis.

Figure 41 Character 41. Meron microtrichose (0); with microtrichia reduced or absent (1). A, Chonocephalus. B, Javanoxenia. C, Ctenopleuriphora. D, Dohrniphora. E, Hypocera. F, Peromitra.

Figure 42 Character 42. Dense setulae of scutum restricted to dorsum (0); setulation extending onto the anepisternum (1). A, Chonocephalus. B, Termitophilomyia. C, Gymnophora. D, Burmophora. E, Abaristophora. F, Epicnemis.

Figure 43 Character 43. Anterior spiracle position below level of dorsal margin of anepisternum (0); anterior spiracle position above level of dorsal margin of anepisternum (1). A, Chonocephalus. B, Beckerina. C, Conicera. D, Neopleurophora. E, Thaumatoxena. F, Misotermes. Dashed white line = dorsal margin of anepisternum; dashed black line = position of anterior spiracle.

Figure 44 Character 44. Strong postpronotal seta present (0); reduced (1); absent (2). A, Callomyia. B, Lonchoptera. C, Sciadocera. D, Chonocephalus. E, Javanoxenia. F, Latiborophaga.