Sobarocephala Czerny

Sasakawa, Mitsuhiro, 2011, Oriental species of clusiid flies (Diptera: Clusiidae: Clusiinae), Zootaxa 3038, pp. 1-28 : 6

Genus Sobarocephala Czerny

Sobarocephala Czerny, 1903: 85 . Type species, Sobarocephala ruebsaameni Czerny, 1903 , fixed by original designation. Sobarocephaloides Soós, 1964 : Lonsdale and Marshall, 2006: 165.

Diagnosis. This genus belongs to the subfamily Clusiinae , and has the following diagnostic characters: oc and poc present; occiput flat to shallowly concave; arista densely to sparsely plumose; dc two or three, prsc rarely present; sc variable in number; mid tibia always with dp, rarely fore tibia with short one; crossvein bm-cu either absent or present but incomplete at base, M1 ratio 2.5–4.5, ultimate section of CuA1 1/2–2/3 as long as penultimate section; surstylus varying in shape, usually large, lobate, sparsely spinose along anterior ventroapical margin on inner side; paraphallus usually with minute spinules.

Remarks. This is a predomionantly Neotropical genus, as stated by Hennig (1938), but it is also known to occur almost throughout the world except for Europe. In the Oriental region, two species, Sobarocephala nepalensis and S. vockerothi , have been recorded.

The Clusiidae have traditionally been divided into two subfamilies that were originally outlined by Frey (1960), the Clusiinae and Clusiodinae ( Soós 1964; Sasakawa 1998). Lonsdale and Marshall (2006) designated a new subfamily, Sobarocephallinae, including the three genera Sobarocephala , Chaetoclusia Coquillett, 1904 , and Procerosoma Lonsdale and Marshall, 2006 , on the basis of the wing venation (M1 ratio 3.0 or more, cell bm confluent with cell dm), thoracic and leg chaetotaxies (prs and fb absent, fore femur entirely setulose), male genitalic characters (surstylus large, hypandrial ventral lobe as long as hypandrial arm, pregonite small), and loss of the sixth spiracle. Also, they transferred two genera, Heteromeringia Czerny, 1903 and Tranomeringia Sasakawa, 1966 , from the Clusiinae to the Clusiodinae . Sobarocephala is here retained in the Clusiinae , following Hennig (1938), McAlpine (1960), Soós (1964) and Sasakawa (1998), treating the inclinate third (lowermost) or as homologous to that found in Heteromeringia .

In the Oriental species of Sobarocephala here examined, the M1 ratio is 2.7–4.5, prs is absent, the hypandrial ventral lobe is almost as long as the hypandrial arm, and the pregonite is small. However, cells bm and dm are separated by crossvein bm-cu in all species, although this crossvein is slightly broken just before reaching the medial vein. Furthermore, refuting the subfamilial definition of the Sobarocephalinae cited above, the fore femora of three new species, S. baculigera , S. fuscifacies , and S. megastylis , have several fb (usually three on the dorsodistal part and two on the posterodorsal) as seen in many species of Clusiinae (an entirely setulose femur is an additional character purportedly defining the Sobarocephalinae); also, while the surstyli of S. baculigera , S. eurystylis sp. nov., S. megastylis , and S. vockerothi are large (about 0.7 as long as the epandrium), those of S. fuscifacies and S. geniculata sp. nov. are narrowly projecting, as seen in species of Heteromeringia ( Sasakawa 1966) .

A high M1 ratio of 4.0 to 8.5 (mostly around 5.5) is found in the Oriental, Australasian/Oceanian, and Afrotropical species of Heteromeringia ( Sasakawa 1966, Stuckenberg 1973), agreeing with Sobarocephala in the diagnostic character given by Lonsdale and Marshall (2006). In the species of the genera C lusia Haliday, 1838 and Phylloclusia , the hypandrial ventral lobe is almost as long as the hypandrial arm ( Sasakawa 1965: fig. 4, as Paraclusia omogensis ). Moreover, in Sobarocephala zuluensis Stuckenberg, 1973 , the sixth spiracle is present between the sixth and seventh sternites ( Stuckenberg 1973: fig. 6). Therefore, no clear-cut distinction can be found between Clusiinae and Sobarocephalinae.