Dichetophora Rondani, 1868

Li, Zhu, Yang, Ding & Murphy, William L., 2019, Review of genera of Sciomyzidae (Diptera: Acalyptratae) from China, with new records, synonyms, and notes on distribution, Zootaxa 4656 (1), pp. 71-98 : 81-82

8. Dichetophora Rondani, 1868 (New record)

( Figs. 11–14 , 49–50, 53, 55 , 65 )

Dichetophora Rondani, 1868: 9 . Type species: Scatophaga obliterata Fabricius, 1805 (original designation).

Diagnosis. Body slender. Ocellar setae absent or rather short and weak (compared to those of Euthycera ). Lunule clearly visible. Most species with 1 pair of scutellar setae. Hind femur of both males and females with distinct blunt ventral spines in apical 1/3 (indistinct or absent in Euthycera ). Wing in most species hyaline with reticulated pattern or with sparse pale spots.

Remarks. Of the 12 described species of Dichetophora , 5 [ D. finlandica Verbeke, 1964 ; D. japonica Sueyoshi, 2001 ; D. kumadori Sueyoshi, 2001 ; D. meleagris (Hendel, 1933) ; and D. obliterat a ( Fabricius, 1805)] are restricted to the Palearctic Region, 1 ( Dichetophora intermedia Hendel, 1912 ) is restricted to the Oriental Region, and 6 are restricted to the Australian Region.

During our study, we determined 2 species [ D. japonica Sueyoshi, 2001 and D. meleagris (Hendel, 1933) ] from China. We think that at least 3 more species will be added to this number when we have completed our examination of specimens.

About 36 males and 25 females in our study were determined to be D. japonica . Before our study, Dichetophora japonica had been reported only from the Palearctic Region [Hokkaido, Honshu, Japan ( Sueyoshi 2001)]. The 61 specimens that we determined include specimens not only from locations in the Palearctic Region of China such as Beijing, Ningxia, Gansu Province, and Shaanxi Province but also from locations in the Oriental Region of China such as Tibet, Sichuan Province, Chongqing, Guizhou Province, Hubei Province, and Zhejiang Province. Thus, 2 species of Dichetophora — D. intermedia and D. japonica —are now known from the Oriental Region.

Rozkošný (1992) transferred Euthycera meleagris (Hendel, 1933) from Euthycera to Dichetophora as a new combination, " Dichetophora meleagris (Hendel, 1943) " [(sic); error for Hendel, 1933]. Euthycera meleagris Hendel, 1933 thus became a junior synonym of Dichetophora meleagris (Hendel, 1933) . Euthycera meleagris had been recorded from China before our study. Hendel (1933) described E. meleagris on the basis of 2 males from “Süd- Kansu ” (Gansu Province) in northwestern China. Rozkošný (1987) redescribed E. meleagris based on 1 of the 2 males of Hendel's types. The most prominent character of E. meleagris is the pattern of the wing, with numerous white spots, to which the species' name refers.

In September 2017, 5 males and 16 females of Sciomyzidae , wings of which had small, round, white spots, were collected by use of Malaise traps in Mentougou, Beijing, China over a period of a few days. At first glance, the 21 specimens appeared to consist of a single species, but after careful examination we determined that they were 2 groups, representing a number of different species or even different genera. Seven females (Group 1, Figs. 51–52, 54, 56 ) belong to Euthycera , whose typical characters are 1) scutellum with 2 pairs of setae ( Fig. 54 ), 2) ocellar setae developed ( Fig. 54 ), and 3) hind femur in both sexes without distinct blunt ventral spines ( Figs. 51–52 ). Other external characters from Hendel's (1933) description, including “Legs yellow ( Fig. 51–52 ), the white spots reaching almost directly to the edge the wing ( Fig. 56 ),” fit well with his original description of E. meleagris , and the external characters “Legs yellow, costal margin of wings with 6 subquadrate pale spots ( Fig. 56 )” fit well with Rozkošný's (1987) redescription of E. meleagris . Although the type specimens are not available, we can confirm that the 7 females are indeed E. meleagris Hendel, 1933 .

We observed that 5 males and 9 females (Group 2, Figs. 49–50, 53, 55 ) have characters that place them in the genus Dichetophora : 1) scutellum only with 1 pair of setae ( Fig. 53 ), 2) ocellar setae undeveloped ( Fig. 53 ), and 3) hind femur of males and females with distinct blunt ventral spines in apical 1/3 ( Figs. 49–50 ). Besides the differences at the generic level, Group 2 differs from Group 1 in the following 2 characters: 1) legs pale in basal half and yellow in apical half ( Fig. 50 ), and 2) apex and posterior margin of the wing paler and the white spots not reaching the edge of the wing ( Fig. 55 ). Judging from fact that all of these specimens were collected in the same place and within a few days of each other, it is clear that 2 similar-appearing species belonging to 2 different genera truly exist. We hereby remove Euthycera meleagris Hendel, 1933 from synonymy with Dichetophora meleagris (Hendel, 1933) and resurrect Euthycera meleagris Hendel, 1933 as a valid species.

The characters of the species of Dichetophora in Group 2 do not match those of any of the 4 known Palearctic species; it is as yet unknown whether it is a described species or a new species. In any instance, the species in Group 2 should be given a name other than Dichetophora meleagris , which is preoccupied and thus unavailable. If it proves to be a new species, we will name it in a paper we are preparing.

Specimens examined. CHINA, Beijing, Mentougou : 1♂ 1♀, 1176 m, 2017. IX. 20, Hu Li ( CAU) ; 2♂ 3♀, 1143 m, 2017. IX. 20, Hu Li ( CAU) ; 1♀, 1176 m, 2017. IX. 20, Hu Li ( CAU) ; 1♂, 1176 m, 2017. IX. 20, Hu Li ( CAU) ; 1♂, 1471 m, 2017. IX. 20, Hu Li ( CAU) ; 4♀, 1128 m, 2017. IX. 20, Hu Li ( CAU) .

Figures

FIGURE 65. Geographical distribution of genera of Sciomyzidae from China (1).

FIGURES 9–16. Characters and morphological terms for the family Sciomyzidae (II).

FIGURES 49–56. Genera Dichetophora and Euthycera.