Metoponia robertsoni,

Daniels, Greg, 2016, A new genus and two new species of soldier fly (Diptera: Stratiomyidae: Chiromyzinae) from Australia, one found infesting sugarcane in central Queensland, Zootaxa 4092 (2), pp. 572-582: 574

publication ID

http://dx.doi.org/10.11646/zootaxa.4092.4.7

publication LSID

lsid:zoobank.org:pub:25F568D2-7969-49E1-9149-ED1A49B64E8C

persistent identifier

http://treatment.plazi.org/id/03E487B3-FFD7-3926-FF0F-EE9AFB10F964

treatment provided by

Plazi

scientific name

Metoponia robertsoni
status

 

Metridius Daniels nov. gen.

( Figs 1–21View FIGURES 1 – 8View FIGURES 9 – 15View FIGURES 16 – 21)

Type species. Metridius robertsoni  nov. sp., by present designation.

Diagnosis. This genus can be separated from the other Australian Stratiomyidae  by the following combination of characters: Eyes distinctly separated in both sexes and with sparse ommatrichia. Flagellomeres indistinct, at most represented by slight dorsal and/or ventral indentations; the first flagellomere is sometimes present in M. robertsoni  nov. sp. Wings of male lacking discal medial cell, vein M 3 absent; females apterous. Scutum of female without dorsal sutures and scutellum absent; scutum of male with usual sutures and scutellum present. Male terminalia ( Figs 6–8View FIGURES 1 – 8) small; aedeagus single pronged. Gonocoxite medially attenuate distally, extending almost to apex of aedeagus. Epandrium ( Figs 8View FIGURES 1 – 8, 26View FIGURES 22 – 26) with prominent posterior corners. Female terminalia ( Figs 13–15View FIGURES 9 – 15). Ovipositor not apparent; sternite 8 viewed ventrally, is convex and longer than combined length of tergites 8 and 9.

Description. Male ( Figs 1 –8View FIGURES 1 – 8, 22– 26View FIGURES 22 – 26). Head ( Figs 1 –2View FIGURES 1 – 8, 23View FIGURES 22 – 26). Yellow-brown with short erect setae; transversely broadened; ocellar tubercle black or black brown and raised above vertex. Frons visible when viewed laterally especially in M. robertsoni  nov. sp. Frontal index 0.5–0.8. Ratio of frons width to head width 1.0:2.0– 2.6. Eyes distinctly separated and with sparse ommatrichia. Flagellomeres indistinct, at most represented by slight dorsal and/or ventral indentations; the first flagellomere is sometimes present in M. robertsoni  nov. sp.

Thorax about 1.5 times longer than wide and entirely yellowish brown or deep brown, with scutellum, humeral callus, postalar callus and laterotergite yellowish. Anepisternum shining, mostly devoid of setae. Wings ( Figs 4View FIGURES 1 – 8 and 24View FIGURES 22 – 26) about 2.5 –3.0 times longer than wide and lacking discal medial cell and vein M 3. Legs yellowish. First tarsomere on all legs shorter or longer than tibia.

Abdomen yellowish uniformly covered with short suberect setae. Male terminalia ( Figs 6 –8View FIGURES 1 – 8, 25– 26View FIGURES 22 – 26) broadly triangular to subquadrate. Cerci one segmented. Gonostyli concave distally. Aedeagus single pronged. Gonocoxite medially attenuate distally, extending almost to apex of aedeagus.

Female ( Figs 9–15View FIGURES 9 – 15). Differing from male by being apterous and lacking halters, scutellum and most lateral thoracic pleura. Head (figs 9–10). Frontal index 0.6–0.7. Ratio of frons width to head width 1.0: 2.5–2.6.

Thorax. Scutum without dorsal sutures and scutellum. Wings absent, halters absent. Legs shorter than male and first tarsomere shorter than tibiae.

Abdomen. Terminalia ( Figs 13–15View FIGURES 9 – 15). Ovipositor is not apparent; sternite 8 viewed ventrally is convex and longer than combined length of tergites 8 and 9.

Etymology. The name of the genus comes from the Greek metridios, filled with seed, pertaining to the enlarged ovaries of the type species which occupy most of the abdominal and thoracic cavities.

Geographic Distribution. Australia (Queensland and New South Wales).

Comments. Metridius nov. gen. differs from Inopus  in having eyes with sparse ommatrichia; in males the flagellum is at least three times as long as the combined length of the scape and pedicel, and the eyes are distinctly separated; females are apterous and lack scutal sutures and scutellum. From Boreoides  and the Chiromyza  group, Metridius nov. gen. differs in having an almost flat frons. Female Boreoides  are micropterous, having vestiges of the wings and halters, in M. robertsoni  nov. sp. they are entirely absent. The ovipositor of Boreoides  and many Chiromyza  is comprised of segments 5–8; in Inopus  the ovipositor is comprised of segments 7 and 8, while in Metridius nov. gen. the ovipositor is not well developed. Sternite 8 in Chiromyza  , Inopus  and Boreoides  is more or less flat and tapers distally, in Inopus  it is almost square, in Boreoides  and Chiromyza  it is about twice as long as wide; in Metridius nov. gen. sternite 8 is convex, its length subequal to its basal width, and the apical margin about half the basal width. Tergite 8 and sternite 8 are subequal in length in Boreoides  , Inopus  and Chiromyza  ; in Metridius nov. gen., the combined length of tergites 8 and 9 approximates the length of sternite 8.