Zhenia burmensis, Zhang & Zhang, 2019

Zhang, Qingqing & Zhang, Junfeng, 2019, Contribution to the knowledge of male and female eremochaetid flies in the late Cretaceous amber of Burma (Diptera, Brachycera, Eremochaetidae), Deutsche Entomologische Zeitschrift 66 (1), pp. 75-83 : 76-80

Zhenia burmensis sp. nov. Figures 4 , 5 , 6 , 7 , 8D

Diagnosis.

Rs deviating from R just at level of M fork; R2+3 meeting R1 before C (i.e. cell r1 closed with short petiole); R4+5 simple; section C between R4+5 and M1 slightly shorter than section C between M1 and M2; M1 straight, ending at apex of wing; M3 straight; haltere with globose knob; abdominal fourth segment longest; basitarsus of hindleg longer than tarsomeres II-V combined; male genitalia with subovate gonocoxite, straight and clavate gonostylus, aedeagus long, obviously reaching beyond hind margin of gonocoxite; female ovipositor relatively short and stout.

Description.

Male. Body and legs brown (Fig. 4A, B ), covered with dense short hairs (Fig. 4C, D ). Head large, subovate. Eyes large, holoptic, occupying almost the entire head (Figs 4A , 5A ).

Thorax relatively small, nearly globose, almost as wide as but slightly longer than head. Scutellum rather shorter but relatively wide, over three times wider than long (Figs 4A , 5A ). Wing narrow and long, 3.3 times longer than wide, apex of wing round (Fig. 5A ). Costal vein terminating at the wing apex; vein Sc short, ending nearly at level of middle of distal cell; Rs deviating from R just at level of M fork, section of Rs stem nearly as long as section bR4 + 5; R2 + 3 slightly arched apically, running slightly convergent to R1, fused with R1 just before anterior margin of wing; cell r1 narrow and long, fusiform, with short petiole; section of R4 + 5 + M1 separating from anterior margin of cell d nearly at its end, forked distinctly distal to the level of the apex of the discal cell, about 1.5 times longer than section bM2; M1 straight, terminating nearly at wing apex. M2 and M3 almost straight; M4 absent; cell d hexagonal, nearly 2.7 times longer than wide; m-m long, straight; bM3 short; m-cu long, twice longer than bM3; cell br obviously longer than, but nearly as wide as, cell bm; cell cu (traditionally anal cell) closed with short petiole (Fig. 5A ). Haltere thin and long, club relatively small, subglobose (Fig. 5A ). Forelegs and midlegs relatively thin and short but with pulvillus and empodium extremely elongate, very similar in length and in shape to the hindleg; hindlegs relatively stout and long; femur clavate, less than half of abdominal length; tibia subcylindrical, longer and obviously narrower than femur; tarsus very short, less than one-half of length of tibia, basitarsus longer than tarsomeres II-V combined, ratio of tarsomeres 1.0:0.16:0.11:0.11:0.36, empodium longer than pulvillus, narrowly phylliform in lateral view, less than one-third of length of tarsus (Fig. 5C ).

Abdomen thin and long, subcylindrical, nearly 2.4 times longer than head and thorax combined; eight segments visible; first very short, fourth longest, ratio of segments 1.0:2.9:3.6:4.0:3.1:2.9:2.1:1.7; ninth segment forming male genitalia, clearly shorter than eighth (Figs 4A, B , 5A ). Genitalia covered with thin and long hairs; hypandrium large, triangular, 1.7 times wider than long, separated from epandrium, and articulated horizontally with gonocoxite; gonocoxite stout and long, subovate, distinctly narrowed basally; gonostylus relatively small, straight, clavate, slightly thickened medially, rounded apically, and articulated horizontally on gonocoxite; aedeagus (phallus) stout and long, cylindrical, distinctly extending beyond hind margin of gonocoxite, simple (not forked apically), rounded apically; cercus one-segmented, short and wide, subtriangular, slightly longer than wide, not reaching apex of aedeagus (Figs 4D , 5B ).

Female. Body dark brown, legs brown (Fig. 6A ). Head large, subovate; antennal first flagellomere conical, basally distinctly wider than apically; arista rather thin and long. Eyes large, occupying almost whole head in lateral view (Figs 6B , 7A, B ).

Thorax relatively large, nearly globose, clearly longer than head. Scutellum rather shorter (Figs 6A , 7A ). Wing narrow and long, 2.8 times longer than wide, apex of wing round (Fig. 7A ). Costal vein terminating at the wing apex; vein Sc short, ending nearly at level of middle of distal cell; Rs deviating from R just at level of M fork, section of Rs stem nearly as long as section bR4 + 5; R2 + 3 nearly straight, running slightly convergent to R1, but not coalesced with R1; cell r1 narrow and long, narrowly open apically; section of R4 + 5 + M1 separating from anterior margin of cell d nearly at its end, forked distinctly distad to level of d’s end, about twice longer than section bM2; M1 smoothly arched, terminating nearly at wing apex. M2 and M3 almost straight; M4 absent; cell d hexagonal, nearly twice longer than wide; m-m long, straight; bM3 short; m-cu long, about three times longer than bM3; cell br obviously longer and wider than cell bm; cell cu (traditionally anal cell) closed nearly at hind margin (Fig. 7A ). Hindlegs relatively stout and long; femur clavate, about half of abdominal length; tibia subcylindrical, slightly shorter and narrower than femur; tarsus very short, about one-third of length of tibia, basitarsus slightly longer than tarsomeres II-V combined, empodium and pulvillus narrowly phylliform, about one-third of length of tarsus (Figs 6D , 7A ).

Abdomen thin and long, subcylindrical, nearly 1.8 times longer than head and thorax combined; eight seg ments visible; first very short, third, and fourth longest, ratio of segments 1.0:1.6:1.8:1.8:1,5:1.0:0.5:0.9; ovipositor formed from modified eighth and ninth segments: eighth elongated, separated in two or three sections, its sternite only moderately (not extremely) elongate, ninth forming sclerotised aculeus, cerci (if present) located at apex of aculeus (Figs 6E , 7C , 8D ).

Dimensions.

Holotype (male) NIGP170825, body length ca 8.6 mm; head length 1.2 mm; thorax length 1.5 mm; wing length 5.5 mm, width 1.7 mm; hindleg length ca 6.8 mm (femur 2.4 mm, tibia 2.9 mm, tarsus 1.5 mm); abdomen length 6.3 mm. Paratype (female) NIGP170826, body length approximately 7.1 mm; head length 0.8 mm; thorax length 1.5 mm; wing length 3.2 mm, width 1.3 mm; hindleg length ca 4.4 mm (femur 2.0 mm, tibia 1.8 mm, tarsus 0.6 mm); abdomen length (excluding ovipositor) 4.0 mm, ovipositor length 0.8 mm.

Distribution.

Myanmar amber, Late Cretaceous (Cenomanian); Hukawng Valley, Kachin Province, Myanmar.

Remarks.

Based on the following characters, male Z. burmensi s sp. nov. can be distinguished from male Z, Zhenia xiai : knob of haltere is globose; third and fourth abdominal segments are longest; basitarsus of hindleg is longer than combined tarsomeres II-V; genitalia has ovate gonocoxite, straight and clavate gonostylus, and longer aedeagus, which obviously reaches beyond the hind margin of the gonocoxite.

On the other hand, the wing venation, ratio of abdominal segments and ratio of tarsi of hindleg of this female specimen resemble closely that of male Z. burmensi s sp. nov., and, thus, it can be provisionally regarded as a member of Z. burmensi s sp. nov. Female Z. burmensis sp. nov. can also be separated from female Z. xiai in that: the first flagellomere of the antenna becomes conical instead of subcylindrical; cell r1 runs open apically, R4+5 is simple (not forked apically); tarsus of hindleg is relatively short and stout; and ovipositor is relatively short and stout.

Nevertheless, owing to the clearly smaller size than that of male Z. burmensi s sp. nov., the female described here may represent another, as yet, undescribed species.

Figures

Figure 4. Zhenia burmensis sp. nov. Photomicrographs (A-C) and Confocal microscopic photograph (D), holotype NIGP 170825, male A habitus (dorsal view) B habitus (ventral view) C male genitalia (ventral view) D male genitalia (ventral view). Scale bars: 1 mm (A, B); 0.1 mm (C, D).

Figure 5. Zhenia burmensis sp. nov. Line drawings, holotype NIGP 170825, A habitus (dorsal view) B male genitalia (ventral view) C tarsus of hindleg. Scale bar: 1 mm (A); 0.1 mm (B, C).

Figure 6. Zhenia burmensis sp. nov. Photomicrographs, paratype NIGP 170826, female A habitus (lateral view) B antenna C wing D tarsus of hindleg E ovipositor (lateral view). Scale bars: 1 mm (A, C); 0.1 mm (B, D, E).

Figure 7. Zhenia burmensis sp. nov. Line drawings, paratype NIGP 170826, female A habitus (lateral view) B antenna C ovipositor (lateral view). Scale bar: 1 mm (A); 0.1 mm (B, C).

Figure 8. Difference and similarity between four sets of ovipositors. Line drawings (lateral view), A Rhagoletis pomonella (Walsh, 1867) (ovipositor extended, after Cumming and Wood 2009) B Rhagoletis pomonella (Walsh, 1867) (ovipositor not extended, after Norrbom 2010) C Zhenia xiai Q. Zhang et al., 2016 D Zhenia burmensis sp. nov. Scale bars: 1 mm (C, D). ac gl - accessory gland; acul - aculeus; cerc - cercus; cloac op - cloacal opening; ev mem - eversible membrane; ovscp - oviscape; sg - segment; spmth - spermatheca; st - sternite; tg - tergite; v rep - ventral receptacle.