Zaitzeviola dubitabila (Mamaev & Zaitzev)

Jaschhof, Mathias & Jaschhof, Catrin, 2020, The Porricondylini (Diptera: Cecidomyiidae: Porricondylinae) of Sweden revisited: descriptions of nineteen new species of ten genera, including a new genus, Zootaxa 4728 (2), pp. 151-182 : 180-181

Zaitzeviola dubitabila (Mamaev & Zaitzev)

Figs 53–55

This species, described as a Neocolpodia by Mamaev & Zaitzev (1998) and designated as type species of the genus Zaitzeviola by Fedotova & Sidorenko (2007a), was previously known from a single male collected in Kamchatka, in the Russian Far East. The present senior author examined and sketched that specimen in October 2012. Based on notes made on that occasion we were able to establish the identity of several porricondyline males collected in southeast Sweden with the species in question, Z. dubitabila . All our specimens, altogether 15 males, were Malaise trapped in 2015–2018 in five different sites on the island of Öland, so may be regarded as belonging to one and the same population. Even so, those specimens show an unusual extent of variation in the number of flagellomeres, ranging from 12 to 14, with 13 flagellomeres being the most common condition found. (In the holotype of Z. dubitabila only 8 flagellomeres are retained.) No such variation has been observed in any other species of Zaitzeviola , where a constant 14 flagellomeres is found ( Jaschhof & Jaschhof 2013: 266 ff.). This might indicate that Z. dubitabila , on the one hand, and the six species regarded as congeneric in our 2013 revision of Zaitzeviola , on the other hand, are not as closely related as previously thought. Alternatively, Z. dubitabila might well be an untypical member of this genus in that male morphology includes regressive character traits (note that this species is considerably smaller compared with other Zaitzeviola )―this hypothesis is favored here.

Diagnosis. Zaitzeviola dubitabila differs from all congeneric species in having mostly fewer than 14 flagellomeres and the palpus being shorter than the head height. Circumfila are present on flagellomeres 1–8, which compares with 1–12 to 14 in other Zaitzeviola . Furthermore, Z. dubitabila is the only species of the genus in which true gonocoxal processes are absent (but there is a thin, membranous structure in the same position where such processes should occur). The gonostylus is unique in combining a subtriangular outline with the presence of a pectinate claw ( Fig. 53 , ↓ 3).

Other male characters. Body size 1.2–1.5 mm. Head. Setae mostly confined to posterior half of head capsule. Eye bridge without dorsal ommatidia for a long distance. Antenna about as long as body. Scape and pedicel yellowish, lighter than flagellum. Neck and node of fourth flagellomere equally long ( Fig. 55 ) or neck up to 1.2 times as long as node. Palpus 4-segmented, apical segment longest of all. Thorax. Pronotum with 2–5 setae; anepisternum usually non-setose, rarely with 1–2 setae; anepimeron with 2–5 setae. Wing longer than both body and antenna. Length / width ratio 2.9. M 1+2 absent. M 4 weak, separate from CuA, or absent. Legs. Foreleg: femur 0.9 times the length of tibia, tibia 1.5 times the length of T 2. Claws with 1 large and 2–3 finer teeth basally. Empodia broad, nearly as long as claws. Genitalia ( Fig. 53 ). Gonocoxal synsclerite broader than long, markedly narrowed anteriorly; ventral setae of varying length including several conspicuously long ones; no setae around the ventral emargination, along the longitudinal axis and anteriorly; ventral emargination U-shaped, with sclerotized margin of varying extent; dorsal apodemes moderately long, ending before ventroanterior gonocoxal edge. Gonostylus about twice as long as broad, straight rather than bent; apical claw smaller than found in other Zaitzeviola ; basolateral apophysis small. Parameres thin, moderately sclerotized, markedly bent; apices either parallel to, or approaching each other ( Fig. 54 ), usually connected by a thin membrane (↓ 4); transverse bridge weak; apodemes inconspicuous. Aedeagal apodeme thin, shorter than gonocoxae, poorly sclerotized, even more so apically. Ducts of accessory glands indistinct (not illustrated).

Material studied. Sweden: 1 male, Öland, Borgholm, Norra Bäck, Mossberg’s summer premises, backyard with herb-rich meadow and bushes, 1 June–4 August 2018, MT, MCJ (spn. CEC 2464 in NHRS) ; 1 male, Borgholm, Lindreservatet NR, mixed broadleaf forest, 7 May–10 June 2015, MT, MCJ (spn. CEC 2465 in NHRS) ; 2 males, Borgholm, Horns kungsgård NR, mixed broadleaf forest at lakeside, 6 May–11 June 2015, MT, MCJ (spns CEC2452 and CEC 2466 in SDEI) ; 9 males, Öland, Mörbylånga, Ullevi, herb-rich meadow near broadleaf forest, 10 May–1 June 2016, MT, MCJ (spns CEC2455 – CEC 2463 in SDEI) ; 1 male, Mörbylånga, Skogsby, Station Linné, backyard with compost pile, 29 July–25 August 2015, MT, MCJ (spn. CEC 2453 in NHRS) ; 1 male, Station Linné, swampy meadow next to willow scrub, 2 June–4 July 2016, MT, MCJ (spn. CEC 2454 in NHRS) .

Figures

FIGURES 50–55. Male morphology of Isocolpodia unidentata (50–52) and Zaitzeviola dubitabila (53–55), specimens from Sweden. 50: Basitarsus of foreleg, lateral. 51: Fourth flagellomere, lateral. 52: Genitalia, ventral. 53: Genitalia, ventral. 54: Parameres and aedeagal apodeme, ventral. 55: Fourth flagellomere, lateral. Scales 0.05 mm. Arrows refer to characters described in the diagnoses.