Winnertzia imbecilla, Jaschhof & Jaschhof, 2020

Jaschhof, Mathias & Jaschhof, Catrin, 2020, Reevaluation of species richness in Winnertzia (Diptera, Cecidomyiidae, Winnertziinae), with descriptions of 37 new species from Sweden, Peru and Australia, Zootaxa 4829 (1), pp. 1-72 : 13-14

Winnertzia imbecilla sp. nov.

Figs 10–13

The specimen designated here as the holotype of W. imbecilla was published in error as the first Swedish find of W. brachypalpa ( Jaschhof & Jaschhof 2017) . Another specimen of W. imbecilla from Sweden we detected in the NHRS collection, again misidentified as W. brachypalpa . This leaves the genuine W. brachypalpa , a species originally described from the Russian Far East ( Mamaev 1975) and subsequently reported to occur in Ukraine ( Spungis 1992), without valid record in Sweden.

Diagnosis. A medium-sized, brown Winnertzia with vestigial mouthparts. A combination of male genitalic characters is diagnostic of W. imbecilla , as follows ( Fig. 10 ). The compact gonostylus has dense, large microtrichia apically and medially (↓ 4); the base of the gonocoxal emargination is angular rather than rounded (↓ 5); the tegmen is markedly tapered towards the blunt-ended, microtrichose apex (↓ 6); and the parameral apodemes are unusually short and broad (↓ 7). Winnertzia brachypalpa , a generally similar species whose holotype we studied in 2012, is distinguished from W. imbecilla by the subtriangular tegmen with pointed apex and by the small, inconspicuous parameral apodemes. Also, the gonostylar apex of W. brachypalpa seems to be more slender compared with W. imbecilla , a possible distinction that is difficult to assess in the holotype specimen. Winnertzia angustistylus , another species of the discreta group with vestigial mouthparts, differs from both W. imbecilla and W. brachypalpa by the conspicuously slender gonostylus ( Fig. 2 ), to name just one of the distinctions. Females and preimaginal stages of W. imbecilla are unknown.

Other male characters. Body size 1.7 mm. Head. Eye bridge 3–4 ommatidia long dorsally. Antenna slightly longer than half body. Scape and pedicel same size, both concolorous with flagellum. 11 flagellomeres, apical flagellomere long, composed of two nodes; translucent sensilla present on flagellomeres 1–10. Fourth flagellomere: neck 0.6–0.7 times as long as node; node 1.5 times as long as broad; sensory hairs sparse; both lateral and medial translucent sensilla long, filiform, linear to variously bent ( Figs 12–13 ). Palpus much shorter than head height, 3 segments with mostly long setae; apical segment napiform, longer than preceding two segments together ( Fig. 11 ). Labella vestigial. Thorax. Pronotal setae 6. Anepimeral setae absent. Lateral mediotergal microtrichia slightly enlarged. Parascutellar area inconspicuous, vaguely contoured. Wing slightly shorter than body, 2.6 times as long as broad. Costal cell slightly reinforced. M 4 long, straight, CuA moderately bent, both veins extending to edge of wing. Legs. Scales pointed. Basitarsal spines absent. Fore tibia 1.4 times length T 2. Acropods: claws slightly bent, basal tooth large; empodia vestigial. Abdomen. Pleural membrane devoid of setae. Genitalia ( Fig. 10 ). Ninth tergite about half gonopodal length; setae confined to posterior portion; posterior edge emarginated medially, the emargination darkly pigmented; anterior edge straight, indistinct. Gonocoxal synsclerite slightly broader than long; a short portion ventrobasally non-setose; ventral emargination with broad, darkly pigmented border, membranous basally; ventroanterior edge straight; ventroposterior portions enlarged, markedly protruding beyond dorsoposterior portions; dorsal apodemes moderately long, subtriangular. Gonostylus twice as long as broad; basolateral apophysis normal size, angulated. Aedeagal apodeme gently broadened shortly before the apex, then slightly constricted; solid basal portion long. Aedeagal bulge apparently devoid of microtrichia. Tegmen slightly reinforced apically; flaps narrow, indistinct.

Etymology. The Latin adjective imbecilla means weak, an allusion to the fact that the morphology of males is partly regressive.

Type material. Holotype. Male , Sweden, Öland , Borgholm, Skepparsäng Nature Reserve, dry pine forest, 22 July–23 August 2015, Malaise trap, M. & C. Jaschhof (spn CEC 270 in NHRS).

Other material studied. Sweden: 1 male, Södermanland, Tyresta NR, May 2002 firesite north of Haningealpen Station , 31 May–17 June 2002, MT, B. Viklund (spn GULI000021001 in NHRS) (previously labeled as W. brachypalpa Mamaev by V. Spungis) .

Distribution and phenology. Both specimens known of W. imbecilla were collected in dry pine forests in the southern half of Sweden (Öland, Södermanland). Available data suggest the adult flight period is June–August.

Figures

FIGURES 7–13. Male morphology of Winnertzia brachytarsus (7–9) and Winnertzia imbecilla (10–13), holotypes. 7: Fourth flagellomere, lateral. 8: Ditto, medial. 9: Genitalia, ventral. 10: Genitalia, ventral. 11: Palpus, lateral. 12: Fourth flagellomere, lateral. 13: Ditto, medial. Scales for 7–10 and 12–13, 0.05 mm; for 11, 0.025 mm. Arrows refer to characters described in the diagnoses.

FIGURES 1–6. Male morphology of Winnertzia angustistylus. 1: Genitalia, ventral, holotype. 2: Gonostylus, ventral, paratype. 3: Fourth flagellomere, lateral, holotype. 4: Ditto, medial. 5: Palpus, lateral, paratype. 6: Wing, dorsal, specimen from Södermanland. Scales for 1, 3 and 4, 0.05 mm; for 2 and 5, 0.025 mm; for 6, 0.50 mm. Arrows refer to characters described in the diagnosis.