Tachydromia pieltaini (Gil Collado, 1936)

Gonçalves, Ana Rita, Grootaert, Patrick, Andrade, Rui, Paulo, Octávio S. & Mengual, Ximo, 2021, Revision of the morphology, phylogenetic relationships, behaviour and diversity of the Iberian and Italian ant-like Tachydromia Meigen, 1803 (Diptera: Hybotidae), European Journal of Taxonomy 732, pp. 1-56 : 33-35

Tachydromia pieltaini (Gil Collado, 1936)

Figs 1 , 12 , 16 E–F, 18 G–H, 19 C, 21 B–C

Ariasella pieltaini Gil Collado, 1936: 191 .

Tachydromia pieltaini – Shamshev & Grootaert 2018: 425 (comb. nov.).

Diagnosis

Shiny black with distinct yellow parts. Wing dimorphic: male stenopterous; wing with oval apex; stalklike process yellow to light brown; lobed apex with hyaline cells, veins and distal margin black; female stenopterous, stalk-like portion yellowish with minute lobed apex pale brown. Proboscis and antennae black; palpi yellow; postpedicel roundish, approximately as long as pedicel. Legs overall yellow only with the distal tarsomeres black. Abdomen black, tergites and sternites overall covered with setae; grey microtrichia present at last apical tergite and most sternites, resulting in shiny appearance of dorsal surface.

Type material (not examined, lost) SPAIN • 1 ♀; Asturias, Porra de Enol ; C. Bolívar leg.

Additional material examined

SPAIN • 3 ♂♂, 3 ♀♀; Asturias, Cangas de Onís, Covadonga ; 43°18′42.4″ N, 5°03′28.0″ W; 26. Apr. 2011; R. Andrade leg. • 2 ♂♂, 2 ♀♀; same collection data as for preceding; ZFMK • 2 ♂♂, 4 ♀♀ (all male terminalia studied, RBINS); Asturias, Cangas de Onís ; 43º21′14.6″ N, 5º07′25.9″ W; 9 Apr. 2016; A.R. Gonçalves leg.

Redescription

Similar to Tachydromia cantabrica sp. nov. except for the following:

Male (previously undescribed)

MEASUREMENTS. Body length: 2.6–2.9 mm (n = 5). Wing length: 0.9–1.1 mm (n = 5).

HEAD. Ocellar tubercle glabrous. Lateroclinate ocellars 2 times as long as postpedicel. Proclinate verticals 1.8 times as long as postpedicel.

ANTENNA. Yellow. Postpedicel roundish, as long as wide and, approximately as long as pedicel; stylus almost 4 times as long as scape, pedicel and postpedicel combined.

PALPUS. About 4 times as long as wide. Yellow in ground colour.

THORAX. Postpronotal lobe, notopleuron, episternum, anepisternum, sternopleuron, katepimeron and meron weakly differentiated. Scutellum short, postscutellum longer and metanotum well developed. Prosternum and basal half of episternum densely covered by grey microtrichia. Postpronotal lobe bearing 7 setae laterally, 5 acrostichal setae, irregularly placed; notopleuron with 1 strong, prominent, very long seta, plus 3 smaller ones

WING ( Fig. 21B ). Lobed apex oval. Stalk-like portion rigid, yellow to light brown; lobed apex with hyaline cells, veins and distal margin black. Venation very reduced (costal, longitudinal and cross veins distinguishable), forming 4 cells.

LEGS. Overall yellow, with the following brown to black: dorsal strip on fore and mid femora, posterior coxae, tarsomere 5 of fore and mid-legs, apical portions of tarsomeres 2 and 3, tarsomeres 4 and 5 of hind leg. Mid trochanter with several black anteroventral marginal setae. Mid femur with small roundish posteroventral projection on basal surface with several black denticle-like setae and ca 3 black setae. Mid tibia anteroventral apical spur produced into distinct, long elongation ( Fig. 19C ); slightly longer than diameter of tibia at apex. Spur covered with microtrichia and> 10 short, blunt denticle-like setae; additionally, with 6 longer, stout, curved setae along lateral margin. Elongation mostly glabrous with a few setae arising marginally and apically.

ABDOMEN. Shiny black, with grey microtrichia covering only last tergite and almost all sternites, except for sternites 1 and 2. Tergites and sternites overall covered with setae, except for dorsal surface of all tergites and most of sternite 1 (distal margin with a few setae); apical sternite and tergite with longer setae.

TERMINALIA ( Fig. 12 ). Right surstylus short with irregular margins, narrowing distally, bearing long setae, with several (ca 8) distinct denticle-like setae aggregated on distal margin. Right cercus longer than left. Right cercus with setae on apical ½; left cercus with setae of unequal lengths on apical half and 2 long apical setae. Left epandrial lamella ½ shorter than left cercus, with setae of similar length on apical half of ventral surface and on apex of dorsal margin. Left surstylus longer than right cercus, with very long setae on lateral and apical margins.

Female

Similar to male, except for following features: stenopterous (length of wing (n = 2): 0.7–0.8 mm), with very minute lobed apex, stalk-like portion yellowish with lobe light brown, covered by grey microtrichia ( Fig. 21C ); legs covered with regular rows of setae, with distinct circle of setae on fore femur and anteroapical setae on coxae; without other distinctive hairs or setae; spurs on mid tibia absent; cercus pale brown with grey microtrichia and setae.

Distribution

Spain. Only known from the Picos de Europa mountain range.

Figures

Fig. 1. Currently known distribution of the Iberian ant-like Tachydromia Meigen, 1803. Each dot represents a presence point, with each colour corresponding to a different species. When two species co-occur in the same area, their presence is represented by a smaller dot on top of a dot of regular dimension, each of those with the colour corresponding to the co-occurring species. The dots surrounded by a black circle with a vertical line represent localities previously known.

Fig. 12. Terminalia of Tachydromia pieltaini (Gil Collado, 1936) from Spain, Asturias, Covadonga (RBINS). A. Right surstylus and right epandrial lamella. B. Epandrium with cerci. C. Left epandrial lamella and left surstylus. D. Right surstylus. Scale bar: 0.1 mm.

Fig. 16. Habitus of live specimens of the Iberian ant-like Tachydromia Meigen, 1803 and the Italian flightless Tachydromia. Males are pictured in the left column, females in the right.A–B. T. iberica (Arias, 1919). C–D. T. semiaptera (Gil Collado, 1923). E–F. T. pieltaini (Gil Collado, 1936). G–H. T. pandellei (Séguy, 1941). I–J. T. apterygon Plant & Deeming, 2006 (Italy).

Fig. 18. Mounted specimens of the Iberian ant-like Tachydromia Meigen, 1803. Males are pictured in the left column, females in the right. A–B. T. cantabrica Gonçalves, Grootaert & Andrade sp. nov. C–D. T. iberica (Arias, 1919). E–F. T. semiaptera (Gil Collado, 1923). G–H. T. pieltaini (Gil Collado, 1936). I–J. T. pandellei (Séguy, 1941). Scale bars: 1 mm.

Fig. 19. Images obtained by scanning electron microscopy of the spur-like structures present on the apical portion of the male mid tibia. A. T. lusitanica (Grootaert, Shamshev & Andrade, 2009). B. T. pandellei (Séguy, 1941). C. T. pieltaini (Gil Collado, 1936). D. T. ebejeri Gonçalves, Grootaert & Andrade sp. nov. E–F. T. semiaptera (Gil Collado, 1923). G. T. stenoptera Gonçalves, Grootaert & Andrade sp. nov. H. T. cantabrica Gonçalves, Grootaert & Andrade sp. nov. I. T. nigrohirta Gonçalves, Grootaert & Andrade sp. nov. J. T. apterygon Plant & Deeming, 2006. Scale bars: 10 µm.

Fig. 21. Drawings of the tip of stenopterous wings and images obtained by scanning electron microscope (SEM) of the micropterous wings. Males are pictured in the left column, females in the right. A, C. T. pandellei (Séguy, 1941). B–C. T. pieltaini (Gil Collado, 1936). D–E. T. semiaptera (Gil Collado, 1923). F–G. T. stenoptera Gonçalves, Grootaert & Andrade sp. nov. Scale bars: A–D, F = 50 µm; E, G = 10 µm.