Botanophila collini ( Ackland, 1968 ) Ackland, 1968

Michelsen, Verner, 2014, Taxonomic assessment of Chirosiomima Hennig (Diptera: Anthomyiidae), with proposal of a new genus for Hylemyia curtigena Ringdahl, Zootaxa 3790 (1), pp. 86-102 : 94-96

Botanophila collini ( Ackland, 1968) , comb. nov.

( Figs. 15–20 , 21–26 )

Chirosiomima collini Ackland, 1968: 652 , figs. 1–7; Hennig 1976a: 928.

Relationships. Ackland (1968) described a small anthomyiid fly from Kyrgyzstan as Chirosiomima collini based on some male specimens found on excrement at 2600m. The primary reason for referring this new species to Chirosiomima was obviously the presence of a row of 4–6 enlarged, inclinate setae basally on the posterior lobes of sternite V, a defining character of the only species described in Chirosiomima by Hennig (1966). However, new evidence has proven Hennig to be wrong: these specialized setae are present in C. obscurinervis but not in the closely related species C. gestroi . The male terminalia in C. collini deviate in most respects substantially from those of C. obscurinervis and C. gestroi , which suggests that the superficially similar chaetotaxy of sternite V in C. collini and C. obscurinervis has been attained through homoplasy. Other specialized character states that Ackland’s species share with Chirosiomima (male head feminized; scutellum without setulae beneath tip; lower calypter reduced in size; and hind tibia with apical pv seta) are relatively trivial as they tend to develop in concert as a consequence of turning from a plesiomorphic “aerial” life habit to an apomorphic “terrestrial” one. This shift in life habit has evidently taken place repeatedly in the anthomyiid evolutionary tree. The structure of the pregonites and phallus in C. collini is in good agreement with the specialized state of these parts in the large, immensely diverse genus Botanophila Lioy and I propose therefore, assented by D. M. Ackland (in litt.), the new combination Botanophila collini ( Ackland, 1968) .

Material examined. KYRGYZSTAN: Chong Kizyl-Suu river, Terskei Plateau, 2600m, on excrement, paratype ♂, 1.v.1965 (Vtorov) [ UMNH]. RUSSIA: Respublica Altai: Kosh-Agachskiy Rayon, Naryn-Gol River [49°49’N 89°32’E], 2520m, in marmot burrow, 1♂ 15–19.vii.2009 (V. Sorokina) [ ZMUC].

Description. Male. ( Fig. 15 ). Very small, wing length c. 2.8mm.

Colour: Head, body and appendages dark brown to black, extensively covered in dark grey dusting, even on prementum. Head ochre yellow on lower half of broad frons, dusting on parafrontals and parafacials without usual silvery shine, parafacials above middle with a reflecting dark mark. Brown striping pattern faintly developed on mesonotum, especially along dorsocentral setal rows. Calypteres and halter whitish with a light brown tinge. Abdomen with a broad, poorly delimited middorsal dark stripe; tergo-sternite VII + VIII shiny black on anterolateral parts.

Head ( Figs. 15, 16 ): Fully feminized; lower facial margin lying slightly behind fronto-parafacial angle in profile view; parafacial in middle only half as wide as postpedicel; gena in profile about as wide as postpedicel, with a single row of robust setae; frons broad, frontal vitta c. 3/5 as wide as total frontal width, with strong inner and outer vertical setae, a pair of interfrontal setae, three orbital setae and two frontal setae plus some setulae; upper occiput practically bare beneath short postoculars. Antenna short; arista pubescence distinct, but shorter than greatest basal diameter of arista. Proboscis short with small labella and normal bicuspid teeth.

Thorax: Setulae on anterior declivity of mesonotum and postpronotal lobes rather coarse and stiff. Acrostichal rows standing closer to each other than to dorsocentral rows, middle pair in front of suture enlarged. Prealar seta shorter than posterior notopleural seta. Proepisternals 2 setae; proepimerals 1 seta and 1 setula. Anepisternum without setae in upper anterior corner. Katepisternals 2 + 1. Lower calypter reduced to an almost linear, narrow fold.

Wings: Rather slender due to weakly developed anal angle. Vein C with a row of v setulae on more than basal two-thirds, basal to costal break with slightly enlarged av spinules. Cross-vein dm–cu straight and upright.

Legs: Fore tibia with ad seta, without p or pv setae, apically only with ad seta and longer d seta. Mid femur with a few av setae basally and some longish pv setae in basal half; mid tibia with 1 ad and 2 pd setae. Hind femur with a row of robust av setae and a few long pv setae near middle; hind tibia with 1 av seta, 3 ad setae, 2 pd setae, without any p or pv setae and apically without pd seta but with short but robust pv seta.

Abdomen ( Fig. 15 ): Short and club-shaped with enlarged terminalia. Tergites III–V with marginal setae weak except laterally on tergite V, without discal setae. Tergite VI exposed, bare. Sternite I setulose; sternites II–IV ( Fig. 17 ) foreshortened, wider than long; sternite V ( Figs. 18, 19 ) enlarged, its basal apodeme reaching beneath three preceding sternites. Cerci and surstyli robust, relatively large compared to epandrium ( Figs. 21–23 ); surstyli with subapical incision reduced, forming a tiny notch at midlength ( Fig. 22 , arrow); cerci apically acutely pointed and freely projected between surstyli. Hypandrium, gonites and phallic complex ( Figs. 24–26 ) of the Botanophila - type, i.e. pregonites shallow, firmly connected to central plate of hypandrium; distiphallus very reduced.

Female. Unknown.

Distribution. Central Asia. Previously known only from the type locality in Kyrgyzstan ( Ackland 1968); presently also from Respublica Altai in Russia.

Biology. Males have been found on excrement at 2600m in Kyrgyzstan ( Ackland 1968) and in burrows of the Altai Marmot ( Marmota baibacina Kastschenko ) at 2520m in the Altai Mts. Details about the latter locality are given by Sorokina & Pont (2011). These authors also document the importance of alpine marmot colonies as a habitat for muscid and fanniid Diptera , whether as obligate commensals exploiting marmot excrement and carcasses as food and breeding substrate, or as adventitious visitors using the burrows as shelter from harsh weather conditions. The female and immature stages are unknown, but the “terrestrial” appearance of the male fly suggests that Botanophila collini belongs to the community of dipteran commensals in marmot burrows.

Figures

FIGURES 15 – 20. Botanophila collini, male from Altai Mts., Russia. 15. Habitus. 16. Head, dorsolateral view. 17. Sternites II – IV (and fragment of I). 18 – 20. Sternite V in dorsal, laterodorsal and lateral views. Scale bars: 1 mm (15, 16); 0.1 mm (17 – 20).

FIGURES 21 – 26. Botanophila collini, male from Altai Mts., Russia. 21 – 23. Hypopygium in lateral, posterolateral and posterior views. 24. Hypandrium, pre- and postgonites, dorsolateral view (hyp = hypandrium; pog = postgonite; prg = pregonite). 25. Hypandrium, gonites, phallapodeme, phallus and ejaculatory pump, lateral view. 26. Phallapodeme, phallus and ejaculatory pump, lateral view (bph = basiphallus; dph = distiphallus; ejac = ejaculatory apodeme; eph = epiphallus; phap = phallapodeme). Scale bars: 0.25 mm.