Prime segnalazioni di Cercagnota collini (Czerny, 1928) (Diptera: Anthomyzidae) per l’Italia peninsulare (Emilia Romagna – Veneto)
The Anthomyzidae is a small family of acalyptrate flies allied to Opomyzidae. Anthomyzids are distinctively slender and delicate flies which are most often found among wetland vegetation and herbaceous undergrowth of leafy and mixed forests (Roháček, 2006) where they probably develop mostly as micro-bial grazers. The family comprises approximately ninety described species, most of them from the Holarctic Region, with an especially diverse faunal com-position in Europe (Roháček, 2006, 2009). The monotypic genus Cercagnota Roháček & Freidberg, 1993 is morphologically well characterised and can be easily distinguished from all other genera of Palaearctic Anthomyzidae by the characters given in Roháček (2006).
Material and methods
Three double mounted specimens, micropinned in a block of plastic material, were examined.
Their study required the use of dissecting and compound microscopes. The specimens are housed in the dipterological collection of the Natural History Museum, Venice.
Taxonomic and distributional accounts
Cercagnota collini is the sole described species included in this genus. It is ararely collected, tiny species (1.39-1.57 mm) with a wide distribution in the southern Palaearctic Region, ranging from Central Asia to Mediterranean, northwards reaching England. In particular, C. collini has been reported from southern England, France (Provènce), Israel, Italy (Sardinia and north-eastern Italy (new)), Malta, Spain (Mediterranean coast), Uzbekistan. Detailed citations and references for the above countries can be found in Roháček (2006, 2009). Among the plentiful unsorted fly material housed in the Natural History Mu-seum of Venice I found three female specimens belonging to this species. All of them were collected by the late Prof. A. Giordani Soika by using an autocatch-er-like net placed over a moving car, at height of about 250 centimetres from the ground level (“in aeroplankton”, according to the collector).
Italy: Emilia Romagna, [Lido di] Volano [province of Ferrara], beach road, 30.vi.1983, at 20:00 [08:00 p.m.], 1 ♀; ibidem, 17.ix.1983, at 12:00 [12:00 a.m.], 1 ♀; Veneto, Adige River, from the Romea road to the mouth, 27.vii.1983, at 19:00 [07:00 p.m.], 1 ♀.
The sites where this species was found are two close places on the maritime coast of southern Veneto and eastern Emilia Romagna, both bordering on the Po River delta, to the north and to the south respectively. Based on a single male specimen, C. collini was previously recorded from Sardinia (Dorgali region, Cala Luna, south of Cala Gonone) by Roháček (2006). Therefore, the localities reported in the present work represent the first records of this rare species from peninsular Italy.
The specimens examined here show three obvious, large, ochreous spots on the shiny brown scutum, the mid one (between the anterior dorsocentral setae) is rather large, roundish, the other two spots are arranged laterad. Roháček (2006) states that most of mesonotum in this species is brown to blackish brown or scutum shows lateral subtriangular spots around suture or also with a pair of small oval ochreous spots between the anterior dorsocentral setae. Other morphological and chromatic characters perfectly match the description given in Roháček (2006).
I wish to express my gratitude to Dr. Jindřich Roháček (Slezské zemské mu-seum, Opava, Czech Republic) for useful information about possible recent distributional records for the species dealt with in the present note.
Roháček, J. (2006) – A monograph of Palaearctic Anthomyzidae (Diptera), Part 1. Časopis Slezského zemského Muzea, Opava (A) 55, supplement 1: 1-328.
Roháček, J. (2009) – A monograph of Palaearctic Anthomyzidae (Diptera), Part 2. Časopis Slezského zemského Muzea, Opava (A) 58, supplement 1: 1-180.