Sciadia tenebraria
Creators: name: Huemer, Peter
name: Hausmann, Axel
Publisher: name: Zenodo
Year: 2009
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Lepidoptera
Geometridae
Sciadia
Sciadia tenebraria

description: Sciadia tenebraria species group
Diagnosis. Sciadia tenebraria and related taxa are easily recognized and separated from species of the genus Psodos, for example, by the large wingspan, pectinate antennae of the male, and the usually developed light fasciae on the underside of the wings. Closely related species of Elophos are light-coloured and head and labial palpi are less hairy. The female genitalia of the S. tenebraria group differ from those of Psodos and Elophos particularly by the prominent antrum, but comparative morphological studies are largely missing. Both genitalia characters and external appearance show some individual and somewhat clinal geographical variation.
Description. Adult (Figs. 1 –32). Head and labial palpi remarkably hairy; head, thorax, tegulae, abdomen, legs and antennae dark brown to greyish-brown, rarely lighter; antennae pectinate (ɗ), or filiform (Ψ). Wingspan ɗ 22–31 mm, Ψ 22–29 mm; apex of forewing pointed in ɗ, rounded or rarely pointed in Ψ; ground colour of wings dark brown to shiny greyish-brown, fringes normally concolorous with ground colour. Forewing upper side with broad and comparatively dark medial fascia, widened towards costa, edged by darker and serrated, usually light edged postmedial and antemedial lines, postmedial line inwardly angled towards costa; subterminal fascia of underside sometimes showing through; discal spot usually well developed, dark brown with light centre, rarely reduced. Hindwing upper side with medial area edged by serrated and usually pale postmedial line; subterminal fascia of underside sometimes showing through; discal spot small, frequently much reduced. Forewing underside without gloss; subterminal transverse fascia whitish to yellowish, ranging from narrow and contrasting line to ill-defined broader fascia, or almost obsolete, moderately to strongly curved inwards at costa; proximal and costal area frequently mottled with whitishyellow scales, particularly in Ψ; costa without or more rarely with whitish-yellow patch. Hindwing underside without gloss; subterminal transverse fascia whitish to yellowish, ranging from narrow and contrasting line to ill-defined broader fascia, rarely obsolete; proximal area occasionally weakly mottled with light scales. Male genitalia (Figs. 33–40). Uncus subtriangular, apically slightly rounded; gnathos reduced, small lateral sclerites present; tegumen well developed, smooth, anterior part with short to rather prominent and stout saccus; valva broad at base, distal part narrow, costa strongly sclerotized with few strong setae and occasionally with small hump; juxta with pair of moderately to extremely long and digitate ventral lobes and short horn-shaped dorsal lobes; distal part of phallus with pointed sclerotized wall laterally, vesica armed with number of slender and spine-like cornuti grouped together and with or without an additional cornutus ranging from small dentate plate to large horn-shaped spine. Female genitalia (Figs. 41–48). Papillae anales broadly rounded, densely covered with setae; apophyses posteriores moderately long and thin; apophyses anteriores shorter; seventh sternite weakly sclerotized, anteriodorsal margin straight; antrum heavily sclerotized ventrally and broadly funnel-shaped, smooth, with posterior margin emarginated ventromedially, with or without specialized lateral sclerotization; corpus bursae subovate, membranous and distinctly wrinkled to heavily sclerotized and largely wrinkle-free posterior part, corpus bursae frequently recurved posteriorly and overlapping anterior part of antrum; ductus seminalis inserted posterioventrally on corpus bursae; spiny signum in anterior part of corpus bursae present or reduced.
Ecology. Species of the S. tenebraria species group are restricted to rocky habitats and alpine scree above the timber-line with sparse vegetation, both on calcareous and siliceous soil. However, limestone habitats are exclusive for species such as S. slovenica and S. dolomitica sp. nov. Rarely adults are found in open alpine grassland. The occurrence normally ranges from about 2000 m to 3300 m, only exceptionally at lower or higher altitudes. Towards the northern part of the range the habitats are at lower altitudes than in the south. All taxa are diurnal, flying exclusively in sunshine. The flight of the males is hasty, whereas the slightly shorterwinged females only fly short distances. Frequently adults can be observed feeding on cushion plants, especially Silene acaulis L. (Caryophyllaceae). The flight period lasts from early July to early September. According to Vorbrodt and Müller-Rutz (1914) and other authors the larva lives under stones from where it feeds on a variety of herbs such as Saxifraga caesia L. (Saxifragaceae), S. oppositifolia L. (Saxifragaceae), Silene acaulis L., (Caryophyllaceae), Ranunculus glacialis L. (Ranunculaceae), and also on cryptogams. Probably the larval period lasts over at least two seasons. However, all these data need verification according to our revised taxonomic conception.
Distribution (Maps 1–2). Restricted to European mountain systems: Alps, Pyrenees, and the southern Dinaric Alps. Records from the Apennines are erroneous (Parenzan and Porcelli 2006). The area of distribution of most of the species does not overlap, but in the eastern Alps S. tenebraria and S. innuptaria occasionally occur sympatrically.
MAP 1. The distribution of the Sciadia tenebraria species group in Europe.
description: Published as part of Huemer, Peter & Hausmann, Axel, 2009, A new expanded revision of the European high mountain Sciadia tenebraria species group (Lepidoptera: Geometridae), pp. 1-30 in Zootaxa 2117 on pages 4-5, DOI: 10.5281/zenodo.188004