Delia rimiventris Michelsen, sp. nov.
Creators: name: Michelsen, Verner
Publisher: name: Zenodo
Year: 2007
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Diptera
Anthomyiidae
Delia
Delia rimiventris

description: Delia rimiventris Michelsen, sp. nov.
Figs. 1–3, 4, 6–9.
Etymology. The specific epithet ‘ rimiventris ’ is an adjectival form derived from the Latin ‘ rima ’ (crevice) and ‘ venter ’ (belly) and refers to the split male sternites III and IV.
Material examined. Type material. Holotype male, NORWAY: Oppland, northern: Vinstra, 19– 29.vii.1983 (O. Karsholt & V. Michelsen), ZMUC. Paratypes: NORWAY: Same data as for holotype, 11 males, 16 females, ZMUC.
Additional material. NORWAY: Vest-Agder, outer: Flekkefjord, Hidra, Kråkedal, 1 male in Malaise trap 4.viii.1981 (A.J. Nilsen), ZMBU. FINLAND: Regio aboensis: Naantali, 1 male 22.vii.1945 (L. Tiensuu), FMNH; Karelia australis: Vehkalahti, 1 male 27.vii.1974 (L. Tiensuu), FMNH.
Description. This species closely resembles the common and widespread Delia nuda, for which detailed general descriptions are given by Hennig (1974b) and Griffiths (1991a), except for the notably different male sexual characters described below. The following differential description will help to distinguish D. rimiventris from D. nuda in both sexes:
Male. Prealar seta nearly as long as to slightly longer than p notopleural seta vs. slightly to distinctly shorter than p notopleural seta. Proepimerals 1–2 setae and 0–2 setulae vs. 2 setae and 2–5 setulae. Fore tibia without apical pv seta vs. with a short apical pv seta. Mid femur without subapical a seta vs. with subapical a seta. Tergite III on ventro-flexed lateral hind margins with some long setae reaching beyond sternite V (Fig. 3) vs. without such long setae. Sternite III divided into a pair of lobes with tufts of long postero-lateral setae (Fig. 4) vs. undivided, with dense, erect setulae on posterior part. Sternite IV broader than sternite V, split along midline and sparsely setated (Fig. 4) vs. normally wide, entire and less sparsely setated laterally. Surstyli markedly asymmetrical, distally strongly flexed backwards (Figs. 6–7) vs. slightly asymmetrical and barely flexed backwards apically. Gonites (Fig. 8) and phallus (Fig. 9) similar in both species.
Female. Prealar seta nearly as long as to slightly longer than p notopleural seta vs. slightly to distinctly shorter than p notopleural seta. Proepimerals 1–2 setae and 0–2 setulae vs. 2 setae and 2–5 setulae. Lower p katepisternal seta nearly as long as upper p katepisternal seta vs. much shorter and weaker. Vein C bare on v surface between humeral and subcostal breaks vs. with series of setulae more or less ventrally displaced from av row of alternating spinules-setulae.
Distribution and biology. Known so far only from a few localities in southern Norway and southern Finland. The Norwegian type locality where Delia rimiventris was found in numbers is situated 3km SE of Vinstra village in the upper part of Gudbrandsdalen valley. It is a south facing scree of debris formed at the foot of a cliff of calcareous slate (see Karsholt et al. 1986 for further details) with a strikingly continental and summer-warm local climate compared to the surrounding valley. This is reflected by the occurrence of several notably southern species of plants and insects. The larval host plant of Delia rimiventris is unknown but should be sought among the larger Caryophyllaceae, notably Silene spp., growing at Vinstra.
description: Published as part of Michelsen, Verner, 2007, Two new European species of Delia Robineau-Desvoidy (Diptera: Anthomyiidae) with a bipartite male sternite III, pp. 51-57 in Zootaxa 1469 on pages 53-54, DOI: 10.5281/zenodo.273742