Gymnometriocnemus (Raphidocladius) autumnalis, Stur, Elisabeth & Ekrem, Torbjorn, 2015

Stur, Elisabeth & Ekrem, Torbjorn, 2015, A review of Norwegian Gymnometriocnemus (Diptera, Chironomidae) including the description of two new species and a new name for Gymnometriocnemusvolitans (Goetghebuer) sensu Brundin, ZooKeys 508, pp. 127-142 : 133

Taxon classification Animalia Diptera Chironomidae

Gymnometriocnemus (Raphidocladius) autumnalis sp. n. Figs 4D, 5D

Type material.

Holotype: Male adult (NTNU-VM slide no. 136299), Norway, Finnmark, Porsanger, small pond near Gaggavann, 69.8306°N; 25.1856°E, 107 m a.s.l., 03.ix.2010, leg. Alyssa Anderson [BOLD ID: Finnmark201]. 3 Paratypes, male adults: 1 Norway, Finnmark, Vardø, Nedre Domen, lake and pond at road E75, 70.3215°N; 31.0341°E, 120 m a.s.l., 05.ix.2010, leg. Alyssa Anderson; 1 Norway, Finnmark, Nordkapp, Nordkapp-Plateau, 71.1446°N; 25.7641°E, 220 m a.s.l., 01-ix-2010, leg. Trond Andersen; 1 Norway, Oppland, Dovre, Rondane National Park, Vidjedalsbekken (upper), Malaise trap, 61.9717°N; 9.83606°E, 1280 m a.s.l., 15.ix.2008, leg. Terje Hoffstad.

Etymology.

The species is named “autumnalis”, Latin adjective meaning belonging to autumn, referring to the time of the year when the type material was collected.

Diagnosis.

Gymnometriocnemus (Raphidocladius) autumnalis can be separated from other Gymnometriocnemus species by the following combination of characters in the adult male: body brown, dark brown; virga long and conspicuous with strong lateral sclerotization, anal tergite without dorsal anal point or ridge, gonostylus with convex outer margin and well-defined median crista dorsalis.

Description.

Male adult (n = 4 unless otherwise stated). Wing length 1.30-1.52, 1.43 mm. Colouration completely brown, dark brown except for pale transverse bands posteriorly on abdominal tergites V–VIII, narrower on tergite V.

Head. Antennal ratio in Table 1. Temporal setae 8-10, 9; palp lengths (in µm): 25/35/80-90/75-90/105-125.

Thorax. Antepronotum with 2 setae. Dorsocentrals 10-11; acrostichals 8-9, minute and difficult to discern; prealars 4-6; scutellars 2-5.

Wing (Fig. 5D). Costa moderately extended, not reaching half way to apex of M1+2; R2+3 approaching costa at ½ distance between R1 and R4+5. Macrotrichia frequent on membrane in apical 1/3 of wing, absent from cell m, few (0-6) in cells cu+an. Veins Sc, R2+3, M, Cu, PCu and pseudovein without setae.

Legs. Fore tibia with one spur, 40 µm long; mid tibia with two spurs ca. 20 µm long; hind tibia with well-developed comb and 2 spines, ca. 50 µm long. Fore leg ratios in Table 1.

Hypopygium (Fig. 4D). Ninth tergite with 16-19, 18 setae, without anal point or ridge. Virga 110-120, 115 µm long consisting of two spines, with strong lateral sclerotization. Inferior volsella well-developed lobe; gonostylus with slightly convex outer margin and well-defined median crista dorsalis.

Female and immature stages unknown.

Remarks.

The species is morphologically similar to Gymnometriocnemus (Raphidocladius) brumalis and Gymnometriocnemus (Raphidocladius) kamimegavirgus , but different in lacking an anal point or ridge on the anal tergite. This character is similar to characters reported for Gymnometriocnemus terrestris and Gymnometriocnemus tairaprimus , but these two species can according to original descriptions be separated by having a higher AR (1.4 in Gymnometriocnemus terrestris ) and a different shape of the superior volsella ( Krüger and Thienemann 1941; Sasa and Okasawa 1994). The virga of Gymnometriocnemus terrestris has not been described, but the species is listed as a member of subgenus Gymnometriocnemus in the World Catalogue of Chironomidae ( Ashe and O’Connor 2012). We have examined two males and one female between cellophane strips on two separate pins from the Goetghebuer collection; labels reading "Allemagne, Dr Thienemann, Bonn 1939". Only one pin with a female bears a type label, but all specimens are likely part of the type series and regarded as syntypes. A small virga is visible in a rather well mounted and cleared hypopygium on one of the specimens. We can confirm placement in subgenus Gymnometriocnemus and that none of the specimens we have collected in Norway belong to this species. Gymnometriocnemus (Raphidocladius) autumnalis has so far only been recorded from the very north of mainland Norway and the Rondane mountains (1280 m a.s.l.) in Central Norway.