Euxoa muldersi Lafontaine & Hensel, 2010

Lafontaine, Donald & Troubridge, James, 2010, Two new species of the Euxoa westermanni species-group from Canada (Lepidoptera, Noctuidae, Noctuinae), ZooKeys 39 (39), pp. 255-262 : 257-259

Euxoa muldersi Lafontaine & Hensel , sp. n.

urn:lsid:zoobank.org:act:13A91C23-B4CC-426C-B961-9E0066029FD8

Figs 1–4, 19, 24

Type material. Holotype ♁: Canada, Nunavut: Austin Island, Maguse Point , 29 km N of Arviat, 12 July 1996, H. Hensel & R. Mulders [ CNC] . Paratypes 38♁, 13♀: same locality as for holotype ; 26 July 1992, R. Mulders; 12, 16 July 1996, H. Hensel & R. Mulders; 18 July 1996, H. Hensel; 7, 8 July 1998, H. Hensel; 17 July 2000, H. Hensel; vicinity of Arviat , 11, 12 July 1998, H. Hensel ; 18–27 July 2000, H. Hensel; 16–22 July 2002, H. Hensel. BMNH, CNC, HHC, JTTC, USNM, and personal collection Hartmut Rietz, Hamburg, Germany .

Other material examined. Canada. Canada, Northwest Territories, Ford Lake, 63°11'N 107°19 W, 25 June 1966, G. E. Shewell (2♁).

Etymology. The species is named for Robert Mulders, a biologist at Arviat who collected the first specimen and brought it to the attention of Henry Hensel.

Diagnosis. In the key to species of the Euxoa westermanni species-group in Lafontaine (1987) E. muldersi keys out to Euxoa churchillensis McDunnough. It differs from E. churchillensis (Figs 5–7, 20, 25) in larger size (forewing length 13–15 mm versus 10–13 mm in E. churchillensis ), more blurry forewing pattern usually with brown shading, basally paler more mottled hindwing, reduced, vestigial frontal tubercle, shorter, stouter saccular extension and straight sub-basal diverticulum (curved in E. churchillensis ) in the male genitalia (compare Figs 19 and 20). In females, the anal papillae are broad and more rounded compared to bullet-shaped in E. churchillensis .

Description. Adult: Head – Frontal tubercle vertically elongated but small, low, only slightly raised from frons; male antenna slightly biserrate, about 1.3 × as wide as shaft; eye reduced, ellipsoid, with sparse surface hair; vestiture of head and thorax a highly variable mixture of buff, brown, and black hair-like and strap-like scales, usually covering frontal tubercle. Thorax – Legs: tibia with spiniform setae typical for Euxoa . Wings (both sexes); most common form (Fig. 1 [80% of specimens]) ground color a variable mixture of pale-gray, brown, and black scales, usually with darker colors predominating in medial area; basal dash and antemedial and postmedial lines black but diffuse and appearing blurry; terminal area dark gray to black with diffused streaks extending into subterminal area; reniform and orbicular pale gray, sometimes with

Figures Ι–Ι8. Euxoa adults. Ι–4 E. muldersi , Ι ♁ holotype 2 ♁ paratype, Maguse Point, Austin Island, 29 km N of Arviat, Nunavut, Canada 3 ♀ 4 ♀ paratypes, Maguse Point, Austin Island, 29 km N of Arviat, Nunavut, Canada; 5–7 E. churchillensis , 5 ♁ 6 ♀ 7 ♀, Arviat, Nunavut, Canada; 8,‹ E. apopsis , 8 ♀ paratype, Mt. McLean, British Columbia, Canada 9 ♁ holotype, Gott Peak, 7100’, British Columbia, Canada; Ι0–Ι2 ♁ E. macleani, Gott Peak , 7100’, British Columbia, Canada; Ι3–Ι8 E. chimoensis , Ι 3 ♀, Schefferville, Labrador, Canada Ι 4 ♀, Post-de-la-Baleine, Quebec, Canada Ι5 ♁, L’Anse au Loup, Labrador, Canada Ι6 ♁ Ι 7 ♀ Ι8 ♁, Northern Study Centre, 24 km E Churchill, Manitoba, Canada.

darker outline and darker central spot; paler form (Fig. 2 [10% of specimens]) with less brown shading and less mottling of ground color; dark shading in reniform spot filling most of spot; pale form (Figs 3, 4 [10% of specimens]) mainly pale gray with blurry dark-gray transverse lines and reniform spot. Hindwing dirty white mottled with fuscous shading, especially on outer half of wing, postmedial line, and discal spot; fringe white. Male genitalia – Similar to those of E. churchillensis in most details except saccular extension shorter and slightly stouter (0.54–0.58 × as long as ampulla of clasper (harpe) versus 0.60–0.68 × as long in E. churchillensis ); subbasal diverticulum in vesica straight (curved in E. churchillensis ). Female genitalia – Similar to those of E. churchillensis but anal papillae broad and more rounded in lateral view (bullet shaped in E. churchillensis ).

Distribution and biology. Euxoa muldersi is known only from north central Canada with all specimens except two from the vicinity of Arviat, Nunavut. The species must use a similar pheromone to E. churchillensis because H. Hensel observed males of E. churchillensis being attracted to calling E. muldersi females, although no attempts at mating were observed. It is restricted to open dunes where it flies close to the sand. The reduced frontal tubercle is typical of Euxoa species that inhabit dunes.