Lypoglossa angularis

1. Lypoglossa angularis (Mäklin in Mannerheim, 1853)

(Figs. 1–12, 15, 17, 25–50)

Myrmedonia angularis Mäklin in Mannerheim, 1853: 181.

Euryusa obtusa LeConte, 1866: 373, syn. nov.

Dasyglossa angularis: Bernhauer, 1906: 348 (as synonym of Dasyglossa prospera (Erichson, 1839)).

Dasyglossa fenyesi Bernhauer, 1907: 402.

Lypoglossa fenyesi: Fenyes, 1920: 239 (as valid species).

Dasyglossa angularis: Fenyes, 1920: 359 (as synonym of Dasyglossa prospera (Erichson, 1839)).

Lypoglossa fenyesi: Bernhauer & Scheerpeltz, 1926: 597 (as valid species).

Dasyglossa angularis: Bernhauer & Scheerpeltz, 1926: 766 (as synonym of Dasyglossa prospera (Erichson, 1839)).

Lypoglossa fenyesi: Moore & Legner, 1975: 448 (as valid species).

Devia angularis: Moore & Legner, 1975: 396 (as synonym of Devia prospera (Erichson, 1839)).

Lypoglossa fenyesi: Seevers, 1978: 271 (as valid species).

Lypoglossa angularis: Lohse & Smetana, 1985: 293 (as valid species).

Lypoglossa angularis: Hoebeke,1992: 390, ex parte (as valid species).

Lypoglossa fenyesi: Hoebeke, 1992: 391 (as synonym of L. angularis)

Examined material. Listed separately for each subspecies except for the following female specimens unassigned to subspecies: UNITED STATES: Oregon: Deschutes Co.: Ψ, 12 mi. SW Sisters, FSR 1551, 4400', 23.vii.1979 (J.M.Campbell & B.A.Smetana) (CNCI); California: El Dorado Co.: Ψ, Lake Tahoe, Cascade Lake, 6300', 11.viii.1969 (A.Smetana) (CNCI).

Diagnosis. Lypoglossa angularis differs from the Palaearctic L. lateralis in the following characters: pronotum and elytra lighter than head and abdomen; punctation of head and pronotum not asperate, and a distinct shape of the aedeagus (Figs. 25–30; 72–77) and spermatheca (Figs. 32; 78).

Lypoglossa angularis differs from L. franclemonti in having a more transverse pronotum, less elongate antennal articles; the apex of the median lobe (in parameral view) constricted basally (Figs. 25–27, 33–35; 64–65), with a dentiform projection on each side of the apex base (Figs. 25–29; 64–67); the proximal loop of the spermatheca narrower, with parallel sides (Figs. 32, 40; 70).

Lypoglossa angularis can be distinguished from L. manitobae in having a larger body size, and longer and sharper dentiform projections at the base of the apex of median lobe (Figs. 25–29; 55–59).

Description. Length 3.9–4.4 mm. Head and abdomen dark brown; pronotum lighter, brownish red to brown with lighter margins; elytra brownish yellow to brown, with darker scutellar area and posterolateral angle; legs, mouthparts and 3 basal antennal articles brownish yellow, antennal articles 4–11 darker, reddish brown.

Head surface glossy, with weak isodiametric microsculpture, with strong punctation, distance between punctures equals 1–2 times their diameter. Eyes 1.1–1.4 times as long as temples. Antennal articles 4–5 elongate, 6 slightly elongate or subquadrate, 7–10 subquadrate or slightly transverse (Fig. 12).

Pronotum transverse, 1.5 times as wide as head, width 0.91–1.04 mm, length 0.64– 0.74 mm, width to length ratio 1.4; surface glossy, with weak isodiametric microsculpture; punctation finer than on head, distance between punctures equal to their diameter. Elytra wider (1.00– 1.17 mm) and longer (0.71–0.86 mm; measured from humeral angle) than pronotum (elytral length to pronotal length ratio 1.1), 1.3–1.4 times as wide as long, surface glossy, with weak isodiametric microsculpture; punctation slightly asperate and stronger than on pronotum, distance between punctures equals ½–1 times their diameter.

Abdominal terga with very fine (poorly visible at 70x) microsculpture consisting of transverse waves; terga 3–5 matte due to fine and dense punctation, distance between punctures equals 1–2 times their diameter, terga 6–7 glossy, with sparser punctation, distance between punctures equals 2–5 times their diameter.

In males, head with weak medial impression and pronotum with broad impression along midline.

Aedeagus as in Figs. 25–31, 33–39, 41–47.

Spermatheca as in Figs. 32, 40, 48.

Distribution. Lypoglossa angularis is widely distributed in the western North America, from Alaska, Yukon Territory and British Columbia in the north to the high mountains of California, Colorado, New Mexico and Arizona in the south. There is an isolated population of this species in the northeastern states and provinces (Newfoundland, Quebec, Maine and New Hampshire) (Fig. 18). In Alaska L. angularis is continuously distributed and along the coast occurs at sea level. In interior British Columbia and Alberta and further south Lypoglossa angularis is restricted to boreal forests in high mountains and does not occur in valleys. Further south the localities are at higher elevations in the mountains. Despite the fact that in the interior United States the recorded distributions of L. lateralis consists of isolated populations, I could find no gaps in any morphological characters between the specimens from different isolates. Apparently the isolation between these populations is recent and L. angularis probably had a continuous distribution in the interior United States during colder and/or wetter periods of the Pleistocene.

I recognize three valid subspecies within L. angularis (Fig. 18). The main reason for interpreting the three geographic varieties as subspecies is that there is no distinct hiatus between them and intermediate forms are occasionally found. The subspecies are para­ or allopatric in their distribution. The differences between these subspecies are discussed below.

Natural History. Lypoglossa angularis is common in forest litter and moss in boreal forests. It was also collected in dung, gopher burrows and by pitfall traps.