Allotrichoma (Allotrichoma) bifurcatum, Mathis, Wayne N. & Zatwarnicki, Tadeusz, 2012

Mathis, Wayne N. & Zatwarnicki, Tadeusz, 2012, Revision of New World Species of the Shore-fly Subgenus Allotrichoma Becker of the Genus Allotrichoma with Description of the Subgenus Neotrichoma (Diptera, Ephydridae, Hecamedini), ZooKeys 161, pp. 1-101 : 27-30

Allotrichoma (Allotrichoma) bifurcatum sp. n. Figs 914

Description.

This species is distinguished from congeners by the following combination of characters: Small shore flies, body length 1.35-1.85 mm. Head: Medial facial carina above facial prominence shallow; labella broad, fleshy, shorter than mediproboscis; clypeus microtomentose, usually gray.

Thorax: Presutural supra-alar seta present. Wing with costal vein ratio 0.27-0.29; M vein ratio 0.47-0.50.

Abdomen: Male 5th sternal flap in lateral view (Fig. 12) much longer than wide, truncate apically, bearing numerous, apical setae; 5th medial process in lateral view (Fig. 12) elongate, bar-like, bearing 4-5 apical setulae. Male terminalia (Figs 9-11, 13): Epandrium in posterior view (Fig. 9) like an inverted U with short, apical medial flanges ventrally; epandrium in lateral view (Fig. 10) simple, bar-like, height more than twice width; cercus in posterior view (Fig. 9) pointed, nipple-like dorsally, first gradually broadened ventrally then rather abruptly curved laterally than medioventrally, generally gradually tapered, although medioventral portion almost parallel sided, dorsal and lateral portion bearing numerous setulae, most of medioventral portion bare except for 3 setulae at apex; cercus in lateral view (Fig. 10) very shallowly curved anteriorly, wider dorsally, ventral half slightly tapered, nearly parallel sided, apex not abruptly broadened and bearing 3 setulae, these setulae about same length as setulae on dorsal portions; surstylus a ventral extension from ventral margin of epandrium, becoming slightly wider apically and bifurcate, anterior process bearing several setulae anteriorly, posterior process bearing a single setula; aedeagus in ventral view (Fig. 11) elongate, narrowly ovate, slightly tapered apically, in lateral view (Fig. 13) elongate, nearly straight; phallapodeme in lateral view (Fig. 13) triangular, keel shorter than length, pointed; gonite in ventral view (Fig. 11) somewhat bar-like, lateral margins sinuous, wider basally, apex with a short, nipple-like process medially that bears a single, short setula, also a subapical, setula; gonite in lateral view (Fig. 13) wide basally, shallowly C-curved apically, tapered to apical point, with a subapical, nipple-like process, and apical portion narrow, elongate.

Type material.

The holotype male is labeled "USA. UTAH. Utah: Lake Shore (40°06.9'N, 111°41.8'W; 1370 m), 11 May 2007, D.&W.N.Mathis/HOLOTYPE ♂ Allotrichoma bifurcatum W. Mathis & T. Zatwarnicki USNM [red]/USNM ENT 00117956 [plastic bar code label]." The holotype is double mounted (minuten in a block of plastic elastomer), is in excellent condition, and is deposited in the USNM. Eighteen male paratypes bear the same locality label data as the holotype. Other paratypes are as follows: UTAH. Salt Lake: Butterfield Canyon (40°29.2'N, 112°08.2'W; 1890 m), 14 May-13 Aug 2007, 2008, D. and W. N. Mathis (8♂, 1♀; USNM). Utah: Thistle (40°0.4'N, 111°29.7'W; 1530 m), 11 May 2007, D. and W. N. Mathis (7♂, 2♀; USNM).

Type locality.

United States. Utah. Utah: Lake Shore (40°06.9'N, 111°41.8'W; 1370 m).

Other specimens examined from the New World.

CANADA. BRITISH COLUMBIA. Wasa Lake (49°47.6'N, 115°44.3'W), 17 Jul 1974, P. H. Arnaud, Jr. (1♂, 3♀; CAS).

UNITED STATES. IDAHO. Boundary: Dawson Lake (48°46.3'N, 116°14.3'W; 885 m), 3 Jun 2006, D. and W. N. Mathis, T. Zatwarnicki (2♂, 1♀; USNM); Solomon Lake (48°47.6'N, 116°06.1'W; 825 m), 3 Jun 2006, W. N. Mathis, T. Zatwarnicki (3♂; TZ, USNM). Latah: Bear Creek (46°37.8'N, 116°32'W), 28 Aug 1990, R. S. Zack (1♂; WSU); Big Meadow Creek (46°44'N, 116°45.5'W), 31 Jul 1979, R. S. Zack (5♂; WSU); Helmer (1.6 km W; Little Boulder Creek; 46°48'N, 116°29'W), 28 Aug 1990, R. S. Zack (1♂; WSU); Moscow (9.5 km N, 46°45'N, 117°W), 22 May 1971, W. J. Turner (1♂; WSU). Nez Perce: Lake Waha (46°12.4'N, 116°50.1'W), 9 Jun 1918, A. L. Melander (1♂; USNM).

OREGON. Baker: Goose Creek (35 km E Baker City; 44°49.2'N, 117°27.79'W; 825 m), 7 Jun 2006, D. and W. N. Mathis, T. Zatwarnicki (3♂; TZ, USNM); Lower Goose Creek (44°49.2'N, 117°27.79'W; 1220 m), 25 Jul 1976, E. J. Davis (1♂; WSU). Deschutes: Tumalo Reservoir (44°08.4'N, 121°24.9'W), 23 Jun 1954, G. F. Knowlton (1♂; KU).

UTAH. Cache: Hyde Park (41°47.9'N, 111°49.1'W), 4 Jul 1935, G. F. Knowlton (1♂; KU); Wellsville Canyon (41°36.2'N, 111°56.7'W), 28 Jun 1954, G. F. Knowlton (1♂; KU). Carbon: Deadman Canyon (16 km NE Price; 39°41.7'N, 110°44'W; 2055 m), 14 Aug 2008, D. and W. N. Mathis (1♂; USNM). Salt Lake: Butterfield Canyon (40°29.2'N, 112°08.2'W; 1890 m), 14 May– 13 Aug 2007, 2008, D. and W. N. Mathis (7♂, 1♀; USNM); Draper (40°31.6'N, 111°55.1'W; Jordan River; 1320 m), 10 May 2007, D. and W. N. Mathis (2♂; USNM). Utah: Lake Shore (40°06.9'N, 111°41.8'W; 1370 m), 11 May 2007, D. and W. N. Mathis (19♂; USNM); Provo Canyon, Sundance (40°23.1'N, 111°34.9'W), 20 Jul 2001, I. Winkler (1♂; BYU); Thistle (40°0.4'N, 111°29.7'W; 1530 m), 11 May 2007, D. and W. N. Mathis (7♂, 2♀; USNM).

WASHINGTON. Columbia: Dayton, Curl Lake, Tucannon River (46°15.2'N, 117°40.3'W), 17 Jul 2009, D. Mathis (1♂, 1♀; USNM). Okanogan: Little Goose Lake (48°16.5'N, 119°31'W), 22 Jul 1983, R. D. Akre, R. S. Zack (1♂; WSU).

Distribution.

(Fig. 14) Nearctic : Canada (British Columbia), United States (Idaho, Oregon, Utah, Washington).

Etymology.

The species epithet, bifurcatum, is of Latin derivation and refers to the bifurcate apex of the surstylus of this species.

Remarks.

The distribution of this species is somewhat related to the Great Basin in western North America, where current climatic conditions are semiarid, although there is a northern extension into northern Idaho and British Columbia. Better sampling may reveal this species to be more widespread.