Allotrichoma (Allotrichoma) dynatum, 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 : 33-35

Allotrichoma (Allotrichoma) dynatum sp. n. Figs 2126

Allotrichoma laterale of authors, not Loew 1860 [misidentification]. Becker 1896: 121 [generic combination]. Williston 1897: 4 [compared with Allotrichoma abdominale Williston]. Cresson 1942: 108 [list, west coast of United States]. Wirth and Stone 1956: 467 [key]. Wirth 1965: 736 [Nearctic catalog, in part]. Cole 1969: 397 [list]. Mathis and Zatwarnicki 1995: 151-152 [world catalog, in part].

Description.

This species is distinguished from congeners by the following combination of characters: Small to moderately small shore flies, body length 1.40-2.00 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 0.35-0.36; M vein ratio 0.47-0.52.

Abdomen: Male 5th sternal flap in lateral view (Fig. 25) relatively shallow but long, bearing 6-8, tuberculate setae; 5th medial process in lateral view (Fig. 25) robust, greatly enlarged basally, with a posterior projection, broadly pointed apically, bear row of setulae anteroapically. Male terminalia (Figs 21-24): Epandrium in posterior view (Fig. 21) ovately rounded on dorsal half, wider than high; epandrium in lateral view (Fig. 22) with anterior and posterior margins of dorsal half nearly straight and parallel sided; cercus robust, thick, in posterior view (Fig. 21) pointed dorsally, gradually broadened ventrally then rather abruptly curved laterally and ventrally as a slightly tapered, elongate process that bears numerous long setulae apically and along posterior margin; cercus in lateral view (Fig. 22) slightly curved, wider dorsally, ventral half nearly parallel sided, apex broadened and bearing setulae; surstyli in posterior view as parallel, narrow, elongate processes that bear setulae on apical portion, apex narrowly rounded; surstylus in lateral view shallowly curved, basal half slightly tapered, apical half almost parallel sided, apical portion bearing short setulae, apex tapered to narrow point; aedeagus in ventral view (Fig. 23) elongate, moderately narrowly ovate, tapered apically, in lateral view (Fig. 24) narrowly elongate, somewhat lunate; phallapodeme in lateral view (Fig. 24) very narrowly triangular, digitiform keel shorter than length, pointed; gonite in ventral view (Fig. 23) bar-like, very slightly wider basally, apex with short, lateral process, apex bearing setula, in lateral view (Fig. 24) wide basally, gently curved, tapered to apical point, with a subapical, short process that bears a setula.

Type material.

The holotype male is labeled "OREGON BentonCo Finley WildlRefg 18 June 1976 Wayne N. Mathis/HOLOTYPE ♂ Allotrichoma dynatum W. Mathis & T. Zatwarnicki USNM [red]/USNM ENT 00117957 [plastic bar code label]." The holotype is double mounted (minuten in a block of plastic), is in excellent condition, and is deposited in the USNM. Fifty paratypes (27♂, 23♀; USNM) bear the same locality data as the holotype but with collection dates from 3 Jul 1972 to 18 Jun 1976.

Type locality.

United States. Oregon. Benton: Finley National Wildlife Refuge (44°24.6'N, 123°19.5'W).

Other specimens examined from the New World.

CANADA. BRITISH COLUMBIA. Revelstoke, Murphys Ranch (50°58'N, 118°48'W), 1 Jul 1968, W. W. Wirth (1♂; USNM). Savona (50°45.2'N, 120°50.6'W), 19 Jul 1988, R. Danielsson (1♂; ZIL).

UNITED STATES. OREGON. Benton: Cary's Grove (44°22.6'N, 123°36.1'W), 2 Sep 1974, W. N. Mathis (2♂, 1♀; USNM); Corvallis (44°33.9'N, 123°15.7'W), 15 Jul 1972, W. N. Mathis (1♂; USNM); McDonald Forest, Oak Creek (44°33.3'N, 123°16.7'W), 30 Jun 1971, G. C. Steyskal (1♂; USNM); Rock Creek (6.4 km SW Philomath; 44°30.1'N, 123°26.2'W), 29 May 1972, W. N. Mathis (1♂; USNM). Douglas: North Umpqua River (42°43.2'N, 122°60'W; 250 m), 31 Jul 2005, D. and W. N. Mathis (1♂; USNM). Josephine: Grants Pass (42°26.3'N, 123°19.7'W), 4 Aug 1952, H. A. Scullen (1♂; OSU). Linn: Waterloo (44°29.6'N, 122°49.5'W), 24 Jul 1974, W. N. Mathis (3♂; USNM).

WASHINGTON. Clallam: Sequim (48°04.8'N, 123°06.1'W), 2 Aug 1951 (1♂; USNM). Pacific: Ocean Park (46°29.5'N, 124°03'W), 22 Aug 1957, M. T. James (1♂; USNM).

Distribution.

(Fig. 26) Nearctic: Canada (British Columbia), United States (Oregon, Washington).

Etymology.

The species epithet, dynatum, is derived from the Greek work dynamis, meaning strong or powerful, alluding to the well-developed cerci of this species.

Remarks.

In the Nearctic Region, this is a western species that has been collected west of the Sierra/Cascade cordillera in the states of Oregon and Washington and in the province of British Columbia.