Hydrochasma annae, Mathis, Wayne N. & Zatwarnicki, Tadeusz, 2013

Mathis, Wayne N. & Zatwarnicki, Tadeusz, 2013, A revision of the shore-fly genus Hydrochasma Hendel (Diptera, Ephydridae), ZooKeys 363, pp. 1-161 : 73-76

25. Hydrochasma annae sp. n. Figs 137-141

Diagnosis.

This species is distinguished from congeners by the following combination of characters: Small to moderately small shore flies, body length 1.75-2.20 mm. Head: Antenna mostly dark gray; parafacial silvery white, concolorous with facial coloration. Gena moderately high, height usually slightly higher than length of basal flagellomere; gena-to-eye ratio 0.24-0.26. Thorax: Wing hyaline with costal vein ratio 0.75-0.76; M vein ratio 0.51-0.53. Forecoxa gray to silvery gray; hindtibia with only pale, yellowish setae ventroapically. Abdomen: Tergites 2-4 with brownish gray, relatively narrow, medial stripe, lateral margin of darkened areas lacking wedge-like markings; tergite 5 of male gray. Male terminalia (Figs 137-140): Combined structures generally elongate, in posterior view (Fig. 137) height about 2.5 × width, narrowly diamond shaped; epandrium with dorsal arch above cerci attenuate, not connected, becoming slightly wider to dorsal 1/3, thereafter ventrally tapered to shallowly bilobed ventral apex, generally bearing setulae, in lateral view (Fig. 138) mostly parallel sided with anterior shallowly sinuous, apical 1/3 tapered to moderately rounded apex; cerci moderately long, height slightly more than twice width (Figs 137); aedeagus in lateral view (Fig. 140) very elongate, narrow, with length of sclerotized, basal portion about 10 × or more width, apical, membranous portion not greatly expanded or ballooned apically, at most slightly swollen, in ventral view (Fig. 139) also narrow and very elongate, almost parallel sided; phallapodeme in lateral view (Fig. 140) narrow, elongate, unevenly clavate toward hypandrium, keel slightly developed, apical width, including keel, slightly more than greatest aedeagal width, in ventral view (Fig. 139) with hypandrial end narrowly as a double T (2 bars), thereafter toward base of aedeagus bar-like, parallel sided; gonite in lateral view (Fig. 140) narrow, elongate, very shallowly sinuous, in ventral view (Fig. 139) narrow, bar-like with apices slightly curved in opposite directions; hypandrium in lateral view (Fig. 140) elongate, moderately shallow, width slightly more than 1/4 length, very shallowly curved, in ventral view (Fig. 139) generally V-shaped with posterior margin very deeply V-shaped, anterior margin moderately narrow, truncate.

Type material.

The holotype male of Hydrochasma annae is labeled "USA [UNITED STATES]. UT. Grand: Green River (15.3 km N; 39°7'N, 110°6.6'W; 1255 m), 30 Jul 2007, D.&W.N.Mathis/USNM ENT 00117970 [plastic bar code label]/HOLOTYPE ♂ Hydrochasma annae Mathis & Zatwarnicki, USNM [red]." The holotype is double mounted (minuten in a block of plastic), is in excellent condition, and is deposited in the USNM. Seven paratypes (3♂, 4♀; USNM) bear the same label data as the holotype. Other paratypes are as follows: UTAH. Emery: Green River (3 km N; 38°59'N, 110°09'W), 30 Jul-5 Aug 1992, 2007, D. and W. N. Mathis (1♂, 3♀; USNM); Green River (Green River; 38°59.6'N, 110°08.5'W; 1240 m), 19-31 Jul 1988, 2007, D. and W. N. Mathis (1♂, 2♀; USNM). Grand: Thompson Spring (8.9 km N Thompson Springs; 39°02.3'N, 109°43.4'W; 1740 m), 1-16 Aug 2007, 2008, D. and W. N. Mathis (3♂, 4♀; USNM).

Type locality.

United States. Utah. Grand: Swasey Beach (15.3 km N Green River; 39°07'N, 110°06.6'W; Green River; 1255 m).

Other specimens examined.

Nearctic. UNITED STATES. CALIFORNIA. Imperial: Yuma (32°44'N, 114°37'W), 3-5 May 1918, J. C. Bradley (1♂, 2♀; CU).

COLORADO. Montezuma: McPhee Reservoir (37°29.7'N, 108°33'W; 2115 m), 3 Aug 2007, D. and W. N. Mathis (1♀; USNM).

MISSOURI. Boone: Columbia (38°57.1'N, 92°20'W), 26 May-8 Jun 1906, C. R. Crosby (1♂, 6♀; ANSP). Jackson: Atherton (39°11.2'N, 94°18.3'W), (1♀; ANSP).

NEW MEXICO. Catron: Gila River (33°13.6'N, 106°15.1'W; 1750 m), 15 Aug 2007, D. and W. N. Mathis (1♂; USNM). Grant: Mimbres River (NM Highway 61 and Royal John Mine Road; 32°43.8'N, 107°52'W; 1665 m), 1-22 Aug 2008, 2009, D. and W. N. Mathis, T. Zatwarnicki (33♂, 13♀; USNM). Lincoln: Capitan (3.2 km E; Salado Creek; 33°32.6'N, 105°32.3'W; 1890 m), 10 Aug 2007, D. and W. N. Mathis (1♂; USNM). Sandoval: La Cueva (Junction of Highways 126 & 4; 35°52'N, 106°38.4'W; 2342 m), 15 Jun 2011, D. and W. N. Mathis (2♂; USNM). Valencia: Río Puerco (34°47.8'N, 106°59.5'W; 1575 m), 9 Aug 2007, D. and W. N. Mathis (1♂; USNM).

SOUTH DAKOTA. Bon Homme: Springfield (42°51.2'N, 97°53.8'W), 26 Jun 1924 (1♂, 1♀; ANSP).

TEXAS. Galveston: Galveston Island (25°10'N, 95°05'W), 14 May 1993, D. and W. N. Mathis (2♀; USNM). St. Augustine: Rayburn Park (31°04'N, 94°05'W), 15 May 1993, D. and W. N. Mathis (3♂, 2♀; USNM).

WASHINGTON. Franklin: Columbia River N of Pasco (46°21.5'N, 119°15.5'W), 29 Jul 1998, W. N. Mathis (7♂, 1♀; USNM); Ringold (4.8 km N; 46°30.9'N, 119°15.3'W), 2 Jul 1988, D. and W. N. Mathis (1♀; USNM).

Distribution

(Fig. 141). Nearctic: United States (California, Colorado, Missouri, New Mexico, South Dakota, Texas, Utah, Washington).

Etymology.

The species epithet, annae, is a feminine genitive patronym to recognize Ms. AnnaLee Thayn who inspired us while collecting in the Southwest.

Remarks.

Externally, this species is very similar and evidently closely related to Hydrochasma andeum and Hydrochasma avanae but can be distinguished from either of these two species by having a hindtibia with only yellowish setulae ventrally near the apex, less sinuous margins of the epandrium, and by having a more delicately developed hypandrium that is deeply V-shaped in ventral view (Fig. 139).