Hydrochasma dolabrutum, 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 : 39-41

13. Hydrochasma dolabrutum sp. n. Figs 77-80, 142

Diagnosis.

This species is distinguished from congeners by the following combination of characters: Small shore flies, body length 1.65-1.90 mm. Head: Antenna mostly dark gray; parafacial silvery white, concolorous with facial coloration; gena-to-eye ratio 0.21-0.23. Thorax: Wing with costal vein ratio 0.69-0.71; M vein ratio 0.49-0.52. Forecoxa yellowish to tan; forefemur lacking a distinctive, comb-like row of stout setulae along anteroventral surface; tibiae mostly gray. Abdomen: Tergites 3-4 with distinct, deep, wedge-like marking laterally but tergites 2-4 with wide medial area extensively dark slate gray to black; tergite 5 light gray to silvery gray with undifferentiated posterior margin, uniformly colored (Fig. 142); medial coloration on tergites 1-4 narrow, sometimes only a stripe, slightly darker than color of lateral margins. Male terminalia (Figs 77-80): Combined structures generally elongate, in posterior view height nearly 2.5 × width; epandrium (Fig. 77) with dorsal arch above cerci attenuate, not connected, dorsal 1/3-1/2 somewhat quadrate with angles rounded, ventral portion as 2 digitiform, thick, abutting, parallel lobes that connect subapically for a short distance, ventral margin concave with a medial, narrow incision, dorsal half bearing longer setulae than ventrally, ventral setulae lacking on apical portion, in lateral view (Fig. 78) mostly parallel sided and nearly straight, apical 1/8 angled anteroventrally as a tapered, narrowly pointed apex; cerci relatively very short, in lateral view (Fig. 77) height about twice width, narrowly semicircular, attached to epandrium ventrally; aedeagus in lateral view (Fig. 80) elongate, with length of sclerotized portion about 8 × width, basal portion parallel sided, apical half greatly enlarged, bulbous, membranous, with apex broad, membrane bearing sub-basally numerous scale-like spicules, in ventral view (Fig. 79) also showing expanded apex, basal 1/2 comparatively narrowed, slightly wider at base, thereafter slightly tapered to expanded, broadly obovate apical half; phallapodeme in lateral view (Fig. 80) narrow, very elongate, evenly shallowly arched, keel very weakly developed, barely evident at end toward attachment with hypandrium, in ventral view (Fig. 79) with hypandrial end T-shaped with 2 crossbars, thereafter toward base of aedeagus gradually expanded to blunt apex; gonite in lateral view (Fig. 80) narrow, elongate, bar-like with slight, sinuous curvature, in ventral view (Fig. 79) moderately narrow, elongate, rod-like, apices narrowed; hypandrium in lateral view (Fig. 80) elongate, roughly rectangular, moderately shallow, width slightly more than 1/4 length, very slightly angulate, in ventral view (Fig. 79) generally U-shaped with base very thick, posterior margin deeply U-shaped, anterior margin moderately narrowly rounded.

Type material.

The holotype male of Hydrochasma dolabrutum is labeled "DOM[INICAN]. REP[UBLIC]. Barahona: Barahona (18°12'N, 71°5.3'W), 20 May 1998, D. and W. N. Mathis/USNM ENT 00087042 [plastic bar code label]/HOLOTYPE ♂ Hydrochasma dolabrutum 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. Nine paratypes (7♂, 2♀; USNM) bear the same label data as the holotype. Other paratypes are as follows: DOMINICAN REPUBLIC. Azua: near Pueblo Viejo (18°24.8'N, 70°44.7'W), 19 May 1998, D. and W. N. Mathis (6♂, 6♀; USNM). Barahona: Barahona (18°12'N, 71°5.3'W), 25 Mar 1999, W. N. Mathis (1♂; USNM). Pedernales: Pedernales (19 km N; 18°09.2'N, 71°44.8'W; 230 m), 20 Mar 1999, W. N. Mathis (4♂; USNM).

Type locality.

Dominican Republic. Barahona: Barahona (18°12'N, 71°5.3'W).

Other specimens examined.

Nearctic. UNITED STATES. FLORIDA. Miami-Dade: Miami (25°46'N, 80°12'W), 20 Apr 1930, A. L. Melander (2♂; ANSP).

Neotropical. COSTA RICA. Limón: R. V. S. Gandoca-Manzanillo, desembocadura de Laguna Gandoca (09°35.4'N, 82°35.8'W), 18 May 2004, D. Briceño (1♂, 3♀; INBIO); Parque Nacional Cahuita, Sector Puerto Vargas (09°44'N, 82°49'W; 1 m), 27-28 Jun 2001, J. D. Gutierrez (1♂; INBio); Puerto Vargas (09°43.9'N, 82°48.9'W; beach), 28 Jun 2001, W. N. Mathis (1♂; USNM); Westfalia (4 km S; 9°54.5'N, 82°59'W; beach), 27 Jun 2001, A. Freidberg, W. N. Mathis (10♂, 5♀; USNM).

GUYANA. Hope Beach (06°44.7'N, 57°57.3'W), 20 Aug 1997, W. N. Mathis (1♂; USNM); Mahaica (6°42.8'N, 57°55.6'W), 22 Apr 1995, W. N. Mathis (1♂, 2♀; USNM).

HONDURAS. Cortés: Omoa (16°47.8'N, 87°58.4'W), 26 Sep 1995, D. and W. N. Mathis (2♂; USNM); Puerto Cortés /Omoa (15°49'N, 87°56.2'W), 26 Sep 1995, D. and W. N. Mathis (6♂, 3♀; USNM).

MEXICO. Chiapas: Boca de Cielo (17 km S Puerto Arista; 15°51.1'N, 93°40.4'W), 18 May 1985, A. Freidberg, W. N. Mathis (6♂, 4♀; USNM).

TRINIDAD and TOBAGO. Tobago. St. John: Charlotteville (beach; 11°19.5'N, 60°32.9'W), 16-18 Apr 1994, D. and W. N. Mathis (3♂; USNM); Charlotteville (5 km S; Hermitage River and beach; 11°18.9'N, 60°34.5'W), 22 Apr-11 Jun 1993, 1994, D. and W. N. Mathis (1♂, 2♀; USNM); Speyside (Doctor River; 11°18.2'N, 60°31'W), 19 Apr 1994, D. and W. N. Mathis (1♂; USNM). St. Patrick: Pigeon Point (beach; 11°9.7'N, 60°50'W), 19 Apr 1994, D. and W. N. Mathis (6♂, 2♀; USNM). St. Paul: Delaford, Kings Bay (11°16'N, 60°32.8'W), 13 Jun 1993, W. N. Mathis (2♂, 2♀; USNM). Trinidad. St. Andrew: Lower Manzanilla (14 km S; 10°23'N, 61°01'W), mouth of Nariva River, 20 Jun 1993, W. N. Mathis (1♂; USNM). St. George: Blanchisseuse (beach; 10°48'N, 61°19'W), 25 Jun 1993, W. N. Mathis (3♂; USNM).

West Indies: ANTIGUA. near airport (17°08.2'N, 61°47.6'W), 19 Mar 1989, W. N. Mathis (6♂, 4♀; USNM).

BARBADOS. Christ Church: Rockley Beach (13°04.3'N, 59°35.2'W), 21 May-11 Sep 1996, 1997, D. and W. N. Mathis, H. B. Williams (1♂, 1♀; USNM). St. Andrew: Long Pond (13°15.1'N, 59°33.3'W), 10-11 Sep 1996, W. N. Mathis (12♀; USNM).

CUBA. Matanzas: Playa Larga (22°15.9'N, 81°09.9'W), 1 May 1983, W. N. Mathis (4♂, 18♀; USNM).

GRAND CAYMAN. Spotts (2 km N; 19°18'N, 81°19'W), 20 Feb 1993, F. J. Burton, W. E. Steiner, J. M. Swearingen (3♂, 1♀; USNM).

GRENADA. St. Andrew: Pearls Airport (12°08.7'N, 61°36.6'W), 17 Sep 1996, W. N. Mathis (2♂, 3♀; USNM).

HAITI. Baie de Chouchou (19°49'N, 72°28.5'W), 8 Jun 1978, L. Raccurtt, R. Lowrie (2♂, 1♀; USNM).

JAMAICA. Clarendon: Barnswell Beach (17°45.'N, 77°08.5'W), 13 May 1996, D. and W. N. Mathis, H. B. Williams (1♀; USNM); Farquhars Beach (17°50.9'N, 77°22.8'W), 9 May 1996, D. and W. N. Mathis, H. B. Williams (1♂, 4♀; USNM); Milk River Bath (17°51'N, 77°22'W; mangroves), 11 Mar 1970, T. Farr, W. W. Wirth (2♂, 11♀; USNM). Manchester: Mandeville (18°03.5'N, 77°31.9'W), 7-13 May 1996, D. and W. N. Mathis, H. B. Williams (4♀; USNM). St. Elizabeth: near Port Kaiser (17°52.3'N, 77°34.9'W), 8 May 1996, D. and W. N. Mathis, H. B. Williams (1♀; USNM). St. Mary: Port Maria (1 km W; 18°22.8'N, 76°53.6'W), 18 May 1996, D. and W. N. Mathis, H. B. Williams (2♂, 1♀; USNM). St. Thomas: Bath Fountain Spring (17°57.6'N, 76°21.3'W), 15 May 1996, D. and W. N. Mathis, H. B. Williams (1♂, 1♀; USNM).

PUERTO RICO. Maricao (18°11.1'N, 66°58.9'W), 21 Sep 1995, D. and W. N. Mathis (1♂; USNM).

ST. VINCENT. St. Patrick: Cumberland Bay (13°16'N, 61°15.6'W), 8-10 Jun 1991, D. and W. N. Mathis (1♂; USNM).

Distribution

(Fig. 76). United States (Florida). Neotropical: Costa Rica ( Limón), Guyana, Honduras ( Cortés), Mexico (Chiapas), Trinidad and Tobago, West Indies (Antigua, Barbados, Cuba, Dominican Republic, Grand Cayman, Haiti, Jamaica, Puerto Rico, St. Vincent).

Etymology.

The species epithet, dolabrutum, is of Latin derivation and means axe, referring to the shape of the extended epandrium in lateral view.

Remarks.

Structures of the male terminalia of this species are similar to those of Hydrochasma parallelum but are distinguished from the latter species by having a comparatively more robust extended epandrial process (best seen in posterior view). Moreover, the hypandrium in general is wider, more robustly developed, and the anterior margin is broadly rounded rather than truncate as in Hydrochasma parallelum .