Hydrochasma robustum, 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 : 101-103

33. Hydrochasma robustum sp. n. Figs 186-190

Diagnosis.

This species is distinguished from other congeners by the following combination of characters: Small to moderately small shore flies, body length 1.45-2.10 mm. Head: Antenna mostly dark gray; parafacial silvery white, concolorous with facial coloration; gena-to-eye ratio 0.18-0.19. Thorax: Wing with costal vein ratio 0.71-0.74; M vein ratio 0.59-0.61. Forecoxa mostly yellow, especially apically, basal portion partially silvery gray. Abdomen: Tergites 3-4 with gray wedges laterally, these sometimes deep and wide. Male terminalia (Figs 186-189): Combined structures generally moderately elongate, in posterior view (Fig. 186) more or less rectangular, height slightly more than twice width, generally setulose but with setulae on ventral 1/3 smaller than those on dorsal 2/3; epandrium with dorsal arch above cerci attenuated, not connected, in posterior view (Fig. 186) with wide medial area membranous, widest at midlength, sclerotized ventral portion tapered to sharp point, ventral margin almost truncate, in lateral view (Fig. 187) with posterior margin more or less evenly curved, anterior margin irregular with a shallow protuberance at ventral 1/3; cerci moderately long, height nearly twice width, narrowly semi-hemispherical (Fig. 187), almost attached lateroventrally with epandrium; aedeagus in lateral view (Fig. 189) complex, robust, moderately deeply trilobed, posterior 2 lobes digitiform, anterior lobe narrow, shallowly angulate, apex bilobed, in ventral view (Fig. 188) basal half relatively narrow, thereafter wider, apex narrowed, width subequal to basal width, delicately serrate laterally; phallapodeme in lateral view (Fig. 189) elongate, narrow, rod-like, mostly parallel sided, apex at hypandrial end, widened, in ventral view (Fig. 188) an elongate, robust, T-shaped process with width of crossbar only slightly greater than width of stem; gonite in lateral view (Fig. 189) narrow, elongate, bar-like, nearly straight, in ventral view (Fig. 188) bar-like, nearly straight; hypandrium in lateral view (Fig. 189) robust, irregularly shaped, with 2 basal notches, broadly rounded apically, in ventral view (Fig. 188) widest posteriorly, thereafter anteriorly gradually tapered, anterior margin obtusely narrowed, posterior margin shallowly but broadly emarginate.

Type material.

The holotype male of Hydrochasma robustum is labeled "BRAZIL. São Paulo: Praia Puruba (23°21'S, 44°55.6'W; beach),29Mar2010[,] D. & W. N. Mathis/USNM ENT 00117967 [plastic bar code label]/HOLOTYPE ♂ Hydrochasma robustum Mathis & Zatwarnicki, DZUP [red]." The holotype is double mounted (minuten in a block of plastic), is in excellent condition, and is deposited in the DZUP. Twenty paratypes (20♂; USNM) bear the same label data as the holotype.

Type locality.

Brazil. São Paulo. Ubatuba, Praia Puruba (23°21'S, 44°55.6'W; beach).

Other specimens examined.

Neotropical. ARGENTINA. Tucumán: La Cavera ( Tafí Viejo; 26°45'S, 65°16'W), 23-28 Nov 1951, M. L. Aczel, R. Golbach (1♂; USNM).

BRAZIL. Paraná: Bocaiúva do Sul (25°16.6'S, 48°58.5'W; 770 m), 16 Feb 2010, D. and W. N. Mathis (1♂; USNM); Bocaiúva do Sul (ca. 10 km NW; 25°14.9'S, 49°08.9'W; 890 m), 2-4 Nov 2010, D. and W. N. Mathis (3♂, 5♀; DZUP, USNM); Curitiba, Universidade Federal do Paraná, Reserva Biológica (25°26.9'S, 49°14'W; 915 m), 14 Dec-8 Jan 2009, 2010, D. and W. N. Mathis (4♀; DZUP); Matinhos (N.; 25 °46.4'S, 48°30.8'W; 1 m; beach/estuary), 30 Jan-9 Apr 2010, D. and W. N. Mathis (4♂, 1♀; DZUP, USNM); Matinhos (Rio da Onça; 25°47.4'S, 48°31.6'W; 3 m), 12 Nov 2010, D. and W. N. Mathis (8♂, 1♀; DZUP, USNM); Prainha (5 km S Matinhos; 25°51.2'S, 48°33.6'W; beach), 15 Nov 2010, D. and W. N. Mathis (2♂; DZUP, USNM). São Paulo: Estação Biológica de Boracéia (23°38.9'S, 45°52.8'W; 850 m), 27 Feb 1967, M. E. Irwin (3♂; USNM); Ubatuba, Praia do Estaleiro (23°20.5'S, 44°53'W; beach), 30 Mar 2010, D. and W. N. Mathis (1♂; DZUP, USNM). Rio de Janeiro: Ilha da Marambaia (23°03.6'S, 43°59.1'W), 4 Sep 2000, W. N. Mathis (1♂; USNM).

COSTA RICA. Alajuela: Volcán Tenorio, El Pilón (10°44.1'N, 84°59.5'W; 967 m), 9 May 2002, J. D. Gutierrez (1♂; INBio). Guanacaste: Bagaces Fortuna Z. P. Miravalles (10°43.1'N, 84°51.3'W; Sendero Cabro Muco; 980 m), 8-31 Jul 2002, J. D. Gutierrez (1♂; INBio); Parque Nacional Santa Rosa ( Estación; Camino Cafetal; 10°51.5'N, 85°36.7'W; 300 m), 3-5 Aug 2002, D. Briceño (1♂, 1♀; INBio); Sector el Hacha, Finca el Oro, 5 km SW Hacienda Alemania (11°00'N, 85°33'W; 400 m), 14-19 Apr 2002, D. Briceño (2♂, 4♀; INBio).

ECUADOR. Napo: San Francisco de Borja (0°25.4'S, 77°50.5'W; 1610 m), 17 Jan 1978, W. N. Mathis (2♂, 13♀; USNM).

GUYANA. Menzies Landing (05°10.1'N, 59°29.5'W), 23 Aug 1997, W. N. Mathis (1♂; USNM).

West Indies. DOMINICAN REPUBLIC. Barahona: Cortico, La Mina (18°06.7'N, 71°13.4'W; 1300 m), 23 Mar 1999, W. N. Mathis (1♂; USNM); Paraíso (6 km NW; Río Nizao; 18°02'N, 71°12'W; 170 m), 21 Mar 1999, W. N. Mathis (1♂; USNM); San Rafael (18°01.9'N, 71°08.4'W), 25-26 Jul 1990, J. E. Rawlins, S. A. Thompson, C. Young (1♂; USNM).

Distribution

(Fig. 190). Neotropical: Argentina ( Tucumán), Brazil ( Paraná, São Paulo, Rio de Janeiro), Costa Rica (Guanacaste), Ecuador (Napo), Guyana, West Indies (Dominican Republic).

Etymology.

The species epithet, robustum, is of Latin derivation and means robust, referring to the generally robust structures of the male terminalia.

Remarks.

This species is very similar and is evidently closely related to Hydrochasma capsum , as evidenced by the similar shapes of their respective epandriums in posterior view. This species can be distinguished from Hydrochasma capsum by the more elongated hypandrium in ventral view (longer than wide) and the unique, basal, hypandrial notches (best seen in lateral view; Fig. 189).