Haloscatella balioptera, Mathis, Wayne N., Zatwarnicki, Tadeusz & Marris, John W. M., 2004

Mathis, Wayne N., Zatwarnicki, Tadeusz & Marris, John W. M., 2004, Review of unreported shore­fly genera of the tribe Scatellini from the New Zealand subregion (Diptera: Ephydridae) with description of three new species, Zootaxa 622, pp. 1-27 : 6-10

Haloscatella balioptera , sp. nov. (Figs. 1–9, 13)

Diagnosis. This species is distinguished from congeners by the following characters: Small shore flies, body length 1.50–1.90 mm (averaging 1.75 mm); body mostly dark brown; arista macropubescent; prescutellar acrostichal seta well developed; wing generally infuscate with pattern of white spots or markings in some posterior cells; posterior notopleural seta at elevated insertion compared to anterior seta.

Description. Head: Head ratio 0.72–0.74; frontal triangle and fronto­orbits faintly subshiny, brown with some grayish coloration, contrasted with more densely microtomentose, somewhat blackish parafrons; frontal triangle bearing a few setulae along anterolateral margins; ocellar triangle concolorous with mesofrons; 2 large, lateroclinate, frontoorbital setae and 1–2 setulae anterior and/or between these; 1 well­developed ocellar seta, setal length greater than distance between anterior ocellus and ptilinal suture. Antenna black, microtomentose; arista macropubescent, length longer than combined length of pedicel and 1st flagellomere. Face silvery gray on dorsal 2/3, ventral 1/3 brownish gray, densely microtomentose; face wider than high, not greatly protrudent; face usually bearing 3 lateral facial setae and 6–8 well­developed setae along oral margin; 8 facial/genal setulae, none well developed. Eye oval; eye ratio 0.90–0.93. Gena mostly gray; gena­to­eye ratio 0.11–0.14. Palpus blackish.

FIGURES 1–7. Structures of the male terminalia of Haloscatella balioptera ( New Zealand. Chatham Island: Tennants Lake). 1, Epandrium, and cerci, ventral view. 2, Same, lateral view. 3, Internal genitalic structures (aedeagus with basiphallus shaded, phallapodeme, gonite and hypandrium), and 5th sternite, ventral view. 4, Same, lateral view. 5, Aedeagus (shaded) and phallapodeme, ventral view. 6, Gonite and hypandrium, ventral view. 7, 5th sternite, ventral view.

Thorax: Mesonotum mostly brown but with gray anterior stripes laterad of acrostichal track and with grayish presutural spot and a short grayish postsutural stripe laterad of dorsocentral track; scutellum blackish brown, darker than scutum; postpronotum grayish; acrostichal setulae in 2 rows and with a distinctive, larger prescutellar pair of setae; posterior notopleural seta at elevated insertion compared to anterior seta; anepisternum mostly dark brown, dorsal and anterodorsal margins grayish, only moderately microtomentose, faintly subshiny; anepimeron dark brown, more densely microtomentose than anepisternum, mostly dull colored; katepisternum mostly gray, somewhat brownish anteroventrally. Wing ( Fig. 13 ) generally infuscate; with a white spot in cell br, basad of crossvein r­m; a narrow, elongate, white marking at base of cell r4+5 and a spot at apical 2/3; a white spot in discal cell near crossvein dm­cu, and a white horizontally, U­shaped marking in cell M; costal vein ratio 0.21–0.22; M vein ratio 0.42–0.44. Legs from trochanter to apical tarsomere black; forecoxa and to a lesser extent midcoxa grayish.

Abdomen: Tergites brownish black to black, very sparsely microtomentose, especially apical tergites, mostly shiny; 5th sternite in ventral view (Fig. 7) bar­like with an anteromedial, tapered projection, projection at about same position as gonal apices. Male terminalia (Figs. 1–6): Epandrium in ventral view (Fig. 1) wider posteriorly than anteriorly, slightly tapered on anterior 1/3, bearing numerous short setulae over broad, medial area, anterior margin (fused surstyli) bilobed, each lobe gradually narrowed anteriorly and generally setulose, some setulae long and irregular; cerci lunate, almost symmetrical and generally setulose; epandrium and cercus in lateral view (Fig. 2) with anterior margin evenly rounded and moderately broad; aedeagus in lateral view (Fig. 4) with basiphallus irregularly rectangular, angle at articulation with phallapodeme drawn out, in anterior view (Figs. 3, 5) narrow, twice as long as wide, tapered on apical 1/3, distiphallus membranous, almost twice length of basiphallus, ultrastructure on surface of distiphallus shown in square; phallapodeme in lateral view (Fig. 4) narrow, width more or less even although external margin irregular, shallowly arched, in ventral view (Figs. 3, 5) T­shaped; gonite in lateral view (Fig. 4) with apical projection narrow and pointed, hypandrium somewhat like a skewed C, in ventral view (Figs. 3, 6) hypandrium Y­shaped with medial arm widened at articulation with phallapodeme.

Type material. The holotype male is labeled “ NEW ZEALAND. CH [atham]. IS[and]. Tennants Lake 43º49.4'S, 176º34'W, 14 Oct 2002, D. and W.N. Mathis/[bar code] USNM ENT 00184407/ HOLOTYPE ɗ Haloscatella balioptera Mathis Zatwarnicki & Marris [red].” The holotype is double mounted (minuten in a block of plastic), is in excellent condition, and is deposited in the NZAC. The allotype female and 14 other paratypes (9ɗ, 6Ψ; NZAC, USNM) bear the same locality label as the holotype. Other paratypes are as follows: OFFSHORE ISLANDS. Chatham Islands. Chatham Island: Lake Te Roto, 12 Feb 1967 (1ɗ; NZAC); Rotoparaoa Lake (43º48.7'S, 176º35.3'W), 14 Oct 2002, D. and W. N. Mathis (3ɗ, 1Ψ; USNM); Tuku River (mouth; 44º03.9'S, 176º39.2'W), 13 Oct 2002, D. and W. N. Mathis (1ɗ, 1Ψ; USNM); Waitangi Creek (43º47.1'S, 176º48.3'W), 14 Oct 2002, D. and W. N. Mathis (2ɗ; USNM).

NORTH ISLAND. ND: Poor Knights Island, Tawhiti Rahi, 2 Dec 1980, C. F. Butcher (1ɗ, 1Ψ; NZAC); Whananaki South (beach; 35º31.1'S, 174º27.2'E), 6 Oct 2002, D. and W. N. Mathis (1ɗ; USNM). WN. Waikanae Beach (40°52.3'S, 175°0.5'E), 7 Jan 2004, W. N. Mathis (2ɗ; USNM).

SOUTH ISLAND. DN: Otago Peninsula, Hoopers Inlet, Allans Beach Road (45°52.0'S, 170°41.3'E); 13 Jan 2004, W.N. Mathis (2Ψ; USNM)

Distribution. Australasian/Oceanian: New Zealand (DN, ND, WN, Chatham Islands).

Natural history. This species has only been collected at habitats directly associated with maritime shores or at sites immediately adjacent, such as the type locality on Chatham Island. The type locality, Tennants Lake ( Figs. 8–9 ), is a freshwater lake immediately behind large coastal sand dunes. Specimens of this species were more commonly found in slight depressions in the sand along the shore where there was algae and some emergent vegetation.

Given the considerable distance between the known localities for this species more collecting along coastal sites with this type of habitat is needed to verify the actual distribution in the New Zealand subregion.

Etymology. The species epithet, balioptera , is of Greek derivation, meaning spotted wing in reference to the pale spots on the generally infuscate wing of this species.

Remarks. This species is somewhat similar to some species of Philotelma , such as P. defectum (Haliday) , but may be distinguished from it and other similar congeners by the mostly bare arista (macropubescent), well­developed prescutellar acrostichal seta, faintly spotted wing, elevated position of the posterior notopleural seta (higher than the anterior seta), and structures of the male terminalia.

Some years ago, we examined a specimen of Haloscatella that was taken from a plane that had arrived in the United States most immediately from the Azores (Terceira Island: Lajes). This specimen, although very similar to H. balioptera in having a faintly maculate pattern on its wing, differs in being much lighter in color, especially the microtomentose, gray to brown abdominal tergites (in H. balioptera the tergites are almost bare and are subshiny to mostly shiny, brownish black to black). This second species, possibly from the Azores, may be closely related to H. balioptera and may indicate an Old World species group that is primarily insular in distribution.

Figures

FIGURES 13 – 15. Wings of Haloscatella species. 13, H. balioptera (New Zealand. Chatham Island: Tennants Lake). 14, H. harrisoni (New Zealand. Bounty Islands. Depot Island). 15, H. karekare (New Zealand. AK: Karekare).

FIGURES 8 – 9. Tennants Lake, the type locality of Haloscatella balioptera.