Parahyadina angusta, Mathis & Zatwarnicki, 2019

Mathis, Wayne N. & Zatwarnicki, Tadeusz, 2019, Revision of the Shore-fly Genera Parahyadina Tonnoir and Malloch and New Zealand Hyadina Haliday (Diptera: Ephydridae), Zootaxa 4623 (3), pp. 401-440 : 410-412

Parahyadina angusta , sp. nov.

( Figs. 2 , 7–10, Map 2 )

Diagnosis. This species is distinguished from congeners by the following combination of characters: Adults. Small shore flies, body length 2.10 mm.

Head ( Fig. 2 ): Lateroclinate fronto-orbital seta well developed, basal diameter comparable or only slightly reduced compared to basal diameters of vertical setae.

Thorax ( Fig. 2 ): Scutum with distinct, longitudinal, shiny, medial vitta, width about equal to distance between posterior ocelli; either side of medial vitta with thinner, gray, longitudinal stripes; 1 pair of posterior, dorsocentral setae, and a slightly enlarged pair of setulae at sutural level. Wing amber colored; Costal vein ratio: 0.97; M vein ratio 0.30.

Abdomen: Tergites with ventrolateral margins rounded; male tergite 5 extended posteriorly in same plane as tergite 4. Male terminalia ( Figs. 7–10 ): Epandrium in posterior view ( Fig. 7 ) a narrow, oval-shaped band, in lateral view ( Fig. 8 ) elongate, narrow posterior margin nearly straight, anterior margin sinuous; surstylus in posterior view ( Fig. 7 ) narrowly triangular, sinuous, bear cluster of setulae at midlength, recurved subapically apex narrowly rounded, bearing a single, curved setulae, in lateral view ( Fig.8 ) widest at base, thereafter ventrally tapered, curved and apical portion recurved, with a shallow, wide, posterior notch near apex; cercus in lateral view ( Fig. 8 ) crescentshaped completely covered with small setulae, bearing long setae in rows along medial margin and laterally with medial posteromedial cercus devoid of long setae, in lateral view ( Fig. 7 ) semihemispherical; aedeagus in lateral view ( Fig. 10 ) with basal half parallel sided, deeply notched or bifurcate basally, apical half expanded, apical margin wide, shallowly convex, in ventral view ( Fig. 9 ) slightly longer than wide, bell-shaped, base with medial dipple, apical margin very shallowly concave; phallapodeme in lateral view ( Fig. 10 ) irregularly triangular with elongate basal processes, process toward aedeagal base longest, digitiform, process toward hypandrium narrowly triangular, in ventral view ( Fig. 9 ) narrowly spool-like, with basal portion twice as wide as apical portion; hypandrium-gonite in lateral view ( Fig. 10 ) elongate, irregularly L-shaped, hypandrial portion with base deeply and moderately widely bifurcate, each prong of bifurcation about subequal, gonal portion triangular, tapered to narrow point; in ventral view ( Fig. 9 ) about as wide as long, apical margin widely and moderately deeply concave, both lateral processes oriented slightly medially.

Type Specimen. The holotype male is labeled “ NEW ZEALAND. S. Isl. OL: Queenstown (45°01.6’S, 168°39.6’E; 330 m); 27 Jan 2004, W. N. Mathis (1♂; USNM)/ USNM ENT 00285204 [plastic bar code label]/HO- LOTYPE ♂ Parahyadina angusta Mathis & Zatwarnicki NZAC [red].” The holotype is glued to a block of plastic elastomere (came off minuten while making dissection), is in good condition (abdomen and structures of male terminalia stored in microvial), and is deposited in the NZAC.

Type locality. New Zealand. South Island. OL. Queenstown (45°01.6’S, 168°39.6’E; 330 m) .

Distribution ( Map 2 ). Australasian/Oceanian: New Zealand. South Island (OL).

Etymology. The species epithet, angusta , is of Latin derivation and means narrow, referring to the shape of the narrow, surstylar apex.

Remarks. This species is similar to P. atra in having amber colored wings and long, narrow, straight surstyli. This species is distinguished from P. atra by the more robust, squat, somewhat rectangular aedeagus in lateral view ( Fig. 10 ), and by the shape of the hypandrial-gonal structure in ventral view ( Fig. 9 ), specifically the bank-like, transverse hypandrium and the irregularly bifurcated apical portion of the gonite in lateral view( Fig. 10 ).

Figures

MAP 2. Parahyadina angusta.

FIGURES 1–2. Antero-oblique photo of head and thorax (Scale bar = 0.2 mm). 1. Hyadina breva sp. nov. (female; New Zealand. South Island. FD: Monowai River). 2. Parahyadina angusta sp. nov. (male; New Zealand. South Island. OL: Queen- stown).

FIGURES 7–10. Parahyadina angusta sp. nov. (male; New Zealand. South Island. OL. Queenstown). 7. Epandrium, cerci, and surstyli, posterior view. 8. Same, lateral view. 9. Internal structure of male terminalia, ventral view. 10. Same, lateral view (scale bar = 0.1 mm).