Parahyadina lacustris Tonnoir and Malloch 1926
Creators: name: Mathis, Wayne N.
name: Zatwarnicki, Tadeusz
Publisher: name: Zenodo
Year: 2019
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Diptera
Ephydridae
Parahyadina
Parahyadina lacustris

description: Parahyadina lacustris Tonnoir and Malloch
(Figs. 44, 49–52, Map 10)
Parahyadina lacustris Tonnoir and Malloch 1926: 17.— Miller 1950: 112 [catalog, Diptera of New Zealand].— Harrison 1959: 232–233 [fauna of New Zealand].— Cumber 1962: 176 [cereal crop survey].— Mathis 1989 a: 646 [Australasian/Oceanian catalog].— Mathis and Zatwarnicki 1995: 209 [world catalog].
Diagnosis. This species is distinguished from congeners by the following combination of characters: Adults. Small to moderately small shore flies, body length 1.35–2.15 mm.
Head (Fig. 44): Frons with brown ventrolateral triangles with sparse yellowish silver microtomentum, anterior semicircle shiny brown with sparse yellowish silver microtomentum. Occiput brown laterally with yellowish silver microtomentum, medially with silvery gray microtomentose round spots. Lateroclinate fronto-orbital seta well developed, basal diameter comparable or only slightly reduced in comparison to basal diameters of vertical setae; lateral vertical seta 1/2 length of medial vertical setae; orbital seta 2/3 length of outer vertical seta. Scape and pedicel yellowish brown; basal flagellomere brown dorsally, yellowish brown ventrally. Facial background brown, with silvery white microtomentum extended to gena, medially the microtomentum less dense; medially along parafacial, a band with sparse or no microtomentum extended lateroventrally below gena; band of silvery white microtomentum along eye margin beginning at antennal bases, extending and contiguous with silvery white microtomentum on gena. Gena and postgena covered with dense silvery white microtomentum contiguous with lateral thoracic stripe pattern. Maxillary palpus brown with silvery gray microtomentum; prementum brown.
Thorax (Fig. 44): Mesonotum dark yellowish brown with sparse yellowish silver microtomentum; scutellum dark brown shiny with sparse yellowish silver microtomentum; anatergite brown with silvery gray microtomentum; proepisternum with silvery gray microtomentum; pre-episternum with silvery gray microtomentum ventrally; anepisternum with silvery gray microtomentum dorsally, katepisternum with silvery gray microtomentum dorsally. Costal sections II and III about equal in length; costal vein ratio 0.97–1.40; M vein ratio 0.18–0.33; amber background with brown veins and cross veins; vein R 2+3 slightly lighter in coloration. Legs dark brown; first tarsomere yellowish brown on all legs. Chaetotaxy: Anterior postsutural dorsocentral seta 1/4 length of posterior postsutural seta, posterior seta displaced laterally, one setula between postsutural setae, and row of 4 presutural setulae, longest presutural setulae posterior with each successive anterior in row slightly shorter; lateral scutellar seta 1/4 to 1/3 length of apical seta.
Abdomen: Background brown; tergites 1–3 shiny, dorsally with very sparse, yellowish silver microtomentum; tergites 3–5 with ventrolateral margin shallowly rounded; tergites 4 and 5 bare, shiny; male tergite 5 extended posteriorly in same plane as tergite 4. Male terminalia (Figs. 49–52): Epandrium in posterior view (Fig. 49) generally oval with a ventral gap, mostly a relatively thin band, in lateral view (Fig. 50) with dorsal 2/3 band-like, narrow, ventral third expanded, spatulate; surstylus (fused to ventral margin of epandrium) in posterior view (Fig. 49) very elongate, narrowly triangular and nearly straight, bearing 2 setulae just basad of midlength, bearing a short, curved, apical setulae, in lateral view (Fig. 50) epandrium elongate, narrowly rectangular, swollen slightly a merger with surstylus, surstylus tapered, elongate, shallowly sinuous, apical portion digitiform, apex narrowly rounded; aedeagus in lateral view (Fig. 52) generally more or less rectangular, longer than high, base asymmetrically bifurcate, one extension digitiform, other process robust, almost as wide as high, apex with short, tapered process, in lateral view (Fig. 52) almost as wide as long, more or less rectangular, lateral margins shallowly emarginated, apex with broad, very shallow, medial extension; phallapodeme in lateral view (Fig. 52) with extensions to aedeagal base and to hypandrial base tapered, extension toward aedeagal base more elongate and narrowly developed, extension toward hypandrium more obtusely tapered and shorter, in ventral view (Fig. 51) a very narrow and elongate, tapered, with a cross piece at basal third, extensions short, base slightly widened, apex bifurcate, extension of keel pointed apically; hypandrium-gonite in lateral view (Fig. 52) more or less L-shaped, hypandrial portion narrower, rectangular, gonal portion shorter but more robustly developed and with a subapical, digitiform process, in ventral view (Fig. 51) more or less quadrate with corners extended as thumb-like process posteriorly and as shallowly bifurcate, broad process anterolaterally, anterior margin concave.
Type Specimen. The holotype male is labeled “[New Zealand.] Horseshoe Lake [CHRISTCHURCH] 17/9/24 [17 Sep 1924]/ TYPE Parahyadina lacustris T & M[,] A. Tonnoir det. [pink; species name and “T & M” handwritten].” The holotype is double mounted (small pin in small rectangular sheet of celluloid), is in poor condition (head, most legs, and apex of abdomen missing), and is deposited in the NZAC.
Type locality. New Zealand. South Island. MC. Christchurch, Horseshoe Lake (43°29.7’S, 172°40.5’E).
Other specimens examined. NORTH ISLAND. AK: Brown’s Bay (36°43’S, 174°45’E), 12 Aug 1950, R. Harrison (1♂; NZAC); Corwallis Peninsula (37°0.7’S, 174°36.3’E), 18 Feb 1998, V. Hollmann (2♂, 2♀; NCAC); Huia Dam (36°59.7’S, 174°33.9’E), 5–18 Feb 1998, W. N. Mathis (3♀; USNM); Huia Reservoir (36°59.2’S, 174°33.9’E), 18 Feb 1998, W. N. Mathis (2♀; USNM); Lynfield (36°56’S, 174°43’E), 31 Oct 1976, B, A. Hol- loway (1♂; NZAC); Karekare (beach; 36°59.1’S, 174°28.8’E), 5 Feb 1998, W. N. Mathis (3♀; USNM); Karek- are (beach; 37°00.2’S, 174°28.8’E), 10 Oct 2002, D. and W. N. Mathis (1♂, 5♀; USNM); Mangere (36°58.7’S, 174°45.8’E), 6 Feb 1998, V. Hollmann, W. N. Mathis (1♂, 4♀; NZAC, USNM); Noises Islands. Otata Island (NW slope; 36°41.7’S, 174°58.4’E), 4 Nov 1977, L. L. Deitz (1♂, 2♀; NZAC); Whatipo (37°02.2’S, 174°30’E), 5 Feb 1998, V. Hollmann, W. N. Mathis (3♂, 1♀; NZAC, USNM). BP: Hamurana Stream (38°02.1’S, 176°15.6’E), 7 Feb 1998, W. N. Mathis (1♀; USNM); Paradise Valley (38°07.9’S, 176°09.6’E), 7 Feb 1998, W. N. Mathis (3♂, 1♀; USNM); Rotora (38°07.7’S, 176°45.8’E), 6 Feb 1998, V. Hollmann (2♂, 2♀; NZAC); Tauranga Harbour (be- hind airport; 37°38’S, 176°05’E), 24 Nov 1970, JG (1♂; NZAC); Waipapa River (Road 2; 39°39.5’S, 176°0.1’E), 8 Feb 1998, W. N. Mathis (1♂; USNM). CL: Kirikiri Saddle, Forest E (37°10’S, 175°39’E; 400 m), 2 Nov 1977, E. I. Schlinger (1♂; NZAC). ND: Hailes Road (35°31.1’S, 174°25.8’E; quarry), 19 Feb 1998, W. N. Mathis (2♂, 1♀; USNM); Lake Manuwai (35°09.9’S, 173°51.9’E), 7 Oct 2002, D. and W. N. Mathis (1♀; USNM); Poor Knights Island, Tawhiti Rahi (35°28.1’S, 174°44.2’E), 3 Dec 1980, CFB (1♀; NZAC); Russell (beach; 35°15.6’S, 174°07.3’E), 7 Oct 2002, D. and W. N. Mathis (1♂, 3♀; USNM); Sandy Bay (beach; 35°33.4’S, 174°28.5’E), 6 Oct 2002, D. and W. N. Mathis (5♂, 7♀; USNM); Spirits Bay (34°26’S, 172°48’E), 3 Dec 1977, A. K. Wise (1♀; NZAC); Takou Bay (beach; 35°06.3’S, 173°56.7’E), 7 Oct 2002, D. and W. N. Mathis (1♀; USNM); Whananaki South (mangrove and beach; 35°31.1’S, 174°27.2’E), 6–8 Oct 2002, D. and W. N. Mathis (1♀; USNM); Whangaroa (rocky beach; 35°02.7’S, 173°44.9’E), 7 Oct 2002, D. and W. N. Mathis (12♂, 6♀; USNM). TO: National Park (12 km N; 39°8.8’S, 175°30.6’E; 840 m; Whakapapanui Stream and Mahuia Rapids), 4–5 Jan 2004, W. N. Mathis (2♂; USNM); Lake Taupo (38°55’S, 175°49’E), 23 Sep 1971, J. Gillespie (1♂; NZAC). WI: Turakina beach (S of Wanganui; 40°04.2’S, 175°07.7’E), 10 Nov 1977, E. I. Schlinger (1♂; NZAC). WN: Pauatahanui (E side of Porirua Harbour; 41°06.4’S, 174°55’E), 11 Nov 1977, E. I. Schlinger (1♂; NZAC).
SOUTH ISLAND. BR: Lake Rotoiti (41°50’S, 172°50’E), 24 Mar 1977, A. K. Wise (1♂; NZAC). CO: Danseys Pass (1.2 km SW; 44°57.2’S, 170°22.0’E; 856 m), 11 Jan 2004, W. N. Mathis (1♂; USNM). FD: Monowai River (45°46.7’S, 167°35.7’E; 171 m); 17–18 Jan 2004, W. N. Mathis (7♂, 4♀; USNM). KA: Hapuku Stream (42°13’S, 173°45.3’E; 420 m), 8 Jan 2004, W. N. Mathis (2♂, 1♀; USNM). MC: Christchurch (Styx Mill Reserve; 43°27.8’S, 172°36.8’E; 9 m); 2 Feb 2004, W. N. Mathis (1♂; USNM); Horseshoe Lake (43°29.7’S, 172°40.5’E), 23 Apr 1924 (1♂ (holotype), 1♀ (paratype); NZAC); Lake Lyndon (43°17.6’S, 171°42.5’E), 15 Feb 1998, W. N. Mathis (1♀; USNM). NC: Hurunui River (near mouth; 42°54.6’S, 173°16.7’E), 14–15 Feb 1998, W. N. Mathis (1♀; USNM); Napenape Scenic Reserve, Hurunui River Mouth (42°54.7’S, 173°17’E), 17 Nov 1977, E. I. Sch- linger (12♂, 6♀; NZAC). NN: Flora Saddle (41°11.4’S, 172°44.2’E), 12 Feb 1998, V. Hollmann, W. N. Mathis (3♂, 3♀; NZAC, USNM); Graham Stream (41°11.9’S, 172°48.6’E), 12 Feb 1998, W. N. Mathis (3♂, 2♀; USNM); Graham Valley (41°12.1’S, 172°50.8’E), 12 Feb 1998, V. Hollmann. W. N. Mathis (2♂, 1♀; NZAC, USNM); Maitai Dam (41°17.6’S, 173°22.1’E), 11 Feb 1998, W. N. Mathis (1♂; USNM); Nelson (airport; 41°18.2’S, 173°13.6’E), 11 Feb 1998, V. Hollmann (1♂; NZAC); Nelson (Maitai River; 41°16.5’S, 173°19.2’E), 10 Feb 1998, W. N. Mathis (2♀; USNM); Road-Cable Bay (41°11.7’S, 173°25.3’E), 13 Feb 1998, V. Hollmann, W. N. Mathis (4♂, 2♀; NZAC, USNM). OL: Cardrona River (44°53’S, 169°0.2’E; about 800 m), 7 Dec 1977, E. I. Schlinger (1♀; NZAC). SC: Peel forest, Scotsburn Stream (43°54.9’S, 171°15.7’E), P. G. McGregor 24–31 Jan 1975 (2♂, 3♀; CMNZ); Station Peak (44°45.1’S, 170°34’E; 900 m), Kurow (44°43.9’S, 170°28’E), 7 Jan 1977, P. M. Johns (6♂, 1♀; CMNZ); Queenstown (45°01.6’S, 168°39.6’E; 330 m); 27 Jan 2004, W. N. Mathis (1♀; USNM). SL: Orepuki (46°17’S, 167°44.3’E), 8 Feb 1976, L. L. Deitz (1♂, 1♀; NZAC); Te Waewae Lagoon (46°12.3’S, 167°38.1’E); 19 Jan 2004, W. N. Mathis (1♀; USNM). WD: Lake Matheson (1 km S; 43°25.6’S, 170°02.2’E), 28 Feb 1976, L. L. Deitz (1♀; NZAC).
Distribution (Map 10). Australasian/Oceanian: New Zealand. North Island (AK, BP, CL, ND, TO, WI, WN), South Island (BR, FD, KA, MC, NC, NN, OL, SC, SL, WD).
Remarks. This species seems to occur where there are lentic aquatic systems (sluggishly flowing fresh water or ponds, i.e., Lake Te Roto, Horseshoe lake, Lake Matheson), but is also found in some faster flowing river sites, i.e., Cadrona. The available collection records suggest that this species may be like some species of Scatella, living in moist soils associated with aquatic systems.
According to Roderick P. Macfarlane (deceased, personal communication), specimens of this species in the Canterbury Museum (Christchurch) were probably misidentified as a species of the genus Brachydeutera and were recorded as this genus in Winterbourn et al. (2000).
This species is very similar to P. bifurcata and reference to structures of the male terminalia is necessary to distinguish between these two species, especially the gonite-hypandrium and phallapodeme in ventral view (Fig. 51).
description: Published as part of Mathis, Wayne N. & Zatwarnicki, Tadeusz, 2019, Revision of the Shore-fly Genera Parahyadina Tonnoir and Malloch and New Zealand Hyadina Haliday (Diptera: Ephydridae), pp. 401-440 in Zootaxa 4623 (3) on pages 432-434, DOI: 10.11646/zootaxa.4623.3.1, http://zenodo.org/record/3258532