Zemacrosaldula australis ( White, 1876 ) White, 1876

Larivière, Marie-Claude & Larochelle, André, 2015, Zemacrosaldula, a new genus of Saldidae (Hemiptera: Heteroptera) from New Zealand: taxonomy, geographic distribution, and biology, Zootaxa 3955 (2), pp. 245-266 : 249-251

Zemacrosaldula australis ( White, 1876) new combination

Salda australis White, 1876: 106 . Holotype male (BMNH; seen by Larivière & Larochelle 2004); New Zealand. Acanthia australis: Kirkaldy, 1909: 27 .

Saldula australis: Drake & Hoberlandt, 1950: 7 .

Description. Body length 4.22–5.89 (4.91) mm; elongate-ovate ( Fig. 1 ). Dorsal colour largely black, with uniformly dark or narrowly pale lateral margins of pronotum and several whitish markings on hemelytra; frequently with irregular coalesced marks on exocorium. Facial colour ( Figs 5–7 ) slightly to moderately contrasted. Head, pronotum and scutellum slightly shiny, contrasting slightly against mostly dull hemelytra. Dorsal pubescence short, reclined to semi-erect, whitish, more or less evenly distributed. Dorsal microsculpture rugulose on head, pronotum and scutellum. Head black. Face ( Figs 5–7 ) pubescent. Transverse swelling whitish yellow to pale brown; lateral portions separated by a narrow to rather wide dark gap or, rarely, almost contiguous (nearly touching) near facial midline. Mandibular plates whitish yellow to pale brown or nearly black. Maxillary plates, anteclypeus and labrum whitish yellow to pale brown; anteclypeus often marked with brown basally. Antennae 4.07–4.33x longer than pronotum + collar medially, largely dark; segment I whitish yellow to yellowish brown, with ventral and dorsal sides dark brown to black (often striped), sometimes nearly entirely black; segment II dark brown to black, often paler in apical fourth, 2.40–2.77x longer than segment I; segments III–IV dark brown to black, sometimes slightly darker than segment II. Thorax. Lateral margins of pronotum subrectilinear to very slightly sinuate-concave, uniformly dark or, more rarely, narrowly pale (pale area usually narrower than, sometimes about as wide as antennal segment II). Underside black, with sharply contrasting broadly or narrowly pale acetabula I–III (acetabulum III rarely completely dark) and partially (posterior quarter to half) to almost completely pale lateral margins; pubescence rather dense, silvery, appressed (except for glabrous lateral margins). Legs moderately dark; fore, mid femora, and often hind femora striped with dark brown to nearly black on ventral and dorsal sides, along part or entire length, otherwise whitish yellow with some brown spots, or, nearly completely black; tibiae with dark brown to black dorsal stripe over most of length (mid and hind tibiae often infuscate only) and black subapical annulus, otherwise whitish yellow with dark spines; hind tibiae 2.70–2.76x longer than tarsal segments II+III combined; tarsal segment II darkened or not apically, otherwise whitish yellow, segment III brown in apical half (more rarely completely brown); pretarsal claws long, about half the length of tarsal segment III. Scutellum black, 1.76–1.91x longer than pronotum + collar medially. Hemelytra: corium ( Fig. 11 ) largely black with several irregular, often coalesced, whitish markings; endocorium with a line of four pale spots along R vein, a few additional spots subapically along membrane, and sometimes a longitudinal mark about middle; exocorium frequently with rather large irregular coalesced markings on basal third to three-quarters and an irregularly shaped medial mark subapically; colour pattern in female consistent with that of male but often paler overall with broader markings; pale markings in darker individuals not coalesced, reduced in size and numbers, with line of four spots still visible but reduced to diminutive spots or speckles; corium in darkest individuals almost entirely black with only a few speckles; corium and clavus largely pruinose; basal pale spot of clavus present or absent; subapical pale spot of clavus present or, more rarely, absent; membrane dark brown to black basally with a pale mark near tip of clavus, brown medially within cells, pale elsewhere, and with dark brown to black veins. Abdomen. Venter black, with or without posterior margin of most segments narrowly pale (generally more broadly pale in female). Pubescence rather dense, silvery, appressed in both sexes. Male parandria ( Fig. 19 ) narrowly subtriangular, acuminate at tip; inner margins evenly curved; basal margin slightly sinuate. Male paramere ( Fig. 15 ) without distinct processus sensualis; instead, with flat cuticular surface bearing less than 10 setae; processus hamatus acuminate and slightly upturned at tip. Apical half of male aedeagus ( Fig. 21 ), in lateral view, with 3 main visible sclerites (elongate median sclerite; subelongate, bent anterolateral sclerite; small, often subtriangular anterolateral sclerite). Male aedeagal sclerites, in ventral view, as in Fig. 23 . Male filum gonopori ( Fig. 24 ) coiled 1.5 times. Female subgenital plate (segment VII, ventrally) black with apical half pale or plate largely pale. Other characters as in generic description.

Geographic distribution ( Fig. 26 ). North Island and northeastern South Island.

Material examined. A total of 621 specimens including holotype, from the following localities. North Island. BP —Kaimai Range, Dickey Flat Road end ( NZAC); Papatea, Waiti Stream ( NZAC); Urewera National Park, Waimana River Valley, Pohatu Track, 3.2 km E Tauwhare ( NZAC); Waioeka Gorge, N of Oponae and S of Opotiki ( AMNZ). CL —Coromandel Range, Stony Bay ( NZAC); Coromandel Range, West of Kirikiri Saddle ( NZAC); Coromandel Range, Tapu River Valley ( AMNZ). GB —Karakatuwhero River Valley, by upper ford ( NZAC); Mangatuna ( NZAC); Morere ( AMNZ); Te Awha Stream, Rangitukia Road ( NZAC); Urewera National Park, Aniwaniwa ( NZAC); Urewera National Park, Te Taita a Makaro ( NZAC). HB —Kaweka Forest Park, Lawrence Road access, Tutaekuri River ( NZAC); Tangoio (near) ( AMNZ); Tukituki River, Pourerere Road, 10km E of Waipawa ( NZAC); Wakarara, upper Waipawa River ( NZAC). RI —Kawhatau River, Junction of Toetoe & Potaka Roads ( NZAC); Mangaweka, Rangitikei River bridge ( AMNZ); Vinegar Hill, Junction of Vinegar Hill Road & Rangitikei River ( NZAC). TK —Inglewood, Manganui River ( AMNZ); Mangorei ( AMNZ); Mount Egmont (N side) ( AMNZ). TO —Lake Taupo ( AMNZ); Mount Ruapehu (Whakapapanui Stream above Chateau ( AMNZ); Whakapapanui Stream, dam ( AMNZ)); Owhango, Whakapapa River ( AMNZ); Taupo ( NZAC); Whakapapanui Stream, Junction of Mahuia Rapid & Highway 47 ( NZAC). WA —Dannevirke, Manawatu River, Aerodrome Road end ( NZAC); Makaretu River, 2 km N of Takapau ( NZAC); Mangatewainui River, Junction with Gundry Road ( NZAC). WI —Whangaehu River, 5km N of Mangamahu ( NZAC). WN —Kimberley Scenic Reserve (S of Levin), Ohau River ( NZAC); Ngatiawa River ( NZAC); Otaki (6 km S ( NZAC); 6 km SE ( NZAC)); Otaki Forks ( AMNZ). WO —Mangaotaki River, S of PioPio ( AMNZ). South Island. BR —Buller River, Gowan River Bridge ( NZAC); Maruia River, Maruia Falls ( NZAC); Rotokohu, Inangahua River ( NZAC); Inangahua area, White Cliffs, Buller River ( AMNZ). KA —Clarence River mouth ( NZAC); Clarence River, 12 km inland via Clarence Valley Road ( NZAC); Oaro ( LUNZ), Omihi Stream mouth ( LUNZ). MB —Pelorus River, Daltons Bridge ( NZAC); Wairau River (2.5 km N of Leatham Road ( NZAC); Church Lane end ( NZAC)). MC —Highway 73, 15 km W of Springfield ( NZAC); Rakaia River ( NZAC); Waimakariri Gorge ( CMNZ), N of Waddington ( NZAC); Waimakariri River ( CMNZ). NC —Hurunui Bridge (N side) ( CMNZ); Junction of Hope River & Highway 7 ( NZAC); Kairaki Beach ( CMNZ).

Biology. Altitudinal range. Lowland (mostly) to low montane, more rarely high montane (e.g., central North Island volcanic plateau). Not usually coastal; may be present in predominantly freshwater habitats located near the mouth of rivers that also harbour inland populations. Habitat. Occurs along stony-gravelly (or shingled) riverbanks, riverbeds or, less frequently, lakeshores; saxicolous, found mainly on gravel, stones or boulders near the water’s edge, usually within 0.5 to 3 m from the waterline, as well as on stones or boulders emerging from the water; mostly in sandy environments, also in slightly silty or clayish situations; primarily near moderate to fast running water, also near calmer water (e.g., side river channels or temporary backwaters). Sometimes found on bare ground patches between stones or boulders near the waterline or, occasionally, near rocky seepages away from a main river channel. Nymphs live in the same habitat, on the ground surface between and under stones or among gravel. Seasonality. Adults collected from October to April; mating pairs observed in December; newly emerged adults (tenerals) collected mostly in December and March; nymphs found from October to March—suggesting overwintering in the egg stage, nymphal development in the spring and emergence of a new summer generation from December, possibly with a one or two month delay in southern parts of the distribution range or at higher altitudes. Food. Predator or scavenger. Behaviour. Jumps from stone to stone, flies short distances (usually less than 2 m), dashes quickly into the space between stones or into water when disturbed. Heliophilous; hides under and between stones, in cloudy or rainy weather.

Remarks. Zemacrosaldula australis is the most widely distributed species of this genus. It is the only Zemacrosaldula species known from the North Island and it occurs also in northern areas of the South Island. Zemacrosaldula australis closely resembles the South Island endemic Z. kapekape and can be difficult to distinguish from it although the two species are largely allopatric. In addition to characters of the male genitalia Z. australis bears the following distinguishing features: hemelytra usually with larger, more coalesced pale markings; antennae with longer segment II; paramere with more acutely tipped processus hamatus. Dissection of the male genitalia is necessary to diagnose the two species with certainty, especially when dealing with darker specimens with reduced hemelytral markings or populations that occur in relatively close proximity (e.g., on the South Island west coast).

On the North Island Z. australis should not be confused with Saldula trivialis Cobben, 1961 or Saldula maculipennis Cobben, 1961 . These two taxa may be conspecific or part of an unresolved species-complex. They superficially resemble Z. australis albeit in a diminutive version with highly distinctive, acutely tipped male parandria (see Fig. 30 in Cobben 1961) and broadly pale sides of the female abdominal venter.

Morphologically speaking, Z. australis is the most highly variable species in this genus. As a general rule this species is more darkly coloured and somewhat smaller in body size in southern parts of its range, in more mountainous or generally colder habitats (e.g., central North Island volcanic plateau) although Z. australis is not typically monticolous. Anomalous looking specimens of Z. australis , somewhat reminiscent of Z. whakarunga , were observed from several South Island populations, especially in the lowlands and along the coast in a Kaikoura (KA), North Canterbury (NC), and Mid Canterbury (MC). The identity of these specimens could only be confirmed when male specimens were available for genitalic dissection.

Variations in facial colour, pubescence, and degree of development of transverse swelling ( Figs 5–7 ) encountered in this species are similarly observed in Z. kapekape and Z. whakarunga .

Figures

FIGURE 26. Collecting localities of Zemacrosaldula species, New Zealand.

FIGURES 1 – 4. Dorsal views of Zemacrosaldula species (legs and antennae omitted). Scale bar = 1 mm. (1) Z. australis, (2) Z. kapekape, (3) Z. whakarunga, (4) Z. pangare.

FIGURES 5 – 10. Facial views of Zemacrosaldula species. (5 – 7) Z. australis, (8) Z. kapekape, (9) Z. whakarunga, (10) Z. pangare.

FIGURES 11 – 12. Eunomy (left corium), with more frequently observed pigmentation patterns indicated by an asterisk (*). (11) Zemacrosaldula australis (cl = clavus, en = endocorium, ex = exocorium), (12) Z. kapekape.

FIGURES 15 – 24. Schematic views of male genitalia. (15 – 18) Paramere, ventral view. (15) Zemacrosaldula australis, (16) Z. kapekape (ph = processus hamatus), (17) Z. whakarunga (ps = processus sensualis), (18) Z. pangare. (19 – 20) Parandria, posterior view. (19) Z. australis, (20) Z. whakarunga. (21 – 22) Anterior half of aedeagus, lateral view. (21) Z. australis, (22) Z. whakarunga. (23) Sclerites of aedeagus, Z. australis, ventral view. (24 – 25) Filum gonopori, lateral view. (24) Z. australis, (25) Z. whakarunga.