Choeras zygon Fagan-Jeffries & Austin, 2019

Fagan-Jeffries, Erinn P., Cooper, Steven J. B. & Austin, Andrew D., 2019, New species of Australian microgastrine parasitoid wasps (Hymenoptera: Braconidae: Microgastrinae) documented through the ‘ Bush Blitz’ surveys of national reserves, Zootaxa 4560 (3), pp. 401-440 : 407-408

Choeras zygon Fagan-Jeffries & Austin sp. nov.

( Figs 5–6 )

urn:lsid:zoobank.org:act:246CA6AB-857D-47E3-9986-E616D861A21E

Material examined (including Genbank numbers of DNA barcodes). Holotype: Queensland: ♀ Lamington NP - 28.21° 153.139°, 15–25/i/2007, C. Lambkin, N. Starick, 474m, IBISCA Plot # IQ-500-C, rainforest Malaise trap (QM: T208374 ; Genbank COI: MH138822 WG: MH139278 ). Paratypes: New South Wales: ♀ East Boyd State Forest, Goanna Rd , 37°12'05"S 149°46'30"E, 06/xii/2004 – 12/i/2005, C. Lambkin & N. Starick, Malaise across disused snig-track in forest 56 km SE Bombala, 219 m ( ANIC: 32 130201; Genbank COI: MH 138605 ) . Queensland: ♀ Lamington NP, -28.262 153.17, 11–21/iii/2008, C. Lambkin & N. Starick, 1140m, IBISCA Plot # IQ-1100-D, rainforest Malaise trap ( QM: T208375 ; Genbank COI: MH 138872 ) . South Australia: ♀ Cox Scrub Conservation Park , 35°19'52"S 138°44'51"E, 25/i/2016 – 13/ii/2016, A. Austin, Malaise trap ( WINC; Genbank COI: MH 138601 WG: MH 139098 ) . Tasmania: ♀ Pieman River State Reserve Bush Blitz: E of Corinna campground, SSS2, -41.6556 145.0819, 27/i/2015, S. Grove, Malaise trap ( TMAG: F59027 ; Genbank COI: MH 138612 WG: MH 139106 ) . Victoria: ♀ Vic, Grampians National Park Bioscan, 37°19'51"S 142°11'36" E, 26–28/xi/2012, B. Patullo, P. Lillywhite, Malaise trap, Ming Ming Swamp GB442 ( MV: HYM-61350; Genbank COI: MH 138614 ) . ♀ Vic, Grampians National Park Bioscan, 37°19'53"S 142°11'17" E, 26–28/xi/2012, B. Patullo, P. Lillywhite, Malaise trap, Ming Swamp GB442 ( MV: HYM-61351; Genbank COI: MH 138615 WG: MH 139107 ; stored in ethanol) .

Diagnosis. Choeras zygon can be separated from the other Australasian species of Choeras with a small fore wing areolet by having T2 narrowing posteriorly (as opposed to the almost parallel sided T1 of C. calacte and C. parvoculus ) and differs from C. papua by a lack of pale orange colouration over the entire body.

Description. FEMALE. Colour: body dark, ranging from ‘black’ in Tas, SA and Vic specimens to ‘reddishbrown’ in specimens from Qld and NSW, pale non-sclerotised areas of T1-2, sternites, and hypopygium; antenna dark, sometimes with paler scape and pedicle; coxae (pro-, meso-, metacoxa) pale, pale, dark fading to pale in distal half; femora (pro-, meso-, metafemur) dark, dark, dark, although colour much paler in Qld and NSW specimens; tibiae (pro-, meso-, metatibia) dark with pale area in proximal third, colour much paler in Qld and NSW specimens; tegula and humeral complex pale in Qld and NSW specimens, dark in others; pterostigma dark; fore wing veins dark. Head: antenna approximately equal to body length; body length (head to apex of metasoma) 2.3– 2.9 mm; ocular–ocellar line/posterior ocellus diameter 2.0–2.6; interocellar distance/posterior ocellus diameter 1.5–2.0. Mesosoma : anteromesoscutum smooth with shallow punctures associated with setae; mesoscutellar disc completely smooth with sparse setae; number of pits in scutoscutellar sulcus 8–10, maximum height of mesoscutellum lunules/maximum height of lateral face of mesoscutellum 0.3–0.6. Wings: fore wing length 2.2–2.6 mm; length of veins r/2RS 1.5–2.0; vein r slightly curved; length of veins 2RS/2M 0.7–0.9; length of veins 2M/ (RS+M)b 0.9–1.4; pterostigma length/width 2.5–2.8; fore wing areolet small and closed. Legs: metatibia inner spur length/metabasitarsus length 0.3–0.4. Propodeum: often with short carinae or rugosity radiating from centre of posterior boundary, sometimes with a medial longitudinal carina in posterior half, or a complete medial longitudinal carina, posterior lateral corners of propodeum rugose, sometimes area either side of medial longitudinal carina rugose, remainder of propodeum smooth. Metasoma: T1 length/width at posterior margin 2.1– 2.7; T1 narrowing slightly posteriorly, anterior half often with rugosity on lateral edges, often smooth in centre, posterior half shallowly punctate with surrounding rugosity, sometimes with smooth semi-circle at border with T2; T2 width at posterior margin/length 2.6–4.0; T2 sculpture mostly smooth, sometimes with longitudinal striations right at border with T1, sometimes with very shallow pits near border with T3; hypopygium large with membranous area mid-ventrally; ovipositor sheaths length/metatibial length 1.1–1.2.

MALE. Unknown.

Etymology. The name ‘zygon’ references the shape-shifting race of aliens on the BBC television show Doctor Who. The shape-shifting nature of this fictional race mirrors the large morphological variability within C. zygon , which appears to ‘shape shift’ (i.e. variation in colour and sculpture) between different populations whilst retaining extremely small molecular divergences. The Zygon in Doctor Who also consume their ‘host’, a trait particularly relevant to endoparasitoid wasps. The species name is a noun in apposition.

Distribution. This species is widespread and currently known from South Australia, southern Qld, New South Wales, Victoria and Tasmania.

Remarks. This species shows variation in characters often used to separate species of Microgastrinae, namely the sculpturing of the propodeum and T1, and also shows geographical variation in colour. However, there is less than 1.4% divergence among the COI sequences of these specimens, well below the threshold often used to delimit species in this subfamily. As such, we describe this species as one with substantial morphological variation associated with different populations, which nonetheless has distinct characters that separate it from other described species of Choeras from Australasia. However, the variation in the propodeal and T1 sculpture will need to be taken into account when more species are described, particularly those which are shown from molecular analyses to be closely related. Specimens from South Australia, Victoria and Queensland shared a WG haplotype, however the WG sequence of the specimen from Tasmania is 4 bp (of a total 443 bp sequence length) different. The nearest neighbour with available COI DNA barcodes is an unidentified species of Choeras from Queensland, at a distance of 2.9%. The BOLD BIN for C. zygon is BOLD:ADL3152.

Figures

FIGURE 5. Choeras zygon holotype. A. dorsal habitus; B. mesosoma and T1–2; C. anterior head; D. fore wing; E. lateral habitus.

FIGURE 6. Choeras zygon range of propodeal and T1 sculpturing. A. specimen from NSW, propodeum with radiating short carinae and no clear longitudinal medial carina with much reduced rugosity in medial area; B. paratype from Qld, indistinct medial carina, rugosity around centre longitudinal area; C. specimen from Tas, as in B; D. specimen from Vic, strong medial longitudinal carina, rugosity surrounding medial area, T1 with smooth area at border with T2. Scale bars = 0.5 mm.