Gasteruption youngi, Jennings & Parslow, 2014

Jennings, John T. & Parslow, Ben, 2014, Gasteruption youngi sp. nov. (Hymenoptera: Evanioidea: Gasteruptiidae) from South Australia; an unusual species with trichoid sensilla on the ovipositor sheaths, Zootaxa 3872 (1), pp. 95-100 : 96-97

Gasteruption youngi sp. nov.

( Figs 1–7 , 10 )

Material examined. Holotype: ♀, “S. AUST. Wirrabara Forest , Sweeping, 7.iv.2007 J. T. Jennings.” SAM.

Paratypes: South Australia: 3♀♀ Melaleuca Cottage, Vivonne Bay, Kangaroo Island . 35°58.690S 137°10.870E, hovering above open ground, 15Feb2010, D.A. Young. Associated with bee. ( WINC). [♀ bee with same locality data separately pin mounted]

Female. Length. 5.71 mm (4.75–6.20 mm), excluding ovipositor.

Colour. Head and mesosoma black, antennae and metasoma dark brown-black ( Figs 1–2 ); mandibles and genae largely orange-brown; labio-maxillary complex mostly white ( Fig. 4 ); legs dark brown, except cream band at apex of trochanters, base and apices of femurs, fore and mid tibiae cream, tarsi paler brown ( Fig. 1 ); apical third of ovipositor white, tip brown; apical third of ovipositor sheaths white ( Fig. 7 ); wing veins and pterostigma brown ( Fig. 5 ).

Head. 1.98 (1.8–2.1) × as long as wide in dorsal view ( Fig. 3 ); face punctate, rugulose, pubescence long, denser near clypeus ( Fig. 3 ); frons with indistinct medial carina, punctate-rugulose, long setae near antennal scrobes; vertex punctate-rugulose, scattered long setae, denser medially; occipital carina narrow; genae punctaterugulose, scattered setae ( Fig. 5 ); malar space 0.1 × height eye ( Fig. 4 ); clypeus 0.37 × as wide as high, margin sinuate, with long setae; mandibles broad, with 1 large median tooth; distance between lateral ocellus and inner eye margin 0.76 (0.67–0.83) × distance between lateral ocelli ( Fig. 3 ); scape 2.64 (2.35–2.84) × length pedicel; first flagellomere 0.42 (0.37–0.53) × as long as scape, 0.77 (0.72–0.83) × length second flagellomere.

Mesosoma. Propleura punctate-rugulose, pubescence long; pronotum punctate-rugulose; mesoscutum in lateral view rounded antero-dorsally, median and lateral lobes punctate-rugulose, tending to reticulate anterolaterally, with long setae anteriorly; notauli U-shaped, marked by punctures; mesoscutellum and axillae with a few scattered punctures; mesopleura and metapleura punctate-rugulose, with scattered long setae; propodeum punctate-rugulose; hind coxae punctate-rugulose; hind trochanters and femora punctate-rugulose, pubescence short; prefemora small, about one-third length of trochanters; hind tibiae strigate-rugose on outer surface, with scattered punctures, pubescence generally short, with scattered long setae, inner surface punctate-rugulose, with dense short setae; hind femora 0.67 (0.60–0.71) × length hind tibiae; hind tibiae with ventro-apical pecten of short robust spines; hind tarsomeres 1–5 with ventro-apical pecten of short robust spines, tarsomere 1, 2.78 (2.65–2.85) × length tarsomere 2; tarsomere 2, 1.26 (1.05–1.46) × length tarsomere 3; tarsomere 3, 1.46 (1.36–1.6) × length tarsomere 4; tarsomere 4, 0.53 (0.5–0.61) × length tarsomere 5; hind tarsal claw 0.49 (0.38–0.61) × length tarsomere 5; wings hyaline, fore wing vein 1-Rs+M forming a node at 1-Rs, M+Cu and 1-Cu ( Fig. 5 ); fore wing vein 2-M spectral, except apical third nebulous ( Fig. 5 ); hind wing with 3 hamuli ( Fig. 5 ).

Metasoma. 2.0 (1.95–2.06) x length of mesosoma; metasomal tergites reticulate medially, smoother laterally, with scattered punctures on T 3– T 8, most punctures with a long, thin trichoid sensillum (mean length ~ 0.27 mm), sensilla denser laterally, with density increasing gradually towards end of metasoma ( Fig. 7 ); terebra 1.26 (1.20–1.30) mm; ovipositor sheath dorsally coarsely strigate near base progressing to smooth apically, with stout trichoid sensilla (mean length ~ 0.27 mm) on the dorsal (outer) surface ( Fig. 7 ).

Male. Unknown.

Variation. One specimen from Kangaroo Island has an extra cross-vein in the discal cell of the left fore wing ( Fig. 6 ).

Host/associations. On Kangaroo Island, this species has been collected with Euryglossula microdonta ( Rayment, 1934) (Apoidea: Colletidae : Euryglossinae ) ( Figs 8–9 ).

Etymology. This species is named in honour of D. A. (Andy) Young, Kangaroo Island, South Australia.

Diagnosis. This species can be readily separated from all other Australian Gasteruption species by the abundant stout trichoid sensilla on the ovipositor sheaths ( Fig. 7 ).

Remarks. The authors have examined several thousand Gasteruption specimens from Australasia and other biogeographical regions, and as far as is known, the presence of stout trichoid sensilla on the ovipositor sheaths is unique to this species. It should also be noted that Hyptiogaster (Hyptiogastrinae) have exserted ovipositors, but none have setose ovipositor sheaths ( Jennings & Austin 1997, 2002). The exact function of the stout trichoid sensilla on the ovipositor sheaths has not been determined.

The long, thin trichoid sensilla on metasomal tergites T3–T8, which are denser laterally and towards the apex of the metasoma ( Fig. 7 ), are apparently also distinctive for this species. Their function is also unknown.

The specimens from Kangaroo Island were collected along with the bee Euryglossula microdonta , and it is highly likely that this is the host of Gasteruption youngi sp. nov. These small bees that are ~ 3.5 mm in length ( Figs 8–9 ) have a disjunct distribution, being known from various localities in South Australia (Kangaroo Island, Keith, Tintinara and Wallaroo— Fig. 10 ) and the type locality, Rottnest Island, Western Australia ( Rayment 1934).

Figures

FIGURE 10. Distribution of Gasteruption youngi sp. nov. (■) and Euryglossula microdonta (●) in South Australia.

FIGURES 1–2. Gasteruption youngi sp. nov., paratype ♀. 1. Dorsal habitus; 2. Lateral habitus.

FIGURES 3–7. Gasteruption youngi sp. nov., paratype ♀. 3. Frontal head; 4. Lateral head; 5. Left fore and hind wings; 6. Left fore wing showing discal cell variation; 7. Lateral ovipositor and ovipositor sheaths.

FIGURES 8–9. Euryglossula microdonta ♀. 8. Lateral habitus; 9. Dorsal habitus.