Aulacus obcordellus Jennings & Parslow, 2018

Jennings, John T., Parslow, Ben A. & Austin, Andrew D., 2018, Systematics of the parasitoid wasp genus Aulacus Jurine (Hymenoptera: Evanioidea: Aulacidae) from Australia, Zootaxa 4538 (1), pp. 1-113 : 69-70

Aulacus obcordellus Jennings & Parslow , sp. nov.

Figs 37 , 64 .

Material examined. Holotype. ♀, " Arve Valley [Tasmania], ex Nothofagus cunninghamii, Host : Nascoides quadrinotata, coll. 27.1.[19]83 R. Bashford. ( TMAG) . Paratypes. Queensland: 1♀, Mt Glorious , Dec. 12, no other data ( AEI) . Victoria: 3♀, Mt. Dandenong , 200 m . 11-22.ii (no year) ( AEI). Tasmania: 1♀, Frenchmans Cap, Franklin River , 14-21 Feb., no other data ( AEI) ; 1♀, Franklin River, 22 Feb. –26 Mar., no other data ( AEI) .

Description. FEMALE. Length. 7.9 (6.6–9.4) mm, excluding ovipositor.

Colour. Meso and metasoma orange, head black except variable amounts of orange on sub-antennal grooves, antenna black except flagellomeres 5–7 white, ovipositor sheaths black except tips pale orange ( Figs 37A, B ). Wings hyaline, brownish tinge ( Fig. 37B ).

Head. 1.64 (1.43–1.97)× wider than long when viewed dorsally ( Fig. 37C ); face punctate-reticulate, pubescence long; deep sub-antennal groove; frons pronounced lateral medial carina above toruli, punctatereticulate except smooth below carina where scape fits, with short pubescence; vertex reticulate with a few scattered shallow punctures, a few striations posteriorly, with scattered short setae; gena reticulate, a few shallow punctures near eye, with scattered short setae; posterior margin of head sinuate in dorsal view; occipital carina absent; malar space 0.35 (0.33–0.38)× height eye; clypeus 2.8× as wide as high, margin sinuate, weak medial process; distance from lateral ocellus to eye margin 1.2 (1.1–1.3)× distance between lateral ocelli; scape 2.3 (2.1– 2.5)× length pedicel; first flagellomere 1.30 (1.14–1.46)× as long as scape, 0.53 (0.47–0.60)× as long as second flagellomere.

Mesosoma. Propleuron rugulose and with short setae dorsally, smooth and with long setae laterally, ventrolateral carina broad, flange-like; pronotum punctate-reticulate dorsally to smooth ventrally; mesoscutum in lateral view distinctly angular antero-dorsally, medial lobe distinctly heart shaped in dorsal view, medial and lateral lobes coarsely strigate, with scattered short setae ( Fig. 37D ), admedial lines indistinct; notauli distinct, carinate, narrow and shallow; scutellum and axillae coarsely strigate, scutellum anteriorly with a single shallow depression ( Fig. 37E ); metapostnotum scrobiculate, posterior margin convex; mesopleuron rugose, coarse ventrally, with scattered short setae; mesepimeron broad, carinate dorsally, smooth ventrally; metapleuron smooth dorsally, rugose ventrally with scattered short setae; propodeum coarsely rugose, almost areolate, posterior margin scrobiculate; hind coxa rugulose, with short scattered setae, ovipositor guide absent; hind trochanter imbricate, with scattered short setae; prefemur on hind leg present; hind femur imbricate, with scattered short setae; hind tibia imbricate, pubescence short, with scattered stout emergent setae; hind femur 0.76 (0.74–0.78)× length hind tibia; hind tibia with blunt dorso-apical process; hind tarsomeres 1–4 with ventro-apical pecten of short robust spines, tarsomere 1, 3.0 (2.6– 3.3)× length tarsomere 2; tarsomere 2, 1.6 (1.4–1.8)× length tarsomere 3; tarsomere 3, 2.1 (1.8–2.3)× length tarsomere 4; tarsomere 4, 0.49 (0.45–0.55)× length tarsomere 5; hind tarsal claw 0.44 (0.42–0.45)× length tarsomere 5; fore wing veins 2r-m and 3r-m largely spectral; hind wing venation complete, R+Rs, M+Cu, Cu, r-m and 2-M spectral, with 3 hamuli.

Metasoma. Ovate, 1.19 (1.12–1.21)× length of mesosoma ( Fig. 37B ); T1 and T2 broad, several shallow and indistinct punctures antero-dorsally; ovipositor 6.3 (5.2–7.0) mm.

MALE. Unknown.

Etymology. This species is named obcordellus , meaning 'small heart shaped', in reference to the shape of the medial lobe of the scutellum when viewed dorsally ( Fig. 37F ).

Distribution. This species has been collected from three widely separated localities, Mt Glorious, southeastern Queensland, Mt Dandenong, Victoria, and Frenchmans Cap, western Tasmania ( Fig. 64 ).

Biology. The holotype was reared from Nascoides quadrinotata ( Buprestidae ) infesting Nothofagus cunninghamii (Nothofagaceae) , Arve Valley, Tasmania.

Comments. Aulacus obcordellus keys out with A. scitulus . Although very similar in appearance, they can be separated by the sculpturing on the face, punctate-reticulate in A. obcordellus and punctate-rugose in A. scitulus . Both species have a black head and orange meso- and metasoma, but there are some minor colouration differences. For example, A. obcordellus has black antennae except flagellomeres 5–7 white, and ovipositor sheath black except tip pale orange, whereas A. scitulus has black antennae except flagellomeres 4–7 cream, and ovipositor sheath brown. There are also differences in the metasoma, with A. obcordellus having metasoma 1.19 (1.12–1.21)× length of the mesosoma, and T1 and T2 broad with several shallow and indistinct punctures antero-dorsally, whereas in A. scitulus the metasoma is 1.3× the length of the mesosoma, and T1 and T2 are narrow, glabrous, and smooth tending to imbricate with scattered, small punctures posteriorly.

Further collecting of these two species may reveal that the differences highlighted are simply intra-specific and that the two species are synonymous.

Figures

FIGURE 37. Aulacus obcordellus sp. nov., paratype female, (A) dorsal habitus; (B) lateral habitus; (C) dorsal head; (D) lateral head; (E) dorsal mesosoma; (F) dorso-lateral pronotum and mesoscutum.

FIGURE 64. Distribution of Aulacus obcordellus sp. nov., A. pallidicaudis (Cameron), A. pallidus sp. nov., and A. planiceps (Szépligeti).