Gulgonga Oberprieler, Rasnitsyn & Brothers

Oberprieler, Stefanie K., Rasnitsyn, Alexandr P. & Brothers, Denis J., 2012, The first wasps from the Upper Jurassic of Australia (Hymenoptera: Evanioidea, Praeaulacidae), Zootaxa 3503, pp. 47-54 : 49-50

Genus Gulgonga Oberprieler, Rasnitsyn & Brothers , gen. nov.

Type species. Gulgonga beattiei Oberprieler, Rasnitsyn & Brothers , sp. nov.

Etymology. Named after the town of Gulgong, which is located 25 km south-west of the Talbragar Fish Bed fossil site and has served as the base for the excavators during recent years; gender feminine.

Diagnosis. Generalised representative of the subfamily Praeaulacinae except metasoma widely rounded basally, even wider than in Praeaulacinus Rasnitsyn, 1972 , the only other genus with the metasomal base rounded (neither triangular nor tubular), with first metasomal tergum wider than head (narrower than that in Praeaulacinus ); size large, with forewing ca. 4 mm long (unlike Praeaulacinus , 1.9–2.5 mm), antennae setiform (narrowing towards acute apex) and long (longer than forewing).

Species included. Type species only.

Remarks. Assignment of Gulgonga to the family Praeaulacidae is not unequivocal. Among Jurassic hymenopterons, it shares a combination of four features with only Ephialtitidae , Megalyridae (Cleistogastrinae) and Praeaulacidae : (i) medial mesonotal suture well developed, (ii) forewing venation moderately complete (with only SC, RS2, 1r-rs, 2A and interanal crossvein absent, compared with the hymenopteran groundplan), (iii) metasomal attachment apparently of apocritan type, (iv) external ovipositor long. Among these three taxa, Gulgonga differs from all known Cleistogastrinae in having the forewing with 2–3r-m cell longer (Cleistrogastrinae with wings shorter and wider, with 3r-m cell less than 1.5 times as long as high). Unlike Gulgonga, Ephialtitidae retain 2A and the interanal crossvein (except rare forms with a short ovipositor and a distal position of cu-a with respect to the base of M). Praeaulacidae are unique among Jurassic Apocrita in having the metasoma attached high, with much of the posterior propodeal face extending below the metasomal attachment (see Rasnitsyn & Zhang (2010) for details). Unfortunately the present fossil is preserved in an obliquely dorsoventral position, which prevents identification of the position of the metasomal attachment. Nevertheless, the balance of available evidence suggests that its best placement is in Praeaulacidae , which may however need to be revised if more complete fossils are found.

Within Praeaulacidae, Gulgonga conforms well with the diagnosis of Praeaulacinae, possessing long, polymerous antennae with smooth contours (the flagellum showing no boundaries between individual flagellomeres), forewings with a comparatively narrow pterostigma (neither widely triangular nor semicircular), the M+Cu fork much closer to the pterostigma than to the wing base, 2–3r-m and probably 2m-cu present, 3r cell not very wide and 2A absent, and hindwings with C absent. Unfortunately the poor preservation of the only known specimen renders the phylogenetic position of the genus obscure, even though its generic distinction from other Praeaulacinae is beyond doubt.