Gastrancistrus, Westwood, 1833

Mitroiu, Mircea-Dan, 2016, Pireninae (Hymenoptera: Pteromalidae) of Papua New Guinea: key to genera and description of new taxa, Mémoires du Muséum national d'Histoire naturelle 209, pp. 307-320 : 311-312

Genus GASTRANCISTRUS Westwood, 1833

Figure 1

Gastrancistrus Westwood, 1833: 444 .

Type species. Gastrancistrus vagans Westwood, 1833 ; by monotypy.

REMARK – According to Bouček (1988) the genus Gastrancistrus can be separated from Premiscogaster Girault, 1933 by the shape of the antenna: Premiscogaster has a conspicuously asymmetric clava and pedunculate flagellomeres, whereas Gastrancistrus has a symmetric clava and not or hardly pedunculate flagellomeres. However, according to Bouček (1988) and my personal observations, Premiscogaster is very close to Gastrancistrus , some diagnostic characters overlapping in the two genera. For example, Bouček (1988: 475) wrote that “all [ Premiscogaster ] species examined have […] a deep round or oval fovea on the upper part of the scrobes (at least in the females) and at least some coarse punctures on the

sides of the frons. […] The deep fovea on the scrobes is present also in Gastrancistrus punctatiscutum , which also has

coarse punctures on the head and is similar in colour to the typical Premiscogaster . However, the antennal flagellum in that species is simple and compact, with a normal, symmetric, 3-segmented clava”. Moreover, in many species from the PNG material examined, the flagellomeres before the clava are distinctly pedunculate, a deep scrobal fovea is present, but the clava is virtually symmetric (Figure 1). According to Noyes (2015), there are 18 species of Gastrancistrus and two species of Premiscogaster described from the Australasian region, mostly by Girault. Without a revision of both genera, I therefore hesitate to describe any new species.