Trigastrotheca Cameron

Quicke, Donald L. J., Butcher, Buntika A., Ranjith, A. P. & Belokobylskij, Sergey A., 2017, Revision of the non-Afrotropical species of Trigastrotheca Cameron (Hymenoptera: Braconidae: Braconinae) with descriptions of four new species, Zootaxa 4242 (1), pp. 95-110 : 96-97

Trigastrotheca Cameron

Trigastrotheca Cameron (type species Trigastrotheca trilobata Cameron, 1906 )

Coelodontus Roman (type species Ichneumon costator Thunberg, 1822 ) synonymized by Quicke (1987) but see below. Odontopygia Enderlein (type species Odontopygia tridentata Enderlein [1918] 1920 )

Kenema van Achterberg (type species Kenema quickei van Achterberg, 1983 ) synonymized by Quicke (1987)

The descriptions of Coelodontus and Odontopygia are only based on females and therefore share the unique modification of the 5th metasomal tergite of other Trigastrotheca species. Quicke & Stanton (2005) explained the nomenclatural difficulties posed by Roman’s (1912) ‘improvement’ of the name given by Thunberg for the type species of Coelodontus, and so proposed the replacement name T. romani . The genus Kenema was a genus described by van Achterberg (1983) based on a male specimen collected by the senior author near the town of Kenema in Sierra Leone. It was not known at that time that male Trigastrotheca lack the submedial emarginations of the 5th metasomal tergite that females have, but instead have a very elongate and densely sculptured 5th tergite. We have seen numerous, mixed-sex, series of specimens (from Africa) that shows that this is a simple sexual dimorphism. Unfortunately, several of the new species described below are known only from males, but examination of mixed-sex series of what are virtually certainly conspecifics, indicates that apart from the modified 5th metasomal tergite, morphological characters and colour patterns are not noticeably intra-specifically variable. We therefore feel confident in describing new species of two species herein based only on males, though this might not normally be sensible within the Braconinae. Interestingly, there is very little size variation within a species of Trigastrotheca irrespective of sex, and therefore they do not display the normal sexual dimorphism that so many other idiobiont parasitoids do ( Quicke 2015).

Female Trigastrotheca may be recognised by using the key to Old World braconine genera provided by Quicke (1987), and can be distinguished from all other braconines by the pair of submedial emarginations of the 5th metasomal tergite separated by a pointed medial protuberance ( Figs 2 , 6 B, C). Males lack this modification and instead have a strongly sculptured and elongate 5th metasomal tergite. This sexual dimorphism led van Achterberg (1983) to believe that a male Trigastrotheca actually represented a separate genus and described it as Kenema. Quicke (1987), having seen mixed-sex, apparently conspecific series from the same locality, synonymised Kenema with Trigastrotheca , but not before van Achterberg & Sigwalt (1987) had described a further species under the name of Kenema.

Figures

FIGURE 2. Trigastrotheca luzonensis Quicke & Butcher sp. nov., holotype, female, (♀). A, metasomal tergites 2 – 5, posterodorsal view; B, metasomal tergite 5, lateral view.

FIGURE 6. Trigastrotheca pariyanonthae Quicke & Butcher sp. nov., holotype, female, (♀). A, fore wing; B, metasoma, posterior view; C, metasomal tergites 4 – 5, lateral view.