Markshawius Fernandez-Triana, 2018

Fernandez-Triana, Jose L & Boudreault, Caroline, 2018, Seventeen new genera of microgastrine parasitoid wasps (Hymenoptera, Braconidae) from tropical areas of the world, Journal of Hymenoptera Research 64, pp. 25-140 : 81-82

Markshawius Fernandez-Triana gen. n.

Type species.

Markshawius erucidoctus Fernandez-Triana & Boudreault, here designated.

Diagnostic description.

Female head elongate and strongly concave posteriorly, modified to be tightly appressed to and follow the contour of anterior margin of pronotum (pronotum also concave). Upper margin of face produced dorsally between the antennal insertions into a triangular flange (Figs 28B , 29B , 30B , 31B ). Face looking almost depressed, and with very strong sculpture including transverse striae and punctures (Figs 28B , 29B , 30B , 31B ). Frons very elongate, with ocelli clearly much higher than normally found in Microgastrinae . Frons with strong excavation at antennal base -better appreciated on a lateral view of the head (Figs 29C , 31E ). Antenna very short (much shorter than body length, usually shorter than the combined length of head and mesosoma), with all flagellomeres but first with a single row of placodes (Figs 28A, E , 29A , 30A , 31A ). Pronotum only with lower sulcus (which is sometimes barely visible). Propodeum with median carina clearly visible on posterior half (sometimes that carina looks divided, giving the impression of actually being the posterior half of a very thin areola). Propodeum sometimes with transverse rugosity medially, including a poorly and partially defined transverse carina (Figs 28D, F , 29F, G , 30E, F , 31G, H ). Fore wing with large, four-sided areolet (Figs 28C , 29D , 30D , 31D ). Legs in general short and stout, especially metafemur (Figs 28A , 29A , 30A , 31A ). T1 with unusual, very distinctive shape: in some species being extremely long and thin (T1 length at least 6.0 × its width centrally) (Figs 29E-G , 30D, E ), in other species very thin on anterior 0.3-0.4, then strongly widening towards posterior margin (width at posterior margin around 3.0 × its width centrally) (Figs 28D, F , 31F, G ). T2 either trapezoidal and with lateral margins strongly sculptured, or subtriangular and with lateral margins less sculptured (Figs 28D, F , 29E-G , 30D, E , 31F, G ). Ovipositor sheaths almost without setae (with only very few, small setae near apex that are usually invisible at less than 100 × of magnification), ovipositor strongly narrowing toward apex, where it looks almost needle-like.

Putative autapomorphies and potentially related genera.

The carination pattern of propodeum is unique among Microgastrinae . The two known shapes of T1 are also highly unusual. All species of Protomicroplitis and Wilkinsonellus , and some species of Apanteles , Diolcogaster and Venanides have very long and thin T1; however, they have a strong median sulcus on T1 ( Diolcogaster , Protomicroplitis and Wilkinsonellus ) or are completely unrelated genera with many different and distinguishing features compared to Markshawius ( Apanteles and Venanides ). The shape of the head is similarly shared with a few species of other genera (e.g., Diolcogaster and, to a lesser extent also some species of Cotesia , Keylimepie and Venanides ). All of those genera, except for Diolcogaster , are unrelated to Markshawius , suggesting that trait likely evolved independently several times within Microgastrinae parasitizing stem borers.

Biology.

Hosts are unknown at present. However, it is here hypothesized that the modification of head and pronotum serves the purpose of facilitating entering into or egressing from narrow tunnels where the caterpillar hosts live, and those hosts most likely are stem borers, perhaps from the Lepidoptera superfamily Pyraloidea .

Distribution.

All known species are found in the Oriental region (Thailand, Vietnam).

Molecular data.

Only one sequence available (a complete barcode), but it is very unique, 11.2 % different than next Microgastrinae sequence available in BOLD.

Etymology.

The genus name refers to and honors the British braconid expert Mark Shaw, in recognition of his outstanding contributions to the knowledge of Hymenoptera , especially host/parasitoid biology. Throughout the years, Mark has been a mentor, dear friend, and an inspiration for the first author to continue his work with parasitoid wasps. The gender of the genus is neuter.

Comments.

The species described below have two different sculpture patterns of propodeum, as well as two different shapes of T1. Future studies may find that those species are better placed in separate genera, but due to the paucity of specimens we prefer to keep them all within one single genus for the time being.

Species.

We recognize three different species, all new and described below. They can be separate using the following key.

Figures

Figure 28. Markshawius erucidoctus female holotype. A Habitus B Head frontal C Fore wing and hind wing D Metasoma dorsal E Antenna F Mesosoma dorsal.

Figure 29. Markshawius francescae female holotype. A Habitus B Head frontal C Head lateral D Fore wing E Metasoma dorsal F Propodeum G Mesosoma dorsal.

Figure 30. Markshawius francescae female paratype CNC 878540. A Habitus B Head frontal C Head dorsal D Fore wing, inset: details of the areolet E Metasoma dorsal F Mesosoma dorsal.

Figure 31. Markshawius thailandensis female holotype. A Habitus B Head frontal C Head dorsal D Fore wing E Head lateral F Metasoma dorsal G Propodeum H Mesosoma dorsal.