Archigonatocerus Huber

Huber, John T., 2015, World reclassification of the Gonatocerus group of genera (Hymenoptera: Mymaridae), Zootaxa 3967 (1), pp. 1-184 : 13-14

Archigonatocerus Huber , gen. n.

( Figs 39 , 40 )

Type species. Archigonatocerus balticus Huber , by present designation.

Diagnosis. Within Gonatocerini, females of Archigonatocerus are distinguished from those of the genera of extant Gonatocerini as well as from the four previously described fossil species in Gonatocerini, all originally classified in Gonatocerus , by the following combination of features: fore wing venation almost 0.5 wing length or more; hypochaeta (only visible in one species) next to proximal macrochaeta.

Description. FEMALE. Large specimens, 1820–1840 in length. Colour. Body uniformly dark brown (but apparently yellow in A. longivena Huber because entire body enclosed in thin layer of trapped air). Head. Face bulging below toruli, so toruli apparently horizontal, facing upward. Length about 0.8× height. Antenna. Funicle with 8 segments. Mesosoma. Dorsellum rhomboidal. Wings. Fore wing wide, with venation almost half (0.45×) or more (0.6×) ( Figs 39 b, 40b) as long as fore wing length, with an asetose line or fold (not always visible depending on lighting) extending from stigmal vein apex to posterior margin of wing near the apex ( Figs 39 a, 40a), and with microtrichae present behind venation (in one species sparser behind base of venation). Parastigma with hypochaeta much closer to proximal than to distal macrochaeta ( Fig. 39 b). Stigmal vein with apex apparently truncate apically. Postmarginal vein apparently present in one species ( Fig. 40 b) and possibly several times as long as its width, longer than stigmal vein. Metasoma. Petiole evidently short, not visible. Gaster longer than mesosoma. Ovipositor sheaths as long as gaster and slightly exserted.

MALE. Unknown

Discussion. Two plesiomorphic features suggest that Archigonatocerus is the most ancenstral of the genera included in Gonatocerini. The long venation (almost half the wing length or more) and the position of the hypochaeta in next to the proximal macrochaetae (only visible in one of the species). A third feature that may be plesiomorphic is the longitudinal fold that extends obliquely from the stigma almost to the posterior margin of the wing towards the apex ( Figs 39 , 40 ).

The three extinct species from the Kishenehn shale formation in Montana, USA ( Huber and Greenwalt 2011), transferred below from Gonatocerus to Cosmocomoidea , differ from the two new species of Archigonatocerus by having a much shorter gaster and ovipositor sheaths, shorter fore wing venation, and shorter, thicker funicle segments. The fourth previously described fossil species in Gonatocerus , G. henneberti Meunier from Baltic amber ( Meunier 1905), may indeed belong correctly to Gonatocerus based on the relatively narrow fore wing, but the type is lost so the specimen cannot be re-examined to confirm its placement; it has much narrower fore wing and shorter gaster than the new fossil species of Gonatocerus , described below. The fossil record for Gonatocerini thus includes three genera with at least one fossil species in each: Archigonatocerus, Cosmocomoidea , and Gonatocerus .

Etymology. From archi-, Greek for beginning + Gonatocerus . The name refers to the fact that this is a fossil genus, assumed to be the earliest lineage in Gonatocerini. The gender is masculine.

Included species:

Archigonatocerus balticus Huber. TL: Eocene Baltic amber, present day European locality not given.

Archigonatocerus longivena Huber. TL: Eocene Baltic amber, present day European locality not given.

Figures

FIGURE 39. Archigonatocerus balticus, holotype in amber: a, habitus; b, wings showing venation detail. Scale bars = 500 Μm.

FIGURE 40. Archigonatocerus longivena, holotype in amber: a, habitus (body enclosed in air bubble); b, right fore wing showing venation detail. Scale bars = 500 Μm.