Type species: Hymenopterites deperditus Heer, 1870; GrønfjordenNW (SE of Festningsodden), Spitsbergen, Norway; Early Palaeocene.

Emended diagnosis.—Based on hemelytral characters only. Two distal cells between M, Rs and R, an ambient vein along distal margin of wing, cell (M) between Cu andMvery long and broad; cell (t) rhomb in shape with acute distal angle.

Material.—Holotype specimen, NRM Ar. 46 (impression in a piece of black shale), leg. A.E. Nordenskiöld, 1868 (Stockholm, Sweden).

Description.—An incomplete hemelytra, membraneous and apparently hyaline except along the darker costal margin, elongate and very narrow, preserved part 7.10 mm long and 1.70 mm wide, probable complete length 8.0 mm; a dark broad area along costal margin from wing base to wing apex, 0.25 mm wide in widest part and 0.10mmwide in narrowest part, near wing apex; M+Cu parallel to posterior wing margin near wing base, forming a strong angle and reaching R, then R+M+Cu parallel to costal margin more distally, only apical part of vein R present as a short vein reaching M+Cu just basal to point of separation between Cu and M; second longitudinal vein Pcu straight and closely parallel to posterior wing margin; short vein cu-pcu between M+Cu and Pcu, aligned with basal part of M+Cu and distal part of Pcu, emerging from M+Cu 5.50 mm from wing apex and 0.20 mm long; Cu emerging from M+Cu 0.30 mm distal of point of fusion of R with M+Cu, straight, 1.0 mm long; cell (t) formed by cubital and postcubital veins in membrane of forewing is rhomb in shape, with apex acute and oriented posteriad; Mseparating from R 2.70 mm distal of base of Cu and 2.60 mm from wing apex; a very large and broad cell (M) between Cu, Pcu, and M, 4.50 mm long and about 1.10 mm wide; Rs emerging from R and directed posteriorly towards M; R, M, and Rs defining a triangular cell, 1.3 mm long, 0.60 mm wide, a second cell distal to this first cell, distally limited by an ambient vein formed by R, M, and Pcu fusing together.

Discussion.—This fossil was originally described as a wasp under the name of Hymenopterites deperditus by Heer (1870: 96, pl. 16: 45). It was later revised by Birket-Smith (1977: 34, fig. 21) suggested that it was perhaps not an insect wing at all but a winged seed similar to that of an Acer sp.We disagree with both opinions because this fossil has not enough cells and veins to be a membrane of awinged seed and has not the venation of any living or fossil Hymenoptera, especially in the presence of an ambient vein in the apical part of the structure. In fact it corresponds in all visible details to the hemelytron of a reduviid bug, particularly those of the subfamily Saicinae in which the wing is also very narrow in its basal half and more rounded apically, with twomain more-or-less parallel longitudinal veins, with three more-or-less oblique veins between them (cu-pcu, Cu, andM) that define large cells, and an ambient vein in the apical half of the wing (see Blinn 1994; Ishikawa and Yano 2002; Weirauch 2008). Some other heteropteran groups also have hemelytra with large cells (especially in the Enicocephalomorpha and Gerromorpha), but none have a similar pattern of organization of the veins R,M, and Cu in the basal half of wing, proper to the Reduviidae. Thus, we consider that the fossil belongs to the Reduviidae. Few subfamilies have a hemelytral venation showing some similarities with this fossil. More precisely, the nearly completely membraneous hemelytra (with reduced corium to basal part of the wing) is an apomorphy present in the subfamilies Ectrichodiinae, Emesinae, Holoptilinae, Saicinae, Tribelocephalinae, and Visayanocorinae. The median and cubitus form a combined vein, an apomorphy present in the Ectrichodiinae, Saicinae, Tribelocephalinae, Vesciinae, and Visayanocorinae, while the shape of cell (t) is a specialized character present in Saicinae and in Visayanocorinae (Weirauch 2008). Thus Hymenopterites can be attributed to a bug closely related to the Saicinae because its wing venation strongly differs from those of the Visayanocorinae, in the narrower costal area (Miller 1952; Malipatil 1990). Ectrichodiinae, Tribelocephalinae, and Vesciinae have also hemelytra distinctly broader than in Hymenopterites. Nevertheless the dark “pterostigma” of Hymenopterites goes close to the wing apex, which is unlikely in modern Saicinae. It is quite possible that it can turn out to be a representative of some specific tribe or even subfamily (Yuri Popov, personal communication 2011). The fragmentary state of preservation of this fossil prevents a precise attribution as to subfamily except to note that it probably belongs to the complex of subfamilies of the “emesine-saicine clade” sensu Weirauch (2010).

Reduviidae have had a checkered history over the last fewcenturies, and even today there is little agreement on how many subfamilies Reduviidae contain. Since no study on the phylogeny of extant and extinct Reduvioidea has been done so far, the divergence times of most scarab families remain widely uncertain (Weihrauch and Schuh 2011). For Reduviidae,Weihrauch (2008) has tested hypotheses of subfamily-level relationships within assassin bugs that corroborate the nesting of phymatine or ambush bugs within Reduviidae, establish a sister-group relationship between Ectrichodiinae + Tribelocephalinae, show Reduviinae to be polyphyletic, and recover Triatominae as monophyletic.

The only described Mesozoic taxon that has been attributed to the Reduviidae is Liaoxia longa Hong, 1987, based on a body compression from the Early Cretaceous of China. Except for the rostrum that seems to be more or less curved, there is no clear argument supporting this family assignment (Hong 1987). Yao et al. (2006) transferred Hong's species into their Mesozoic family Vetanthocoridae. Putshkov and Moulet (2009: 110) indicated the presence of undescribed compressions of Reduviidae from the Cretaceous of Mongolia, but these have not been described formally. Other fossil reduviids are all Cenozoic in origin, the oldest described being the harpactorine Amphibolus disponsi Kinzelbach, 1970 from the middle Eocene Messel Formation (Germany) (Kinzelbach 1970; Forero et al. 2004). As already mentioned, Manevalia pachyliformis Piton, 1940 from the Palaeocene of Menat (France), was attributed originally to the Reduviidae but is in fact the hind wing of a symphytan wasp (Piton 1940; Nel 1992). Thus, H. deperditus can be considered as one of the oldest definitive record of the Reduviidae. Its attribution to the “emesine-saicine” group, which is one of the most derived clades in the lineage, strongly supports the conclusion that the Reduviidae diversified much earlier, during at least the Cretaceous (Patterson and Gaunt 2010). According to current opinion, the emergence of the predatory reduviids during the early Cretaceous period (135-70 Ma) is consistent with their current wide diversity in continents then connected as Gondwanaland. The calculated time for the separation of Gondwanaland is about 100-90 Ma (Pitman et al. 1993). Africa and South America began to divide at their southern end about 120 Ma but did not become completely separated until less than 100 Ma (Smith et al. 1981). Divergence of the ancestors of the Triatomini and Rhodniini is then put at the time when South America was already separated from Africa.

Hymenopterites deperditus belongs to a group of insectivorous bugs, and its presence in the Palaeocene high latitudes of Svalbard demonstrates the presence of a complex insect ecosystem, revealed and confirmed by the 19th century discoveries of terrestrial and aquatic carnivorous, phytophagous, and detritivorous beetles (Heer 1870; Birket-Smith 1977).Modern Reduviidae of the “emesine-saicine group” are mainly pantropical, living in rather warm climate regimes, at least of the Mediterranean type (Putshkov and Moulet 2009). Thus, H. deperditus also suggests a similar climate for Svalbard during the Palaeocene (Greenwood et al. 2010; Harrington et al. 2011; Harding et al. 2011;Wappler and Denk 2011).

It is perhaps not a coincidence that this bug was of a gracile form given that these insects are transported easily to isolated islands by wind (analogous with the modern fauna from the Pacific area; Putshkov and Moulet 2009).

Lastly, Palaeocene mimicry of a heteropteran bug based on a hymenopteran model implies a relative long coevolution between the model and its mimic, and probably a relative diversity of the model lineage in the surrounding environment, or at least an obvious ecological importance or abundance which would drive the evolution of such a mimetic association. If Müllerian mimicry is supposed (both mimic and model are vulnerable for predators), this also implies the presence of at least one aculeate harmful wasp species and supports the hypothesis that the insects were an important component of the forests thriving in the higher latitudinal ecosystems.