Woldstedtius Carlson 1979

Klopfstein, Seraina, 2014, Revision of the Western Palaearctic Diplazontinae (Hymenoptera, Ichneumonidae), Zootaxa 3801 (1), pp. 1-143 : 107-108

Woldstedtius Carlson 1979

Type species. Bassus biguttatus Gravenhorst 1829

Diagnosis. The Western Palaearctic species of Woldstedtius are quite uniform in morphology, whereas the Neotropical species show a larger variation. In the Western Palaearctic, the genus can be recognized by the transversely truncate ovipositor sheaths which leave the tip of the ovipositor exposed, by the lack of notauli, areolet or tyloids in males, and the very even, weakly coriaceous microsculpture. Except for three very rare species, the hind tibia is black with a white base, a character only shared by Enizemum species. From Enizemum , Woldstedtius species can readily be identified by the lack of or short median dorsal carinae on the first two tergites which reach at most over half the tergite and are about as far apart as they are distant from the sides of the tergite.

Face coriaceous and matt, without vertical impressions, in females entirely black or with a yellow central patch, in males entirely yellow. Clypeus with apical margin thin, with a basal elevation that makes it flat or even convex in profile, relatively broad and short. Antenna with apical flagellomeres longer than wide, without tyloids and without long setae. Mesoscutum without notauli; weakly punctate on a strongly coriaceous background, yellow shoulder marks present or absent; mesopleuron mostly coriaceous, often rather smooth and shining on upper half, with or without punctures; epicnemial carina complete ventrally. Propodeum with carinae partly or more often fully reduced, enclosing only lateral areas or no areas at all; propodeal spiracle inconspicuous; scutellum only carinate basally. Fore wing areolet absent; hind wing with 2–3 basal hamuli. Hind tibia usually black with a white base, in males with light colouration often extending to half the length of the tibia, rarely hind tibia all dark ( W. melanocnemis ) or yellow or orange with a dark apex (in W. nigrolineatops ). Female metasoma dorsoventrally depressed, tergites convex, without transverse impressions, with median dorsal carinae absent or weakly indicated basally. Second and third tergites with spiracles dorsal, above lateral folds. Metasoma black, in males often with yellow markings on tergites 3 and 4. Ovipositor sheaths 0.3 times as long as hind tibia, parallel-sided and not compressed, about circular in cross-section, transversely truncate and open towards apex, with dense setae apically. Males with tergites 9 and 10 as separate sclerites, sternite 9 about two times wider than long, emarginated apically, thus forming two lobes, their outer corners rounded (in W. citropectoralis , sternite 9 with a median weakly sclerotized area, making it superficially unilobate).

Phylogeny. The monophyly of the five common Western Palaearctic Woldstedtius species is supported by numerous morphological and molecular characters ( Klopfstein et al. 2010a; Klopfstein et al. 2011). The rare W. melanocnemis and W. nigrolineatops are more divergent morphologically, and have not been analyzed by molecular methods. However, they fit well into the circumscription of the genus when also considering the tropical representatives.

Distribution. Worldwide, except Afrotropics. This is the only genus discussed here with a predominantly tropical disbtribution; of the 36 currently recognized species, 17 have been reported from the Neotropics and five from Australasia. The distribution gap in the Afrotropics might only represent the lack of sampling in this region.

Biology. Woldstedtius species have been reared from a wide range of Syrphinae , including some Pipizini and Bacchini ( Thirion 1994) .

Notes. There is rather little morphological variation found in the Western Palaearctic species and one often has to rely on colour characters. Males of most species are often difficult to identify because of large intra-specific variation, especially in the colour of the coxae. The key given below thus only partly works for male specimens.

Key to species

1. Hind tibia black with a white base ( Fig. 13 B), or entirely black. Propodeum usually with carinae completely reduced...... 2

- Hind tibia mostly orange or yellow with a dark apex. Propodeum with petiolar area at least partly enclosed or indicated by carinae, its surface rugose................................................................................. 7

2. Mid coxa mainly black, either with a yellow or reddish apex, hind coxa at least basally black (males may have to be traced through both halves of the couplet)........................................................................ 3

- Mid and hind coxae entirely orange....................................................................... 4

3. Antenna with 24 to 25 flagellomeres. Mid coxa black with a yellow stripe or spot on outer surface. Central face patch in females large, covering almost entire elevated central part. Larger species, fore wing length 4.1–5.5 mm ............................................................................................. Woldstedtius holarcticus (Diller)

- Antenna with 21 to 23 flagellomeres. Mid coxa black basally, irregularly yellow apically, or with some reddish parts. Central face patch in females smaller, distinctly narrower than elevated central part. Smaller species, fore wing length 3.5–4.9 mm ............................................................................... Woldstedtius bauri sp. nov.

4. Hind tibia entirely black or dark brown. Propodeum with carinae mostly reduced but with apical parts of median longitudinal carinae present, often with transverse carina indicated by rugae and with some rugae centrally on petiolar area..................................................................................... Woldstedtius melanocnemis (Bauer)

- Hind tibia black with more or less extended white base. Propodeum with carinae reduced, at most with very short posterior parts of longitudinal carinae, coriaceous and matt also on petiolar area............................................ 5

5. Antenna with 21 or fewer flagellomeres, very rarely with 22. In males, face conspicuously widened ventrally, inner orbits much further apart from each other below than above ( Fig. 27A ), less so in females ( Fig. 27B ). Propodeum sometimes with orange markings which can extend to mesopleuron and/or to first metasomal tergite................................................................................................. Woldstedtius citropectoralis (Schmiedeknecht)

- Antenna with 22 or more flagellomeres. Face not conspicuously widened ventrally ( Fig. 27C, D ). Propodeum black, but metasoma sometimes marked with orange...................................................................... 6

6. Yellow coloration reduced, females without central face patch and shoulder marks, males with mesopleuron yellow only in front of epicnemial carina, at most with small shoulder marks. Smaller species, fore wing 3.5–4.5 mm. Face broad and not very high ( Fig. 27C )......................................................... Woldstedtius biguttatus (Gravenhorst)

- Yellow coloration well developed, females with yellow face patch, males with mesopleuron yellow on more than half of its surface, both sexes usually with yellow shoulder marks. Large species, fore wing length 4.3–6.3 mm. Face not conspicuously broad ( Fig. 27D )...................................................... Woldstedtius flavolineatus (Gravenhorst)

7. Fore and mid coxae black with yellow apices, hind coxa orange with a black base and yellow apex. Femora usually with a black line on ventral surface, hind femur with base and apex often yellow. Mesopleuron irregularly wrinkled. Metapleuron black. Larger species, fore wing length 4.9–5.2 mm .............................. Woldstedtius nigrolineatops (Bauer)

- Coxae red, only base of fore coxa dark, but trochanters marked with black. Femora all red. Mesopleuron evenly coriaceous and with inconspicuous punctures. Metapleuron marked with red below. Smaller species, fore wing length 4.6–4.8 mm .......................................................................................... Woldstedtius patei Dasch

Etymology. This species is gratefully dedicated to the entomologist and chalcidologist Hannes Baur who introduced me to the varied and inspiring work with Hymenoptera .

Diagnosis. Fore wing length 3.4–4.9 mm. Antenna of both sexes with 20–23 flagellomeres. Face not broadened, not conspicuously widened ventrally. Mesopleuron finely and evenly coriaceous. Propodeum devoid of carinae, evenly coriaceous also on petiolar area.

Figures

FIGURE 27. Faces of the more common Woldstedtius species. A. Woldstedtius citropectoralis ♂. B. Woldstedtius citropectoralis ♀. C. Woldstedtius biguttatus ♀. D. Woldstedtius flavolineatus ♀. Scale bars represent 500 µm.

FIGURE 13. A. Diplazon multicolor ♀, metasoma. B. Diplazon pectoratorius ♀, propodeum. C. Tymmophorus obscuripes ♀, propodeum. D. Xestopelta gracillima ♀, mesoscutum showing colour pattern. E. Campocraspedon caudatus ♀, metasoma. F. Campocraspedon caudatus ♂, metasoma. G. Daschia brevitarsis ♀, metasoma. H. Homotropus nigritarsus ♂, antenna. I. Enizemum ornatum ♂, antenna.