Thaumatogelis pilosus ( Capron, 1888 ), 1995

Vas, Zoltán & Schwarz, Martin, 2018, Contributions to the taxonomy, identification, and biogeography of Thaumatogelis Schwarz, 1995 (Hymenoptera: Ichneumonidae), Zootaxa 4444 (4), pp. 421-436 : 422-425

Thaumatogelis pilosus ( Capron, 1888)

This species was described by Capron (1888) as Pezomachus pilosus Capron, 1888 based on three type specimens from the United Kingdom. Its generic placement in the genus Gelis Thunberg was established by Ceballos (1925) and confirmed by Fitton (1976), who designated the lectotype from the type series ( Fitton 1976). Since its original description, it was redescribed by Morley (1907), Ceballos (1925), Schmiedeknecht (1933), and by Schwarz (1995, 2001), revealing a history of taxonomic confusion.

Capron’s (1888) original description undoubtedly fits that of the types, except he mentioned 5–6 mm body length, which is clearly a mistake, as his types are c. 4 mm long. Morley’s (1907) and Schmiedeknecht’s (1933) works basically repeat the original description. However, the Spanish specimens identified as Gelis pilosus ( Capron, 1888) by Ceballos (1925) might well refer to another species, especially for the depicted short and wide first tergite (see Ceballos 1925: Fig. 23) that distinctly differs from the long and slender first tergite of the types of the species. Here, we considered the Spanish record of this species as doubtful.

Schwarz (1995) transferred this species to the genus Thaumatogelis Schwarz. Unfortunately , his redescription of the species ( Schwarz 2001) was based on specimens from Sicily instead of on the type specimens of T. pilosus (Capron) . The examination of both the types of T. pilosus (Capron) and the Sicilian specimens of T. pilosus (Capron) sensu Schwarz (1995, 2001 ) clearly revealed that they are not conspecific, and the Sicilian specimens represent a not yet described Thaumatogelis species. The latter is described as T. tisiphone Vas & Schwarz sp. nov. in this paper. A redescription of T. pilosus (Capron) based on Capron’s type specimens is provided here, as due to its misinterpretation, this species was not redescribed in Schwarz’s revision ( Schwarz 1995, 1998, 2001, 2002).

However, the current generic placement of T. pilosus (Capron) is still doubtful. This species shows some intermediate characteristics between Thaumatogelis and Gelis . Most importantly, the striae on the lateral side of first tergite, though present, are rather indistinct and weak, weaker than in other Thaumatogelis species, and the antennae are more widened toward apex (at the widest part almost twice as wide as the width of first flagellomere) than in any other known Thaumatogelis species (see Figs 1–4 ). Both of these characteristics, especially the latter, may suggest Gelis rather than Thaumatogelis , and, by using the generic key of Schwarz (1995), it is a good chance that this species is keyed out as Gelis . Additionally, this species is similar, though certainly not conspecific, to Gelis rotundiventris (Förster) . The latter is the sole member of the Gelis rotundiventris -group sensu Schwarz (1995, 1998), and discussed there as showing some common features with Thaumatogelis species ( Schwarz 1995, 1998). For now, as it seems that no certain decision could be made on the generic placement solely by morphology, we decided to leave T. pilosus (Capron) in Thaumatogelis , mainly because of the presence of the weak striae on the lateral side of the first tergite. A future study involving genetic analysis is needed to clarify the phlyogenetic and taxonomic position of T. pilosus (Capron) and G. rotundiventris (Förster) among the other Gelis and Thaumatogelis species.

Material examined. Lectotype: female, United Kingdom, Surrey County, Shere [on label: Sheer , Surrey], 1887, Capron coll., Claude Morley Collection B.M. 1953-159, B.M. type Hym. 3B.2040, det. M.G. Fitton, 1974, des. M.G. Fitton, 1976 . Paratypes: two females, same locality and date. The lectotype and paralectotypes are in BMNH . We also examined a female from Hungary, Hajdú-Bihar county, Nagyhegyes ( Vajdalapos ), 22.viii.–19.x.1976, pitfall trap, leg. Hámoriné, HNHM Hym . Coll. Id. No. 152938.

Description. Female ( Figs 1–4 ). Body length 4 mm.

Head: Antenna distinctly widened to the apex, clavate, at widest part about almost twice as wide as width of first flagellomere, at apex slightly narrowed, with 17–18 flagellomeres. First flagellomere 2.0–2.2 × as long as wide, fifth flagellomere 0.9–1.0 × as long as wide, first flagellomere 0.9–1.0 × as long as second flagellomere. Width of eye in dorsal view 2.5–2.7 × as long as gena, head behind eyes constricted. OOL as long as POL. Inner eye orbits divergent ventrally. Vertex, gena and malar space coriaceous, matt, punctures indistinct, lower gena slightly shinier. Frons coriaceous, matt, punctures indistinct, slightly shinier above toruli. Face coriaceous with indistinct punctures; face with short, dense, whitish hairs; face convex in lateral view. Clypeus less coriaceous and shinier than face and with scattered and more distinct punctures; clypeus convex in profile, apical margin curved; hairs on clypeus longer than on face. Malar space 1.5 × as long as basal width of mandible, groove indistinct. Mandibular teeth about the same length.

Mesosoma: Mesosoma coriaceous, matt, with indistinct punctures, and with dense, long, whitish hairs. Pronotum and mesonotum fused with distinct margin. Mesonotum convex without median furrow; scutellum very short, weakly separated; mesonotum 0.9–1.0 × as long as wide, and about as long as or slightly shorter than anterior area of propodeum; groove between mesonotum and propodeum deep. Mesopleuron and metapleuron coriaceous, slightly coarser ventrally than dorsally. Epicnemial carina laterally and ventrally very strong, posterior transverse carina of mesosternum ventrally strong, mesosternum shorter than width of first flagellomere. Propodeum convex, about as high as or slightly higher than mesonotum in lateral view, anterior and posterior area indistinctly separated; posterior transverse carina laterally distinct. Legs finely coriaceous, coxae (especially hind coxa) with weak, scattered punctures; hind femur 4.0–4.5 × as long as high; tarsal claws simple, small, only little longer than arolium.

Metasoma: Metasoma with sparse, long, whitish hairs. First tergite coriaceous, 2 × as long as apically wide; dorsal and dorsolateral carina lacking, at most present at extreme basal and/or extreme apical parts; lateral parts of first tergite coriaceous with weak punctures, and with a few, indistinct irregular wrinkles basally. Second and third tergites fused, margin weak; laterotergite of second tergite separated, reduced, narrower than width of basal flagellomeres. Metasoma from second tergite onwards shinier than other parts of the body, very finely coriaceous to shagreened or almost smooth, punctures indistinct. Sixth tergite normal, not enlarged. Ovipositor sheath 0.5–0.6 × as long as hind tibia; ovipositor slender, dorsal margin without distinct, steep angular elevation before nodus; ovipositor tip 3.5–4.0 × as long as high.

Colour: Head black, ventrally brown; mouthparts brown to yellowish brown, mandibular teeth dark brown. Scapus mainly brown, pedicellus mainly orange; basal flagellomeres orange to reddish brown; middle and apical flagellomeres from about fifth flagellomere onwards dark brown to blackish. Mesosoma orange with dark brownish to blackish patches. Pronotum mainly dark brown to blackish, orange around upper hind corner. Mesonotum orange with brown to blackish patch in the middle and around hind edge. Mesopleuron and metapleuron mainly brown, dorsally orange. Propodeum medially orange, laterally and posteriorly brown. Legs brownish to yellowish brown. First tergite brownish orange with a more or less distinct transverse brown patch around the level of spiracles. Metasoma except first tergite reddish brown to brown. Ovipositor sheath brown.

Male: Unknown.

Distribution. This species was described from the United Kingdom ( Capron, 1888). It was reported from Spain by Ceballos (1925), although the correct specific identification of this record seems to be doubtful; distributional records from Italy: Sicily ( Schwarz 1995, 2001) are to be rejected, as they undoubtedly refer to another species (see above). Its first record from Hungary is reported in this paper (see below in Biogeography section in details).

Ecological note. No host is known.

Identification. This species is keyed out in the updated identification key of Thaumatogelis species below. However, as we pointed out above, this species might easily be (mis)identified as a Gelis species. For this reason, we also provide a couplet here to distinguish this species from the similar Gelis species. By using the identification keys for Gelis provided by Schwarz (1995, 1998), this species falls in the Gelis rotundiventris -group sensu Schwarz (1995, 1998). T. pilosus (Capron) can be separated from G. rotundiventris (Förster) , the sole member of the Gelis rotundiventris -group sensu Schwarz (1995, 1998) as follows:

1 Mesonotum short, 0.4–0.5 × as long as wide; first flagellomere long, 2.7–3.1 × as long as wide; hairs of body not conspicuously long (body length 3–3.5 mm)................................................... G. rotundiventris (Förster)

- Mesonotum longer, 0.9–1.0 × as long as wide, first flagellomere shorter, 2.0–2.2 × as long as wide; hairs of body, especially on metasoma, conspicuously long (body length 4 mm)............................................ T. pilosus (Capron)

Figures

FIGURES 1–4. Thaumatogelis pilosus (Capron, 1888) type specimens. 1–3, lectotype specimen: 1, dorsal habitus; 2, lateral habitus; 3, first tergite, lateral view. 4, paralectotype specimens, dorsal habitus.