Philoctetes helveticus ( Linsenmaier, 1959 )

Rosa, Paolo, Zilioli, Michele & Jacobs, Maarten, 2017, Notes on endemic Alpine chrysidids, with key to Alpine Philoctetes Abeille de Perrin, 1879, and remarks on two rarely collected species (Hymenoptera, Chrysididae), Natural History Sciences 4 (1), pp. 9-18 : 11-12

Philoctetes helveticus ( Linsenmaier, 1959) ( Figs. 1 A-D,

2A-D, 3A, 7A,C,E)

Omalus (Omalus) helveticus Linsenmaier, 1959: 16 . Holotype ♀; Switzerland: Engadin (Chur); Linsenmaier, 1968: 72; Linsenmaier, 1997: 134.

Pseudomalus helveticus : Kimsey & Bohart, 1991: 267.

Philoctetes helveticus : Tussac & Tussac, 1993: 475.

Pseudomalus helveticus ( Linsenmaier, 1959) synonym of Pseudomalus putoni (du Buysson, 1892) : Strumia, 2001: 89.

Philoctetes helveticus Rosa, 2005: 13 . Revalidated. Rosa, 2006: 122.

Material examined. Switzerland: 1 ♀: [Fourn, 1900 m, de Beaumont] [♀ Type Omalus Pz. helveticus Linsenmaier det.] <handwritten in red> (Chur); 1♂: [Chandolin CH 4.VII.1982 Alpage 2200 m W. Perraudin] [♂ Allotype Omalus Pz. helveticus Linsenmaier det. 1991] <handwritten in red> [25] ( NMLS); 1♀: [Zermatt 10/7] [♀ Omalus Pz. helveticus Lins. Linsenmaier det. 1984] ( NMLS) ; Italy: 1♀: [ Italy, Aosta Valley, Chamolé Lake , 2350 m, 4.VIII.2016, leg. M. Jacobs] (PRC) ( Figs. 3 A-B) .

Distribution. Switzerland and Italy. Specimens have been collected in alpine grassland, shrublands or rocky places between 1600 m and 2350 m ( Fig. 2B ). M. Jacobs, after the recent finding of Ph. helveticus in August 2016, spent extra five days around the collecting place at Chamolé Lake (Pila, Aosta) and its vicinity looking without success for other specimens by visual search, Moerike traps and sweeping grasses, herbs and branches (mainly pine trees and willows). Therefore, it stays unclear if there is a population of P. helveticus present, whereas the species is very rare or is rarely found due to its ecology (flight period, habitat preferences, etc.) or the specimen got there by accident from higher or lower elevation.

Diagnosis. Philoctetes helveticus is closely related to Ph. putoni , but can be easily separated by its distinctly convex metascutellum ending in a short triangular and raised prominence (vs. metascutellum with a subrectangular and elongate plate in Ph. putoni ); T1 densely punctate (vs. T1 antero-medially polished, postero-laterally with tiny dots); metasoma with long, thick, black and erect setae (vs. metasoma with short, appressed and whitish setae).

Description. Body length: 4.4-4.6 mm; fore wing length: 3.0 mm; OOL = 2.7 MOD; POL = 1.9 MOD; MS = 1.0 MOD; relative length of P:F1:F2:F3 = 1:1.2:0.7:0.6.

Head. Frons, vertex and face laterally to scapal basin with small (up to 0.5 MOD) and shallow punctures ( Fig. 1C ). Punctures along posterior margin of vertex smaller, with two impunctate areas posterior to ocelli. Scapal basin glabrous, transversally and irregularly rugulose. Gena with large punctures only; genal carina not bisecting MS ( Fig. 1B ). Ocellar triangle isosceles, postocellar line indistinct, with only short line (<0.5 MOD) starting from ocelli. Mandible tridentate.

Mesosoma. Pronotum antero-laterally with shallow punctures as large as those on vertex; anteromedially with shallower and smaller punctures, intervals and posteromedian surface with tiny dots. Mesoscutum with small (0.5 MOD) and shallow punctures mostly clumped along notauli ( Figs. 1A , 2A ); notaular pit deep and short (about 1 MOD); parapsidal furrows as narrow lines. Mesoscutellum with large punctures (1 MOD) medially with large polished area (0.5 PD). Metascutellum convex, triangular in dorsal view ending in a short triangular and raised median prominence ( Figs. 1B , 2B,C , 7A,B ). Mesopleuron with confluent large punctures. Tarsal claw four-toothed.

Metasoma. T1 and T2 dorsally finely and uniformly punctuate ( Figs. 1A , 7E ), laterally with double punctuation with tiny and larger dots irregularly distributed; T3 with irregular larger punctures; T3 transversely depressed before the apical margin, depression well visible in lateral view ( Fig. 1B ); T3 margin mostly laterally gently curved; towards the middle an undulation abruptly starts and it is followed by a brownish rim to apical notch. Apical notch triangular bordered by a thickened margin ( Fig. 1D ).

Colour. Body metallic green with brassy reflections in living specimens ( Fig. 3A ). Dry collection specimens are darker, green to blue with greenish reflections on scutellum and metanotum ( Fig. 2 ). T1 and T2 medially with large dark to black areas. Legs metallic green to blue, tarsi dark brown. Antenna with metallic green scapus and pedicel, flagellum entirely black.

Vestiture. Head and mesosoma coated with long, standing black setae (1.6-2.2 MOD). Metasoma laterally with long (2-2.2 MOD), standing black setae ( Figs. 1D , 2D ). Legs with short (1 MOD) whitish setae.

Remarks. In the original description, Linsenmaier (1959) placed Omalus helveticus in the subgenus Omalus s.str. rather than in Philoctetes because only the female was known. He considered as belonging to Philoctetes only those species with males having dilated and flattened posterior tibia. Kimsey & Bohart (1991) placed O. helveticus in the genus Pseudomalus without having examined the type. Tussac & Tussac (1993) placed O. helveticus in the genus Philoctetes , based on the description and the drawings provided by Linsenmaier (1959); whereas Strumia (1995) included O. helveticus again in the genus Pseudomalus , and later (2001) synonymized O. helveticus with Ps. putoni after examining the type of the latter, but not the type of O. helveticus . Rosa (2006) revalidated O. helveticus in the genus Philoctetes .

A 1991 labelled “ allotype ” male of Ph. helveticus in Linsenmaier’s collection is not part of the type series, which is based only on the holotype, by monotypy, housed at CHUR.

Since the only cited specimen for Italy [Valle d’Aosta, Val d’Ayas ( Strumia, 2001)] was not available for this study, and Strumia (2001) considered Ph. helveticus as a synonym of Ph. putoni , we were not sure about the presence of Ph. helveticus in Aosta Valley ( Rosa, 2006). Recently, a female specimen has been collected by one of us (M.J.) around the Chamolé lake, Pila (Aosta), 2350 m, and it can be considered as the first reliable Italian record. This species is one of the most rarely collected and only four specimens are preserved in the examined European collections so far.

Linsenmaier (1997) placed O. helveticus in the newly established hirtus species-group [based on Ellampus (Philoctetes) hirtus (Semenov, 1932) ]. Nevertheless, after type examination at ZIN, we confirm Kimsey & Bohart’s (1991) classification, which includes E. hirtus into the genus Pseudomalus ; whereas Ph. hirsutus (Semenov, 1932) from Uzbekistan is undoubtedly the most similar species. The latter is very similar to Ph. helveticus , but has a non protruding metascutellum and deeper body punctuation.

Figures

Fig. 1 - Philoctetes helveticus (Linsenmaier), female: A) habitus, dorsal view; B) habitus, lateral view; C) head, frontal view; D) T3, dorso-lateral view.

Fig. 3 - A) Philoctetes helveticus, female (Photo by M. Jacobs); B) Aosta Valley, Chamolé lake, 2350 m (Photo by C. Monte); C) O. Niehuis looking for P. putoni at Milefonts, 2030 m, Mercantour National Park (Photo by P. Rosa).

Fig. 2 - Philoctetes helveticus (Linsenmaier), male:A) habitus, dorsal view; B) habitus, lateral view; C) scutellum and metascutellum, lateral view; D) T3, dorso-lateral view.

Fig. 7 - A,C,E) Philoctetes helveticus (Linsenmaier), female: A) mesosoma, dorsal view; C) mesoscutum, propodeum and T1, lateral view; E) T1, dorsal view. B,D,F) Philoctetes putoni (du Buysson), female: B) mesosoma, dorsal view; D) mesoscutum, propodeum and T1, lateral view; F) T1, dorsal view.