Research Article |
Corresponding author: Ekaterina V. Tselikh ( tselikhk@gmail.com ) Academic editor: Vladimir Gokhman
© 2021 Ekaterina V. Tselikh, Natalie Dale-Skey.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Tselikh EV, Dale-Skey N (2021) Review of the genus Toxeuma Walker, 1833 (Hymenoptera, Pteromalidae) from Russia, with a key to Palaearctic species. In: Proshchalykin MYu, Gokhman VE (Eds) Hymenoptera studies through space and time: A collection of papers dedicated to the 75th anniversary of Arkady S. Lelej. Journal of Hymenoptera Research 84: 391-403. https://doi.org/10.3897/jhr.84.68627
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Species of the genus Toxeuma Walker, 1833 from Russia are reviewed. A new species, Toxeuma leleji Tselikh, sp. nov., is described from the Russian Far East. Toxeuma fuscicorne Walker, 1833 and T. styliclava (Hedqvist, 1974) are recorded for the first time from Russia; Toxeuma acilius (Walker, 1848) – for the first time for Western and Eastern Siberia and the European part of Russia; Toxeuma paludum Graham, 1959 – for the first time for Western and Eastern Siberia; Toxeuma subtruncatum Graham, 1959 – for the first time for Primorskii Region. An identification key to females of all Palaearctic species of Toxeuma is provided.
Fauna, key, new species, parasitoids, Pteromalinae, taxonomy
The pteromalid genus Toxeuma Walker, 1833 (type species Toxeuma fuscicornis Walker, 1833) belongs to the family Pteromalidae, subfamily Pteromalinae, and is distributed in the Palaearctic, Nearctic, and Neotropical regions. Up to now it comprised nineteen species, only six of which (T. acilius (Walker, 1848), T. discretum Graham, 1984, T. fuscicorne Walker, 1833, T. paludum Graham, 1959, T. styliclava (Hedqvist, 1974), and T. subtruncatum Graham, 1959) inhabit the Palaearctic Region (
Four other species, T. aciculare Heydon, 1988, T. aquilonium Heydon, 1988, T. gerra Heydon, 1988, and T. inopinum Heydon, 1988 are distributed in the Nearctic Region (
Nine species, T. affinis Ashmead, 1901, T. aphareus (Walker, 1839), T. faceta Girault, 1913, T. ferrugineipes Ashmead, 1901, T. hawaiiensis Ashmead, 1901, T. nigrocyanea Ashmead, 1901, T. nubilipennis Ashmead, 1901, T. orobia (Walker, 1842), and T. tarsata Ashmead, 1901 are distributed in the Neotropical Region (
Including the new species from the eastern Palaearctic Region described in this paper, the genus Toxeuma now consists of twenty valid species.
The aim of this work is to describe a new species of Toxeuma from Russian Far East and to give new records of two Palaearctic species of Toxeuma from Russia. An identification key to all Palaearctic species of Toxeuma is also provided.
The material used in this review is deposited in the Hymenoptera collections of the Zoological Institute of the Russian Academy of Sciences, St. Petersburg, Russia (
Morphological terminology, including sculpture and wing venation nomenclature, follows
The scape is measured without the radicle; the pedicel is measured in lateral view. The distance between the clypeal margin and the toruli is measured from the lower margins of the toruli. Eye height measured as the maximum diameter, eye length as the minimum diameter. The mesosoma and metasoma are measured in lateral view, the latter including the ovipositor sheaths.
Observations were made using MC-2 ZOOM and Leica MZ16 stereomicroscopes, and images were acquired using a combination of Olympus SZX 10 stereomicroscope and a digital camera EOS 70D, Micromed 3 microscope and a digital camera ToupCam UCMOS 5.1MP (
Type species: Toxeuma fuscicornis Walker, 1833, by subsequent designation of Westwood (1839: 68).
Cirdania
Hedqvist, 1974: 145. Type species: Cirdania styliclava Hedqvist, 1974, by original designation. Synonymy by
Clypeal margin entire, truncate or slightly arched; antennal clava with or without short or long spicula; antennal formula 11263; pronotum with collar margin carinate; notauli complete; prepectus reticulate, without carinae; sculpture of propodeum at least partly irregular, petiole from transverse to slightly elongate; fore wing with slender M, metasoma ovate or lanceolate (
Palaearctic, Nearctic and Neotropics.
Unfortunately, the biology of most Toxeuma species is unknown. The only biological records exist for T. fuscicorne, which was reared from the primary host Agromyza schineri Giraud, 1861 (Diptera, Agromyzidae) (
The genus can be distinguished from other Pteromalidae genera using the keys of
In this genus, the antennal clava can have three variations: acute (Fig.
The discovery of a previously undescribed spicula in some Palaearctic species suggests that some members of Toxeuma from Nearctic Region described by
1 | Antennal clava with spicula (e.g., Figs |
2 |
– | Antennal clava without spicula and rounded apically (e.g., Figs |
5 |
2 | Antennal clava with long spicula (Fig. |
T. styliclava (Hedqvist) |
– | Antennal clava acute (Fig. |
3 |
3 | Mt2 0.85–0.9 times median length of metasoma (Fig. |
T. leleji sp. nov. |
– | Mt2 0.5–0.6 times median length of metasoma (e.g., Figs |
4 |
4 | All legs with femora and tibia metallic blue-green (Fig. |
T. paludum Graham |
– | All legs with femora and tibia reddish or testaceous (Fig. |
T. acilius (Walker) |
5 | Mt2–Mt8 smooth and shiny (Fig. |
T. subtruncatum Graham |
– | Mt2–Mt8 alutaceous (e.g., Figs |
6 |
6 | Mt8 1.5–1.7 times as long as broad (Fig. |
T. fuscicorne Walker |
– | Mt8 up to 1.15 times as long as broad (Fig. |
T. discretum Graham |
Lamprotatus acilius
Walker, 1848: 169. Lectotype male, (
Toxeuma acilius (Walker, 1848) new combination in Graham, 1959: 104.
Lectotype
male (
Czech Republic, Germany, Netherlands, Romania, Russia (Russian Far East; Western and Eastern Siberia, European part of Russia – new records), Sweden, United Kingdom (
Toxeuma discretum
Graham, 1984: 501. Holotype female (
Holotype
female (
Belgium, France, Sweden, United Kingdom (
Toxeuma acilius holotype male (1) non-type female (2–6) 1 body, dorsal view 2 body, dorso-lateral view 3 antenna (dry material) 4 F6 and antennal clava (slide) 5 antenna (slide) 6 propodeum and petiole, dorsal view Toxeuma discretum holotype female (7–9) 7 metasoma, dorsal view 8 body, dorsal view 9 body, lateral view Scale bars: 1.0 mm.
Toxeuma fuscicornis
Walker, 1833: 378; lectotype female (
Miscogaster lugubris
Walker, 1833: 462. Type specimens possibly lost (
Toxeuma ericae
Walker, 1833: 379; lectotype female (
Gastrancistrus accia
Walker, 1848: 156; lectotype female, (
Other material : Russia: Belgorod Prov., 12 females, 3 males, Borisovka Vill., “Belogor’e” Reserve, “Les na Vorskle”, 11.VI.2018, coll. Tselikh.
Belgium, Croatia, Czech Republic, France, Germany, Hungary, Iran, Netherlands, Romania, Russia (new record), Spain, Sweden, Switzerland, United Kingdom (
Primary parasitoid of Agromyza schineri Giraud, 1861 (Diptera, Agromyzidae) –
Toxeuma leleji is similar to T. acilius (Walker) and T. paludum Graham; the differences between these species are given in the key.
Females of Toxeuma leleji are also similar to those of the Nearctic species Toxeuma inopinum Heydon because they have an antennal clava with needle-like spicula, F1–F4 elongate, fore wing with pilose basal vein, but Toxeuma leleji females have the gena not distinctly hollowed at mouth corner, petiole longer than wide, Mt2 0.85–0.9 times median length of metasoma.
Female. Body length 1.5 mm. Fore wing length 1.5 mm.
Head, mesosoma and metasoma, metallic bluish-green with diffuse coppery lustre; antenna with scape yellow, pedicel yellowish-brown, flagellum brown; all coxae metallic bluish-green with diffuse coppery lustre; all femora, tibiae and tarsi yellow except last segment yellowish-brown; fore wing hyaline, venation yellowish-brown; ovipositor sheath black.
Head in dorsal view 1.93–2.07 times as broad as long and 1.36–1.38 times as broad as mesoscutum; in frontal view 1.28–1.3 times broader than high. POL 1.46–1.57 times OOL. Eye height 1.21–1.26 times eye length and 2.90–2.92 times as long as malar space. Distance between antennal toruli and lower margin of clypeus 0.75 times distance between antennal toruli and median ocellus. Clypeus alutaceous, its lower margin slightly arched. Antenna with scape 0.92–0.96 times as long as eye height and 1.12–1.22 times as long as eye length; pedicel 1.61–1.66 times as long as broad and 1.40–1.42 times as long as F1; combined length of pedicel and flagellum 1.10–1.14 times breadth of head; flagellum almost filiform; F1–F3 longer than broad, F4–F5 subquadrate, F6 transverse (on dry material) and F1 longer than broad, F2–F3 subquadrate, F4–F6 transverse (on slide); clava 2.83–2.86 times as long as broad (on dry material) and 2.58 times (on slide).
Mesosoma 2.20–2.45 times as long as broad. Scutellum finely reticulate, 1.0–1.1 times as long as broad. Propodeum medially as long as scutellum; median carina and plicae present; sculpture reticulate with irregular rugae; nucha short and weakly reticulate. Sculptured part of petiole 1.17–1.25 times as long as broad, with irregular sculpture. Fore wing 2.34–2.89 times as long as maximum width; basal cell bare; basal vein pilose; speculum partly open; M 1.16–1.22 times as long as P and 1.95–2.00 times as long as S.
Metasoma ovate, 1.50–1.64 times as long as broad and 0.40–0.45 times as long as mesosoma and head together; Mt2 0.85–0.90 times median length of metasoma. Ovipositor sheath projecting slightly beyond apex of metasoma.
The species is named in honour of the prominent entomologist, an expert on Mutillidae (Hymenoptera), Prof. Arkady S. Lelej.
Holotype
female (
Paratype
female (
Russian Far East (Sakhalinskaya Prov.).
Toxeuma fuscicorne non-type female (10–14) 10 body, lateral view 11 metasoma, dorsal view 12 scutellum, propodeum and petiole, dorsal view 13 F6 and antennal clava (slide) 14 antenna (slide) Toxeuma leleji sp. nov. holotype female (15, 16, 18–20) paratype female (17, 21) 15 body, lateral view 16 fore and hind wings 17 antennal clava (slide) 18 metasoma, dorsal view 19 propodeum and petiole, dorsal view 20 head, frontal view 21 antenna (slide) Scale bars: 1.0 mm.
Toxeuma paludum
Graham, 1959: 102. Holotype female (
Holotype
female (
Russia (Russian Far East; Western and Eastern Siberia – new records), Sweden, United Kingdom (
Primary parasitoid of Coleophora sp. (Lepidoptera, Coleophoridae) (
Cirdania styliclava Hedqvist, 1974: 145–146. Holotype female (NHRS, not examined).
Toxeuma styliclava
(Hedqvist, 1974) new combination in
Toxeuma mucronatum
Graham, 1984: 501–502. Holotype female (
Paratype
female (
Belgium, France, Russia (Russian Far East – new record), Sweden (
Toxeuma paludum holotype female (23) paratype female (24) non-type female (22, 25, 26) 22 body, lateral view 23 antenna (dry material) 24 antenna (dry material) 25 metasoma, dorsal view 26 scutellum, propodeum and petiole, dorsal view 27 F6 and antennal clava (slide) Toxeuma styliclava paratype female (28, 29) non-type female (30–32) 28 antenna (dry material) 29 body, lateral view 30 F6 and antennal clava (slide) 31 metasoma, dorsal view 32 propodeum and petiole, dorsal view Scale bars: 1.0 mm.
Toxeuma subtruncatum
Graham, 1959: 105. Holotype male (
Paratype
female (
Belgium, Czech Republic, Netherlands, Russia (Russian Far East; including Primorskii Reg. – new record), Sweden, United Kingdom (
The authors are very thankful to Dr James Hogan (
This work was partly supported by grants from the Russian Foundation for Basic Research (project No. 19-04-00027) and the Russian state research project No. АААА-А19-119020690101-6.