Lymaenon gracilentus ( Hellén, 1974 )

Triapitsyn, Serguei V., Koponen, Martti, Vikberg, Veli & Várkonyi, Gergely, 2020, Taxonomy, annotated new records and a checklist of Mymaridae (Hymenoptera) of Finland, with description of a new species of Eustochus, Acta Entomologica Musei Nationalis Pragae 60 (2), pp. 565-589 : 581-583

Lymaenon gracilentus ( Hellén, 1974) , stat. restit. ( Figs 12–13 )

Gonatocerus gracilentus Hellén, 1974: 11 . Type locality: Finland, South Karelia, Parikkala, Tiviä (see explanation below). Resurrected as a valid taxon from the previous synonymy with Lymaenon aureus (Girault, 1911) by T*©ංൺඉංඍඌඒඇ (2013:48, as Gonatocerus (Lymaenon) aureus Girault, 1911 ).

Lymaenon gracilentus (Hellén) : Hඎൻൾ*© (2015): 43 (listed as a synonym of Lymaenon aureus ).

Type material examined. Gonatocerus gracilentus : Hඈඅඈඍඒඉൾ: ♀ ( FMNH) on card labeled: 1. [printed] “Parikkala Hellén”; 2. [very light yellow, faded] “4360” (Kl: Tiviä, 682:363, 16.vii.1940, Salix bushes on moist meadow); 3. [red] “ HOLOTYPE ”; 4. [in red ink, in W. Hellén’s handwriting] “ gracilentus Holotypus m. Hellén det.”; 5. [printed] “HO- LOTYPE checked and labeled Thuróczy 2015”; 8. [barcode] “http:// id.luomus.fi/GL.6282”; 9. [blue] “Photographed 2016 Pekka Malinen”.

Pൺ*©ൺඍඒඉൾඌ (presumed: specimens on which Hൾඅඅඣඇ (1974) based the description of Gonatocerus gracilentus and included in his list of localities but not mentioned nor labeled as such): 2 ♀♀ on cards ( FMNH), labeled: 1. “Bromarf”, 2. “Hellén”; 1 ♀ on card ( FMNH), labeled: 1. “Parikkala Hellén”, 2. [white] “6802”, Kl: Laurila, 683:363, Carex bog; 1 ♀ on card ( FMNH), labeled: 1. “Ekenäs”, 2. “Hellén”, 2. [white] “3” [this specimen belongs to Lymaenon Walker, 1846 but not necessarily to L. gracilentus ]; 1 ♀ on card ( FMNH), labeled: 1. “Ekenäs”, 2. “Hellén”, 2. [white] “432 13.8.1925 ” [this specimen belongs to Lymaenon but not necessarily to L. gracilentus ]; 1 ♂ on card ( FMNH), labeled: 1. “Joutseno”, 2. “Hellén”, 2. [white] “4916” (Honkalahti 678:358, sandy slope) [this specimen belongs to Gonatocerus Nees ab Esenbeck, 1834].

Additional material examined. N: Nurmijärvi,M.Koponen:(6706:3381), 30.vii.1982 (1 ♀, FMNH); (6710:3381), 23.viii.1995 (1 ♀, FMNH); Kiljava (6712:3373), dry meadows, 25.vii.1992 (1 ♀, FMNH). Pyhtää, Ahvenkoski (66709:3470), 14.viii.1981, M.Koponen (1 ♀, FMNH).Sipoo (6688:3400), M. Koponen: 26.vii.1981 (1 ♀, FMNH), 30.viii.1983 (1 ♀, FMNH). Vantaa, Tikkurila (6688:3392), 6.viii.1980, M. Koponen (1 ♀, FMNH). St: Kokemäki,Kauvatsa (6804:3262), 10.viii.1992, M.Koponen (1 ♀, FMNH). Nakkila (6818:3230), 10.viii.1992, M. Koponen (1 ♀, FMNH). Sa: Mikkeli: Otava (6837:3503), 30.vii.1990, M. Koponen (1 ♀, FMNH); Soikkala (6830:3501), 6.viii.1993, M. Koponen (1 ♀, FMNH). Tb: Rautalampi, M. Koponen: Kalajanvuori, 17.vii.1983, M. Koponen (1 ♀, FMNH); Kerkonkoski, 18.vii.1983 (1 ♀, FMNH); East of Maukavuori (6945:3490), dry meadow, 19.vii.1983 (2 ♀♀, FMNH). Vesanto, Niinivesi (6987:3473), 18.vii.1983, M. Koponen (1 ♀, FMNH). Sb: Kuopio (6957:3565), 18.viii.1983, M. Koponen (1 ♀, FMNH). Om: Lappajärvi, Nykälänniemi (7020:3331), 31.vii.1995, M. Koponen (2 ♀♀, FMNH).

Redescription. Female. Holotype ( Fig. 12 ): body length 0.95 mm; body mostly brown to dark brown except base

of gaster light brown; F5, F7 and F8 with mps, F6 without mps; fore wing about 4 times as long as wide, disc more or less uniformly setose between marginal vein and cubital row of setae; ovipositor not exserted.

Non-type specimens from Finland: Body length 0.73–0.93 mm (air-dried, point-mounted specimens). Antenna ( Fig. 13A ) with scape (minus radicle) 3.6–4.2 times as long as wide; pedicel longer than F1; F1–F4 more or less subequal in length, shorter than following funicular segments; F5 about as long as F7 (the longest funicular segment), F8 a little shorter and F6 slightly shorter than F8; mps on F5 (1 or 2), F7 (1 or 2), and F8 (2); clava with 10 mps (4 in the middle and 6 subapical), 2.7–3.2 times as long as wide, a little longer than combined length of F6–F8 but sometimes about as long as it. Fore wing ( Fig. 13C ) 4.1–4.7 times as long as wide; longest marginal seta 0.38–0.47 times maximum wing width; disc almost hyaline, more or less uniformly setose behind marginal vein and densely setose elsewhere. Hind wing ( Fig. 13C ) 28–29 times as long as wide. Metasoma ( Fig. 13B ) with petiole about as wide as long. Ovipositor occupying about 0.6 length of gaster, not exserted beyond its apex, about 0.9 times length of mesotibia.

Male. Known and described from Finland (Hൾඅඅඣඇ 1974) but not necessarily conspecific with Lymaenon gracilentus (like the presumed paratype from Joutseno); additional specimens are likely to be among the material from the country recently identified by S. V. Triapitsyn as Lymaenon spp.

Remarks. The holotype of this species ( Fig. 12 ) is in fair condition (head and antennae are shriveled because the specimen was air-dried) and complete. According to the unpublished handwritten diary of W. Hellén in FMNH,

the exact type locality of the holotype of his Gonatocerus gracilentus was Kl: Parikkala (Tiviä, 682:363 [10 km by 10

km grid number according to the Finnish YKJ coordinate system]); the specimen with the original yellow-colored W.

Hellén’s number 4360 was collected on 16.vii.1940 by W.

Hellén on willow bushes in a moist meadow.

The holotype female of Gonatocerus gracilentus , invalidly designated as a lectotype by Mൺඍඍ*üൾඐඌ (1986: 227) because Hൾඅඅඣඇ (1974: 11) specifically listed the specimen from Parikkala as a holotype, although without providing any other details (T*©ංൺඉංඍඌඒඇ 2013). Its synonymy under Gonatocerus chrysis ( Debauche, 1948) , which is a synonym of Lymaenon aureus (Girault, 1911) (T*©ංൺඉංඍඌඒඇ 2013; Hඎൻൾ*© 2015), by Mൺඍඍ*üൾඐඌ (1986: 227) was not justified because its examination revealed

that it rather fits in the broad diagnosis of Lymaenon litoralis (Haliday, 1833) , as given by T*©ංൺඉංඍඌඒඇ (2013) for Gonatocerus (Lymaenon) litoralis (Haliday, 1833) . In the

key to the Palaearctic species of Lymaenon Walker, 1846

(as Gonatocerus ( Lymaenon )) by T*©ංൺඉංඍඌඒඇ (2013), the holotype of Lymaenon gracilentus and female specimens from Europe similar to it would end up in the second part of Couplet 18 (p. 40) as those Lymaenon litoralis which have the fore wing quite narrow, at least 3.9 times as long as wide. Because Lymaenon gracilentus is an already described species and at least for now can be separated from the typical L. litoralis using proportions of the female fore wing (at most 3.8 times as long as wide in the latter), we reluctantly resurrect the former as a valid taxon from its synonymy with L. aureus , with an understanding that in the future it could potentially be proven (for instance, using molecular methods) to rather be conspecific with L. litoralis .

Distribution. Palaearctic Region ( Finland).

Figures

Fig. 12. Lymaenon gracilentus (Hellén, 1974), female (holotype of Gonatocerus gracilentus Hellén, 1974), habitus in dorsolateral view.

Fig. 13. Lymaenon gracilentus (Hellén, 1974), female (Sipoo, Uusimaa, Finland): A – antenna; B – body; C – fore and hind wings.