Leptostigma longiclava, Archibald & Rasnitsyn, 2023

Archibald, S. Bruce & Rasnitsyn, Alexandr P., 2023, Cimbicidae (Hymenoptera, ‘ Symphyta’) in the Paleogene: revision, the new subfamily Cenocimbicinae, and new taxa from the Eocene Okanagan Highlands, Zootaxa 5278 (1), pp. 1-38 : 13-15

Leptostigma longiclava n. sp.

http://zoobank.org/ urn:lsid:zoobank.org:act:B8F5BDEE-1B98-4F5F-94FB-646D070B6153

Figs. 3K–L , 11–12 .

Holotype. RBCM.EH2017.050.4085.0001a, b (part, counterpart) ( Figs. 3K–L , 11 ). Mostly complete in dorsal aspect but missing much of the abdomen; collected at McAbee by John Leahy; housed in the collections of the RBCM.

Diagnosis. Distinguished from other species of Leptostigma by a combination of antenna with club long, darkened, penultimate segment longer than ultimate, flagellar base formed by long, dark, apparently single (entire) segment. Forewing lightly, evenly infuscate throughout (no fascia or macula). Tentatively diagnostic: R+M shorter than 1-M, 2r-rs joins cell 3rm distinctly behind its middle, 2r-m joins M far behind 2m-cu, anal cells meet at crossvein or are at most minimally separated by a very short fusion of 1A with 2A+3A.

Description. Holotype. Body. Length not known by preservation, tentative specimen F-848 ca. 14 mm as preserved, likely 15–16 mm in life. Head, thorax, scape, pedicel, basal flagellomere, femora dark; antennal club, pterostigma, tibiae, metasoma darkened as preserved; flagellar segment 2 rather pale, wing membrane lightly infuscate throughout. Head as preserved difficult to interpret. Antenna apparently 7-segmented, with scape, particularly pedicel very short, first flagellomere longest (about one third of flagellum), those following gradually becoming shorter and, except apical one, wider, apical one half-oval. Thorax with distinct median longitudinal mesonotal sulcus, notauli complete, meeting well before transverse scutellum; metascutellum narrow (narrower than normal in Pachylostictinae , Corynidinae), cenchri not apparent. Forewing length 14 (holotype)– 16 mm, maximum width 4.5 (holotype)– 5 mm, length/width 3.1–3.2; pterostigma narrow, similar to width of C&R basal of pterostigma; R+M as long as 1-M in left wing, shorter in right; 2r-rs shorter than Rs between 2rm, 2r-rs, entering Rs behind middle of cell 3rm; 2r-m distinctly curved, joins Rs about same level as 2m-cu joining M, joins M behind 2m-cu for more than half length of 2r-m; 3r-m almost straight; 1-M curved; 1-M and 1m-cu slightly diverging toward wing anterior margin; cell 2mcu with M shorter than 1m-cu; 2m-cu slightly curved or angular mid-length; cu-a slightly postfurcal; anal cells minimally separated by a very short fusion of 1A with 2A+3A, no crossvein between them (in F-848, anal cell region not preserved in holotype). Hind wing mostly indistinctly preserved, crossveins 3r-m, m-cu present, distant for less than length of 2r-m. Abdominal tergum 1 possibly split medially, with hind margin straight.

Remarks. Differs from L. brevilatum n. sp. and L. longipallidum n. sp. by its club long and darkened [short, wide, and dark in L. brevilatum n. sp.; long and pale in L. longipallidum n. sp.]; differs venationally, tentatively, from both L. brevilatum n. sp. and L. longipallidum n. sp. in 2r-rs joining cell 3rm distinctly distal to its middle [vs. at or before middle]. Differs from L. longitenebricum n. sp. that has a generally similar antenna (club long, darkened) in that its flagellar base is formed by one long, dark segment [vs. two pale, relatively short ones], and by its penultimate club segment longer than ultimate [vs. shorter]. L. longiclava n. sp. also differs from L. longitenebricum n. sp. in having anal cells at most minimally separated [vs. distant for more than half width/height of cell 2a]. Differs from L. proxivena n. sp., L. fasciatum n. sp., and L. alaemacula n. sp. by its forewing lightly, evenly infuscate throughout [vs. with dark transverse fascia or macula at or basal to level of pterostigmal base] and 2r-m entering M far behind, not close to 2m-cu.

Material. Holotype and tentatively (based on venational characters) specimen F-848 ( Fig. 12 ), collector unknown at McAbee, in the collections of TRU.

Etymology. From the Latin longus, meaning long, and clava, club, referring to the antennae. The epithet is a noun in apposition.

Locality and age. McAbee, British Columbia, Canada, Hoodoo Face beds; mid-Ypresian.

Figures

FIGURE 3. Heads of Cenocimbicinae: A, Leptostigma brevilatum GSC 142839, drawing; B, L. brevilatum GSC 142839, photograph; C, Leptostigma longipallidum GSC 142841, drawing; D, L. longipallidum GSC 142841, photograph; E, Cenocimbex menatensis MNHN-LP-R.11195, drawing; F, C. menatensis MNHN-LP-R.11195, photograph; G, Leptostigma longipallidum F-771, drawing; H, L. longipallidum F-771, photograph; I, Leptostigma longitenebricum F-1565, drawing; J, L. longitenebricum F-1565, photograph; K, Leptostigma longiclava RBCM.EH2017.050.4085.0001, drawing; L, L. longiclava RBCM.EH2017.050.4085.0001, photograph. Scale bars 2 mm.

FIGURE 11. Leptostigma longiclava holotype RBCM-EH2017.050.4085.001, A, photograph, B–E wing drawings: B, right forewing; C, left forewing; D, left hind wing; E, right hind wing. All to scale, 5 mm.

FIGURE 12. F-848, tentative Leptostigma longiclava, A, photograph, B–C, drawings: B, right forewing; C, left forewing. All to scale, 5 mm.