Leptostigma longipallidum, 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 : 15-17

Leptostigma longipallidum n. sp.

http://zoobank.org/ urn:lsid:zoobank.org:act:EEEB4CA5-0EF0-4B45-985E-08D39CF2A996

Figs. 3C–D , 13–15 .

Holotype. GSC 142841 (part, counterpart) ( Figs. 3C–D , 13 ). A very damaged head, thorax, partial abdomen and fragments of legs, both forewings only missing the apical regions overlaying indistinct portions of hind wings; from McAbee ( GSC locality V-016800), collector John Leahy; housed in the collections of the GSC (Vancouver).

Diagnosis. Distinguished from other species of Leptostigma by antenna with a combination of club elongate, paler than flagellar base formed with two long darkened segments; forewing lightly, evenly infuscate throughout. Tentatively diagnostic: R+M longer than 1-M, 2r-rs joins cell 3rm at or before its middle. R+M longer than 1-M, 2r-rs joins cell 3rm at or before its middle, 2r-m joins M far behind 2m-cu, anal cells meet at crossvein.

Description. Holotype. Body length as preserved (F-777, certainly incomplete) 20 mm, dark throughout including small leg fragments, wing membrane lightly infuscate throughout, pterostigma dark; in F-1185 middle part of wing wide with long, dense pubescence (similar in some living cimbicids, cf. Vilhelmsen et al. 2018, Fig. 2A, B , 6D , 13A ; Yan et al. 2019, Fig. 1 ; may be absent in other Cenocimbicinae by preservation). Head (F-777) roundish, slightly transverse, with eyes long, strongly converging forward, reaching rather close to both clypeus and occiput, ocelli in orthogonal triangle, posterior ones somewhat diminished, distant from each other for more than their greatest diameter; toruli touching clypeus, distant for more than their diameter; temples inflated, in front view toward clypeus as wide as eye; clypeus wide, moderately short. Antennal club elongate, paler than funicle, funicle 2-segmented, cylindrical, somewhat darkened. Lateral lobes of pronotum wide; median longitudinal mesonotal sulcus, notauli well developed, joined well before small transverse scutellum, metanotum short. Forewing length holotype 17.8 mm (F-1185, 15 mm; F-777, 16.5 mm), maximum width 4–5.3 mm, length/width 3.4–3.7, pterostigma narrow, tapering, similar to width of C-R basal to pterostigma, R+M longer than 1-M, maximum length of cell 2r shorter than 3r, 2r-rs same length or shorter than Rs between 2r-m and 2r-rs, joins Rs before middle of cell 3rm, 2r-rm curved (more or less sigmoidal), joins Rs similar level to 2m-cu joins M, joins M behind 2m-cu for more than half (for half only in F-1185) of 2r-m length; 1-M more or less curved, cell 1mcu with 1-M, 1m-cu sub-parallel to slightly diverging, 3r-m almost straight, cell 2mcu with M shorter than 1m-cu or (in F-1185) of similar length, 2m-cu slightly bent toward base, cu-a postfurcal (scarcely so if at all in F-777), anal cells meet at crossvein. Hind wing with 3r-m, m-cu, cu-a present, m-cu for its length from 3r-m, cu-a before middle of cell mcu, for twice its length basal to m-cu. Abdominal tergum 1 entire, with hind margin weakly convex.

Remarks. Differs from all congeners with known antenna ( L. brevilatum n. sp., L. longiclava n. sp., and L. longitenebricum n. sp.) by its club paler than its funicle. Differs venationally from L. brevilatum n. sp. and L. longiclava n. sp. by R+M longer than 1-M, from L. longitenebricum n. sp. by its anal cells meeting at a crossvein. Differs from L. proxivena n. sp., L. fasciatum n. sp., L. alaemacula n. sp., with unknown antenna by wing membrane lightly, evenly infuscate throughout (without fascia, macula) and 2r-m entering M far behind, and not close to, 2m-cu.

Material. Holotype and tentatively (by venation) specimen F-777, F-771 (part, counterpart) ( Fig. 14 ), and F-1185 ( Fig. 15 ), both collector unknown, in the collections of TRU.

Etymology. From the Latin longus, meaning long, and pallidus, pale, referring to the antennal club. The epithet is an adjective.

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

Figures

FIGURE 1. Forewing and hind wing of Corynis crassicornis (Rossi) (Corynidinae) with veins (roman font) and cells (italic font) labelled. Drawn from Vilhelmsen (2019) figure 15B. Scale = 2 mm.

FIGURE 2. Cenocimbex menatensis Nel, holotype MNHN-LP-R.11195: A, extract from a reflectance transformation imaging (RTI) file (Cultural Heritage Imaging 2012); B, drawing of left forewing; C, drawing of right forewing preserved portion; D, left hind wing. Scale bars 5 mm.

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 6. F-1182, tentative Leptostigma brevilatum, A, photograph, and B–E, drawings of: B, left forewing; C, right forewing; D, left hindwing, and; E, right hind wing. All to scale, 5 mm.

FIGURE 13. Leptostigma longipallidum, holotype GSC 142841, A, photograph, B–C, wing drawings: B, right forewing; C, left forewing. All to scale, 5 mm.

FIGURE 14. F-771, tentative Leptostigma longipallidum, A, photograph, B–E, wing drawings: B, right forewing; C, left forewing; D, right hind wing; E. left wing. All to scale, 5 mm.

FIGURE 15. F-1185 tentative Leptostigma longipallidum forewing: A, photograph; B, drawing. Scale is 5 mm.