Proneuronema sidorchukae, Makarkin & Perkovsky, 2020

Makarkin, Vladimir N. & Perkovsky, Evgeny E., 2020, A new species of Proneuronema (Neuroptera: Hemerobiidae) from late Eocene Rovno amber, Zootaxa 4718 (2), pp. 292-300 : 293-294

Proneuronema sidorchukae sp. nov.

Figs 1–3

Type material. Holotype SIZK L-116, collected by Nikolai R. Khomich and currently deposited in his collection, but will be ultimately deposited in SIZK. A nearly complete specimen in the resting position, with wings folded steeply roof-like.

Type locality and horizon. Rovno amber (11 km NW from Voronki in Vladimirets District of Rovno Region, Ukraine). Late Eocene.

Etymology. The species is named in memory of Ekaterina A. Sidorchuk (1981–2019), a Russian paleoentomologist.

Diagnosis. Easily distinguished from other species of the genus by forewing maculation: some crossveins in third gradate series broadly margined with dark brown.

Description. Head cuneiform in lateral view, but obscured by milky covering. Eyes relatively large. Postocular lobe narrow. Vertex covered with strong setae. Antennae moderately long. Scapus rather large; pedicellus slightly broader than first flagellomeres; flagellum 41-segmented (right antenna).

Pronotum, mesonotum covered with dense relatively long setae. Prothorax rather short. Mesothorax: prescutum narrow, slightly convex; anterior part of mesoscutum (anteriad parapsidal sutures) triangular, divided into two by longitudinal median suture; posterior part of mesoscutum consisting of two lateral rounded convex lobes, strongly constricted concave medial part; in middle of notum, transversal medial ridge well developed; mesoscutellum rather large, posteriorly rounded, convex.

Legs: Forecoxa very long. Forefemur, mesofemur relatively short, rather stout. Metatibia long (1.5 times longer than metafemora), slightly curved and thinner proximally, not especially swollen medially. Metatarsus relatively short, metabasitarsus longest.

Forewing oval, 5.9 mm long, 2.4 mm wide. Costal space broad, dilated approximately at basal quarter of wing length. Most subcostal veinlets forked once (except three basal veinlets, which are each forked twice in right wing), distal veinlets simple; humeral veinlet strongly recurrent, with five branches (four simple, one forked). One occasional crossvein (aberrant) between stems of two basal veinlets in right wing. Subcostal space moderately broad, with four (right wing) to five (left wing) crossveins: one basal, one intermediate, one to three distal (distal part of subcostal space poorly visible in right wing). RA with few branches distally: posterior trace of RA one forked with one once-forked veinlet in both right, left wings (plus one simple posterior branch in right wing, probably aberrant). RA space (in this genus between RA, ORB2) rather broad with two crossveins belonging to third, fourth gradate series. RP with two ORBs. ORB1 with two branches directed anteriorly, originating proximad third gradate series of crossveins (both branches forked one to three times distad fourth gradate series); posterior trace of ORB1 deeply dichotomously forked proximad fourth gradate series. ORB2 (RP proper) with four branches originating proximad fourth gradate series (of these, one deeply forked in right wing), most forked once. M basally not fused with R, forked distad origin of ORB1. MA deeply forked at third gradate series (right wing) or relatively shallowly forked distad fourth gradate series (left wing). MP deeply forked between third, fourth gradate series. CuA with five (left wings) or four (right wing) pectinate branches, mostly once forked. CuP deeply forked, both branches shallowly once forked, except simple posterior branch in right wing. AA1 rather deeply forked, somewhat distad mid-point; both branches shallowly forked. AA2 deeply forked, proximad mid-point; both branches shallowly forked (right wing). AA3 forked near its origin (anterior branch with two short branches, posterior branch simple). Four gradate series of crossveins present: First (basal) series consists of six crossveins, from M to AA3 (including basal crossvein between CuA, CuP); second series includes three–four crossveins from ORB1 to CuP (crossvein between ORB1, MA not discernible in right wing,); third (“inner”) series consists of nine crossveins, from RA to CuA; fourth (“outer”) series complete, consists of 21 (left wing), 22 (right wing) crossveins from RA to AA1. Two basal-most crossveins proximad first series in anal space: one between AA2, AA3, one between branches of AA3. Four folds clearly discernible: (1) between posterior trace of ORB1, M/MA longest (radiomedial flexion line or medial flexion line); (2) between M, Cu short (mediocubital flexion line); (3) between Cu/CuP, AA1 long (cubitoanal flexion line or claval flexion line); (4) between AA1, AA2 rather long (intraanal flexion line). Wing membrane fuscous with distinct color pattern consisting of broad dark brown bordering of some crossveins in third gradate series.

Hind wings mostly not visible (hidden by forewings), except apical part of right wing, narrow outer to posterior parts of left wing. ScP, RA not fused distally, with at least one distal subcostal crossvein. RA with two forked veinlets.

Abdomen not visible, wholly hidden between wings.

Remarks. Proneuronema sidorchukae sp. nov. is most similar to P. minor in size, number of flagellomeres and wing venation. These species however are easily distinguished by forewing color pattern, by the shape of the costal space, and by the configuration of their subcostal veinlets. Some crossveins in the third gradate series are broadly margined with dark brown in P. sidorchukae sp. nov. (i.e., dark coloration extending broadly on the membrane surrounding the vein, see Fig. 2 ), but this dark bordering is absent in P. minor (its forewing membrane is slightly fuscous almost throughout, lacking distinct maculation). The proximal part of the costal space of P. sidorchukae sp. nov. is markedly narrower with its subcostal veinlets more oblique than those of P. minor .

The two other described species of the genus ( P. gradatum and P. wehri ) differ from P. sidorchukae sp. nov. (and from P. minor ) by many features of forewing venation, e.g., by the dichotomously branched M and the presence of crossveins in the costal space, and by larger size.

Figures

FIGURE 1. Proneuronema sidorchukae sp. nov., holotype SIZK L-116. A, right side; B, left side. Scale bars = 1 mm.

FIGURE 2. Forewing venation of Proneuronema sidorchukae sp. nov., holotype SIZK L-116. A, right forewing; B, left forewing (converted to standard view, with the apex to the right). Scale bar = 1 mm (both to same scale).

FIGURE 3. Proneuronema sidorchukae sp. nov., holotype SIZK L-116. Thorax and anal areas of the forewings (dorsal view). amsc, anterior part of mesoscutum; mr, transversal medial ridge; ms, longitudinal medial suture; mscl, mesoscutellum; par, parapsidal suture; pmsc, posterior part of mesoscutum; prn, pronotum; psc, prescutum; ps, prescuto-scutal suture; vs, scutoscutellar suture. Scale bar = 0.5 mm.