Jonas Damzen lacewing (Proneuronema damzeni) differs from Proneuronema minor and Proneuronema sydorchukae

NEWS - Jonas Damzen lacewing (Proneuronema damzeni sp. nov.) from the late Eocene Ukrainian Rovno amber differs from 2 other species of the Eocene genus, P. minor Makarkin et al. 2016 and P. sydorchukae Makarkin & Perkovsky 2020. Fur Formation Megalomus densistriatus Henriksen 1922 and Baltic amber Proneuronema gradatum Makarkin et al. 2016 as Archibaldia densistriata comb. nov. and A. gradata, comb. nov.

Hemerobiidae currently has more than 550 species distributed worldwide. The oldest fossils are from the Jurassic, but are rare until they became common in the Eocene. To date, 33 fossil species have been described.

Proneuronema Makarkin et al. 2016 assigned to two species from late Eocene Baltic amber (P. minor and Proneuronema gradatum Makarkin et al. 2016), and one species from the early Eocene of western North America, Proneuronema wehri (Makarkin et al. 2003).

Proneuronema damzeni is an extinct species of lacewing in the Hemerobiidae known from fossils found in amber from the type locality of Ukraine (Rovno region), late Eocene. The epithet is given to the family of Jonas Damzen, an amber collector and examiner.

The new species can be distinguished from the other two species in the genus by the larger size of the forewings at 7.3 mm long (vs. 6.3–6.9 mm in P. minor; 5.9 mm in P. sydorchukae), the broader forewings with a length-to-width ratio of 2.14 (vs. 2.46 in P. sydorchukae; 2.17–2.30 in P. minor), and the distinct forewing macules with one spot on the third gradation series (vs. two in P. sydorchukae; none in P. minor).

DESCRIPTION

Head cuneiform with moderately large eyes. Frons and clypeus with scarce, relatively short setae; setae on vertex denser. Postocular lobe narrow. Labrum transverse, with rounded margin. Maxillary palpi 5-segmented; first and second segments short; third and fourth segments approximately twice longer; fifth (terminal) segment largest, fusiform, whole (additional sub-segment absent).

Labial palpi probably 3-segmented; terminal segment large, fusiform. Galea relatively large, with dense short setae apically; sclerotized finger-like apical process (digitus) not detected. Antennae moderately long; scapus relatively large; pedicellus slightly broader and twice as long as first flagellomeres.

Pronotum, mesonotum covered with dense relatively long setae. Pronotum saddle-shaped, with two large dorsal protrusions; lateral projections well developed, protruding more posteriorly than anteriorly.

Mesonotum: presumed prescutum narrow, divided into two halves medially, probably fused with posterior margin of pronotum laterally; anterior part of mesoscutum (anteriad parapsidal sutures) triangular, divided in two by longitudinal median suture; posterior part of mesoscutum consisting of two lateral rounded convex lobes, strongly constricted medially; mesoscutellum posteriorly rounded.

Legs: Procoxa very long; relatively narrow profemur; protibia narrow; basiprotasus longest, fourth tarsomere shortest; first to fourth tarsomeres bear several bristles ventrally arranged in transverse row; claws narrow, acute, strongly curved; empodium large, broad, pad-like. Midleg resembles foreleg except with short, stout mesocoxa. Metacoxa short, stout; metafemur relatively narrow; metatibia long, slightly curved, thinner proximally and slightly swollen medially.

Forewing ovate, 7.3 mm long, 3.4 mm wide. Costal space broad. Most subcostal veinlets are forked once including distal ones (except one in proximal portion, which is forked twice in both forewings); humeral veinlets strongly recurrent, with six branches (three simple, three forked once) in left wing, and five (two simple, four forked once) in right wing. Subcostal space moderately broad, with six crossveins (left wing): one basal, one intermediate, four distal (left wing).

Posterior trace of rA distally simple with two once-forked veinlets (left wing); once forked with one simple and one once-forked veinlet (right wing). rA space (in this species between rA and orB3) rather narrow with two crossveins belonging to third and fourth grade series (left wing); three crossveins: one belongs to third grade series and two closely spaced crossveins belong to fourth grade series (right wing).

rP with three orBs. orB1 deeply forked once distad second grade series; anterior branch of orB1 deeply forked at third grade series; posterior trace of orB1 deeply forked proximate fourth grade series. orB2 forked distad fourth grade series. orB3 (rP proper) with four branches originating proximate fourth grade series (of these, one deeply forked in left wing), forked distally once to three times. M basally not fused with r, forked distad origin of orB1.

MA and MP deeply forked between third and fourth grade series; each branch shallowly forked once. CuA with five (left wings) pectinate branches, forked distally one to three times. CuP deeply forked, both branches shallowly forked once. A1 rather deeply forked, slightly proximate mid-point; anterior branch pectinately forked with four short simple branches; posterior branch twice forked. A2 deeply forked, proximate mid-point. A3 forked near its origin.

Four grade series of crossveins present: First (basal) series consists of six crossveins, from Sc to A3 (crossvein 1r-m absent); second series of four crossveins from orB1 to CuP; third (“inner”) series consists of nine crossveins, from rA to CuA; fourth (“outer”) series complete, consisting of 24 (left wing) from rA to A1.

Three folds clearly discernible: between posterior trace of orB1, M/MA (radiomedial flexion line or medial flexion line); between Cu/CuP, A1 (cubitoanal flexion line or claval flexion line); and between A1, A2 rather (intra-anal flexion line). Fold between M, Cu (mediocubital flexion line) indistinct. Wing membrane fuscous with distinct dark brown spot at intracubital crossvein in third grade series.

Hind wings mostly and abdomen completely not visible, covered by forewings.

Original research

Vladimir N. Makarkin & Sonja Wedmann (2024). A new species of Hemerobiidae (Neuroptera) from the late Eocene Rovno amber. Zootaxa 5538 (6): 595–600, DOI:10.11646/zootaxa.5538.6.6

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