Euroleuctra gillesi Chen, 2018

Chen, Zhi-Teng, 2018, Description of Euroleuctra gen. nov., a new fossil genus of Leuctridae (Insecta: Plecoptera) in Eocene Baltic amber, Zootaxa 4462 (2), pp. 291-295 : 292-295

Euroleuctra gillesi Chen , sp. nov.

Figs. 1–6 .

Description. Macropterous; body length ca. 6.0 mm, generally dark brown; ventral surface of head and thorax covered by unknown substance ( Figs. 1, 2 ).

Head ( Figs. 1, 2 ) rounded and dark brown, slightly wider than pronotum. Ocelli not apparent, compound eyes bulbous. Antennae dark and filiform, with 45 segments, each segment apically fringed with short setae. Maxillary palp four-segmented, basal segment shortest; labial palp invisible.

Thorax ( Figs. 1–3 ): Pronotum rounded, posterior margin concave, with dark stigma. Cervical gills absent; cervix with two oval lateral nubs. Meso- and metathorax slightly wider than prothorax. Legs mostly brown, apical segments dark; forelegs shortest, hindlegs longest; femur slightly shorter but thicker than tibia; tibia with only one clear ventroapical spur; tarsus three-segmented, each segment apically with short setae, second segment shortest; claws short and sharp. Ventral sclerites of thorax invisible.

Wings ( Figs. 1 , 4 ) sub-hyaline and fringed with short setae, without any darker patterns; veins brown. Left forewing length ca. 5.5 mm; ScP reaches RA before ra-rp, anterior margin invisible; radial sector and media veins with separate origins; RP originated from near base of RA, forked at near half length of the wing; Cu basally forked to CuA and CuP; the crossvein m-cu joins CuA1 after CuA divides into CuA1 and CuA2; area between M and CuA with six crossveins; area between CuA and CuP with nine crossveins; AA1 twice curved and elongated, almost reaching CuP; AA2 forked. Hind wing invisible.

Abdomen ( Figs. 1, 2 , 5 , 6 ) segments generally brown, sterna 1–5 and 9–10 darker, sterna 6 sterna 7 each with a pair of median dark spots. Median and posterior area of terga 8–9 membranous, previous terga not visible. Tergum 10 short, cleft at posterior half, dark sclerotized except for the anteromedial membranous area; a subquadrate sclerotized plate present posterior to tergum 10. Sternum 9 longest, mostly sclerotized and covered with long hairs; ventral vesicle present, hairy and rounded; posterior margin of sternum 9 embedded, forming a deep membranous area, which extended backwards but posterior margin not clear; two parallel sclerites originated posterior to the vesicle, covered with long bristles, lateroapically with serrated margins. Subanal probe elongated and straight, gradually narrowed from base to apex, not upcurved; from ventral aspect, median fusion line distinct in most parts of the probe; the probe subapically with two pairs of lateral giant teeth, apex completely fused and slightly enlarged. Cercus hairy and cylindrical, slightly shorter than the subanal probe, without apical lobes.

Holotype. Male, a well-preserved specimen in a piece of Baltic amber from Poland, Eocene (ca. 40-50 Mya). The holotype is deposited in the Chen Amber Collection, Yangzhou, China, No. CZT-PLE-BA3.

Etymology. The new species is named for Gilles Vinçon, Grenoble, France, who has made substantial contributions to the knowledge of European and African stoneflies, including the Leuctridae .

Syninclusions. A piece of leaf.

Figures

FIGURE 4. Euroleuctra gillesi, gen. et sp. nov. Left forewing, dorsal view; anterior margin not visible

FIGURE 5. Euroleuctra gillesi, gen. et sp. nov. Photograph and reconstruction of terminalia, dorsal view

FIGURE 6. Euroleuctra gillesi, gen. et sp. nov. Photograph and reconstruction of terminalia, ventral view

FIGURE 1–3. Euroleuctra gillesi, gen. et sp. nov. 1. Adult habitus, dorsal view; pronotum marked with white dashed line. 2. Adult habitus, ventral view. 3. Apical segments of left foreleg