Euroleuctra 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

Genus Euroleuctra Chen , gen. nov.

Type species. Euroleuctra gillesi gen. et sp. nov., by monotypy.

Diagnosis. The new genus can be assigned to the family Leuctridae by its general habitus and terminalia, including the absence of gills, absence of X-patterned crossveins in forewing, forked AA 2 in forewing, shortest second tarsal segment, and the one-segmented cerci. It can be distinguished from other genera of Leuctridae by having the combination of the following characters: 1) wings without banded patterns; 2) tibia with only one ventroapical spur; 3) crossvein m-cu joins CuA1 after CuA divides into CuA1 and CuA2; AA1 twice curved, almost reaching CuP; 4) ventral vesicle of sternum 9 present; 5) sternum 9 with a median membranous area which extended backwards, the membranous area with two parallel sclerites which with modified apices; 6) subanal probe elongated and straight, gradually narrowed from base to apex, not upcurved, subapically with two pairs of lateral giant teeth, apex completely fused and slightly enlarged; 7) cercus unmodified, apically without lobes.

Based on the terminalia structure, the new genus is most similar and may have a close relationship to Baltileuctra Chen, 2018 , another fossil genus in Baltic amber from Lithuania ( Chen 2018b). However, Euroleuctra can be distinguished from Baltileuctra by the following characters: 1) antenna longer, with apparently ten additional segments; 2) abdominal tergites and sternites not distinctly separated as in Baltileuctra ; 3) tibia with only one ventroapical spur, instead of two in Baltileuctra ; 4) forewings without banded patterns of Baltileuctra ; more crossveins in area between M and CuP; AA1 vein much longer; 5) membranous area of sternum 9 much bigger than Baltileuctra ; sternum 9 with two apically-modified parallel sclerites, instead of the U-shaped pattern in Baltileuctra ; 6) subanal probe more compressed than Baltileuctra , straight and not upcurved, gradually narrowed from base to apex, subapically with large teeth, apex completely fused and slightly enlarged; while in Baltileuctra , the probe is upcurved, shorter but much thicker, and dorsoapically with a circular hole; and 7) cercus without apical lobes as in Baltileuctra .

Etymology. The genus name, Euroleuctra is a combination of the holotype collection locality, Europe, and the extant genus Leuctra , which is the type genus of Leuctridae .