Archipedionis, Dietrich, Christopher H. & Thomas, M. Jared, 2018

Dietrich, Christopher H. & Thomas, M. Jared, 2018, New eurymeline leafhoppers (Hemiptera, Cicadellidae, Eurymelinae) from Eocene Baltic amber with notes on other fossil Cicadellidae, ZooKeys 726, pp. 131-143 : 134-136

Archipedionis gen. n.

Type species.

Archipedionis obscurus sp. n.; by present designation and monotypy.

Diagnosis.

This genus differs from other Macropsini in having the following combination of traits: crown shorter medially than next to eye; face with epistomal suture visible; ocelli slightly mesad of antennal pits, coronal pits dorsolaterad of ocelli; lorum not fused to frontoclypeus or anteclypeus; rostrum extended beyond middle coxae. Pronotum angulately produced medially but extended only slightly anterad of eyes in dorsal view, irregularly rugose. Forewing outer anteapical cell open, veins without markings.

Description.

Head in dorsal view with crown shorter medially than next to eyes; face relatively broad and short, texture minutely and more or less evenly punctate, ocel li slightly closer to eyes than to midline; coronal pits present dorsolaterad of ocelli; epistomal suture visible; gena strongly concave and narrow below eye, exposing flaplike proepisternum; lorum convex, extended nearly to lateral margin of face, not fused to anteclypeus; anteclypeus parallel-sided with apex truncate; rostrum extended past middle coxae, slender. Pronotum shagreen, with irregular transverse rugae. Forewing elongate, appendix narrow, extended around wing apex; most of membrane opaquely sclerotized; veins somewhat obscure, without obvious markings; inner and middle anteapical cells closed, outer anteapical cell open (crossvein s absent); claval veins distinct. Visible portion of hind wing apex with two closed apical cells, anterior branch of R absent. Front femur and tibia without conspicuous setae. Middle femur and tibia without macrosetae. Hind femur macrosetal formula 2+1; tibia strongly flattened, distance between dorsal setal rows much less than distance between dorsal and ventral rows, row AD with 8 preapical macrosetae (PD not visible in fossil), row AV macrosetae extended most of length of tibia, row PV with numerous close-set slender setae subequal in length, tarsomere I with dorsoapical pair of macrosetae well developed, with two rows of plantar setae, pecten with 2 platellae. Female pygofer relatively short, occupying <half total length of abdomen; sternite VII angulately emarginate, covering base of ovipositor.

Etymology.

The genus name, a masculine noun, combines the prefix archi- derived from the Greek archaeos, meaning old, with Pedionis , the name of a modern macropsine genus with similar forewing venation.

Notes.

This genus has forewing venation resembling that of the modern genus Pedionis Hamilton, 1980, i.e., with the s crossvein delimiting an outer anteapical cell absent, but differs in having the structure of the head more plesiomorphic, resembling Zelopsis Evans, 1966. Specifically, the face has the epistomal suture visible and arcuate and the anteclypeus is well delimited laterally and basally by sutures. The pronotum is not strongly produced anteromedially, although it still extended slightly anterad of the eyes medially, and the transverse rugae are only slightly arched anterad medially. Unfortunately, because only one female specimen is known, it is not known whether the structure of the lower part of the face is sexually dimorphic in Archipedionis , as is usual among modern macropsines. The elongate rostrum of this genus is apparently unusual in the modern macropsine fauna and has been reported only in Galboa Distant, 1909 (Seychelles Islands) and Paragalboa Yang, Dietrich & Zhang, 2016 (Madagascar), but also occurs in some species of Pedionis .

Three previously described fossil species from Baltic amber have been included in Macropsini : Bythoscopus homousius Germar & Berendt, 1856, B. punctatus Bervoets, 1910, and Pediopsis minuta Bervoets, 1910 ( Szwedo 2002). Unfortunately, the only known specimens of these species were apparently destroyed during World War II and the original descriptions and illustrations are not sufficiently detailed to facilitate placement or detailed comparison with the species described here. Nevertheless, information provided in the original descriptions appears to indicate that these previously described species are different from the one described here. According Germar and Berendt (1856), B. homousius has the outer anteapical cell of the forewing closed distally (open in Archipedionis ). Pediopsis minuta is much smaller (3 mm vs. 4.5 mm) and has the anterior margins of the head and pronotum much more strongly angulate. B. punctatus is similar in size and in the shape of the head and pronotum to Archipedionis obscurus but the ocelli are closer to the midline of the face and the frontal sutures are not delimited. Collectively, these three species and the new species described below are the oldest representatives of Macropsini known from the fossil record.

Statz (1950) reported another species of Macropsini , Macropsis pectoralis Statz, 1950, from the Oligocene of Germany. The photograph of the holotype provided by Statz (1950: fig. 57) indicates that this fossil is correctly placed in Macropsini based on overall size and the form of the head and pronotum (pronotum angulately extended anterad of eyes) but its forewing venation is only partly visible and other traits that would facilitate detailed comparison with modern taxa are not visible. Bythoscopus sepultus Statz, 1950 may also be confidently placed in Macropsini based on the hind wing venation (absence of vein R2+3, submarginal vein not extended along costal margin basad of R4+5). The shape of the head and pronotum ( Statz 1950: fig. 7) are indistinguishable from those of the modern Holarctic macropsine genus Oncopsis Burmeister, 1838; therefore the new combinations Oncopsis sepultus sepultus (Statz), comb. n. and Oncopsis sepultus austerus (Statz), comb. n. are proposed here. Two additional fossils placed by Statz (1950) in Bythoscopus Germar, 1833 (an isogenotypic junior synonym of Iassus Fabricius, 1803), B. lunatus Statz, 1950 and B. robustus Statz, 1950, also appear to belong to Macropsini but their correct generic placements cannot be determined due to the poor condition of the fossils.