Corresponding author: Christopher H. Dietrich (
Academic editor: J. Zahniser
Two new extinct fossil cicadellid taxa from Eocene Baltic amber, representing the subfamily
Dietrich CH, Thomas MJ (2018) New eurymeline leafhoppers (Hemiptera, Cicadellidae, Eurymelinae) from Eocene Baltic amber with notes on other fossil Cicadellidae. ZooKeys 726: 131–143.
The fossil record of leafhoppers (
Recent molecular phylogenetic studies of leafhoppers have attempted to estimate the ages of various cicadellid lineages (
Six modern cicadellid subfamilies (
Judging from the numerous amber specimens offered for sale online over the past few years by dealers in Lithuania, Poland and elsewhere in Europe, most of the leafhoppers preserved in Baltic amber are nymphs, and many of these are difficult to place taxonomically and phylogenetically, given the still highly incomplete knowledge of the morphology of modern leafhopper nymphs (reviewed by
The new fossil taxa described herein include the oldest known representative of the leafhopper tribe
Fossil specimens were obtained from amber dealers in Palanga, Lithuania. Morphological characters were assessed by examination of the specimens using an Olympus SZX-12 dissecting microscope. Specimens were prepared by grinding flat facets in strategic locations to obtain a clear field of view for detailed photomicrographs according to
The concept of
This genus differs from other described genera of
Head in dorsal view with crown slightly shorter medially than next to eyes; face slightly longer than width across eyes, texture shagreen, area of vertex above ocelli with inconspicuous, fine arcuate parallel striations; ocelli approximately equidistant between eyes and midline, situated above mid-height of eyes; lateral frontal suture nearly straight, extended from antennal pit to ocellus; antennal ledge carinate but only weakly produced over antennal base; antenna shorter than head width, arista attenuate, with conspicuous preapical seta extended mesad; gena strongly concave and narrow below eye, partly exposing small proepisternum; lorum convex, extended nearly to lateral margin of face; anteclypeus broadened near apex; rostrum extended slightly past middle coxae, distal segment somewhat expanded toward apex. Pronotum shagreen, with indistinct transverse rugae. Forewing elongate, appendix broad, extended to wing apex, bordering first and second apical cells; vein R with three branches extended to wing margin; crossvein s absent; with two r-m and three m-cu crossveins (two closed subapical cells); vein CuA reaching submarginal vein near midlength of appendix; claval veins distinct. Front femur with AM1 strongly reduced; intercalary row with several long, fine setae; tibia cylindrical, with conspicuous setae only at apex. 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 fewer macrosetae than PD, row AV macrosetae distributed along distal 3/4 of tibia, row PV with alternating short and long tapered setae through most of length, tarsomere I with dorsoapical pair of macrosetae well developed, without plantar setae, pecten with 2 platellae. Female pygofer and ovipositor narrow and elongate, occupying 3/4 total length of abdomen; sternite VII with deep median parabolic emargination, exposing base of ovipositor.
The genus name, a masculine noun, combines the Greek word
Placement of
Previously reported fossil
Measurements (mm): body length including wings 4.8; head width across eyes 1.4; height of face (crown apex to anteclypeus apex) 1.5; forewing length 3.8; forewing maximum width (across approximately midlength) 1.1 mm; front tibia length 0.7; hind tibia length 1.7; hind tarsus length 0.7; ovipositor length (portion exposed posterad of sternite VII) 1.3. Hind tibia rows PD, AD and AV with 10, 9 and 11 macrosetae, respectively. Other structural features as described for genus. Body apparently uniformly pale brown, without discernible markings or pattern.
The species name refers to the emarginate gena.
Holotype female, Eocene Baltic amber (37–44 Ma), purchased by the first author from an amber dealer in Palanga, Lithuania. Deposited in the Paleontological Collection of the Illinois Natural History Survey (INHSP 10320).
The exoskeleton of the holotype is well preserved and intact except the femoro-tibial joints and adjacent parts of the left legs have been sheared off, apparently during initial processing of the amber piece, and are missing; most of the tibia and the entire tarsus of the left middle leg are also missing. Variable preservation of different parts of the integument give the impression that the holotype specimen has a pattern of dark markings but these appear to be artifacts.
This genus differs from other
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, ocelli 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.
The genus name, a masculine noun, combines the prefix
This genus has forewing venation resembling that of the modern genus
Three previously described fossil species from Baltic amber have been included in
Length including forewing 4.6 mm. head width across eyes 1.6; pronotum width: 1.3; height of face (crown apex to anteclypeus apex, approximate) 1.0; forewing length 3.4; forewing maximum width (across approximately midlength) 1.2 mm; front tibia length 0.7; hind tibia length 1.7; hind tarsus length 0.7; ovipositor length (portion exposed posterad of sternite VII) 0.9. Hind tibia rows AD, AV and PV with 8, 8 and >17 macrosetae, respectively (PD not visible and PV only partly visible in holotype). Other structural features as described for genus. Dorsal coloration uniformly black except pale distal third of forewing (possibly an artifact of preservation), legs testaceous except for black macrosetal sockets on hind tibia. Female sternite VII only slightly longer than sternite VII, posterior margin shallowly obtusely emarginate.
The species name,
Holotype female, Eocene Baltic amber (37–44 Ma), purchased by the first author from an amber dealer in Palanga, Lithuania. Deposited in the Paleontological Collection of the Illinois Natural History Survey (INHSP 10321).
The holotype is well preserved and intact with the right side of the body well visible in dorsal view but the left side largely obscured by a fracture in the amber extended along the midline. In ventral view, much of the head and parts of the legs are obscured by fractures and a milky veil also obscures parts of the legs and abdomen.
This recently described fossil taxon from mid-Cretaceous Myanmar (Burmese) amber (~99 Ma) was originally considered unplaced to subfamily (
We are grateful to Dr. S. W. Heads for advice and for the use of his equipment to prepare and photograph the fossils included in this study. We also thank M. D. Webb and two anonymous referees whose constructive criticism led to substantial improvements of the manuscript. This work was funded in part by a grant from the National Science Foundation (DEB-1239788).