The 197 species (including 2 new species) of the Nearctic leafhopper genus Eratoneura are reviewed. Eratoneura betulae sp.n. from New Brunswick (Canada) and E. mcateei sp.n. from the central and northeastern USA are described as new. In addition, 123 new synonyms are recognized and a lectotype is designated for Typhlocyba hartii Gillette. Key is provided for identification of males. All known species are illustrated, and data on their distributions and host plants are summarized. All species of Eratoneura are native to temperate North America, where they feed and oviposit mainly on woody deciduous trees and shrubs.
Keywords: Auchenorrhyncha, Homoptera, leafhopper, morphology, taxonomy, distribution, identification.
Introduction This revision of the genus Eratoneura completes the series of publications on the New World Erythroneurini (Dietrich & Dmitriev, 2006a, 2007a, 2008a; Dmitriev & Dietrich, 2007a, 2009a). Eratoneura was described by Young (1952b) as a subgenus of Erythroneura Fitch to comprise the Erythroneura maculata species group designated by Robinson (1926a) and comprehensively revised by Beamer in series of publications (1931a, b, c, d, 1932a, c, d, e, f, g, h). In these papers Beamer provided illustrations of the male genitalia for all known species, incorporated these characters into a dichotomous key, and associated males with most of the species and varieties (=subspecies, see ICZN, 1999, Art. 45.6.4) that had been described by McAtee (1920a, 1924c, 1924d, 1926c) and previous authors based on females. Johnson (1935a) independently revised the species of Erythroneurasensu lato (including Eratoneura) from Ohio and provided a key for their identification. She described many new species in this and subsequent papers (Knull, 1944b, 1945b, 1949a, 1951a, 1954b, 1955a; Knull & Auten, 1937a, 1938b). After these revisions, H.H. Ross (with D.M. DeLong) and L.W. Hepner described more than 150 additional species of Eratoneura. Dietrich and Dmitriev (2006a) revised the generic classification of the New World Erythroneurini and elevated Eratoneura to the genus level.
All species of Eratoneura are native to temperate North America, where they feed and oviposit mainly on woody deciduous trees and shrubs. Ross (1957c, 1958c) did an extensive study of coexisting Eratoneura species on sycamore in southern Illinois. Adults overwinter in leaf litter, and in the spring, they emerge and feed on the new leaves of early-emerging deciduous plants before migrating to their “definitive” summer host plants where they mate and lay eggs (Ross & DeLong 1953a). Most species oviposit and undergo nymphal development on a single, or a group of closely related, plant species. In the southern USA, they complete two or more generations per year, but in the north there may be but a single generation. In the fall, adults may again feed on a variety host plants prior to seeking out winter shelter in leaf litter. Most species of Eratoneura have no known economic importance, but a few are recorded as pests of apple (Beamer, 1930a, 1932b; Hamilton, 1985a).
Material and Methods Few previous workers have specifically targeted Eratoneura in their collecting, and specimens from trap catches and other general collecting that find their way into curated collections are often in very poor condition. Because of this, and due to time and budget constraints, this study focused only on collections known to contain large numbers of well-curated specimens of Eratoneura, as well as those housing primary types: Illinois Natural History Survey (INHS), Ohio State University (OSU), University of Kansas Natural History Museum (KSEM), Mississippi State University, Mississippi Entomological Museum (MEM), Canadian National Collection of Insects, Arachnids and Nematodes (CNC), Smithsonian National Museum of Natural History (USNM), California Academy of Sciences (CAS), and Colorado State University (CSUC). The numbers of studied specimens from each collection are summarized in Appendix 1. Future collecting will undoubtedly show that the distributions of most species are much broader than indicated on the maps accompanying individual species treatments. Although these maps show regional biases reflecting the locations and holdings of the studied collections, they are based on vouchered collection records and, thus, accurately reflect current knowledge of species distributions. On the maps the type locality is marked with a star.
Identification of species was mainly based on type material. In some cases, when the type was not located, or the holotype is a female (e.g., most of McAtee’s species), we followed Beamer’s interpretation, based on study of dissected male specimens that he labeled “allotype” to indicate that they had been compared to the female primary types of previous workers. Although Beamer’s “allotypes” have no official standing in nomenclature, these dissected male specimens facilitate unambiguous interpretation of Beamer’s concept of the species.
Morphological terminology follows Dietrich and Dmitriev (2006a, see also Fig. 1). Although individual species have a characteristic color pattern, details and intensity may be highly variable both inter- and intraspecifically. Overwintering individuals tend to be more brightly colored than adults of the summer generation of the same species. This has resulted in many species being described multiple times based on different color forms. In the descriptions below, the pattern of fully colored individuals is described, although completely or almost completely discolored forms are known for most species. Thus, identification keys are based mainly on male genitalia, with external characters used only for supplemental purposes.
This work recognizes numerous synonyms treated as valid species by previous workers. Most junior synonyms represent color variants, or forms differing slightly in the shape of the aedeagus, or the shape and length of the pygofer appendages. A few species were described based on aberrant forms with distorted genitalia, possibly caused by parasitism. In some cases where genitalia were mounted on slides, species were described based on contaminant particles embedded in the balsam.
Each species is illustrated by one or more habitus photos taken using a Microptics digital imaging system. Original drawings were prepared only in cases where those available from other sources were deemed inaccurate. Thus, numerous figures are reproduced from other sources, as noted in the figure captions. Inconsistencies (e.g., in line thickness) among line drawings reflect differences in the drawing styles of previous authors. In all cases, figures reproduced from previous publications are either in the public domain or are reproduced with permission.
Line drawings of the male genitalia accompanying each species treatment are labeled as follows:
a – pygofer or pygofer appendage, lateral view;
b – pygofer or pygofer appendage, dorsal view;
c – style or style apex, broad aspect;
d – aedeagus, lateral view;
e – aedeagus, posteroventral or ventral view.
Nomenclatural, distributional, morphological and host-plant data summarized below were extracted from a relational specimen-level database of Erythroneurini (Dmitriev & Dietrich, 2003 onwards), developed using the 3I software package (Dmitriev, 2006a, Dmitriev & Dietrich, 2008a). The on-line database provides more detailed information for each species, including a complete list of specimens examined, photos of type specimens, and interactive key to species.
In the species treatments below, only summer host plants are listed, although most species have also been collected from plants other than their oviposition hosts.
Specimens of newly described taxa (E. betulae sp.n. and E. mcateei sp.n.) are deposited in the insect collections of the Illinois Natural History Survey (Champaign), Canadian National Collection of Insects, Arachnids and Nematodes (Ontario), and Mississippi State University (State College).
Taxonomy Subfamily Typhlocybinae Tribe Erythroneurini Young, 1952
Genus Eratoneura Young, 1952
Erythroneura maculata species group Robinson, 1926a:109
Erythroneura (Eratoneura) Young, 1952b:84 (Type: Erythroneura dira Beamer, 1931)
Eratoneura Dietrich & Dmitriev, 2006a:133
Diagnosis: Ground color usually pale, often with red or orange maculae distributed on dorsum and black or dark brown spots near costal margin and in inner apical cell; crown without pair of brown or black spots. Male pygofer without ventral appendage or sclerotized ridge; dorsal appendage immovably fused to margin, simple or bifurcated, with additional small projection at base; basolateral setae well developed. Style apex usually with three angulate projections.
Description: Length 2.3–3.7 mm, slender. Head narrower than pronotum. Crown fore margin produced, angulate or rounded. Ocelli absent or vestigial. Face depressed in profile, less than 45° from horizontal. Pronotum smooth, without conspicuous pits. Forewing outer apical cell about 2X as long as wide or longer; second apical cell basally truncate (ir crossvein present); third apical cell parallel sided, straight; CuP vein longer than segment of CuA between Cu and MP; inner apical cell with oblique base, basal segment of CuA and CuP veins forming continuous line; Pcu vein not visible. Hind wing apex truncate; submarginal vein not extended to wing apex; ScR vein present; MP and CuA veins touching at one point, fused for short distance or separated by m-cu crossvein. Front femur anteroventral row with basal seta distinctly larger than others. 2S abdominal apodemes variable, small, narrow and short to large, broad, and extended beyond posterior margin of sternite III (3S). Pygofer not extended to apex of subgenital plate; lobe rounded or angulate; dorsal emargination extended to base of segment; dorsal membrane without fine setae; oblique dorsolateral internal ridge not developed; basolateral setae in distinct group, small; distal and dorsal setae undifferentiated; internal surface of lobe with setae; sparse long fine setae present; microtrichia well developed. Pygofer dorsal appendage immovably fused to margin, without basal suture; appendage simple or bifurcated, with additional small projection at base; ventral appendage or sclerotized ridge absent. Sternite IX with median longitudinal internal ridge. Subgenital plates free; lateral margin with angulate subbasal projection; section basad of medial constriction shorter than distal section; with 4 basal macrochaetae uniseriate along margin; distinct marginal subbasal rigid setae forming continuous row; distal macrochaetae absent. Style free; preapical lobe prominent; apex smooth with 3 points or rarely truncated. Aedeagus articulated to connective; with dorsal apodeme broadly expanded in lateral view; apodeme parallel sided in ventral view, connection to pygofer membranous. Aedeagus shaft symmetrical, usually denticulate distally, sometimes with basal or distal processes. Connective U- or V-shaped, without median anterior lobe, with long arms. Anal tube without processes. Coloration variable, but all known species with crown lacking pair of fuscous preapical spots. Usual color pattern (see E. dira Beamer, Plate 1a, 2a, for example) consisting of pale or dull yellow dorsum with red or orange maculae distributed on crown thorax and forewings and black or dark brown spots near costal margin and near base of inner apical cell.
Distribution: Temperate North America.
Host plants: Deciduous trees, shrubs.
Key to adult males of Eratoneura1 1. Aedeagus with pair of slender distal processes (Fig. 2e, 3e). 2
1'. Aedeagus without slender distal processes (Fig. 1e, 9e). 8
2(1). Aedeagus with pair of processes arising at base or near midlength of shaft (Fig. 2d, e). 3
2'. Aedeagus without processes arising at base or near midlength of shaft (Fig. 5d, e). 4
3(2). Aedeagal shaft curved dorsad, processes arising near midlength of shaft (Fig. 2d, e). Dorsal pygofer appendage extended to pygofer apex (Fig. 2a, b). 2. E. gillettei (Beamer)
3'. Aedeagal shaft curved ventrad, processes arising at base of shaft (Fig. 3d, e). Dorsal pygofer appendage not extended to pygofer apex (Fig. 3a, b). 3. E. imbricariae (Ross & DeLong)
4(2). Tip of aedeagal shaft with short dorsal projection; distal processes extended ventrolaterad (Fig. 4d, 5d). 5
4'. Tip of aedeagal shaft without dorsal projection; distal processes extended dorsolaterad (Fig. 6d). 6
5(4). Distal processes of aedeagus about as long as shaft (Fig. 4e). 4. E. lamucata (Ross & DeLong)
5'. Distal processes of aedeagus about half as long as shaft (Fig. 5e). 5. E. maculata (Gillette)
6(4). Third point of style apex longer than half distance between other two points (Fig. 6c). Distal processes of aedeagus arising subapically, shorter then half length of shaft (Fig. 6e).
6. E. eversi (Ross & DeLong)
6'. Third point of style apex shorter than half distance between other two points (Fig. 7c, 8c). Distal processes of aedeagus arising apically, almost as long as shaft (Fig. 7e). 7
7(6). Third point of style apex short toothlike, subequal in size to second point (Fig. 7c). Aedeagal shaft with prominent lateral lobes, smooth (Fig. 7d, e). Pygofer appendage compressed (Fig. 7a, b).
7. E. noncuspidis (Beamer)
7'. Third point of style apex almost as long as half distance between other two points (Fig. 8c). Aedeagal shaft without lateral lobes, with teeth (Fig. 8d, e). Pygofer appendage not compressed (Fig. 8a, b). 8. E. teshi (Hepner)
8(1). Aedeagus with pair of processes arising at base of shaft (Fig. 9d, e, 10d, e). 9
8'. Aedeagus without processes arising at base of shaft (Fig. 17d, e). 15
9(8). Pygofer appendage not extended to pygofer apex, bulbous subapically (Fig. 9a, b). Forewing basal half uniformly red (Plate 2i). 9. E. osborni (DeLong)
9'. Pygofer appendage extended to or beyond pygofer apex, not bulbous subapically (Fig. 10a, b). Forewing basal half yellow with reddish maculae (Plate 2a). 10
10(9). Third point of style apex longer than distance between other two points (Fig. 10c). Pygofer appendage curved upward, widest at midlength (Fig. 10a). Basal processes of aedeagus small toothlike (Fig. 10d, e). 10. E. sandersoni (Ross)
10'. Third point of style apex shorter than distance between other two points (Fig. 11c). Pygofer appendage straight or curved downward, widest at base (Fig. 11a). Basal processes of aedeagus longer (Fig. 11d, e). 11
11(10). Pygofer appendage with ring of long spines near midlength (Fig. 11a, b). Aedeagal shaft strongly compressed, with dorsal carina or distal lobe; basal processes appressed to shaft (Fig. 11d, e). 12
11'. Pygofer appendage without ring of long spines (Fig. 14a, b). Aedeagal shaft without dorsal carina or distal lobe; basal processes divergent from shaft (Fig. 14d, e). 13
12(11). Aedeagal shaft broad in lateral view, only about twice as long as wide; basal processes extended along dorsal margin of shaft (Fig. 11d). 11.