Homalodisca ignota Melichar 1924
Creators: name: Takiya, Daniela M.
name: Cavichioli, Rodney R.
name: Mckamey, Stuart H.
Publisher: name: Zenodo
Year: 2006
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Hemiptera
Cicadellidae
Homalodisca
Homalodisca ignota

description: Homalodisca ignota Melichar, 1924
Figs 1, 2, 5–15
Type locality. Brazil.
Length. male 13.5 mm; females 14.0–16.0 mm.
Description
External morphology. Crown with median length approximately nine–tenths interocular width and half transocular width; anterior margin rounded in dorsal aspect; transition crown­face slightly angulate and with median longitudinal blunt elevation; disc flattened; median fovea incomplete, becoming broader and shallower anteriorly; pubescence dense; posterior margin with M­shaped elevation. Frontogenal sutures extending onto crown and attaining ocelli. Ocelli located on imaginary line between anterior eye angles; each equidistant from adjacent eye angle and median line of crown. Antennal ledges protuberant in dorsal aspect; dorsally carinate and with anterior margin slightly oblique in lateral view. Frons flattened medially and depressed; median area mostly smooth or slightly striated; muscle impressions distinct; pubescent. Epistomal suture incomplete for short median distance. Clypeus continuing profile of frons; apical margin convex; pubescent. Prothorax with dorsopleural carinae complete. Pronotum narrower than transocular width; lateral margins parallel to slightly divergent anteriorly; median length approximately seven­tenths transhumeral width; disc rugose, punctate, and pubescent; posterior margin broadly concave. Mesothorax with katepisternum enlarged and inflated; scutellum not striate. Forewings hyaline, except for large sclerotized area on costal region covering entirely outer discal, base of inner discal, and apices of all anteapical cells; veins distinct and elevated; anteapical cells closed; with four apical cells, base of third more apical than those of second and fourth; without supernumerary crossveins; claval veins fused at mid­length for distance equal or longer than longer separated branch. Hind wings extending almost as far posteriorly as forewings; vein R2+3 incomplete. Hind legs apical femoral setal formula 2:0:0; tibial anteroventral (AD) setal row without intercalary macrosetae; tibial setal row AV in females with over thirty elongate and hook­shaped modified setae throughout most of length; first tarsomere slightly shorter or subequal than combined length of two more distal tarsomeres; with two parallel rows of short setae on plantar surface.
Male genitalia. Pygofer (Fig. 5) moderately elongate; posterior margin broadly round; ventral process well developed, spiniform; microsetae numerous on posterior half; few macrosetae on dorsal portion. Valve (Fig. 6) linear, transverse. Subgenital plates (Figs 5, 6) subtriangular, extending posteriorly as far as mid­length of pygofer; several microsetae distributed throughout disc; apex narrowly rounded. Connective (Fig. 7) approximately Ushaped, arms widely separated; with short dorsal keel. Styles (Fig. 7) short, extending posteriorly slightly beyond apex of connective; with distinct pre­apical lobe; microsetae present; apex narrowly rounded. Aedeagus (Figs 8, 9) symmetrical; preatrium (Fig. 8: PA) elongate, articulated basally with connective; atrium with basolateral flange and single pair of short spiniform processes directed posterolaterally (Figs 13, 14: AP); apex of shaft with pair of short spiniform processes directed laterally (Fig. 9: SP).
Female genitalia. Abdominal sternite VII (Fig. 10) with microsetae distributed throughout disc; posterior margin with shallow median concavity. First valvifers longer than tall; few microsetae on posteroventral margin. First valvulae of ovipositor (Fig. 11) with bases broadly round. Internal abdominal sternite VIII (Fig. 12) mostly membranous, forming two main lobes; ventral lobe in lectotype (Fig. 12), in dorsal view, more anteriorly produced than in other specimens, in which it is positioned just below dorsal fold; dorsal fold with pair of conspicuous sclerotized lateral regions over bases of first valvifers. Pygofer (Fig. 13) in lateral view moderately produced; microsetae distributed throughout disc; posterior margin narrowly round. Second valvulae of ovipositor (Fig. 14) regularly broadened beyond basal curvature throughout apical four­fifths; blade bearing approximately 31 continuous teeth; each tooth (Fig. 15) subtriangular, declivous posteriorly, with denticles throughout entire dorsal margin; preapical ventral prominence present; apical portion with denticles on dorsal and ventral margins; apex narrowly obliquely truncate.
Coloration. Head, thorax, and legs tan (lectotype) to dark brown; mesokatepisternum dark brown to black (Figs 1, 2). Forewings (Figs 1, 2) sclerotized areas and venation purplish red (lectotype) or dark brown. Abdomen tan to dark brown; dorsal median region black; sternites with dark brown to black transverse band basally.
Material examined
Lectotype: Ψ, “ Brésil ”, “Collectio \ Dr. L. Melichar \ Moravské museum Brno”, “ignotus M. \ det. Melichar”, “ type ”, “ Lectotype \ Homalodisca \ ignota \ Melichar \ Young & Lauterer”, “Invent \ 2992/Ent. \ Mor. Museum, Brno”, MMBC. Additional material: BRAZIL, RIO DE JANEIRO: ɗ, Petrópolis, XI.1940, Parko, MNRJ; Ψ, Rio de Janeiro, Jacarepaguá, 12.XI.1952, N. Santos, MNRJ; Ψ, Rio de Janeiro, Parque Nacional da Tijuca, III.1951, C. Seabra, MNRJ; SÃO PAULO: Ψ, Ubatuba, Parque Estadual da Serra do mar, Núcleo Picinguaba, Equipe Laboratório de Entomologia da UFRJ, 4­ 7.XII.2002, MNRJ.
Taxonomic notes
The lectotype of H. ignota was designated by Young & Lauterer (1966) and the female sternite VII illustrated in Young (1968). Although the unprepared female sternite VII of this specimen is slightly distorted, it was indicated to be strongly distorted by Young (1968: Fig. 189i). After preparation using KOH, the female sternite became completely symmetrical as is herein illustrated (Fig. 10).
Homalodisca ignota may be mistakenly keyed out to either Dichrophleps or Pseudophera Melichar in Young´s (1968) key to Proconiini genera because its claval veins are fused for a much longer distance than in most other Homalodisca and females can measure up to 16 mm.
Homalodisca ignota is apparently more closely related to H. ignorata, H. apicalis Schmidt, and H. nitida (Signoret). Although specimens of the last species were not studied here, this species is possibly conspecific with H. apicalis (Young 1968). These species share with related genera (e.g., Dichrophleps, Propetes, and Pseudophera) the plesiomorphic hind leg setal row AV with modified elongate and hook­shaped setae along most of apical half of tibiae and the ventral pygofer processes spiniform and elongate (Fig. 5). In most other Homalodisca species (e.g., H. spottii sp. nov.), row AV is only modified apically (having up to about 6 setae) and the ventral pygofer process is reduced to a dentiform projection (Fig. 16). H. ignota can be easily distinguished from other Homalodisca species by its aedeagal morphology, being the only Homalodisca species with processes on the apical portion of the shaft (Fig. 9: SP).
This species was described from Brazil without further specification of its distribution. Herein it is first recorded from Rio de Janeiro and São Paulo states, in areas dominated by Atlantic Rainforest.
description: Published as part of Takiya, Daniela M., Cavichioli, Rodney R. & Mckamey, Stuart H., 2006, Brazilian sharpshooters of the genus Homalodisca Stål, 1869 (Hemiptera, Cicadellidae): notes, new records, key to species, first description of the male of H. ignota Melichar, 1924, and a new Northeastern species, pp. 23-36 in Zootaxa 1249 on pages 27-30, DOI: 10.5281/zenodo.172992