Dasmeusa Melichar, 1926

Pecly, Nathalia H., Takiya, Daniela M., Cavichioli, Rodney R. & Mejdalani, Gabriel, 2023, Taxonomic revision and phylogeny of the sharpshooter genus Dasmeusa Melichar, 1926, with a scanning electron microscopy study of D. pauperata (Fabricius, 1803) (Hemiptera: Cicadellidae: Cicadellini), Arthropod Systematics & amp; Phylogeny 81, pp. 655-687 : 655

3.1.1. Genus Dasmeusa Melichar, 1926

Figs 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18

Type-species.

Cicada pauperata Fabricius, by subsequent designation of China (1938: 183).

Diagnosis.

Specimens preserved in collections usually pale yellow; whitish-yellow to greenish-yellow in life; forewing with preapical area with irregular orange transverse band or with second apical cell with distinct red spot. Head moderately to strongly produced anteriorly; coronal suture distinct, elongate, extending anteriorly beyond interocellar line; frons, in lateral view, with inferior third slightly angulate. Pronotum with lateral margins convergent anteriorly; posterior margin rectilinear. Forewing subhyaline; apex slightly expanded and obliquely truncate; with four apical cells, base of fourth approximately aligned with base of third; costal apical cell broadened posteriorly. Male terminalia with pygofer bearing basiventral lobe; without processes; subgenital plate triangular, not fused basally to its counterpart; style without preapical lobe; aedeagus with shaft short, usually with single process, rarely with pair of processes; paraphyses present, biramous, with or without processes on stalk. Female terminalia with sternite VII well produced posteriorly; pygofer well produced posteriorly; valvula I abruptly narrowed apically, with ventroapical margin somewhat sinuous and apex acute; valvula II with dorsal margin convex, teeth non-contiguous, mostly subtriangular. See systematic notes after the generic description and section 4.3 of the discussion for additional information on the identification of the genus.

Description.

Length. ♂♂ 7.4-10.8 mm; ♀♀ 8.4-10.3 mm. Head: in dorsal view, moderately to strongly produced anteriorly; median length of crown varying from 5/10 to 9/10 of interocular width and from 4/10 to 6/10 of transocular width; anterior margin generally rounded; without carina at transition from crown to face; coronal suture distinct, elongate, extending anteriorly beyond interocellar line; frontogenal suture extending onto crown and usually attaining ocellus; ocelli large or of moderate size, located approximately on imaginary line between anterior eye angles, or slightly before or slightly behind this line, each ocellus approximately equidistant between median line of crown and adjacent eye angle; antennal ledge, in dorsal view, varying from not protuberant to slightly protuberant; in lateral view, with anterior margin oblique and convex. Frons, in anterior view, convex; median area mostly smooth; muscle impressions distinct; in lateral view, inferior third slightly angulate; epistomal suture incomplete medially; clypeus, in lateral view, convex, continuing inferior contour of frons. Thorax: pronotum, in dorsal view, with width slightly greater than or approximately equal to transocular width of head; lateral margins convergent anteriorly; posterior margin rectilinear; dorsolateral carina complete, rectilinear, declivent anteriorly; disk without pubescence or punctures. Mesonotum with scutellum not transversely striate and without punctures. Forewing with membrane indistinct; veins not elevated; apex slightly expanded and obliquely truncate; with four apical cells, base of fourth approximately aligned with base of third; with three closed anteapical cells, their bases located more proximally than claval apex; costal apical cell broadened posteriorly; without anteapical plexus of veins; texture subhyaline. Hind wing with vein R2+3 incomplete. Hind leg with femoral setal formula 2:1:1; first tarsomere longer than combined length of two more distal tarsomeres, with two longitudinal parallel rows of small setae on plantar surface. Coloration: head, pronotum, mesonotum, forewings, and legs of preserved specimens usually yellow (whitish-yellow to greenish-yellow in life); preapical area of each forewing with irregular orange transverse band or with distinct red spot on second apical cell. Male terminalia: pygofer, in lateral view, moderately to strongly produced posteriorly; with basiventral lobe; without processes; anteroventral margin with distinct group of microsetae. Subgenital plate, in ventral view, not fused basally to its counterpart; not extending as far posteriorly as pygofer apex. Connective, in dorsal view, usually T-shaped, rarely V-shaped; arms broad. Style, in dorsal view, without preapical lobe. Aedeagus, in lateral view, with shaft usually short and bearing single ventral process, more rarely with pair of processes or with apical digitiform projection. Paraphyses present, symmetrical or slightly asymmetrical, with or without processes on stalk. Female terminalia: sternite VII, in ventral view, well produced posteriorly; narrowing gradually towards apex. “Internal” sternite VIII, in dorsal view, usually without sclerotized areas. Pygofer, in lateral view, well produced posteriorly; posterior margin narrowly rounded to subacute; macrosetae distributed mostly on posterior half. Valvula I, in lateral view, abruptly narrowed apically, ventroapical margin somewhat sinuous, apex acute; dorsal sculptured area extending from basal portion to apex of blade, formed mostly by scale-like processes arranged in oblique lines (strigate); ventral sculptured area restricted to apical portion of blade, formed mostly by scale-like processes; base of valvula forming lobe directed anterad; ventral interlocking device located on basal third or basal half of blade. Valvula II, in lateral view, with dorsal margin convex; blade with about 45 to 60 non-contiguous, mostly subtriangular teeth; preapical prominence distinct; apex obtuse; denticles distributed on teeth and on dorsal and ventral apical portions of blade (ventral dentate apical portion longer than dorsal portion); valvula with ducts extending towards teeth and apical area. Gonoplac of the usual Cicadellinae type: in lateral view, with basal half narrow; apical half expanded, gradually narrowing towards apex; latter obtuse.

Systematic notes.

According to the results of our cladistic analysis, the genus Dasmeusa can be distinguished from other members of the Paromenia group, as well as from other sharpshooters, by a combination of the following synapomorphic traits: (1) posterior margin of pronotum rectilinear (Fig. 8A ); (2) apex of forewing obliquely truncate (Fig. 8B ); (3) base of fourth apical cell of forewing approximately aligned with base of third apical cell (Fig. 8B ); (4) anteroventral margin of male pygofer with distinct group of microsetae (Fig. 3B ) (this character state is present in all known species of the genus; however, it was not illustrated herein for all of them because the delicate setae are sometimes not adequately preserved after the preparation of specimens in 10% KOH); (5) presence of paraphyses (Fig. 8G-I ).

Figures

Figure 1. Species of Dasmeusa, body in dorsal view (antennae and legs not depicted). A D. basseti, B D. dinizi sp. nov., C D. falcifera sp. nov., D D. imperialis, E D. isabellina, F D. mendica, G D. oriximina sp. nov., H D. pauperata (type-species), I D. rafaeli sp. nov. Scale bars: 2 mm.

Figure 2. Dasmeusa basseti Cavichioli & Chiamolera, 1999. A - G Male. A head, pronotum, and mesonotum, dorsal view; B pygofer, lateral view; C subgenital plate, ventral view; D connective and style, dorsal view; E ejaculatory bulb and aedeagus, lateral view; F paraphyses, dorsal view; G paraphyses, lateral view; H - I female; H sternite VII, ventral view; I pygofer, lateral view.

Figure 3. Dasmeusa dinizi sp. nov., male. A Head, pronotum, and mesonotum, dorsal view; B pygofer, lateral view; C subgenital plate, ventral view; D connective and style, dorsal view; E ejaculatory bulb and aedeagus, lateral view; F paraphyses, dorsal view; G paraphyses, lateral view.

Figure 4. Dasmeusa falcifera sp. nov. A - G Male. A head, pronotum, and mesonotum, dorsal view; B pygofer, lateral view; C valve and subgenital plate, ventral view; D connective and style, dorsal view; E ejaculatory bulb and aedeagus, lateral view; F paraphyses, dorsal view; G paraphyses, lateral view; H - I female; H sternite VII, ventral view; I pygofer, lateral view.

Figure 5. Dasmeusa isabellina Cavichioli & Chiamolera, 1999, male. A Head, pronotum, and mesonotum, dorsal view (male holotype, DZUP, UFPR); B pygofer, lateral view; C subgenital plate, ventral view; D connective and style, dorsal view; E ejaculatory bulb and aedeagus, lateral view; F paraphyses, dorsal view; G paraphyses, lateral view.

Figure 6. Dasmeusa mendica Young, 1977, male. A Head, pronotum, and mesonotum, dorsal view; B pygofer, lateral view; C subgenital plate, ventral view; D connective and style, dorsal view; E ejaculatory bulb and aedeagus, lateral view; F aedeagus, ventral view; G paraphyses, dorsal view; H paraphyses, lateral view.

Figure 7. Dasmeusa oriximina sp. nov., male. A Head, pronotum, and mesonotum, dorsal view; B pygofer, lateral view; C subgenital plate, ventral view; D connective and style, dorsal view; E ejaculatory bulb and aedeagus, lateral view; F paraphyses, dorsal view; G paraphyses, lateral view.

Figure 8. Dasmeusa pauperata (Fabricius, 1803), type-species, male. A Head, pronotum, and mesonotum, dorsal view; B forewing; C pygofer, lateral view; D subgenital plate, ventral view, with SEM of surface sculpturing (microtrichia); E connective and style, dorsal view; F aedeagus, lateral view; G paraphyses, dorsal view; H apical portion of paraphyses, posterior view; I paraphyses, lateral view.

Figure 9. Dasmeusa pauperata (Fabricius, 1803), type-species, female. A Sternite VII, ventral view; B pygofer, lateral view; C valvifer I and valvula I, lateral view; D dorsal sculptured area; E apical portion; F valvula II, lateral view (schematic, see associated photos [G, H, I] for details of teeth and other structures); G basal teeth; H median teeth; I apical portion. DEN = denticle; DSA = dorsal sculptured area; DUC = duct; PPR = preapical prominence; RAM = ramus; TOO = tooth; VID = ventral interlocking device; VLI = valvifer I; VSA = ventral sculptured area.

Figure 10. Dasmeusa flavescens Metcalf, 1955, female lectotype. A Body, dorsal view; B body, lateral view (arrow indicates location of angle at inferior portion of frons); C labels; D face, anterior view; E apical portion of abdomen, ventrolateral view; F apical portion of abdomen, ventral view. The name Dasmeusa flavescens was proposed by Metcalf (1955) as a replacement for Tettigonia lurida Signoret, 1853, which was preoccupied by Tettigonia lurida Germar, 1821. This species is herein considered a junior synonym of D. pauperata (Fabricius, 1803). Photos: Werner Holzinger, © Naturhistorisches Museum Wien (NHMW).

Figure 11. Erythrogonia bicolor Metcalf, 1949, male holotype, which was treated by Young (1977) as incertae sedis. A Body, dorsal view; B labels. This species is herein considered a junior synonym of D. pauperata (Fabricius, 1803). Photos: © North Carolina State University Insect Museum (identifier NCSU 45348; http: // specimens. insectmuseum. org / public / specimen / show / 39215).

Figure 12. Dasmeusa rafaeli sp. nov., male. A Head, pronotum, and mesonotum, dorsal view; B pygofer, lateral view; C subgenital plate, ventral view; D style, dorsal view; E connective, dorsal view; F ejaculatory bulb and aedeagus, lateral view; G paraphyses, dorsal view; H paraphyses, lateral view.

Figure 13. Dasmeusa spp. A Maipaima Eco Lodge, Nappi Village, Guyana; photo: Tom Murray, March 18, 2012. B Centre Spatial Guyanais, French Guiana; photo: Elendil Cocchi, July 20, 2020. C Same as preceding, July 18, 2020. D Sinnamary, French Guiana; photo: Elendil Cocchi, November 26, 2021.

Figure 14. Scanning electron microscopy (SEM) of the head of Dasmeusa pauperata (Fabricius, 1803). A Compound eye: ommatidia; B interommatidial sensillum trichodeum; C brochosomes on ommatidium; D antenna: scape, pedicel, and base of flagellum; E microtrichia sculpturing on antennal pedicel; F scale-like sculpturing on antennal flagellum; G surface of frons; H sculpturing on frons; I surface of gena covered by brochosomes; J sensillum placodeum on frons; K organ of Evans on maxillary plate; L organ of Evans at higher magnification, with adjacent sensillum trichodeum.

Figure 15. Scanning electron microscopy (SEM) of the head of Dasmeusa pauperata (Fabricius, 1803). A Microtrichia at apex of clypeus; B apex of clypeus and labrum; C labrum and second article of labium; D third article of labium and apex of maxillary stylets; E apex of third article of labium and maxillary stylet; F sensilla coeloconica of third article of labium; G sensillum coeloconicum at higher magnification; H maxillary stylet and lateral projections of mandibular stylet (asterisks); I apex of maxillary stylets, with brochosomes.

Figure 16. Scanning electron microscopy (SEM) of the thorax of Dasmeusa pauperata (Fabricius, 1803). A Mesonotum surface; B mesonotum surface at higher magnification, showing microtrichia; C higher magnification of mesonotal microtrichia; D surface of scutellum covered by brochosomes; E higher magnification of scutellar brochosomes; F base of forewing; G base of forewing at higher magnification, with microtrichia; H claval sulcus of forewing; I claval sulcus of forewing at higher magnification, with brochosomes; J appendix of forewing; K appendix of forewing at higher magnification, showing microtrichia; L same as preceding at still higher magnification.

Figure 17. Scanning electron microscopy (SEM) of the hind leg of Dasmeusa pauperata (Fabricius, 1803). A Surface of coxa, trochanter, and femur; B surface of coxa and femur at higher magnification, showing group of setae; C apex of femur showing macrosetal formula 2: 1: 1; D one seta of the macrosetal formula covered by brochosomes; E brochosomes on seta at higher magnification; F setae of tibia; G tarsus and pretarsus, ventral view; H detail of basal tarsomere; I articulation between median and distal tarsomere, showing microtrichia; J microtrichia of distal tarsomere; K apex of tarsus and pretarsus; L apex of tarsus and pretarsus at higher magnification.

Figure 18. Scanning electron microscopy (SEM) of the abdomen of Dasmeusa pauperata (Fabricius, 1803). A Surface of sternite V, showing rows of microtrichia; B sternite V, with sensillum coeloconicum; C sensillum coeloconicum at higher magnification; D sensillum trichodeum of sternite V; E sculpturing of sternal surface, including microtrichia, s. coeloconica, and s. trichodea; F surface of sternite V at higher magnification, showing microtrichia and s. coeloconicum; G s. coeloconicum; H s. coeloconicum at higher magnification; I s. coeloconicum of sternite V surrounded by microtrichia; J s. trichodeum from segment III; K laterotergite VIII showing spiracle; L spiracle at higher magnification.