Tetramelasma, Stiller, 2011

Stiller, M., 2011, A new leafhopper genus and four new species from the Grassland Biome of South Africa (Hemiptera, Cicadellidae), Zootaxa 2794 (1), pp. 35-51 : 36-37

publication ID	https://doi.org/ 10.11646/zootaxa.2794.1.2
DOI	https://doi.org/10.5281/zenodo.5294710
persistent identifier	https://treatment.plazi.org/id/03E3291C-1C40-9240-5C8D-FF73C0F852B8
treatment provided by	Felipe
scientific name	Tetramelasma
status	gen. nov.

Treatment

Tetramelasma View in CoL gen.n.

( Figs 9a–g View FIGURE 9 ; 10a–k View FIGURE 10 ).

Type species: Tetramelasma tanyphysis sp. n.

Gender feminine.

Etymology. Compound word in Greek, tetra, four, melasma, a black spot, for the four dark markings on the vertex. Gender feminine.

Diagnosis. Moderately large leafhoppers (4–5 mm long), vertex with paired fuscous markings ( Figs 2a View FIGURE 2 ; 3a View FIGURE 3 ; 5a View FIGURE 5 ; 6a&b View FIGURE 6 ; 7a View FIGURE 7 ; 9a View FIGURE 9 ; 10a View FIGURE 10 ). Hind wing about ½ as long and ¾ as wide as tegmina, tegmina reaching apex or beyond apex of abdomen. Tegmina without appendix, or very narrow ( Figs 7g View FIGURE 7 , 9f View FIGURE 9 ). Aedeagus narrow, tubular ( Figs 1g &h View FIGURE 1 , 4e View FIGURE 4 , 7e&f View FIGURE 7 , 9e View FIGURE 9 ), base fused to connective (e.g. Figs 4e View FIGURE 4 , 9e View FIGURE 9 ), shaft with subapical dorsal gonopore. Plate variable, generally truncate, length either up to ½ as long as pygofer ( Figs 3c&d View FIGURE 3 , 4a&b View FIGURE 4 , 9b&c View FIGURE 9 ), or about as long as pygofer, viewed laterally ( Fig. 1c&d View FIGURE 1 ). Style either with apophysis elongate, with ventral tooth ( Figs 1f View FIGURE 1 , 9d View FIGURE 9 ) or short, invaginated posteriorly, variably dentate ( Figs 4c&d View FIGURE 4 ; 7d View FIGURE 7 ). Female valvulae exposed basally ( Figs 2b View FIGURE 2 , 5b&c View FIGURE 5 , 8a View FIGURE 8 , 10b View FIGURE 10 ); sternite 7 variable, with wide notch of variable depth; variably produced laterally ( Figs 2b–e View FIGURE 2 ; 5b–f View FIGURE 5 ; 6c–g View FIGURE 6 ; 8a–d View FIGURE 8 ; 10b– e View FIGURE 10 ).

Colour. Male & female. Base colour yellowish-brown. Vertex dorsoapically with two paired fuscous markings: apical pair usually triangular, close together; basal pair close to anterior margin of compound eyes, roughly circular; markings of variable size. Vertex, pronotum and rarely scutellum sometimes dorsally with faint to darkbrown longitudinal stripes. Clypeus yellowish overlain by pale to dark-brown horizontal arcs, sometimes extending dorsally into vertex. Tegmina translucent smoky-yellowish-brown or almost colourless, veins pale to transparent; costal cell pale yellow, other cells sometimes bordered with light-brown markings (especially in apical cells) (e.g. Figs 3a View FIGURE 3 , 7a View FIGURE 7 , 9a View FIGURE 9 ).

Tegmina & hind wings. Male & female. Tegmina macropterous ( Figs 3a View FIGURE 3 , 5a View FIGURE 5 , 6b View FIGURE 6 , 7a View FIGURE 7 , 9a View FIGURE 9 ) or submacropterous ( Figs 2a View FIGURE 2 , 6a View FIGURE 6 , 10a View FIGURE 10 ). Hind wing usually reduced, ½ as wide and ¾ as long as tegmina, jugal lobe present, small. ( Figs 1i View FIGURE 1 , 2f View FIGURE 2 , 7h&i View FIGURE 7 , 9g View FIGURE 9 ), M1+2 sometimes fused to R4+5. Rarely hind wing fully developed (256 specimen’s wings examined, 12 specimens with hind wing as long and wide as tegmina).

External morphology. Male & female. Vertex 1.3–2.0 times longer medially than length of vertex next to eye, width of head 1.0–1.1 times wider than width across pronotum, diameter of ocellus 28 µm, ocellocular distance up to 48 µm. Vertex narrowly rounded to face, shagreened, disc of vertex smooth. Pronotum smooth. Clypellus rectangular, lateral convergent, subparallel margins. Gena extending slightly beyond posterior margin clypellus, slightly incised below eye. Spinulation of protibia 1+4. Profemur setae in row AV short, relatively thick, intercalary row setae about three times longer than those in AV, AV1 seta slightly longer and thicker than intercalary setae. Mesotibial setal formula 4+4. Metafemoral setal formula 2+2+1, apical paired setae slightly shorter than subapical seta, medial pair of different length and thickness. Metathoracic tibis with four rows of setae, as defined by Davis (1975). In all species of Tetramelasma , except in T. litopyx row III with uniform row of setae, reaching apex of tibia. In T. litopyx with row III without apical seta, but two subapical, heavily sclerotized setae, with tibia around base of these two setae sclerotized, both or one sometimes asymmetrical, about three times longer than basal setae. Internal morphology. Abdominal apodeme. Anterior and posterior apodeme narrow, without significantly enlarged lobes.

Male. Dimensions. Apex of vertex to tips of tegmina 3.9–4.5 mm, vertex 1.1–1.5 times longer medially than length next to eye, head 1.1–1.3 times wider than pronotum, vertex 0.7–1.3 times longer than medial length of pronotum, vertex 0.3–0.5 times longer than width of head across eyes.

Genital capsule. Segment 10 weakly sclerotized, lateral margins concave ( Fig. 1b View FIGURE 1 ) or straight ( Fig. 3b View FIGURE 3 ), incised ⅓ or ½ way into pygofer. Pygofer, viewed laterally, with posterior lobe bluntly triangular or rounded ( Figs 1d View FIGURE 1 , 3c View FIGURE 3 , 4b View FIGURE 4 , 7b View FIGURE 7 , 9c View FIGURE 9 ); ventral margin usually bulbous, of variable size, sometimes larger than pygofer posterior lobe ( Fig. 9c View FIGURE 9 ). Medial surface of ventral pygofer lobe with spine-like process of variable length; apex of spine diagnostic in some species:

a. Narrowly acuminate ( Fig. 4a&b View FIGURE 4 ).

b. Wide with subapical tooth ( Figs 3c View FIGURE 3 , 7b View FIGURE 7 ).

c. Bipinnate ( Fig. 9c View FIGURE 9 ).

d. Reduced ( Fig. 1d View FIGURE 1 ).

Ventral pygofer lobe sometimes reduced ( Fig. 1d View FIGURE 1 ). Plate variable: commonly short, about one fifth the length of pygofer, posterior margin truncate, lateral and medial margins rounded or straight ( Figs 3c&d View FIGURE 3 , 4a&b View FIGURE 4 , 7b&c View FIGURE 7 , 9b&c View FIGURE 9 ); rarely about as long as length of pygofer ( Fig. 1d View FIGURE 1 ); posterior, medial and lateral margins rounded, sinuous subapically ( Fig. 1c View FIGURE 1 ); dorsolateral margin with sclerotized process apically, process digitate or rounded, variably extended beyond posterior margin of plate. Macrosetae grouped lateromedially, 4–8 in number. Style apophysis generally short (about 1–2 times as long as greatest basal width), shape variable:

a. Expanded, barrel-shaped, posteriorly excavated, with mediolateral margin variably toothed, either with series of 5–6 distinct, uniseriate teeth ( Figs 4c View FIGURE 4 , 7d View FIGURE 7 ) or serration reduced to rounded protrusion and cluster of 2–4 denticles ( Fig. 4d View FIGURE 4 ).

b. Narrowly produced with medioventral or lateral serration ( Figs 1f View FIGURE 1 , 9d View FIGURE 9 ).

Style basally with lateral lobe short, posteriad; medial lobe narrow, elongate, perpendicular to base. Aedeagus with shaft prominent, tubular, straight in dorsal view, curved or undulating in lateral view, gonopore subapical, dorsal ( Figs 1g &h View FIGURE 1 ; 4e View FIGURE 4 ; 7e&f View FIGURE 7 ; 9e View FIGURE 9 ); dorsal apodeme reduced. Connective linear, of uniform width, arms fused anteriorly, fused to aedeagus ( Fig. 1e View FIGURE 1 ).

Female. Dimensions. 4.2–5.0 mm from apex of vertex to tips of tegmina, vertex 1.3–1.5 times longer medially than length next to eye, head 1.1 times wider than pronotum, vertex 1.1–1.5 times longer than medial length of pronotum, vertex 0.4–0.6 times longer than width of head across eyes.

Genitalia. Abdominal sternite 7 narrow, with three basic shapes:

a. Falcate, with posterolateral margin produced uniformly ( Fig. 6c–g View FIGURE 6 ).

b. Falcate, with posterolateral margin folded under lateral margins ( Figs 5b–f View FIGURE 5 ; 8a–d View FIGURE 8 ).

c. Trapezoid, posterior margin with medial, narrow V-shaped notch, lateral margins straight, angled slightly posteriad, medial disc membranous, laterally more or less sclerotized ( Fig. 2b–e View FIGURE 2 ).

Valvula 3 without major setae, only fine setae ( Figs 2j&l View FIGURE 2 ; 6k&l View FIGURE 6 ; 8j&k View FIGURE 8 ; 10j&k View FIGURE 10 ). Valvula 2 finely serrate ( Figs 2h&k View FIGURE 2 ; 6j View FIGURE 6 ; 8g &h View FIGURE 8 ; 10g &i View FIGURE 10 ). Valvula 1 lanceolate, with imbricate sculpture ( Figs 2g &i View FIGURE 2 ; 6h&i View FIGURE 6 ; 8e&f View FIGURE 8 ; 10f&h View FIGURE 10 ).

Relationships. Tetramelasma is placed in the tribe Deltocephalini based on the linear shaped connective and fusion between the connective and aedeagus, as defined by Webb & Viraktamath (2009) and Zahniser & Dietrich (2010).

Other Deltocephalini in South Africa include Theronus Stiller, 2009 , Heidinus Theron, 1988 and Maiestas Distant. None of these genera are significantly similar to Tetramelasma , except possibly the simple, tubular aedeagus. The fusion between the aedeagus and connective is distinct in these four genera, with the arms of the connective contiguous. The fusion of the arms of the connective is a distinguishing feature of the Paralimnini , but members of this tribe have the connective articulated with the aedeagus. In some instances this distinction between fusion and articulation becomes vague as pointed out by Webb & Viraktamath (2009).

When compared to Palaearctic genera, Tetramelasma has similar colour and markings to that of Conosanus Osborne and Ball ( Deltocephalinae , Athysanini ) and Turrutus Ribaut ( Deltocephalinae , Deltocephalini ). The excavated apophysis of the style of Ebarrius Ribaut ( Deltocephalinae , Paralimnini ) bears some resemblance to that of Tetramelasma . In the Neotropical Region the shape of the plate of Tetramelasma somewhat resembles that of Haldorus (Parahaldorus) Linnavuori ( Deltocephalinae , Deltocephalini ).