Striduloselymbria, Sanborn, 2024

Genus Striduloselymbria View in CoL gen. nov.

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Remarks. The taxon has the general appearance of a member of the genus Selymbria . However, the presence of the mesonotal stridulatory apparatus along with the multiple characters identified in the Diagnosis section identifies the specimen as a new genus within the Selymbriini .

Type species. Striduloselymbria cabofrioensis View in CoL gen. nov., sp. nov. here designated.

Species included. Striduloselymbria cabofrioensis View in CoL gen. nov., sp. nov.

Etymology. The generic name is in reference to the accessory sound structure (stridulo -) and the similarity of the general appearance to members of the genus Selymbria . The genus is feminine.

Diagnosis. Striduloselymbria gen. nov. is the third known genus of the Selymbriini . The new genus can be quickly distinguished by the presence of the stridulatory apparatus on the dorsolateral mesonotum, a structure unique within the genera currently assigned to the tribe. In addition, the new genus can be distinguished from Prosotettix sphecoidea Jacobi, 1907 by the smaller body size (wingspan about 39mm), the extremely triangular anterior projection of the head and postclypeus, the very large, hooked secondary fore femoral spine that is perpendicular to the femur long axis, the fore wing radial cell is not expanded in the middle, fore wing ulnar cells 1–3 are about the same width, fore wing basal cell about 3.23 times longer than broad, the fore wing cubitus anterior is not highly arched, the dorsum of abdominal tergite 1 is longer than the dorsum of abdominal tergite 2, and the uncus is sinuate in the only known representative of the genus. Members of the genus Selymbria can be distinguished by the eyes being wider than the lateral angles of the pronotal collar, the anterior margin of the supra-antennal plate is angled anteriorly rather than transversely, the supra-antennal plate reaches almost to the eye, the fore wing radial cell is not expanded in the middle, fore wing basal cell is between 3.20–3.50 times longer than broad, the fore wing cubitus anterior is not highly arched, hindwing cubital cell 2 is almost as wide as distal cubital cell 1, the male opercula reach or extend beyond the posterior opening of and cover the tympanal cavity, the recurved margin of the posterior timbal cavity, abdominal epipleurites are reflexed to the ventral surface, upper pygofer lobes that extend from the pygofer, a long, generally curving uncus, and the aedeagus expands distally with large distal lobes.

Description. Medium sized cicada (body length about 19.20 mm, wingspan about 43.80 mm). Head not as wide as lateral angles of pronotum but wider than mesonotum, supra-antennal plate reaches only half the distance to the eye, vertex at area of ocelli a little longer than frons, eyes projecting beyond the anterior angles of the pronotum, ocelli closer to each other than to eyes, epicranial suture expanding in center posterior to median ocellus; postclypeus inflated, with rounded apex when viewed from the dorsal side, shallow, broad central sulcus on ventral postclypeus, postclypeus rounded in transverse cross-section, postclypeal transverse ridges with grooves along their entire length, rostrum reaching to middle trochanters.Pronotum shorter than mesonotum, lateral margins of pronotal collar moderately ampliate, rounded, broadly U-shaped, without lateral tooth; mesonotum to base of cruciform elevation about as long as head and pronotum together, not as wide as lateral pronotal collar, accessory sound structure on lateral mesonotum dorsal to wing bases, cruciform elevation with shallow, smoothly curved posterior margin; metanotum extends laterally beyond wing groove and posteriorly beyond cruciform elevation. Fore wings and hindwings hyaline with eight and six apical cells, respectively, infuscation absent, pterostigma present, basal cell more than 4.35 times longer than broad, anterior costa arched, costa and radius+subcostal vein close together, the radius anterior 1 vein closely aligned with subcostal vein for its length, cubitus posterior+anal vein 1 distinctly arched, cubitus anterior 1 longer beyond crossvein than proximal to crossvein, radial crossvein angled more than radiomedial, ulnar cells of different sizes. Hindwing median and radius posterior veins appear unfused, anal vein 3 curved at distal end and well separated from wing margin, broad anal lobe, distal hindwing cubital cell 2 wider than distal cubital cell 1. Fore femora with erect but angled primary spine, upright secondary spine, and a small tertiary spine, tarsi three-segmented, hindcoxae lacking large, inner protuberance. Male opercula present a squared S-shape with straight posterior margin, not covering tympanal cavity, opercula well separated along midline, completely encapsulating meracanthus, meracanthus triangular, tapering to a point, reaching posterior margin of operculum. Abdomen about as long as the distance between apex of head and posterior of cruciform elevation, male abdominal tergites convex in cross-section, male abdominal tergites 4–7 similar in size to tergites 2 and 3, lateral margins parallel at base until abdomen begins narrowing posteriorly to genitalia at segment 7, abdominal epipleurites not reflexed to ventral surface, lacking obvious channel on lateral abdominal margins. Timbal cover absent, timbal completely exposed, extending below wing bases, tympana not concealed by opercula. Male sternite VIII broadly U-shaped. Pygofer distal shoulder not developed, dorsal beak present, spine-like, pygofer upper lobes present, aedeagus curved in gentle arc not expanding distally, distally with small lobes, without conjunctival claws or pseudoparameres. Female is unknown.

Measurements (mm). Length of body: 19.20; length of fore wing: 23.10; width of fore wing: 8.20; length of head: 2.65; width of head including eyes: 6.30; width of pronotum including suprahumeral plates: 6.35; width of mesonotum: 5.65.

Distribution. The genus appears to be restricted to the South American Neotropics with the only known species of the genus being collected in the state of Rio de Janeiro in southeastern Brazil. This would be similar to what appears to be its closest relative, Selymbria ( Sanborn 2019; Ruschel & Paladini 2024).