Citroriginini, Sanborn, 2021

Sanborn, Allen F., 2021, A new species, genus and tribe of cicada (Hemiptera: Cicadoidea: Cicadidae Tibicininae) from Chile with a list of Chilean cicada fauna, Zootaxa 4952 (1), pp. 87-100 : 88-89

Citroriginini n. tribe

Type genus. Citroriginis n. gen.

Included genera. Citroriginis n. gen.

Remarks. The new taxon cannot be classified into any current tribe of the Tibicininae . There are significant morphological differences in the new taxon from each of the currently assigned tribes of the subfamily. As a result, a new tribe is formed here for the species.

Diagnosis. Head with eyes protruding laterally from head beyond anterior prontoal collar but not as wide as lateral angles, supra-antennal plate reaching about half distance to eye, lateral ocelli about as close to each other as to eyes, vertex at area of ocelli about as long as frons, postclypeus approximately triangular in transverse cross-section extending anteriorly beyond supra-antennal plates, postclypeus dorsal length not as long as dorsal width, not as long as dorsal vertex. Pronotum with ventrally angled paranota, not dilated laterally, lacking medially angulate lateral margins, pronotal collar lateral angle ampliate, mesonotum lacking stridulatory apparati, mesonotum not concealing dorsal metanotum. Fore femora with three spines, hind coxae lacking a large inner protuberance, meracanthus large with triangular terminus, male operculum completely encapsulating meracanthus, S-shaped, not covering tympanal cavity. Fore wings and hind wing hyaline, ulnar cells 1 and 2 parallel, about the same size, ulnar cell 3 more than twice as large expanding to widest point at divergence of median vein 1 + 2, medial cell elongated reaching distally almost to distal apical cell 8, fore wing median vein 3 + 4 arises just distal to arculus, base of cubitus anterior arising near proximal base of basal cell, pterostigma absent, costal vein bowed, cubitus anterior 1 divided by mediocubital crossvein so distal portion shortest, radial and radiomedial crossveins parallel. Abdomen longer than distance between apex of head and posterior of cruciform elevation, male abdomen fusiform, narrowing posteriorly to genitalia at tergite 5 or 6, well developed timbals absent, epipleurites reflexed to ventral surface without V-shaped kink. Pygofer distal shoulder undeveloped, dorsal beak short, pointed, pygofer upper lobe absent, pygofer basal lobe welldeveloped, adpressed to pygofer, uncus long, undivided, not retractable within pygofer, claspers absent.

Distinguishing features. Citroriginini n. tribe can be distinguished from the remaining Tibicininae tribes by the lack of timbal organs, the origin positions of the fore wing cubitus anterior and median vein 3 + 4, parallel ulnar cells 1 and 2 that are about the same size, ulnar cell 3 being more than twice as large as ulnar cells 1 and 2 expanding to widest point at divergence of median vein 1 + 2, and the medial cell elongated reaching distally almost to distal apical cell 8. In addition, Citroriginini n. tribe can be distinguished by having in combination a supra-antennal plate reaching about half distance to eye, epicranial suture widening posterior to lateral ocelli, postclypeus with deep central sulcus and approximately triangular transverse cross-section, pronotum not dilated laterally, lacking medially angulate lateral margins, mesonotum lacking stridulatory apparati, mesonotum not concealing dorsal metanotum, male operculum completely encapsulating meracanthus, hind wing with five apical cells, the additional small cell formed distal to the radial cell where the radius anterior and radius posterior diverge at the node, abdomen begins narrowing posteriorly to genitalia at tergite 5 or 6.

The leaf-mimicry of Hemidyctini Distant, 1905d along with the narrow, triangular head, metanotum covered by the posteriorly extended scutellum forming a long triangular lobe, and the multiple reticulations of the fore wings quickly distinguish Hemidyctini from the new tribe. An additional structure that is helpful in distinguishing Sapantangini Sanborn, Marshall & Moulds, 2020 (in Sanborn et al. 2020) and Selymbriini Moulds & Marshall, 2018 (in Marshall et al. 2018) from the new tribe is the supra-antennal plate almost reaches the eye in species of these tribes but reaches less than half the distance to the eye in the new tribe. Species of Tibicinini Distant, 1905b can be distinguished quickly by the fore wing median vein 3 + 4 arising distal to the arculus and the base of cubitus anterior vein arises from near the distal end of the basal cell while the fore wing median vein 3 + 4 arises just distal to the arculus and the base of the cubitus anterior is near the proximal base of the basal cell in the new tribe. Species of Tettigadini Distant, 1905c are distinguished by the dilated and potentially medially angulate lateral margins of the pronotum and the presence of mesonotal stridulatory apparati. Chilecicadini Sanborn, 2014 has some similar features but can be distinguished by the supra-antennal plate extending more than the half distance to the eye, the well developed timbals, posterior timbal cavity with a turned-back rim, the fore wing median vein 3 + 4 arising distal to the arculus and the base of cubitus anterior vein arises from near the distal end of the basal cell, the expanded fore wing ulnar cell 3, the fore wing median vein reaching almost to the distal end of apical cell 8.

Species of the Platypediini Kato, 1932 are also characterized by a lack of timbal organs and a lack of accessory stridulatory organs. However, species of Platypediini can be distinguished quickly by the shape and proportionate sizes of the fore wing ulnar and medial cells, the almost triangular fore wing ulnar cell 2, the fore wing cubitus posterior and anal vein 1 are partly fused, the fore wing cubitus anterior 1 vein is separated by the radiomedial crossvein so that the distal portion is longer than the proximal portion, the very small opercula, and the uncus that is generally bent or significantly curved in these species. The almost triangular fore wing ulnar cell 2 appears to be diagnostic and an ancestral character since both extant genera and fossil Platypediini possess this feature ( Moulds 2018).

Distribution. The only genus of the new tribe is restricted to central Chile.