Astatometopon sakakibarai gen . & sp . nov . , a montane planthopper from Chile ( Hemiptera : Fulgoroidea : Delphacidae )

Astatometopon gen. nov. is described to accommodate A. sakakibarai sp. nov., a delphacid planthopper distributed in the Nahuelbuta and Andes mountain ranges in the central and south central zones of Chile. The new taxon is placed into Delphacini but it presents some unusual features for the tribe, such as a strongly asymmetrical phallus with a porrect process arising from base, the absence of teeth on the hind margin of calcar, and an exceptional variation in carination of the eumetope. Resumen. Astatometopon gen. nov. es descrito para acomodar a A. sakakibarai sp. nov., un delfácido distribuido en las cordilleras de Nahuelbuta y los Andes en las zonas centro y centro sur de Chile. El taxón es clasifi cado en Delphacini pero presenta características inusuales para la tribu, como un falo fuertemente asimétrico con un proceso porrecto erigido desde la base, la ausencia de dientes en el margen posterior del calcar, y una variación excepcional en la carenación de la eumetopa.


Introduction
The family Delphacidae Leach, 1815 is a species-rich group of planthoppers (Hemiptera: Fulgoroidea) characterized by the presence of a movable spur (calcar) at the apex of the hind tibia.Most of its members are grass feeders and it is the most economically important family within the Fulgoroidea (URBAN et al. 2010).The literature on South American Delphacidae (and particularly the most diverse tribe Delphacini) is sparse, lacking an overview as in BARTLETT et al. (2014) for North America.Most of recent research has been restricted to Argentina, and particularly focused on taxa of economical concern

Materials and methods
The morphological terminology mainly follows ASCHE (1985) with the following modifi cations: phallus is used for the male intromittent organ, segment X is used instead of anal tube, segment XI instead of anal style, styles instead of parameres, and using the terminology proposed in ANUFRIEV & EMELJANOV (1988) for the head, BOURGOIN (1993) for the female genitalia, and BOURGOIN et al. (2015) for the wing venation.For observation of genitalia, the abdomen was removed and placed in saturated KOH solution at room temperature for about 24 hours.Pieces were stored in glycerin in microvials pinned below the respective specimens.Photographs of specimens were taken with a conventional digital camera adapted to a stereoscopic (14)(15)27) or a compound optical microscope (28)(29)(30)(31)(32). Measurements are given in millimeters; mean, minimum, maximum and number of measured specimens are given for body length (not considering wings and postgenital segments), total length (including wings), and body width (at level of tegulae).
The type material is deposited in the following collections:  Type species.Astatometopon sakakibarai sp.nov., here designated.
Description.General body shape (Figs 1-5) oblong, slightly more than twice longer than wide.
Head  wider than or subequal in width to pronotum.Macrocoryphe (Figs 1-2, 4-5) quadrangular, wider than long; apex rounded; anterior side and posterior margin almost equal in width; posterior margin, in dorsal view, medially positioned at anterior half of eyes; coryphe composed by two pentagonal cells enclosed by carinae.Fastigium (Fig. 3) smoothly curved.Superior side of eumetope  wider than its inferior margin; carinae of metope fading on fastigium, then subparallel and converging on lower margin of eumetope; carinae sometimes weak, absent, or reduced to a single carina.Clypeus   Legs.with one lateral tooth near tibiofemoral articulation and another one near middle of its length.Calcar (Fig. 14) without teeth on its hind margin.
Coloration .Dorsal side of head and thorax fulvous to brown (dark brown to blackish in macropterous specimens), medially paler; foveolae of head and pronotum and pair of lateral markings on mesonotum dark (brown to black).Ventral side of head and inferior side of genae dark brown (usually blackish in macropterous specimens), carinae of eumetope and clypeus, and median fringe of eumetope (intercarinal space) pale.Legs fulvous to brown with dark longitudinal stripes.Forewings with brown tonalities, slightly darkened at end of veins and in clavus (the last feature in macropterous specimens), veins brownish, margin (including costa) whitish.Abdomen dark brown to black with lighter parts medially and laterally (orange in males and light brown in females).
Head .Macrocoryphe with length of about three fi fths of basal width; basal width inconspicuously narrower than anterior one, about two fi fths of total head width; cells of coryphe and areolet with rounded foveolae.Eyes (Fig. 3), in lateral view, oblong, height of about fi ve sevenths of length, notch slightly surpassing inferior third of its height.Ocelli (Fig. 3) adjacent to eyes.Genae (Figs 3,(6)(7)(8)(9)(10)(11) bearing row of thin setae.Eumetope (Figs 6-11) rough, with maximum width in second fi fth from superior side, about three fourths of its length; a median fringe normally enclosed (Fig. 6) by paired carinae (meeting near frontoclypeal suture), paired carinae sometimes absent (Figs 7-9), eventually reduced to single carina ; paired or single median carinae fading at fastigium.Clypeus  with basal width of about two thirds of its length.Rostrum with last segment the widest.Antennae with pedicel nearly twice longer than scape.
nuate, medially broadly concave; median length of about fi fth of posterior width; posterior width slightly narrower than head.Mesonotum (Figs 1-2, 4-5) with length from posterior margin of pronotum to its apex of about four sevenths of its width.Tegulae short.
Wings (12)(13).Forewings of brachypterous specimens surpassing abdomen in males, rarely in females (Figs 1-4 Legs .Apex of metatibiae (Figs 14-15) with three outer and two inner teeth; teeth larger to smaller from outermost to innermost, outermost tooth more separated from others; inner teeth smaller than outer teeth, of about same length, in form of truncate lobes with apiculum (Fig. 15); lobe produced innermost of apex of tibiae reaching level of inner teeth (Fig. 15).Calcar (Fig. 14) greater than two thirds of length of metabasitarsus; fore margin basally angled, then smoothly curved; hind margin curved near apex and base; apical tooth present, usually reduced.Metabasitarsi (Fig. 14) near half of length of metatibiae; apex with fi ve outer and two inner teeth; outer teeth slightly and gradually reducing its size from outer-to innermost; inner teeth of about same size, positioned distad of outer teeth.Second metatarsomere (Fig. 14) about half as long as metabasitarsus; apex with four teeth in regular row.
Male abdomen.Sternum I (Fig. 16) with apodemes as short obtuse lobes.Pygofer (Figs 17-18) about twice higher than long in lateral view (Fig. 18); dorsal concavity of posterior margin broad and surpassing middle length of dorsal surface (in dorsal view); median irregular ridge on diaphragm; armature of diaphragm as concave projection, near level of middle of pygofer height; median ridge produced ventrad and acutely onto foramen; foramen small, with ventral margin convex.Segment X (Figs 19-21) short; in dorsal view (Fig. 20) subtrapezoidal, posterior width of about two thirds of basal width; length of about third of basal width (Fig. 20) and two thirds of height (in lateral view, Fig. 21), ventrally not sclerotized; pair of caudoventral spines initially converging, then diverging laterad (Fig. 19).Segment XI  with shaft of about four thirds of length of segment X. Phallus  Figs 12-15.Astatometopon sakakibarai sp.nov.12 -forewing of a macropterous specimen; 13 -forewing of a brachypterous specimen; 14 -hind leg, outer view; 15 -hind leg, inner view.
with suspensorium projected beyond middle of its length; basal process slightly shorter and at side (left) of main limb, slightly inclined ventrad, distally slightly curved laterad, with tooth on inner side near apex; main limb basally abruptly curved dorsocaudad, then straight up to apex where it is abruptly curved ventrad; apex widened after curvature with gonopore opened laterally (on right), inner margin of apex slightly produced craniad; row of teeth running caudocraniad from lateral side at beginning of apical curvature.Styles (Figs 21,(25)(26) short, in caudal view reaching about height of middle of diaphragm, narrowed from outer side in last fourth (Fig. 25); in lateral view (Fig. 26) wide, narrowing dorsad.
Female abdomen.Segment X (Fig. 27) slightly wider basally; length of about two thirds of basal width; slightly higher than long; ventral surface longer than dorsal surface, with posterior margin slightly concave.Segment XI (Fig. 27) longer than segment X. Gonoplacs (Fig. 28) six times longer than wide; apex rounded; dorsal margin entire on distal two thirds.

Discussion
The variation in the carination of the eumetope in Astatometopon sakakibarai sp.nov. is an exceptional feature among Delphacidae.The infrequent single carination which is clear only in one male and one female from Los Sauces and one male from Cajón del río Las Leñas (Figs 10-11) seems to be the basic condition: the median carina is commonly broade- ned (Figs 6-9) letting a pale fringe which is normally coarsened at sides taking the form of paired carinae (Fig. 6).
The tribal placement of Astatometopon gen.nov. in Delphacini is supported by the articulation between suspensorium and segment X (Fig. 21) and the apodemes of sternum I (even though reduced) directed dorsocaudad (Fig. 16) (ASCHE 1990).Additionaly, features typical to some Delphacini such as the diaphragm of the pygofer bearing armature and the symmetrical processes of the segment X are also present in Astatometopon.The new taxon, however, shows also some similarities with Tropidocephalini, particularly the asymmetrical phallus and the calcar devoid of teeth on hind margin; these features are considered convergences.
Astatometopon gen.nov. shares several features with the Afrotropical genus Leptoeurysa Fennah, 1988: the head width in relation to pronotum, short apodemes of sternum I, segment X with two spinose processes, rather long segment XI, bifi d phallus and short styles narrowed at apex (see FENNAH 1988).The relationships between these two taxa, and possible biogeographical implications, would deserve a further study.
Astatometopon sakakibarai sp.nov.inhabits montane habitats; it seems to present a disjoint distribution in the Coastal and Andes mountain ranges.This would be a typical case of a taxon once distributed at lower altitudes during the glacial period, but currently with isolated populations (VILLAGRÁN 2001).
). Venation (Figs 12-13) with nodal line in apical third; vein ScP+R branched into ScP+RA and RP; ScP+RA frequently unbranched in brachypterous specimens (Fig. 13, dotted line); RP unbranched but fused for short distance with MP, then separated; ir crossvein little distad of fusion of RP and MP, enclosing outer subapical cell, frequently absent in brachypterous specimens (Fig. 13, dotted line); MP normally unbranched; crossvein m-cu little basad of fusion of RP with MP and little basad or at level of branching of CuA 1 ; CuA branched near level of fork of ScP+RA; vein CuA 1 branched; crossvein between CuA 1b and CuA 2 , little basad or at level of crossvein between CuA 2 and CuP (icu), enclosing inner subapical cell; sometimes (in brachypterous specimens) CuA 2 ending at end of CuP.
Host plant.Unknown.The type series was collected in herbaceous stratum in open habitats; in Los Corrales, Caramavida, near Angol and Los Sauces it was dominated by tufted grasses.Distribution.Chile: O'Higgins, Bío Bío and Araucanía regions in the Andes and Nahuelbuta mountain ranges.