Schacontia Dyar, 1914: 400

Goldstein, Paul Z., Metz, Mark A. & Solis, M. Alma, 2013, Phylogenetic systematics of Schacontia Dyar with descriptions of eight new species (Lepidoptera, Crambidae), ZooKeys 291, pp. 27-81 : 35-40

Schacontia Dyar, 1914: 400

Type species.

Acontia medalba Schaus, 1904: 163, by subsequent designation.

Type locality:

Brazil.

Etymology.

" Schacontia " seems to be Dyar’s contraction of Schaus and Acontia , the noctuid genus in which Schaus mistakenly attributed medalba and subsequently designated by Dyar as the type species of Schacontia .

Diagnosis.

Schacontia species may be recognized by (character numbers listed parenthetically): Foreweing Rs3 and Rs4 stalked (5); M1 and M2 stalked (6); hindwing M2M3 + CuA1 stalked (13); bullae tympani invaginated in S2 (18); absence of puteoli (22); fornix heavily sclerotized and far removed from the edge of Ve1 (24); fornical angle a low arc> 90 degrees (25); presence of gnathos-ventrotergal rods complex (31), bearing a finger-like middle process (32); presence of teguminal sulcus (34); intrasaccular process a bump or flange towards base of valve or as a trigger-like process at margin of lower lobe of valve (41); pair of terminal black dots on abdominal dorsum of male (53); uncus hood-like, mucronate, or obovoid, with variously modified terminal nipple (35, 36). In addition, the costal bulge in the FW postmedial line is frequently coupled with a color contrast between the FW medial area and the basal and terminal areas, often involving white scaling. Unlike the medalba group (for present purposes including Schacontia speciosa ), the proboscis is not reduced in the ysticalis-themis group, the labial palpi droop, the tympanal fornix is narrow, ribbonlike; venulae secundae tapered to form a “neck.”

Habitus.

In the species most readily identifiable as Schacontia (by virtue of their similarity to the type species Schacontia medalba ), hereafter referred to as the medalba group, the forewings are gray with a metallic sheen and the antemedial and postmedial lines variously suffused with white, the exception being Schacontia umbra , which may be almost uniformly shaded dark brown. Towards the costa, the postmedial line bulges outward; the hind wings are by and large nondescript in pattern beyond the presence of a faint postmedial line. The ysticalis-themis group including the Schacontia themis-rasa sister pair and the Schacontia nyx complex [ Schacontia nyx + Schacontia clotho + Schacontia lachesis + Schacontia atropos ], are distinguished from these in having ocelli present; frons with normal, convex contour, except in Schacontia ysticalis ; and labial palps porrect, extending beyond the clypeus.

Male genitalia.

All Schacontia bear a modification of the intrasaccular region of the valva. In the case of those species surrounding the type species of Schacontia , this comprises a naked or denticled flange; the valvae are characteristically reduced, if not truncate, and the uncus prominent but unadorned, mucronate. The valvae become progressively more complex in the ysticalis-themis group, with the intrasaccular feature transposed laterally to form a sclerotized trigger-like structure. Also in the ysticalis-themis group: the dorsal ridges of the tegumen are cruciate, meeting near the uncus; the tegumen is much wider than the uncus such that the lateral edges of the tegumen appear to taper/fall away from the uncus gradually; the outer margin of the valva is complex, including a variously adorned subcostal process, the costa associated with a fleshy lobe at its terminus and at least one setal tuft; the sacculus bears a localized patch or cluster of setae ventrad; and a membranous area exists between the costa and the subcostal process.

Description.

Head - In medalba group, ocelli and chaetosemata absent; proboscis reduced; frons conical; labial and maxillary palpi straight. In ysticalis-themis group, ocelli present; frons of normal, convex contour except in Schacontia ysticalis ; labial palps porrect, extending beyond clypeus. Thorax - In medalba group, pronotum, mesonotum, legs gray; hind leg of female with 1 pair of tibial spurs. Males of several members of ysticalis-themis group bear a flattened, hind tibial spur, specialized hind tibial scales, a shallow concave spoon-like metatarsal modification, and coremata on 4th abdominal segment (on Schacontia themis , Schacontia nyx , Schacontia clotho , Schacontia lachesis , and Schacontia atropos ); in addition, epipleural setae may be present (in Schacontia rasa , Schacontia clotho , Schacontia lachesis , and Schacontia atropos ); and female hind tibia usually bear two pair of spurs (a medial pair present) except in Schacontia ysticalis and Schacontia rasa . Forewing (FW) - Schacontia exhibit a characteristic curvature of postmedial line, outwardly bulging towards costa. In medalba group FW medial area partially suffused with white; in ysticalis-themis group, FW either unicolorous with basal and postmedial areas or polymorphic, with some specimens more darkly shaded. Rs3 and Rs4 stalked; M1 and M2 stalked. Hindwing - In medalba group, HW generally pale with few contrasting markings; female frenulum with a single seta; postmedial line sometimes present, conspicuous, but never in ysticalis-themis group. [M2M3]+CuA1 stalked. Abdomen - Scales arranged in two terminal black dorsal spots in males, more conspicuous in ysticalis-themis group. Tergites gray with dark-gray scaling in medalba group. Tympanal organs crambiform (tympanum and conjunctivum not co-planar, praecinctorium present, bullae tympani open anteromedially), but somewhat variable. In medalba group, bullae tympani broad, tympanal assemblage wider than long (cf. Solis 2009: 503); processi tympani present, towards antero-lateral end of fornix, prominent, lamellate, hemi-circular; processus spiniformis present; fornix tympani strongly sclerotized, broad, removed from edge of venula prima; fornical ulna gradually arched at approximately>90° angle; pons short, broad, V-shaped, length more or less equivalent to breadth of fornix; rami (posteromedial margins of sacci) weakly sclerotized, arcuate, not strongly angled medially; venulae secundae present, tapering gently such that posterior width only slightly less than anterior width; puteoli absent; posterior lip of saccus weakly sclerotized, saccus indistinct and grading into second sternite; posterior width of tympanal organs narrower than anterior width, but venulae secundae not tapering sharply to form a neck; bullae not conspicuously invaginated in S2. In ysticalis-themis group, tympanal assemblage less asymmetrical than in medalba group (i.e., not conspicuously wider than long); tergo-sternal sclerite robust, conspicuous; bullae tympani longer than wide, saccus or rim of bullae tympani sclerotized at base; processi tympani present, lamellate, thumb-like, towards antero-lateral end of fornix; fornix tympani sclerotized; angle of fornical ulna obtuse; pons elongate, comprising (in part) two parallel, elongate, sclerotized prongs, divergent only at anterior terminus (posteromedial margin of saccus appears delimited by sclerotized rami, extends and remains parallel to pons for most of its length, pons extending towards bottom of saccus); saccus deep, pronounced (cf. "poches ou dépressions tympaniques" of Minet 1985); venulae secundae prominent, tapering such that "partie libre" (sensu Minet) of second sternite forms a “neck” as in Schacontia speciosa ; puteoli absent; posterior width of tympanal organs roughly half of anterior width. Male genitalia (Figs 36-60, part). Medalba group: Uncus oblong, cuspidate or mucronate, terminal edge entire; tegumen robust, divided into two dihedral, di-trapezohedral, or hemispherical bubbles that meet for a length that varies across species such that its dorsal ridges appear cruciate; juncture may appear as an elongate strut that divides anterior to base of uncus, such that anterior margin of tegumen may appear moderately emarginate (as in Schacontia chanesalis ) or more deeply invaginate (as in Schacontia medalba and Schacontia umbra ). A transparent, membranous or sub-sclerotized area within uncus overlies a finger-like process arising from within center of gnathos, configuration harness-like, comprising a plate suspended by four arms, one pair extending to and (apparently) articulating with base of uncus dorso-caudally; other subtergal pair extending ventrally to and articulating with vinculum; connection between gnathal plate and tegumen membranous. Lower arms of gnathos appear to represent a fusion with ventro-tergal rods (Cf. Yoshiyasu 1985). Characteristic reduced male valvae extend straight out at roughly a 90° angle, and with a localized patch or cluster of ventral, filiform saccular setae. Valvae either simple and rounded or broadly emarginate to bilobed; reduced, their most prominent feature a pair of intra-saccular processes (one in each valva) oriented dorsally and variously naked or adorned with spines or denticles. Ventro-marginal setae absent or rudimentary. Juxta U-shaped or broadly V-shaped, robust at base, vaguely taurean. Phallus simple, cornuti absent. Ysticalis-themis group: Uncus obovoid or superficially tridentate (appearing trefoil- or spade tipped); tegumen robust, divided into two obliquely-oriented oval sections meeting caudally near base of uncus, but diverging widely cephalad such that anterior margin of tegumen appears deeply invaginated; gnathos comprising a suspended rectangular plate with arms arising from each corner and a small, nub-like process arising centrally; dorsal arms wrap around anal tube, a ventral pair extend to termini of vinculum, such that gnathos almost appears to articulate both with uncus-tegumen and with vinculum, which is variously U-shaped or horseshoe shaped with pronounced pockets at each terminus. Valvae complex, comprising regions and processes that are variously sclerotized, fleshy in appearance, and/or bearing tufts of setae: intrasaccular flange located towards latero-ventral edge and sclerotized to form a trigger-shaped process; robust, spine-like setae on valva; ventro-marginal setae present on valva, either distributed evenly along length of outer margin of sacculus or concentrated at ventro-saccular “ulna”; costa robust and joined to rest of valva by a narrow membranous area; valva with secondary outer fleshy setose lobe or process below costa; recurved/decumbent setal plume associated with terminus of costa. Juxta robust, V-shaped or broadly U-shaped, ventral tip curved outward forming a small chin-like platform in Schacontia themis and Schacontia rasa ; a less robust, more open U-shape in Schacontia nyx complex. Phallus with two cornuti. Female genitalia (Figs 38-63, part) - Medalba group: Papillae anales convex, partially appressed but separate, setose; posterior and anterior apophyses roughly equivalent in length, not especially robust; antrum may be conspicuous, chalice-like; ductus bursae short, not discretely circumscribed; corpus bursae membranous, elongate, without signa; ductus seminalis arising from posterior end of corpus bursae. Ysticalis-themis group: Papillae anales setose, rounded, not conspicuously dihedral (except in Schacontia lachesis ); colliculum, if present, a partial collar, sometimes shortened to form a narrow ring immediately outside corpus bursae, ductus bursae per se all but eliminated; note that in contrast to Udea Guenée (1845), for example, ductus bursae, if present, developed posterior to colliculum (cf. Mally and Nuss 2011: 63, fig. 3), an elongate band or partial sleeve immediately occupying antrum, appearing as a sclerotized band on floor of ductus bursae; corpus bursae globular or ovoid (more elongate in Schacontia ysticalis ), without signa, one or two accessory bursae posteriad where ductus seminalis attached.

Species variation. Individual species variation with respect to wing polymorphism is especially acute in the Schacontia nyx complex; of particular interest here are the male sec ondary sexual characteristics, which covary imperfectly across species and are discussed below. Schacontia species may vary greatly in size (>100% wingspan).

Distribution. Collectively, Schacontia species are distributed across Mexico, south to Central America (Guatemala, Costa Rica, Panama) and South America (Bolivia, Brazil, Ecuador, Venezuela) and the Caribbean (Puerto Rico, Cuba, Hispaniola). A single North American record of Schacontia themis is reported here from Sanibel Island, Florida (USA: Lee Co.).

Biology.

Larvae are internal feeders that may induce galls, and pupate within the host. The only known host plant records are in Capparaceae : in Costa Rica, larvae have been reared from Podangrogyne decipiens (Triana & Planch.) Woodson (Solis, Nishida and Metz, in preparation); Cleome spinosa Jacq. has been reported as host for Schacontia chanesalis ; Capparis frondosa Jacq., and Capparis verrucosa Jacq. are reported for other Schacontia species.

Remarks.

Schacontia was described by Dyar (1914) to accommodate three species, whose original descriptions were based primarily on wing pattern: the type species Schacontia medalba (Schaus, 1904; formerly Acontia medlba ); Schacontia chanesalis (Druce, 1899), formerly Pionea chanesalis ; and Schacontia replica Dyar, 1914, the last of which accompanied the generic description ( Druce 1899: 557, Schaus 1904: 163, Dyar 1914: 400). Dyar (1925: 8) later described Thlecteria ysticalis from a female specimen, also on the basis of wing pattern, and this species was later removed to Schacontia by Munroe (1995: 42), who also recognized Schacontia pfeifferi Amsel, 1956, raising the total number of species recognized in the genus to five. Amsel’s (1956: 101-102) description of Schacontia pfeifferi , which placed Schacontia in the Schoenobiinae , is the most complete description to date and one of only two works prior to the present to figure or characterize genitalia (the other being Solis 2009). Neither Schaus nor subsequent authors were explicit in their characterization of what makes Schacontia unique or in their rationale for describing and including new species in the genus.

Key to species of Schacontia

Key to species of Schacontia : Male Genitalia + Habitus + Female genitalia (part)