Metacostana Domahovski & Cavichioli 2023, gen. nov.

Genus Metacostana gen. nov.

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Metacostana cornuta gen. et sp. nov.

Head (Fig. 26A), in dorsal view, median length of crown less than half interocular width; crown surface with fine parallel transverse striations (Fig. 25B); ocelli equidistant between median line and eyes; in lateral view (Fig. 26C), crown-face transition thin, with three transverse carinae. Forewing (Fig. 26D) without extra crossveins. Metatibia row AD with intercalary setae between macrosetae. Male sternite VIII (Fig. 26E) long, fully hiding subgenital plates in repose. Male pygofer (Fig. 26G) with ventroposterior process. Subgenital plate (Fig. 24H) bearing filiform setae. Aedeagus (Fig. 26L–M) with apodemal processes. Female first and second valvulae of ovipositor (Fig. 27D, F) not broadened medially and curved ventrally. Second valvula (Fig. 27F) with weakly developed dorsal protuberance; dorsal margin (Fig. 27F) with prominent regular teeth on apical third.

The new genus name is feminine and combines the prefix ‘meta’ (‘different’) + part of the name Costanana, a closely related genus of Gyponini.

STRUCTURE. Head in dorsal view (Fig. 26A): slightly produced anteriorly, median length of crown less than half interocular width; crown surface with fine parallel transverse striations; anterior margin broadly rounded and parallel to anterior margin of pronotum, slightly extending over eye margin; transocular width of head narrower than humeral width of pronotum; ocelli equidistant between median line and eyes and slightly closer to anterior than posterior margin of crown; in frontal view (Fig. 26B), frons longer than wide, flat, not excavated below anterior margin of crown and with a few thin striations, texture shagreen; frontogenal suture distant from eye margins by maximum width of clypeus, not surpassing antennal ledge; antennal ledge carinated, obliquely downwards in relation to frons and extending over frons by short distance; epistomal suture indistinct medially; gena with ventrolateral margins slightly convex at midlength and weakly excavated near eye; maxillary plate produced ventrally as far as clypeus apex; clypeus not inflated, ca 1.5× as long as wide, lateral margins weakly divergent apically, apex emarginated; in lateral view (Fig. 26C), crown-face transition thin, with three transverse carinae. Pronotum in dorsal view (Fig. 26A): transversely striated except near anterior margin; lateral margins convergent anterad; in lateral view (Fig. 26C), moderately declivous; head and pronotum in continuous slope. Scutellum (Fig. 26C), not inflated. Forewing (Fig. 26A) without extra crossveins; venation distinct; M vein with segment after divergence between R+M and before cross vein m-cu 1, as long as length of m-cu 1; outer anteapical cell short, almost half length of central and inner anteapical cells; five apical cells (R1 vein present); appendix well developed and involving first and second apical cells; apex slightly tapered. Profemur elongated, approximately 3.5× as long as wide; AD, AM, and PD rows reduced and poorly defined, with exception of apical setae AD 1, AM 1 and PD 1 respectively; AV row with 3 short setae; PV row with only an apical seta present. Protibia, in cross-section, more or less cylindrical, with longitudinal carina adjacent to PD row weakly developed; AV row formed by long setae, gradually increasing in thickness and length towards apex; AD formed by many small undifferentiated setae; PD row with 3 long setae and intercalary undifferentiated setae; dorsal surface with apical setae AD 1 and PD 1 developed; PV row with 4 setae. Metafemur with setal formula 2:2:1. Metatibia rows PD, AD, and AV with 22–23, 12–13, and 14–15 macrosetae, respectively; AD row with intercalary setae between macrosetae; PV row with setae of apical half formed by sequence of 1 thicker and 3–4 thinner setae, ending with a thick seta. Metatarsomere I inner row of plantar surface with 5–6 setae, outer row very reduced in size; apex with 3 patellae flanked by 1 tapered lateral seta on inner and 1 on external corner. Metarsomere II pecten with 2 platellae flanked by 2 tapered lateral setae on inner and 1 on external corner.

MALE TERMINALIA. Male sternite VIII (Fig. 26E) long, fully hiding subgenital plates. Male pygofer (Fig. 26G) with ventroposterior process. Subgenital plate (Fig. 26H) not more membranous apically than basally, with filiform setae on ventral surface and outer margin. Connective (Fig. 26I) linear. Aedeagus (Fig. 26L–M) with apodemal processes.

FEMALE TERMINALIA. First and second valvulae of ovipositor (Fig. 27D, G) not broadened medially and curved ventrally. First valvula (Fig. 27D) with ventral interlocking device long, reaching the apical fourth. Second valvula (Fig. 27G) with weakly developed dorsal protuberance; dorsal margin (Fig. 27G) with prominent regular teeth on apical third.

Southern Brazil.

The crown of Metacostana cornuta gen. et sp. nov. transversely striated and the anterior margin defined are features present in the genera Acuthana, Costanana, Domahovana, Dumorpha, Delongiana Domahovski et al., 2020, Nullana DeLong, 1976, Ponana Ball, 1920, Regalana DeLong & Freytag, 1975, and some species of Polana DeLong, 1942. Among these genera, the presence of apodemal processes on the aedeagus is shared only with Dumorpha, Ponana and some subgenera of Polana, and the male sternite VIII being well produced posterad, often hiding the subgenital plates, is shared with Acuthana, Costanana, Domahovana, Dumorpha and some species of Polana. Probably the unusual ventrally curved shape of the ovipositor will place Metacostana gen. nov. as sister group of Acuthana, which was the only known genus of Gyponini with this feature. The new genus can be differentiated from Acuthana by the color, with black and yellow maculae (uniformly yellowish-brown in Acuthana), the absence of punctuations and reticulations on the forewings, the male pygofer with process on the ventroapical margin, the subgenital plate not tapered apically, the connective liner, the presence of apodemal processes on the aedeagus, the most strongly curved ovipositor, with smaller dorsal protuberance on the second valvulae, and the apex without denticles on the ventral margin. Unfortunately the ovipositor of females of Dumorpha is unknown, but the new genus can be separated by the color (pale yellow without black markings or only a few in Dumorpha); the ocelli smaller and equidistant between eye and midline (closer to the eye margin in Dumorpha), the presence of a process on the ventroapical margin of the male pygofer, the connective linear shape, and the atrial processes of the aedeagus being broader. Compared to Costanana, the new genus can be differentiated due to the metatibia row AD having intercalary setae between the macrosetae (also present in Dumorpha), the presence of apodemal processes on the aedeagus and the different morphology of the female ovipositor.