Vallissiana Pereira & Arévalo, 2019

Pereira, Cristiano M., Arévalo-Maldonado, Helber A., Triberti, Paolo, Brito, Rosângela, Isaias, Rosy M. S., Gonçalves, Gislene L. & Moreira, Gilson R. P., 2019, Vallissiana universitaria (Lepidoptera: Gracillariidae): a new genus and species of leaf-mining moth associated with Erythroxylum (Erythroxylaceae) in the Atlantic Forest of Brazil, Zootaxa 4604 (1), pp. 141-160 : 144-147

Vallissiana Pereira & Arévalo gen. nov.

( Figs. 2–3 ).

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Type species. Vallissiana universitaria Pereira & Arévalo sp. nov.

Diagnosis. Vallissiana belongs to the Gracillariinae based on the presence on males of the mostly membranous eighth abdominal segment with a reduced tergite and sternite ( Kawahara et al. 2017). It conforms to the Gracillaria group proposed by Kumata (1982) based on the following characteristics: 1) legs with appressed scales (“smoothscaled”), and with foretibiae, midfemur and tibiae bearing long, bristled scales ventrally, appearing as a thickening; 2) forewing Rs and R 1 faint from base to just beyond the region of R 1 branching; 3) forewing R 1 branching near base; 4) hindwing R 2+3 parallel to short Sc+R 1.

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The new genus shows similarity in the male genitalia with Aspilapteryx in the shape of the valva, with the ventro apical corner ending as a rounded lobe. Affinity exists also with Sabulopteryx due to the presence of a process on the mesal face on the basal third of the valva, even if some doubt remains on the homology with the finger-shaped process in Sabulopteryx . The female genitalia are similar to those of Euspilapteryx Stephens , Calybites Hübner , Ectropina Vári , Gracillaria Haworth and Caloptilia theivora (Walsingham) by the presence of one signum on the corpus bursae of the female and to Aspilapteryx by the wide and simple ostium bursae. However, the new genus differs from the others in forewing venation by R 5 and M 1 stalked and the absence of coremata in the male abdomen.

Description of the adult. Small-sized moth, forewing 3.8 – 4.0 mm (n = 5) long. L/W index 6.4, male and female similar in size and coloration ( Fig. 2 ).

Head ( Figs. 2 B–C).Vertex with long appressed scales (“smooth-scaled”) directed anteriorly; occiput with long appressed scales directed towards vertex; frontoclypeus with long appressed scales directed ventrally; ocelli absent. Antenna filiform, ~1× forewing length; scape pectinate; flagellomeres covered by single, dense row of slender scales, each flagellomere 0.5× scape length, except for first one, ~2× longer than others. Labrum bilobed; pilifers developed, subtriangular; maxillary palpus short, 0.3× labial palp length; labial palpus upturned, three-segmented; second palpomere with porrect bristled, enlarged, roughly scaled ventrally; third palpomere 1.5× second palpomere in length; haustellum elongated, well developed, naked.

Thorax ( Fig. 2A ). Forewing narrow, lanceolate, acute apically, posterior piliform scales (=fringe) long, 1.1× longer than width of forewing; racket-shaped scales with apical margin dentate with three to five cusps at outer margin. Venation ( Fig. 3A ): 12 veins, discal cell almost rectangular, with distal margin almost straight. Veins R 1, R 2, R 3, R 4, R 5 + M 1, M 2+3 +CuA 1+2 branching from discal cell; R 1 to R 4 well separated at their bases; Rs and R 1 faint from base to just beyond the region where R 1 branches; R 1 branching near base; R 2 branching more basal on cell than CuA 1+2 branching; R 5 and M 1 stalked; M 2 and M 3 fused; CuA 1 stalked with M 2+3; CuP entirely faint; anal vein simple, almost straight, extending from base to 2/5 of wing length. Retinaculum: female, hooked piliform scales; male, curved triangular fold of subcostal vein. Hindwing narrow, lanceolate, sharply pointed; marginal scales long, ~3× longer than width of hindwing. Venation ( Fig. 3A ): 9 veins, radial veins with two branches; R 2+3 parallel with Sc+R 1, the latter short, extending to 0.4× hindwing length; discal cell open between M 2 and M 3; M 1 and M 2 stalked; CuA 1 and M 3 branching from CuA 2; M 3 branching from CuA 1; anal vein almost straight, short. Frenulum: female with two stout bristles, anterior ~2× thicker than posterior; male with one stout bristle. Legs: epiphysis present; tibial spur pattern 0-2-4, tibial length ratios ~0.4/0.6/1, covered with appressed short scales; foretibia, midfemur and midtibia with long, bristled scales ventrally appearing as a thickening. Tibial spurs of mid leg at subapex, mesal spur ~0.5× tibia length, lateral spur ~0.6× mesal spur length; tibial spurs of hind leg at 1/4 of tibia length and at subapex, meso-basal spur ~0.4× tibia length; latero-basal spur ~0.2× meso-basal spur length, meso-apical spur ~0.2× tibia length, latero-apical spur ~0.9× meso-apical spur; hind tarsus ~1.5× longer than tibia.

Abdomen. Male seventh and eighth segments membranous ( Fig. 3B ), retracted into sixth segment; seventh segment elongated, 1.2× longer than sixth segment; sternite and tergite of segment seventh reduced to thin transverse band; eighth segment short, 0.3× shorter than sixth segment. Female segments unmodified.

Male genitalia ( Figs. 3 C–G). Tegumen mostly membranous, slightly sclerotized. Anal tube nude, protruding posterior to tegumen; subscaphium very slender, from sub-base to posterior margin of anal tube. Valve symmetrical, sub-rectangular, slightly upturned, costal margin relatively straight and distally rounded, cucullus densely covered by long piliform setae, with distal portion membranous, sacculus with sparse setae and a membranous margin, with rounded cuticular projection on mesal surface at basal third, ventral margin with medial region curved, ending distally as a rounded lobe. Vinculum not differentiated; saccus broadly U-shaped; juxta membranous. Phallus tubiform ~1× valva length, base slightly wider than apex, cornuti a group of spines in apical third, apex with two small projections.

Female genitalia ( Figs. 3 H–J). Papillae anales ~0.6× wider than long, connected dorsally, covered with setae and microtrichia; anterior apophysis with wide arms from base to middle, progressively shortening towards apex, reaching beyond distal margin of seventh segment; posterior apophysis curved, reaching sterigma. Lamella postvaginalis united with lamella antevaginalis; ostium bursae placed on intersegmental area between seventh and eighth abdominal segments; corpus bursae with one falciform signum; ductus seminalis arising from caudal region of ductus bursae.

Etymology. The genus name is derived from the Latin word Vallis (= valley) in reference to Campus do Vale – Universidade Federal do Rio Grande do Sul (UFRGS), the type locality. To be treated as feminine.

Figures

FIGURE 2. Adult male of V. universitaria: (A) wing spread moth, dorsal; head (B) dorsal, and (C) lateral. Scale bars: (A) 1 mm, (B–C) 200 µm.

FIGURE 3. Wing venation, abdomen and genitalia morphology of V. universitaria: (A) forewing and hindwing venation; (B) male last, dorsal; (C) male genitalia, ventral (phallus omitted); (D) valva, region of cucullus (indicated by rectangular area marked in C), ventral; (E) valva, detail of process at basal third (indicated by area marked in C), ventral; (F) phallus, lateroventral; (G) spines of cornuti in detail (indicated by rectangular area marked in F), latero-ventral; (H) female genitalia, ventral; (I) signum (indicated by square area marked in H), ventral; (J) sterigma in detail, (indicated by rectangular area marked in H) ventral. Scale bars: (A) 1mm; (B) 200, (C) 100, (D) 15; (E) 10; (F) 50; (G) 20; (H) 200; (I)10; (J) 50 µm.