Oecetis ruschii, Bonfá-Neto & Salles & Vilarino, 2024

Bonfá-Neto, Pedro, Salles, Frederico Falcão & Vilarino, Albane, 2024, New species of the long-horned caddisfly Oecetis McLachlan, 1877 (Trichoptera: Leptoceridae) from the Atlantic Forest, Brazil and their evolutionary relationship, Arthropod Systematics & amp; Phylogeny 82, pp. 551-566 : 551-566

Oecetis ruschii sp. nov.

Figure 4 A – F

Type material.

Holotype: BRAZIL • ♂; Espírito Santo, Santa Teresa, Augusto Ruschi biological reserve, Córrego Roda d’Água ; 19 ° 53 ′ 35.1 ″ S, 40 ° 32 ′ 39.7 ″ W; 810 m a. s. l., 21–22 Oct. 2017; light pan trap; FF Salles, V Costa, P Bonfá Nt leg.; UFVB TR 00337 . Paratypes. BRAZIL • 1 ♂; same data as holotype; UFVB TR 00338 ; • 1 ♂; same data, except 28 Dec. 2017; UFVB TR 00339 ; • 1 ♂; same data, except 17 Jan. – 20 Feb. 2018; Malaise trap; UFVB TR 00340 ; • 1 ♂; same data, except 20–21 Feb. 2018; UFVB TR 00341 .

Diagnosis.

This species is similar to Oecetis furcata and O. falicia , all species presenting a bifurcation in the dorsolateral process of segment IX. Oecetis ruschii sp. nov. can be differentiated by the dorsolateral process of segment IX having a long ventrolateral bifurcation and a short dorsal subapical one, in O. furcata there is a single ventral bifurcation, and in O. falicia it is dorsal and short. The inferior appendage distal lobe in the new species is wider in lateral view than in O. furcata and O. falicia . The apex of this lobe in ventral view is triangular, wide, and flat in the new species while it is regular and digitate in the other species. Additionally, the new species has an asymmetrical projection on the phallic apparatus that is also present in O. falicia but absent in O. furcata .

Description.

Adult male: Forewing length 6.2–7.1 mm (n = 5). — Head. Color yellowish brown (in alcohol). Antennae approximately 3 x forewing length; scape stout, elongate; pedicel enlarged in width, narrower than scape, shorter than first flagellomeres; first flagellomere narrow, with same length as scape, other flagellomeres shorter than first. Maxillary palps yellowish brown, 5 - segmented, segments subequal in length and width, densely covered with setae. Labial palps yellow, apparently 4 - segmented, first segment very small. — Thorax. Pterothorax yellowish brown; forewings yellowish brown; dark bands over cord present; dark spots absent; forks I and V rooted (Fig. 4 A ); sectoral crossvein (s) not aligned with r – m (Fig. 4 A ). Hind wing forks I and V present; false vein near Cu 1 a (Fig. 4 B ). Legs pale yellowish brown, mid legs with row of small spines on tibia and tarsus, and hind legs with row of small spines on the tarsus. Tibial spur formula 1, 2, 2, fore tibial spur small. Genitalia (Fig. 4 C – F ). Segment IX annular and short; dorsolateral process present, long and bilobed, ventrolateral lobe 1 / 3 x main lobe length, with apex acute; main lobe dorsally with short subapical spine-like lobe, apex acute; two acrotergite present dorsolaterally (Fig. 4 C, D ). Preanal appendage long and narrow, digitate, setose (Fig. 4 C ). Tergum X in lateral view, divided into dorsal and ventral lobes; dorsal lobe single, cylindrical, slightly enlarged subapically, digitate, slightly shorter than the length of the ventral lobe, with short apical setae (Fig. 4 C ); ventral lobe in dorsal view, divided mesally by V-shaped incision, forming two lobes, broad basally, tapering apically (Fig. 4 C ); in lateral view broad. Inferior appendage 1 - segmented, broad at base, setose; distal lobe long, cylindrical, apex triangular, with mesal projection in ventral view (Fig. 4 E ); ventral lobe broad, trapezoid in lateral view (Fig. 4 D ); quadrate with small hump on mid inner portion in ventral view (Fig. 4 E ); dorsal lobe reduced (Fig. 4 D ). Phallic apparatus asymmetrical, narrow basally, broad mesally, bent ventrad, with posterolateral spine projection on left side, apex membranous (Fig. 4 F ); endotheca longer than phallobase (Fig. 4 F, G ); phallic spines absent (Fig. 4 F, G ); phallotremal sclerite present (Fig. 4 G ).

Etymology.

The specific epithet is the name of the biological reserve where the specimens were collected, which was named in honor of the naturalist and environmental activist Augusto Ruschi.

Figures

Figure 4. Oecetis ruschii sp. nov., holotype, male (UFVB TR 00337). Venation: A forewing, B hind wing. Genitalia: C dorsal, D left lateral, E ventral. Phallus, F left lateral, G dorsal, H caudal.