Tinodes helix, Gibon, 2017

Gibon, François-Marie, 2017, New species of Tinodes from Madagascar (Trichoptera, Psychomyiidae), Zootaxa 4318 (2), pp. 364-376 : 369-370

Tinodes helix n. sp.

Figs 3 A–3C

Diagnosis. Tinodes helix n. sp. is characterized by an exceptional development of the phallic apparatus that is unusually large and wide. It has two internal sclerites: The proximal one is long and sinuous and the distal one is small and spine-shaped. These characters make this species morphologically unmistakable.

Description. General color pale brown, dorsal sclerites brown, wings pale brown with few small hyaline areas (in alcohol). Length of each forewing 2.7 mm (n = 2); length of each hind wing 2.2 mm (n = 2). Forewing forks 2, 3, 4, and 5; crossveins r (R1–R2+3, hardly visible), r-m (R4+5–M1+2), and cu (Cu1–Cu2, hardly visible); and hyaline line along stem of M present. Hind wing forks 2 and 5 and crossveins r (R1–R2+3) and r-m (R4+5–M1+2) present.

Male genitalia ( Figs 3 A–3C): Sternite IX produced anterad and posterad, strongly produced dorsad, anterior margins deeply concave; posterior shallowly concave in lateral view; distinctly broader then long in ventral view, pentagonal, with anterior part wider than posterior part, lateral margins convergent posteriorly, posterior margin with several ventrolateral setae. Tergite IX with relatively short, straight stalk on each side widening distally to dorsal portion two times as long as stalk, conical with blunt apex in lateral view; lateral margins rounded, posterior margin slightly concave in dorsal view; without setae. Tergite X indistinct. Preanal appendages as long as phallic apparatus, narrow in basal half, moderately broader in distal half, slightly sigmoid in lateral view; apical 3/5 with fine setae. Intermediate appendage divided at basal third into two asymmetrical branches: Left developed above right; both branches moderately long, finger-shaped, curved ventrad, slightly enlarged toward apex, bearing two dorsal preapical spines. Inferior appendages two-segmented; paired first segments fused basally, separated by broad groove distally in ventral view; phallic guide apodeme directed anterad, narrow and relatively short and pointed anteroapically, posteriorly divided, long, sword-shaped, straight, clearly visible in ventral view through wide U-shaped notch of inferior appendages, apices pointing laterad; first segment of each inferior appendage larger than second, ovoid, almost 2 times as long as high; ventral part covered by long and dense setae; second segment smaller than first one, roughly semicircular in lateral view, oval in ventral view, medial side with basal bump with strong seta, with few fine, long setae present on dorsoapical surface. Phallic apparatus almost twice as long as intermediate appendage branches and approximately as long as preanal appendages, very tall and conspicuously asymmetrical. Left side with large sclerotized plate with deep dorsal and ventral incisions in left lateral view; membranous endophallus with two internal phallic sclerites: proximal one thin and long, directed dorsad, sinuous when viewed laterally and almost spiralling when viewed dorsally, apical one stout, short, spineshaped, directed dorsad.

Holotype: Male. MADAGASCAR: Toamasina Prov., brooklet 3 km ESE Amboditafonana , 17°27′32′′S, 48°46′12′′E, approx. 870 m a.s.l., 30.i.2000, swept along shallow slow-flowing brooklet in rain forest, P. Chvojka leg. ( NMPC).

Etymology. Greek “ helix ,” meaning "spiral," a noun in apposition to Tinodes , referring to the spiral shape of the internal proximal phallic sclerite.

Distribution. MADAGASCAR: Endemic. Recorded from only the type locality ( Fig. 7 ).

Figures

FIGURE 3. Tinodes helix n. sp., male genitalia: 3 A, left lateral; 3 B, dorsal, without inferior appendages; 3 C, segment IX and inferior appendages, ventral. Scale bar: 0.25 mm.

FIGURE 7. Schematic distribution maps of the Malagasy Tinodes.