Chimarra bicornis, Cartwright, 2020

Cartwright, David, 2020, A review of the New Guinea species of Chimarra Stephens (Trichoptera: Philopotamidae), Memoirs of Museum Victoria 79, pp. 1-49 : 30-31

Chimarra bicornis sp. nov.

Figures 91–93

Holotype. Male (figured specimen CT-364), PNG (Morobe Province), Wau, Big Wau Creek , 1300 m, about 7° 20' S, 146° 43' E, November 1965, P. Shanahan ( BPBM).

Diagnosis. Chimarra bicornis is similar to C. ulmeri but different to all other New Guinea Chimarra species in having a pair of sclerotised, curved dorsal and ventral branches of the lateral lobes on segment X. In C. ulmeri , the apices of the dorsal or upper branch of the lateral lobes are directed dorsally ( Kimmins, 1962: fig. 16A; Neboiss, 1986a: fig. p. 106) or posterodorsally (fig. 90), whereas in C. bicornis , they are directed dorso-laterally. (There is also a species from northern Australia with a similar pair of curved mesal processes on segment X – C. adaluma Cartwright [ Cartwright, 2002]).

Description. General body colour and wings brownish. Wings similar to those of C. ukarumpana (fig. 7). Length of forewing: male 5.9 mm. Forewing with forks 1, 2, 3 and 5 present, Rs slightly sinuous or curved, slightly thickened, basad of discoidal cell.

Male. Segment IX anterior margin in lateral view, with rounded extension anteroventrally (fig. 91), ventral process small, sub-triangular, situated basally on segment IX (figs 91, 92), in lateral view, length about 0.6 times width (fig. 91). Segment X lateral lobes sclerotised, short, slender, with dorsal and ventral branches, dorsal branch directed dorso-laterally, ventral branch directed ventro-posteriorly, with sensilla not discerned (figs 91, 93). Phallus with two slender spines included subapically (figs 92, 93). Inferior appendages short, robust, acute apices angled dorso-mesally (figs 91–93), in lateral view, angled at about 45° to horizontal, subquadrate, length about 2.5 times width, broadest in distal half, tapered slightly basally (fig. 91), in ventral view, appear sub-ovate, length about 2.8 times width (fig. 92).

Female. Unknown.

Etymology. Bicornis – Latin for two horned, two pronged (paired curved, dorsal branches of lateral lobes on segment X).

Remarks. Chimarra bicornis is known only from the holotype male in north-east PNG.

Figures

Figures 86–93. Chimarra spp.; 86, Chimarra biramosa Kimmins, male, genitalia, lateral. 87–89, Chimarra kewabi sp. nov., male, holotype, genitalia; 87, lateral; 88, ventral, 89, dorsal. 90: Chimarra ulmeri Kimmins, male, genitalia, lateral. 91–93, Chimarra bicornis sp. nov., male, holotype, genitalia; 91, lateral; 92, ventral; 93, dorsal.