Trichomacronema vietnamensis, Uy & Malicky & Bae, 2018

Uy, Christine Jewel C., Malicky, Hans & Bae, Yeon Jae, 2018, Review of the filter-feeding caddisfly subfamily Macronematinae (Trichoptera: Hydropsychidae) in tropical Southeast Asia, Raffles Bulletin of Zoology 66, pp. 664-703 : 697-699

Trichomacronema vietnamensis , new species

( Figs. 268–271 )

Description. Male. Unknown.

Female. Antennae 26 mm in length. Antennal flagellum brown with darker striations. Head dark brown with five lighter setal warts; pair of large anterior setal warts occupying almost anterior half of head, very close to anteromesal setal wart; pair of posterior setal warts smaller. Forewing 23 mm in length ( Fig. 268 ); veins Sc and R1 not joined; Sc vein ending in costa; R1 not ending in costa, obsolete; base of Rs obsolete, joined to R1 by crossvein; discoidal cell present; medial cell obvious; thyridial cell long; nygmas present in middle of thyridial cell and fork II; Cu1 and Cu 2 not joined; crossvein cu-a present. Hind wing 9 mm in length; vein Sc joining R1, ending in costa; nygma present in fork II; median and thyridial cell absent. Wing pattern with alternating dark and brown longitudinal streak marks as shown in Figs. 268, 269 , more evident in forewing; presence of dark brown marking concentrated on half of anterior margin of median cell running towards base of M1 vein of forewing ( Fig. 268 ). Body large (about 12 mm in length) and dark brown in alcohol. Mesoscutum and mesoscutellum without evident markings. Legs brown, with dark brown mark at basal end of tibia; Tibial spurs 1.4.4.

Female genitalia. Segment IX heavily sclerotised with row of long setae ( Fig. 270 ). Ventral membrane with thick walls especially at posterior portion, with shorter setation posteriorly and longer setae anteriorly ( Fig. 271 ). Dorsal papillary lobe close to cerci; ventral papillary lobe shorter and larger with heavy setation, situated distantly from cercus ( Fig. 270 ).

Type material examined. Holotype. Vietnam: female (KUEM0000002403), Lao Cai Province, Sa Pa County Muong Hoa, coll. D.H. Hoang & Y.J. Bae, 23 April 2002 (KU).

Paratypes. Vietnam: 3 females (KUEM0000002404– KUEM0000002406), Lao Cai Province, Sa Pa County Muong Hoa, coll. D.H. Hoang & Y.J. Bae, 23 April 2002 (KU) .

Distribution. Vietnam.

Etymology. The species epithet refers to Vietnam from which the species was collected.

Remarks. This species is obviously distinct from other congeners. Its wing structure is similar to that of T. shanorum Schmid, 1964 , but its wing pattern is different. The radius and median forewing cells of T. shanorum possess white spots, whereas those of T. vietnamensis do not. The body of T. shanorum also possesses brown and dark-brown stripes, whereas that of T. vietnamensis is uniformly brown. As compared to the two species described from Southeast Asia, T. tamdao and T. paniae , this new species is much larger (whole body size was measured longitudinally from the head to the end of the forewing). Body size of T. tamdao and T. paniae are just half the size of T. vietnamensis . At a first glance, T. vietnamensis can be mistaken of a Macrostemum species because of the structure of head and thorax.

Figures

Figs. 258–271. Trichomacronema paniae. 258, right forewing; Male genitalia: 259, lateral; 260, segment X dorsal; 261, Phallus lateral; 262, Phallus tip. Trichomacronema tamdao. 263, right forewing; Male genitalia: 264, lateral; 265, segment X dorsal; 266, Phallus lateral; 267, Phallus tip. Trichomacronema vietnamensis, new species. 268, right forewing; 269, right hind wing; Female genitalia: 270, lateral; 271, ventral. Scale: 258, 263, 268–269 = 2 mm; 259–262, 264–267, 270–271 = 0.02 mm.