Silvatares laetae Ngirinshuti & Johanson, 2019

Ngirinshuti, Leonce, Tabaro, Simon Rukera & Johanson, Kjell Arne, 2019, The Trichoptera diversity of Nyungwe National Park, Rwanda, with description of a new species in the family Pisuliidae, European Journal of Taxonomy 576, pp. 1-11 : 5-6

Silvatares laetae Ngirinshuti & Johanson sp. nov.

urn:lsid:zoobank.org:act:C5D1DE74-9CE5-4461-830F-211CE4BB8DBC

Figs 3–5

Diagnosis

The genitalia of Silvatares laetae Ngirinshuti & Johanson sp. nov. resemble those of S. excelsus (Navás, 1931) , particularly due to the presence of large median lobes of tergum X that are curved downwards, and the inferior appendages consisting of two prominent lobes which both curve inwards in ventral view. The new species is distinguished from S. excelsus by the presence of a wide mouth-like incision ventrally on the tip of the median lobes of tergum X, segment IX which is produced into a pair of triangular and posteriorly pointing lateral lobes, and the presence of a pair of longer needle-like processes originating from the apex of the phallus. In addition, S. laetae Ngirinshuti & Johanson sp. nov. has sword-shaped megasetae on tergum X that are absent in S. excelsus .

Etymology

Laetae, named after Dr Laetitia Nyinawamwiza in recognition of her contribution to supporting young Rwandan academicians interested in research on aquatic biota.

Material examined

Holotype

RWANDA • 1 ♂ (in alcohol); Western Province, Nyamasheke District, Nyungwe National Park, locality Gisakura , Karamba river I; 2.479° S, 29.119° E; 1917 m a.s.l.; 18 Oct. 2018; K.A. Johanson, L. Ngirinshuti and P. Munyaneza leg.; light trap #06-2018; DNA voucher LG8; NHRS.

Paratype

RWANDA • 1 ♂ (in alcohol); Western Province, Nyamasheke District, Nyungwe National Park, Nyamirabyo River ; 2.469° S, 29.108° E; 1905 m a.s.l.; 23–26 Oct. 2018; K.A. Johanson, L. Ngirinshuti and P. Munyaneza leg.; Malaise trap #23-2018; DNA voucher LH9; NHRS .

Description of holotype

LENGTH AND COLOR. Forewing 10.5 mm, hind wing 8.7 mm. Head, thorax and abdomen yellowish-brown ( Fig. 3 ). Antennae dark brown, almost black, slightly longer than forewings. Eyes setose, blackish. Legs brown at proximal segments, tibia and tarsus darker. Spur formula: 2:4:4.

WINGS. Forewings with greyish brown membrane densely covered with dark brownish setae, slightly darker towards apex and anterior margin. Underside with long, thick and golden setae originating from an enlarged part of Cu2 ( Fig. 4 ). Forewing venation nearly similar to that of S. excelsus . Sc and R1 separate basally, connected distally by crossvein. Fork 1 originating before fork 2, fork 4 absent, nygma present in fork 2 and in thyridial cell. Cu1b rudimentary, not reaching wing margin, leaving incomplete fork 5, A1 and A2 fusing near base. Cu 2 in right angle before fusing with A1+2, crossvein present between Cu2 and Cu1b. Hind wings greyish with dark setae. Long setae extending beyond the posterior margin near wing base. R1 inconspicuous, terminating in cell between Sc and Rs. Discoidal cell large, nygma present in fork 2, forks 3, 4 and 5 absent. Cu2 apparently forming distal fork, posterior margin straight behind Cu1.

ABDOMEN (male). Segment VII with small median tooth on sternite. Segment IX protruding into a pair of anteriorly rounded lateral lobes and undulating posterior margin; in dorsal view with deep V-shaped incision of anterior margin. Tergum X in lateral view large, downwardly curving along its length, with U-shaped incision at ventral part of apex; dorsal margin of apex with 3–4 sword-shaped megasetae; in dorsal view deeply divided into pair of posterad branches, division basally triangular. Pair of onesegmented inferior appendages curving mesally along their length, with two deeply incised separated branches. Upper branch with dilated apex, lower branch slender, almost thumb-shaped. Phallus stout and curved, with constriction leading to tapering tip in lateral view, equipped with pair of teeth-like structures standing erect in ventral view.

Figures

Fig. 3. Silvatares laetae Ngirinshuti & Johanson sp. nov., ♂, holotype.

Fig. 4. Silvatares laetae Ngirinshuti & Johanson sp. nov., ♂, holotype. A. Right forewing. B. Right hind wing. C. Right forewing, underside, showing long golden hairs. Scale bar = 1 mm.

Fig. 5. Silvatares laetae Ngirinshuti & Johanson sp. nov., ♂, holotype. A. Right wings. B–D. Genitalia. B. Dorsal view. C. Lateral view. D. Ventral view. E–F. Phallus. E. Lateral view. F. Ventral view.