Indosialis minora (Banks)

Liu, Xingyue, Flint, Oliver S. & Yang, Ding, 2008, Revision of the alderfly genus Indosialis Lestage (Megaloptera: Sialidae), Zootaxa 1677, pp. 47-56 : 53

Indosialis minora (Banks)

( Figs. 3–4 , 13–19 )

Protosialis minora Banks, 1920: 325 . Type locality: Singapore.

Diagnosis. This species is distinguished in the male by the presence of a slender ninth gonostylus and the distal lobes of the tenth sternum being pointed and ventrolaterally curved.

Male. Forewing length 7.5 mm, hindwing length 7.0 mm.

Head orange. Mouthparts yellow with maxillary palpi dark. Compound eyes dark. Antennae dark except for scape and pedicel yellow.

Thorax pale brown. Legs pale brown, with tibiae and tarsi much darker. Wings grayish brown with costal area much darker; veins brown. Costal area proximally with six to seven distinct crossveins on forewing, and proximally with two distinct crossveins on hindwing.

Abdomen reddish brown. Ninth tergum ( Fig. 13 ) with anterior margin broadly emarginate. Ninth sternum ( Fig. 14 ) broad, with posterior margin produced medially. Ninth gonostylus ( Figs. 13–16 ) slender, suboval, slightly narrowed toward tip. Tenth tergum ( Figs. 13, 15–16 ) subtriangular, slightly shorter than ninth tergum, feebly directed medially and ventrad, with blunt tip. Tenth sternum ( Figs. 13–16 ) strongly sclerotized, posteriorly directed; proximal portion expanded as a large flattened subtrapezoidal plate; distal half produced as a pair of long blade–like lobes, distinctly separated and curved ventrolaterally; proximal area of tenth sternal arms inflated in lateral view.

Female. Forewing length 8.0 mm, hindwing length 7.0 mm.

Seventh sternum ( Figs. 17–18 ) broad, subtriangular in lateral view, with posterior margin strongly produced. Eighth sternum separated into a pair of subtriangular lobes with blunt tips. Ninth segment bearing a pair of subuliform processes anteroventrad, with tips connected to tips of eighth sternum. A moderately sclerotized subquadrate plate present beneath ninth segment, with posterior margin slightly incised ( Fig. 18 ). Ninth gonocoxite ( Fig. 17 ) broad, semicircular in lateral view, with a small gonostylus at tip. Tenth tergum ( Fig. 17 ) feebly sclerotized, small, suboval.

Materials examined. 1 ɗ, SINGAPORE, Coll. Baker ( NMNH); 1 &, MALAYSIA, Sarawak, Semengoh For. Res, 15 mi. So. Kuching, 20.IX.1966, J.F.G. Clarke & T. M. Clarke ( NMNH).

Distribution. Malaysia ( Sarawak); Singapore.

Remarks. Males of this species differ from I. bannaensis and I. indicus by having a slender ninth gonostylus and a tenth sternum with the distal lobes curved ventrolaterally. In the latter two species, the ninth gonostylus is robust and the distal lobes of the tenth sternum are directed straight posteriad. The Malaysian female specimen is identified as I. minora due to its similar appearance (orange head and pale brown prothorax) with the male from Singapore. However, the taxonomic status of the Malaysian Indosialis species will be fully confirmed only after a male example is found.

Figures

FIGURES 3 – 4. Habitus photos of the Indosialis species. 3. I. minora (Banks), male; 4. I. minora (Banks), female.

FIGURES 13 – 18. Indosialis minora (Banks). 13. Male genitalia, dorsal view; 14. Male genitalia, ventral view; 15. Male genitalia, lateral view; 16. Male genitalia, caudal view; 17. Female abdominal apex, lateral view; 18. Female abdominal apex, ventral view. G 9: ninth gonocoxite; S 7: seventh sternum; S 8: eighth sternum; S 9: ninth sternum; St 9: ninth gonostylus; T 7: seventh tergum; T 8: eighth tergum; T 9: ninth tergum; T 10: tenth tergum. Scale bar = 0.5 mm.

FIGURES 19. The map showing the geographical distributions of the extant Indosialis species. I. bannaensis Liu, Yang & Hayashi (); I. indicus sp. nov. (); I. minora (Banks) ().