Indosialis bannaensis Liu, Yang & Hayashi

Liu, Xingyue, Flint, Oliver S. & Yang, Ding, 2008, Revision of the alderfly genus Indosialis Lestage (Megaloptera: Sialidae), Zootaxa 1677, pp. 47-56 : 48-50

Indosialis bannaensis Liu, Yang & Hayashi

( Figs. 1 , 5–8 , 19 )

Indosialis bannaensis Liu, Yang & Hayashi, 2006: 33 . Type locality: Yunnan (Xishuangbanna).

Diagnosis. This species is defined by the male ninth gonostylus being strongly narrowed in the distal half and by the male tenth tergum having a blunt tip. Additionally, the male tenth sternum possesses a pair of tightly appressed, posteriorly directed, straight distal lobes.

Male. Forewing length 9.0–9.5 mm. Hindwings tattered.

Head orange; clypeal area slightly paler, post–ocular region somewhat brownish. Mouthparts pale yellow, with maxillary palpi pale brown. Compound eyes black. Antennae black except for scape and pedicel pale yellow.

Thorax orange laterally with pair of brownish spots on metanotum. Fore and middle legs yellow, with tibia and tarsi black; hind legs brown with tibia and tarsi black. Wings pale grayish brown; veins pale brown.

Costal area proximally with five to seven distinct crossveins on forewing, and proximally with two distinct crossveins on hindwing.

Abdomen reddish brown. Ninth tergum ( Fig. 5 ) with anterior margin shallowly arched. Ninth sternum ( Fig. 6 ) broad, with posterior margin slightly produced medially. Ninth gonostylus ( Figs. 5–8 ) robust, distal half strongly narrowed and curved dorsolaterad. Tenth tergum ( Figs. 5, 7–8 ) subtriangular, nearly as long as ninth tergum, slightly curved medially, with blunt tip. Tenth sternum ( Figs. 5–6, 8 ) strongly sclerotized, obliquely directed dorsad, proximal portion expanded as a large flattened plate, distal half produced as a pair of long, straight, spinous lobes with hook–like tips curved ventrad.

Female. Unknown.

Type material. Holotype ď, CHINA: Yunnan Prov., Xishuangbanna, Mengla, Shangyong, Longmen, 650 m, 17.V.2005, X.Y. Liu ( CAU).

Other material examined. 1 ď, VIETNAM: ‘ Cochinchina, Annam, Prov. Haut Donai, Laonam & Blao, 800–1200 m, 30.V /VI.7.1933’ ( NMNH).

Distribution. China (Yunnan); Vietnam (Haut Donai).

Remarks. This species appears to be closely related to the new species, I. indicus , in having a similar robust male ninth gonostylus and tenth sternum with the distal lobes appressed to each other. It can be easily separated from I. indicus by the male ninth gonostylus being distally narrowed and curved and by the male tenth tergum having a blunt tip. However, in I. indicus , the male ninth gonostylus is distally inflated and the male tenth tergum has its tip narrowed into a digitiform process. The Vietnamese male slightly differs from the Chinese one by the ninth gonostylus having its tip anteriorly curved in lateral view. In the Chinese male, the ninth gonostylus is not anteriorly curved at tip. However, we consider them to be conspecific because of the same appearance and shape of the other genital structures. The male ninth gonostylus in Indosialis is not strongly slcerotized, and therefore might present some variation among different individuals.

Figures

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) ().

FIGURES 1 – 2. Habitus photos of the Indosialis species. 1. I. bannaensis Liu, Yang & Hayashi (Holotype), male; 2. I. indicus sp. nov. (Holotype), male.

FIGURES 5 – 8. Indosialis bannaensis Liu, Yang & Hayashi, male from Vietnam. 5. Genitalia, dorsal view; 6. Genitalia, ventral view; 7. Genitalia, lateral view; 8. Genitalia, caudal view. S 9: ninth sternum; St 9: ninth gonostylus; S 10: tenth sternum; T 9: ninth tergum; T 10: tenth tergum. Scale bar = 0.5 mm.