Genus Sinonasutitermes · 华象白蚁属

Fauna Sinica account

The account below is a reorganized and rewritten adaptation of the genus-level description in Fauna Sinica, Insecta Vol. 17, Isoptera (2000) (the genus-level account of Sinonasutitermes in the original book, reorganised and rewritten); the source keys and measurement tables are not reproduced here.

Morphology

Key characters

Soldier dimorphic (trimorphic in a few species), body yellow; head broadly circular and broader than long, the posterior margin broadly rounded; nasus yellow tinged with brown; the sharp teeth of the mandibles very small; antennae 13-segmented in the major soldier and 12-segmented in the minor; pronotum saddle-shaped with its anterior half upright; tarsi 4-segmented.

Soldier

Soldier in two forms, major and minor, the body yellow and the nasus yellow tinged with brown. Head and thorax almost without hairs, the tip of the nasus bearing a few hairs, and the abdominal tergites with a few additional fine short hairs. The major soldier has a head broader than long, broadly circular, the sides rounded and convex, the posterior margin broadly rounded; antennae 13-segmented, the third segment twice as long as the second or longer; the sharp teeth of the mandibles are very small. Pronotum saddle-shaped, its anterior half upright. The minor soldier resembles the major in colour, pilosity and head shape; the sharp teeth of the mandibles are very small, mostly dot-like; antennae 12-segmented. Tibial spur formula 2:2:2 in both forms, tarsi 4-segmented. In a few species (S. admirabilis and S. trimorphus) a medium soldier is further distinguished, so that the soldiers are trimorphic (major, medium and minor).

Alate

Alate head and pronotum densely covered with soft hairs mixed with a few long hairs, the long hairs on the periphery of the pronotum more numerous than those on the head. Head nearly circular, fontanelle oval and with an apical fork; compound eyes oval, large and projecting; ocelli oval, projecting outwards; postclypeus convex, three to four times as wide as long. The apical tooth of the left mandible is larger than the first marginal tooth, the cutting edge between the two teeth straight, and the second marginal tooth is reduced and merged with the posterior cutting edge of the first marginal tooth; the second marginal tooth of the right mandible is close to the first, and the mandibular file bears 8–9 striae. Antennae 15-segmented. Pronotum slightly arched near the middle of the anterior margin. Tibial spur formula 2:2:2, tarsi 4-segmented.

Distribution

Oriental region; distributed in southern China, found in subtropical evergreen broad-leaved forest areas.

Summary

Sinonasutitermes has dimorphic soldiers (a few species are trimorphic, with major, intermediate and minor soldiers: S. admirabilis, S. trimorphus), yellow with a brown-tinged nasus. Head and thorax are almost hairless apart from a few hairs at the nasus tip. The major soldier has a broad rounded head wider than long, 13-segmented antennae with the third twice the second or longer, and very small mandibular points; the minor soldier resembles it but has 12-segmented antennae and points reduced to dots. Alates have a forked oval fontanelle and 15-segmented antennae. The genus is Oriental.

Sources cited: Huang Fusheng, Zhu Shimo, Ping Zhengming, Wang Zhiguo, Li Can and Xu Chungui, 2000. Fauna Sinica, Insecta Vol. 17, Isoptera. Beijing: Science Press. This text is a reorganized adaptation, not a verbatim transcription.