Genus Rhadinotermes · 锥形白蚁属

Morphology

The descriptions below are an adaptation of the original genus-level accounts; terms follow the meaning of the source, and the original is not transcribed verbatim.

Diagnostic characters

Sands placed the genus in the Procornitermes branch; the soldier head capsule is sharply constricted behind the antennal fossae, resembling Fulleritermes, but phylogenetically it is not close to Leptomyxotermes/Grallatotermes, belonging instead to a predominantly Neotropical clade containing Velocitermes, Tenuirostritermes and Diversitermes; its former placement in Coarctotermes was based only on soldier similarity. The soldier is monomorphic, the nasus conical, the mandibles with a small point, the posterior lobe usually only about a quarter wider than the anterior part, the antennae 12-segmented; in the alate the left mandibular index is 0.32–0.36, the second marginal tooth is absent, the right molar plate bears 6–7 transverse ridges diminishing towards the base, the first forming a coarse tooth, and the fontanelle is a very narrow slit, hardly forked anteriorly. The generic name derives from the Greek rhadinos (tapering).

Alate

Head capsule very dark brown to pitch black, the postclypeus and antennae dark sepia-brown, the wings semitransparent pale brown; the posterior margin of the head behind the compound eyes is almost semicircular; the compound eyes do not protrude and are relatively small for the head capsule (W/E 3.4–3.8), slightly angular-oval; the ocelli are small, oval, separated from the compound eyes by about 1.5 times their own least diameter; the postclypeus is strongly arched, 2.2 times as wide as long, its anterior margin slightly concave; the antennae are 15-segmented, segments II, IV and V nearly equal in length, II thinner, III longer. Mandibles: the apical tooth of the left mandible is equal to or slightly shorter than the first marginal tooth, the distance from the apical tooth to the first marginal tooth being about one-third of the distance between the first and third marginal teeth (index 0.32–0.36), the second marginal tooth is absent, and the cutting edge between the first and third marginal teeth is entire; in the right mandible the apical tooth and the first marginal tooth are nearly equal, and the first marginal tooth bears a small accessory tooth proximally; the molar plate of the right mandible has a weak concavity at the base near the anterior margin, its posterior margin extended into a rounded ridge, the first transverse ridge forming a coarse tooth and the remaining 6–7 diminishing towards the base; the fontanelle is very narrow, slit-like, hardly forked anteriorly (more pronounced in the female), slightly paler to distinctly paler than the head colour.

Soldier

Monomorphic. The nasus is conical. The mandibles are reduced, with a small point. The head capsule is sharply constricted behind the antennal fossae, the posterior lobe usually only about a quarter wider than the anterior part. Antennae 12-segmented. Head capsule sepia-brown to pitch black, the nasus black with a reddish apex; the lateral contour of the head is raised and rounded behind the constriction and flatter before it; the nasus is equal to or shorter than the remainder of the head capsule measured from the posterior margin of the antennal fossae; the nasus cone angle is 10–20°; antennal segment II is short, IV and V longer; setae are confined to 4 at the tip of the nasus, a pair on the dorsum of the head, and a few short curved hairs on the dorsum. Specimen no. 25: head length (to the tip of the nasus) 1.17–1.39 mm, head width 0.54–0.66 mm, hind tibia 0.92–1.10 mm.

Sources: Sands, W.A. 1965. A revision of the termite subfamily Nasutitermitinae (Isoptera, Termitidae) from the Ethiopian Region. Bulletin of the British Museum (Natural History), Entomology, Supplement 4: 1–172., p. 71（Genus Rhadinotermes: Imago, Soldier）；p. 72–73（R. coarctatus 种记述，体色、指数与测量）；p. 11（支系归属） This text is an adaptation, not a verbatim transcription of the original.