Acutidentitermes osborni Emerson, 1959 奥斯本尖齿白蚁

Morphology

The description below is paraphrased from the original or a later revision, by caste; the source is cited at the end.

Diagnostic characters

Closely related to Hoplognathotermes but distinguishable as a soldier: head very large, the sides slightly convex and nearly parallel; postmentum more globular, its lateral margins overlapping and concealing the lateral sutures; the suture between the postclypeus and the frons far less distinct; labrum with sharper lateral and median points; the forward-directed mandibular teeth longer, sharper and more forward-pointing; anterior pronotal lobe larger and longer, the median anterior concavity deeper and broader; fore femur relatively long and slender. Alate unknown.

Soldier

Head surface with only a few rather short setae, none near the fontanelle; postmentum completely bare, without setae; anterior 4 abdominal tergites with rather long setae and almost no short hairs, the posterior tergites and sternites with additional short hairs. Head very large, the sides slightly convex and nearly parallel, the fontanelle relatively small. Postmentum more globular than in Hoplognathotermes, the posterior lateral margins overlapping, so that in ventral view the outer sutures are concealed except near the posterior margin; the posterior part of the postmentum without a transverse ridge. Antennal segments 15. The suture between the postclypeus and the frontal region far less distinct than in Hoplognathotermes. Labrum with sharper lateral and median points. Both mandibles with a conspicuous forward-directed tooth, but longer, sharper and more forward-pointing than in Hoplognathotermes; the proximal outward curve of the mandibles weaker; the lateral notch at the junction of tip and base less conspicuous. Anterior pronotal lobe larger and longer than in Hoplognathotermes, the median anterior concavity more conspicuous and broader, the posterior margin more concave. Fore coxa simple, the longitudinal ridge blunt to moderately sharp, the profile straight or slightly convex, without coarse spines; fore femur relatively long and slender. Spur formula 3:2:2.

Worker

The mandibles differ from those of Hoplognathotermes as follows: the angle between the apical tooth and marginal tooth 1 is sharper on both mandibles; the cutting edges of marginal teeth 1 and 2 of the left mandible are proportionally slightly longer; the upper ridge of the molar region of the right mandible is sharper and more concave.

This genus is monotypic, containing only this species; the following is the genus-level description based on the original literature; species-level measurements and intraspecific variation are given in the original.