Engelitermes zambo Romero-Arias, Roisin & Scheffrahn, 2023 赞博恩格尔白蚁

Morphology

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

Diagnostic characters

In overall soldier morphology the closest termites in the world are the African Cephalotermes and the Neotropical Cylindrotermes, but the soldier gut of this genus contains no solid food particles (white-gutted in the original), which distinguishes it from both; its soldiers are consistently smaller than the mandibulate soldiers of the African Termitinae, comparable in size to Forficulitermes planifrons (maximum head width 0.63 mm versus 0.65 mm), but the inner mandible shape is entirely different. The worker mandibles are of the soil-/humus-feeding type, whereas those of Cephalotermes and Cylindrotermes workers are of the wood-feeding type: apical tooth broad, widely separated from marginal tooth 1, molar region concave and without ridges (similar to Crenetermes, Eutermellus, Jugositermes and Thoracotermes); it is especially similar to the worker of Forficulitermes in the wide gap between the apical tooth and marginal tooth 1, and in the well-developed first and fourth hindgut segments. The combination of a single spine with unsculptured pad cuticle in the enteric valve is unique among termite enteric valves; the gizzard is simplified relative to most Termitinae.

Alate

Described from 1 physogastric queen only: head brown, bearing several hundred setae of varying length, mostly directed forwards and arising from hyaline sockets; the median branch of the frontal suture darker than the rest of the head; fontanelle small, round, situated between the ocelli; the anterolateral part of the head with two crescent-shaped patches in front of the fontanelle. Pronotum and postclypeus paler than the vertex, with similar pilosity; postclypeus not inflated. The antennae of the specimen examined are broken, but with more than 10 segments; segments 3 and 4 almost fused, segment 3 shorter than segment 2, segments 3 and 4 together longer than segment 2. Inner mandibular apical tooth narrower than in the worker. Spur formula 2:2:2.

Soldier

Head capsule subrectangular in dorsal view, the lateral margins slightly converging posteriorly; in profile the frontal surface is raised and undulating near the fontanelle; fontanelle small, almost indiscernible; inner mandibles robust, with 1 triangular tooth at the base; antennal segments 12; the anterior and posterior lobes of the pronotum congruent, together forming a straight-line triangle in profile; spur formula 2:2:2; abdomen yellowish white, the gut containing no solid food residues (white-gutted sensu Scheffrahn et al. 2017).

Worker

A large white brain (supraoesophageal ganglion) is visible through the head capsule in dorsal view, in front of the small diamond-shaped frontal gland tissue; in profile the postclypeus is slightly inflated. Inner mandibular apical tooth broad and projecting; the gap between the apical tooth and marginal tooth 1 of the left inner mandible is greater than the distance between marginal teeth 1 and 3; molar region concave, without ridges. Antennal segments 12; spur formula 2:2:2; fore femur slightly inflated. Gizzard lacking the columnar belt, the pulvillar belt with sclerotised spinules, beneath which lie patches of ridge-like scales. Enteric valve composed of 6 smooth, slender pads, each with 1 small spine at its distal end, the pads pointing with the food stream; the enteric valve armature (EVA) has 1 slightly sclerotised pad in front of the ring, bearing 1–2 stout spines and several small spines. Mixed segment absent. Ileum cylindrical, running in a long S along the left side of the abdomen, narrowing posteriorly and folding forwards to meet P2; P4 broad anteriorly and narrow posteriorly; P5 unusually large in volume (but not in all individuals).

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.