Acangaobitermes, Rocha, Mauricio M., Cancello, Eliana M. & Cuezzo, Carolina, 2011

Rocha, Mauricio M., Cancello, Eliana M. & Cuezzo, Carolina, 2011, A new genus and species of mandibulate nasute termite (Isoptera, Termitidae, Syntermitinae) from Brazil, ZooKeys 148, pp. 125-134 : 126-128

Acangaobitermes gen. n.

Type species.

Acangaobitermes krishnai sp. n.

Etymology.

From Tupi, indigenous South American language, acangaobi meaning funneled head and the Latin termes meaning termite, in reference to soldier head capsule shape in profile. The name is masculine.

Description.

Imago. Unknown.

Soldier. Monomorphic. Head capsule sub-quadrangular with almost parallel lateral margins and two very discrete saliencies on the latero-posterior corners (Fig. 7, arrows). Surface of head capsule covered with numerous minute and closely set points of about equal diameter, forming a conspicuous and characteristic microsculpture (Figs 7-8). Frontal tube conical and upturned, in profile, apex with a relatively wide aperture surrounded by a white membrane. Antennae with 14 articles. Piercing slender mandibles; blade strongly curved inwards and upturned; a very small tooth at the base of the blade and a molar plate/prominence fully developed with no ridges. Clypeus very reduced. Labrum with a rounded and flat hyaline tip. Posmentum sub-rectangular with antero-lateral margins slightly concave. Coxae with a keel shape projection, pointing outwards and situated at distal antero-lateral margins (Fig. 2, arrow). Tibial spurs 2:2:2.

Worker. Monomorphic. Head capsule rounded. Postclypeusinflated. Antennae with 14 articles. Left mandible (Fig. 3): apical tooth larger than M1+2, margin between M1+2 and M3 sinuate, M3 distinct and smaller than M1+2, molar tooth conspicuous, partially hidden by molar prominence; molar prominence concave without ridges. Right mandible (Figs 3, 5): apical tooth larger than marginal teeth, M1 and M2 clearly distinct, molar plate concave without ridges (Fig. 5). Coxae smooth without projections. Body slender and elongated, digestive tube visible through abdominal sclerites. Tibial spurs 2:2:2.

Worker digestive tube. Crop asymmetrical, without any constriction separating it from gizzard. Cuticular armature of gizzard with 24 visible folds, six of first order, six of second and 12 of third; ratio between columnar and pulvillar belt approximately equal to one; pulvilli without armature or ornamentation. Mesenteron tubular. Short mixed seg ment present. Mesenteric tongue on the external side of the mesenteric arch, slightly strangled proximally. Two pairs of Malpighian tubules attached at the mesenteron-proctodeum junction, one internal side to the mesenteric arch and the other external. First proctodeal segment (P1), diagonal to body axis, more enlarged than mesenteron with about same size of proximal portion of paunch (P3a); distal end of P1 narrowed, forming a short neck prior to the attachment to P3. Enteric valve (P2) at the left side of the body. P3 slightly constricted between P3a and P3b. Dorsal torsion well-developed. P3 joined to colon (P4) on left side, isthmus short and parallel to body length. P4a dilated, U-Turn and P4b tubular.

Comparisons with other genera of Syntermitinae

Soldiers of Syntermes , Cornitermes , Labiotermes , and Procornitermes have a short frontal tube, not exceeding the labrum; a well-developed hyaline tip to the labrum; straighter cutting mandibles, with well-developed marginal teeth; and a larger body size. Soldiers of Cahuallitermes have straighter cutting mandibles, with well-developed marginal teeth; a well-developed hyaline tip to the labrum; and a larger body size. Soldiers of Embiratermes and Ibitermes have a larger body size, straighter and large mandibles, with well-developed marginal teeth in Embiratermes or totally absent in Ibitermes . Soldiers of Cyrilliotermes and Curvitermes have aberrant mandibles, with a molar plate, molar prominence and marginal teeth very similar to their corresponding worker mandibles; apical tooth fish-hooked in Curvitermes , reduced in Cyrilliotermes ; and the frontal tube cylindrical and elongate in Cyrilliotermes (see more details of these two genera, including the dissected soldier mandibles, in Mathews 1997, page 226). Paracurvitermes has a broader head capsule with well developed conical and shorter frontal tube than Acangaobiermes ; the mandibles are much longer, less curved with triangular teeth, very different from the new genus. The soldiers of Rynchotermes have strongly curved mandibles; a very long frontal tube; procoxae with a spine-like lateral projection; and a much larger body size. Soldiers of Armitermes have the pronotum, mesonotum, and metanotum with serrate lateral margins; mandibles with well-developed marginal teeth; and a larger body size (see Rocha, 2011, for a redescription and new illustrations of the genus). Lastly, the genus Macuxitermes has dimorphic soldiers, with an aberrant head shape; pronotum, mesonotum and metanotum with serrate lateral margins; and mandibles with well-developed marginal teeth.

Despite differences in the shape of the soldier head, Acangaobitermes shares many exclusive traits with Noirotitermes . The worker of Acangaobitermes is very similar to that of Noirotitermes , with same mandibular pattern, body size and shape (elongate), labrum and digestive tract, including the enteric valve armature. The worker differences between both genera are: the inner margin of apical teeth in left and right mandibles are much more concave in Noirotitermes than in the new genus; the M3 in left mandibleand M2 in right mandible both are larger in Acangaobitermes than in Noirotitermes ; and the insertion of the enteric valve is in the body axis, while in Noirotitermes it is perpendicular to the body axis.

The soldiers of both species have the same microsculpturing on the head capsule surface and the internal granulations (Fig. 8), that are otherwise absent in all other species of Syntermitinae . The piercing, upturned mandibles, with a single marginal tooth reduced are nearly identical in both genera, while in all other Syntermitinae the marginal teeth are well-developed (or completely absent in Ibitermes ). The two occipital saliencies are present in both genera and in Macuxitermes , but are much more discrete in Acangaobitermes (Fig. 7, arrows).

The most conspicuous differences between the new genus and Noirotitermes are the shapes of the soldier head and pronotum. The pronotum is aberrant in Noirotitermes and saddle-shaped in Acangaobitermes , as is usual for otherSyntermitinae. The shape of the soldier head in Noirotitermes is unusual, with a very broad frontal tube and two protuberances like sharp corners at the rear, while in the new genus the frontal tube is elongate and conical, similar to Armitermes , and the posterior rear part of the head is devoid of conspicuous projections.