Trapezoid termite (Dentispicotermes trapezia) described based on soldiers and workers from Pantanal-Chaco Region

NEWS - Trapezoid termite (Dentispicotermes trapezia Scheffrahn sp. nov.) described from soldier and worker caste specimens collected in the Pantanal-Chaco in Bolivia and Paraguay differs from its five relatives in having a trapezoidal frontal ridge with parallel marginal teeth.

The five species of Dentispicotermes Emerson 1949 are all from South America, including D. brevicarinatus (Emerson, 1950), D. conjunctus Araujo 1969, D. cupiporanga Bandeira and Cancello 1992, D. globicephalus (Silvestri, 1901) and D. pantanalis Mathews 1977.

A relatively uncommon genus of termite characterized by soldiers with long, thin mandibles, cone-shaped head projections and large yellow labial glands extending well into the abdomen.

Dentispicotermes spp. is a ground-feeder and workers of the species that have been studied have a highly diagnostic enteric valve but apparently no recognizable intraspecific differences. Now, Rudolf Scheffrahn of the University of Florida reports a sixth species.

Soldier: Head capsule in dorsal view narrowing toward anterior, anterolateral corners with stubby knobs; very slight constriction in posterior third; posterior margin evenly convex. In lateral view head ellipsoid with steep frontal protuberance behind antennal sockets; frontal protuberance narrowly trapezoidal and conical in anterior and posterior view.

Frontal protuberance with tiny wart-like bump near middle of posterior margin and two curved setae on either side near summit; summit without opening. Postmentum extending below genae, but not excessively so. Head capsule with pair of long straight setae on vertex behind protuberance and pair projecting laterally anterior to constriction. Four straight setae on submentum.

Mandibles symmetrical, nearly straight with slight bend near bases; apical hooks about one-seventh of mandible lengths. Each mandible with triangular marginal teeth about two fifths length from hooks in lateral view when in resting position.

Thorax and anterior two thirds of abdomen filled with yellow defensive secretion. Antennae with 14 articles, or 15 if third subdivided, article formulae 2>3=4<5 2="" or="">3=4≤5; Tibial spur formula: 2:2:2.

Head capsule length to postclypeus (mm) 1.59, 1.50; left mandible length to ventral condyle 1.54, 1.52; right mandible length to ventral condyle 1.53, 1.52; head width at antennal socket 1.06, 1.05; max. head width 1.30, 1.35; max. head capsule height (postmentum to protuberance) 1.25, 1.17; protuberance height from plane of vertex 0.25, 0.25; max. postmentum width 0.20, 0.19; max. postmentum height, 0.16, 0.16; max. pronotum width, 0.81, 0.78.

Worker: Monomorphic. Subspherical abdomen in dorsal view; integument transparent covered with hundreds of long setae. Postclypeus fully inflated in lateral view. Pronotum angled ca.100º with anterior lobe larger than posterior; about 8–10 long setae along lobe margins. Tibial spur formula: 2:2:2. Fontanelle barely visible. Head capsule covered with sparse long setae. Antennae with 14 articles, or 15 if third subdivided.

Digestive tube with spherical and large crop developed; mixed segment with narrow mesenteric tongue; P1 forming a semicircular tube from MS to P2 insertion; P3 large and globous in ventral view dorsal lobe exiting and partially surrounded by P4; P4 long and narrow.

Enteric valve armature consists of six anterior and three posterior cushions. Posterior cushions with small spines becoming larger entering gut lumen. Anterior cushions project into gut lumen, finger-like; composed of fleshy outer lobes and inner ridges, ridges with about 100 thorny spines.

Mandibles of soil-feeding type. Left mandible with apical tooth twice the size of M1+2, separated by acute angle; a sinuous margin between M1+2 and M3, M3 much smaller than M1+2; molar prominence without ridges, projecting. Right mandible with apical tooth more than twice the size of M1, M2 much smaller than M1, molar plate without ridges and very concave.

Length of head with postclypeus (n=10, min.-max., mean mm) 0.74–0.86, 0.80; max. head width 0.81–0.91, 0.87; length of hind tibia 0.86–0.96, 0.90.

“Trapezia” refers to the trapezoidal shape of the frontal prominence in lateral view. The new species of soldier is unique among its relatives in having a steep frontal protuberance that is narrowly trapezoidal in lateral view and a posterior edge that is angled at about 60° from the vertex plane.

D. trapezia is most closely related to D. globicephalus but the protuberance in D. globicephalus is triangular in lateral view and the posterior edge is angled about 30° from the vertex plane. The intestines of workers and D. trapezia are very similar to those of D. brevicarinatus and D. cupiporanga.

The defensive secretions of Dentispicotermes soldiers originate from labial glands that drain into the salivary ducts through the hypopharynx and exit buccal cavity. Once in alcohol, the yellow secretion polymerizes into a rubbery mass and can be released from the soldier's mouth as a single piece.

Original research

Rudolf H. Scheffrahn (2024). Dentispicotermes trapezia (Isoptera: Termitidae: Amitermitinae), a new termite species from the Pantanal-Chaco Region of South America. Zootaxa 5536 (3): 447–453, DOI:10.11646/zootaxa.5536.3.4

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