Gastrotermes spinatus, Scheffrahn, 2020

Scheffrahn, Rudolf H., 2020, Gastrotermes spinatus gen. n. sp. n., an African soil-feeding termite described from the worker caste (Isoptera, Termitidae, Apicotermitidae), Zootaxa 4789 (1), pp. 291-296 : 292-295

Gastrotermes spinatus sp. nov.

Holotype. Worker, 1DEC2011, Jan Křeček, University of Florida Termite Collection no. AFR1424.

Type repository. University of Florida Termite Collection, Fort Lauderdale , Davie, Florida .

Type-locality. Cameroon, Korup National Park (lat 5.007, long 8.865), elev. 135 m.

Paratypes. Another 30 workers, same colony sample as holotype.

Worker ( Figs. 1-3 ). Monomorphic, intermediate size for subfamily; head, pronotum, and body rather hairy for subfamily ( Fig. 1A ). Head capsule yellowish, covered with a few short but mostly long (ca. 0.12 mm) to very long (ca. 0.22 mm) setae ( Fig. 1C, D ). Postclypeus strongly inflated; fontanelle almost indiscernible; frontal gland paler than surrounding vertex. Antennae with 14 articles, 2=3>4<5. Left mandible with apical tooth about twice as long as M1+2; anterior margins of M1+2 and M3 subequal; posterior margin of M1+2 forming ca. 110° with anterior margin of M3 ( Fig. 1B ). Right mandible with apical tooth about 2.5 times longer than first marginal tooth; second marginal tooth forming 90° isosceles triangle. Fore tibia slightly inflated compared to hind tibia.

Mesenteron forms complete circle, integument in the half nearest P1 with yellow pigmentation. Malpighian knot against the terminal part of midgut. Mixed segment absent, P1 about 3 times as long as wide. Enteric valve seating trilobed, wider than P1; P3a globular; P3b terminus elongate, with longitudinal striations ( Fig. 2A ). Isthmus (P3a-P4) cuticle without ornamentation; P5 about same volume as P3a. Enteric valve contained within lumen of P2. Valve with six subequal ovoid cushions. Each cushion with one to four small thorns near middle. At and below the cushion ring is a ring consisting of about a dozen rounded pleats followed by a more transparent ring ornamented with 4-9 very short spines in line with each cushion. Enteric valve seating trilobed, about 1.7 times wider than middle of P1 and nearly as long; lined with several hundred 6-14 µm-long erect spines. Opening of the P3a lined with about one hundred 51-107 µm-long sclerotized spines at and beyond the EVS constriction. Long spines take two forms; those nearest EVA are simple with sharp points bunched at P3a opening into two groups, one group near interior lobe of EVS and one on opposite (left) side. Spines of the second group with wide, multifurcated termini that form two spiny arms lining the EVS side of the P3a.

Measurements. Workers (mean, range, mm, n=20): HLP 0.65, 0.58-0.70; PCL 0.21, 0.19-0.23; HW 1.01, 0.98-1.05; PW 0.65, 0.61-0.68; HTL 1.13, 1.05-1.18; FTL 0.82, 0.77-0.86; FTW 0.14, 0.12-0.14; FTLW 0.17, 0.15- 0.18.

Diagnosis. Both the EVS and P3a junction, as noted above, and the EVA cuticle of G. spinatus are unique among the Apicotermes group.

Etymology. The specific epithet “ spinatus ” (Latin for spine) refers to the large spines at the juncture of the EVS and P3a.

Discussion. Soldiers are relatively rare in colonies of the Apicotermes group genera so it is possible that G. spinatus possesses a soldier. Except for its subterranean soil-feeding behavior, the biology of G. spinatus is unknown. The only known locality for G. spinatus is in lowland central African rainforest with precipitation exceeding 3 m per annum. Noirot (2001) places the Labidotermes subgroup as basal within the Apicotermes group because, unlike the Eburnitermes , Trichotermes , and Apicotermes subgroups, the EVA is situated on the inner face of P2 and does not project into the EVS or P3a lumen.

Figures

FIGURE 1. Gastrotermes spinatus worker.A) lateral habitus, B) mandibles, C) dorsal head capsule, and D) lateral head capsule and pronotum.

FIGURE 2. Gastrotermes spinatus worker whole gut. A) dorsal, B) right, C) ventral, and D) left aspects. Superimposed on D) in highlighted circle is position, to scale, of spiny section of P3a (Fig. 3C). Abbreviations: C = crop, M = mesenteron, P1 = first proctodeal segment, EVS = enteric valve seating, P3a = posterior portion of third proctodeal segment, P3b = anterior portion of third proctodeal segment, IS = isthmus, P4 = forth proctodeal segment, P5 = fifth proctodeal segment.

FIGURE 3. Gastrotermes spinatus worker gut. A) cuticle of enteric valve armature and portion of EVS, B) EVS, whole mount, C) EVS and adjoining portion of P3a viewed from left aspect (Fig. 2D), D) adjoining portion of P3a viewed from ventral aspect. See Fig. 2 for abbreviations.