Anenteotermescherubimi sp. n., a tiny dehiscent termite from Central Africa (Termitidae: Apicotermitinae)

Abstract Anenteotermescherubimi Scheffrahn, sp. n. is described from workers and male imagos collected in Cameroon and Republic of the Congo. This is the smallest soldierless termite known from Africa. As with many soldierless and soil-feeding termite species, the enteric valve morphology is a robust and essential diagnostic character for An.cherubimi. Preserved workers display pre-autothysis morphology and the effects of abdominal autothysis.


Introduction
In his revision of the soldierless termites of Africa, Sands (1972) described 60 species (51 new) among 16 new genera, all beginning with the letter "A". All were previously placed in the genus Anoplotermes Müller. Sands (1972) described ten new species from his second-largest new genus, Anenteotermes. In his broader treatise on soil-inhabiting termite workers of Africa, Sands (1998) recapitulated his descriptions of Anenteotermes with one exception; he depicted the enteric valve armature (EVA) of "Anenteotermes new species" (plate 8, fig. 9). Sands (1998: 169) also noted "At least one new species awaits description from rain forest". We herein describe this remarkable new Anenteotermes as A. cherubimi sp. n., the smallest known soldierless termite in Africa.

Materials and methods
Preserved workers, stored in 85% ethanol, were positioned in a transparent petri dish filled with Purell® hand sanitizer (70% EtOH). Body sections and dissected guts were photographed as multi-layer montages using a Leica M205C stereomicroscope with a Leica DFC 425 module run with Leica Application Suite software version 3. Mandibles and EVA were mounted on slides with PVA mounting medium (Bioquip Products, Inc.) and photographed with a Leica CTR 5500 compound microscope using bright field lighting and the same montage software. Imagos were photographed in alcohol on sand. Terminology of the worker gut follows that of Sands (1972) and Noirot (2001). Measurements were obtained using an Olympus SZH stereomicroscope fitted with an ocular micrometer. All specimens described here are deposited in the authors' collections under the accession numbers AFR1508 and AFR1282 for RHS and CGO060 for YR.  Figure 1A, B). Postclypeus moderately inflated, fon tanelle indiscernible. Anterior margin of abdomen, in lateral view, raised vertically above metanotum and marked at apex by dehiscence line (Figure 2 A-C). Antennae with 13 articles; 2>3=4=5<6.

Anenteotermes cherubimi
Left mandible with apical and first marginal teeth well separated, long, and projecting well beyond line formed by third marginal tooth and molar prominence. A subsidiary (fourth) marginal tooth visible above molar prominence in dorsal ( Figure 1C) views. Right mandible with apical tooth much longer than first mar ginal; third marginal nearly symmetrical. Fore-tibia moderately inflated; width:length ratio 0.32. Mesenteric tongue long and tubular forming long mixed segment ( Figure 1D). P1 bridged to P3 through a broadly conical EV seating resembling a sunflower receptacle (Figure 3 A-C). Enteric valve cuticle consists of six cushions of unequal size (Figure 4). The largest two cushions comprise a soft basal part covered with fringed scales and 5-6 narrow spines, and bear sclerotized extensions that broaden into wing-like paddles; margins finely pectinate (40-70 compound spines per extension) and approx. a dozen more separated spines in interior of extension ( Figure 4). Other cushions soft and scaly, without spines. Middle one, situated between the largest cushions, approx. half their size. Two cushions lateral to the major ones small, approx. half smaller than the middle one. Cushion opposite to the middle one approx. the same length as it, narrower. Soft cushions anchored in their seating and seating lumen filled with bacterial slime; extensions penetrate to middle of P3 lumen ( Figure 3C).
Description of imago. (male) ( Figure 5, Table 2). Tiny, 7 mm. Head with vertex and frons sepia brown, postclypeus slightly lighter. Genae and labrum light brown. Fontanelle ovoid, hyaline. Eyes dark sepia brown. Pronotum lighter than head capsule. Meso-and metanotum slightly lighter than pronotum, with hind margins tinged with yellow. Abdominal tergites and sternites light brown, sternites paler in middle. Wing membrane light brown, with darker veins. Legs light brown. Head capsule rounded posteriorly. Eyes of medium size, protruding. Ocelli elliptical, close to eyes. Antennae with 15 articles. Pronotum slightly broader than long, semi-octogonal, anterior corners deflected downward, hind margin nearly straight. Hind margins of meso-and metanotum narrow, sinuated. Wings long, approx. half their length beyond extremity of abdomen.
Diagnosis. Anenteotermes cherubimi is the smallest soldierless termite worker in Africa (head width, HW), followed by Acidnotermes praus (0.52 mm HW) and An. nanus (0.56 mm HW). The EVA of A. cherubimi is very diagnostic and unlike that of any other termite species in having two broad and symmetrical pectinate paddles as opposed       to two narrow paddles in other Aneneteotermes spp. or tri-and hexa-radial, or asymmetrical armature as in other soldierless genera. Comments. Sands (1998) placed "Anenteotermes new species" in this genus based on a well-developed mixed segment which is only shared in African soldierless workers by Aderitotermes and Adaiphrotermes (Sands 1972). Of these three genera, only Anenteotermes contain species with a single pair of sclerotized EV extensions penetrating into P3. The Anenteotermes worker key in Sands (1972, p. 194) can accom- Biology and distribution. All records for An. cherubimi are from southern Cameroon and northern Congo. Deblauwe et al. (2008) collected "Anenteotermes sp. nov. (Sands, 1998)" from a subterranean habitat at all five vegetation types sampled in Cameroon (GPS location: 3.42, 13.15; east of above sites) including primary forest, secondary forests, and a riverine forest. Eggleton et al. (1995) collected three new Anenteotermes (possibly including An. cherubimi, as Sands was a coauthor) in Mbalmayo Forest Reserve from a young plantation, old secondary and near primary forest, but not from cleared or fallow land cover. Dibog et al. (1998) also collected Anenteotermes "sp. n. 1, 2" from Mbalmayo Forest Reserve (3.42, 11.48, altitude 701 m) from the Ebogo control plots. Sands (1998) suggests that some Anenteotermes spp., as with many other soil feeding termites, lives in nests built by other termites.
Etymology. Named after the cherubim, the biblical guardian angels. The EVA resembles a pair of angel wings. Sands (1982) described abdominal autothysis in two live soldierless species from Africa, Alyscotermes kilimandjaricus Sands and Ateuchotermes muricatus Sands. Upon grasping an ant with their mandibles, abdominal muscle convulsions were observed causing the integument to split along a line at the back of the metanotum and resulting in expulsion of their hind gut coils. Sands (1982) further noted that Al. kilimandjaricus workers secrete droplets of a clear fluid, stored in enlarged salivary glands and released from the dehiscence line before gut expulsion. In At. muricatus, the entire intestine of workers was expelled in "a few seconds". Sands (1982) did not mention a fluid exudate preceding the autothysis. In preserved workers of An. cherubimi, it was not possible to confirm a fluid reservoir, but the expulsion of guts from the abdomen was obvious (Figure 2A).

Discussion
able Cameroonian samples are deposited in the University of Florida Termite Collection. YR thanks V. Freycon, É. Forni and S. Gourlet-Fleury (CIRAD, Montpellier), for invitation and multifaceted assistance in the field. The trip to the Congo was supported by the DynAfFor project funded by the Fonds Français pour l'Environnement Mondial (FFEM) and the Agence Française de Développement (AFD). Thanks are due to Mokabi SA logging company for facilitating access to the field site. P. Martin and G. Josens helped with microscopic imagery. Financial support was provided by the Belgian F.R.S.-FNRS (PDR T.0065.15).