Isognathotermes magniplanifrons Josens & Deligne, 2025

Josens, Guy, Deligne, Jean, Harry, Myriam, Roy, Virginie, Akama, Pierre D., Coulibaly, Tenon, Dosso, Kanvaly, Goergen, Georg, Hasson, Michel, Kasangij, Patrick Kasangij A, Kifukieto, Carmel, Ru, Bruno Le, Loko, Laura Estelle Yêyinou, Ndiaye, Abdoulaye Baila, Roisin, Yves, Sion, Noémie, Šobotnik, Jan, Stiblik, Petr, Kuenda, Soki Kue Di, Traoré, Saran, Viage, Manuela, Wango, Solange Patricia, Kaymak, Esra, Bourguignon, Thomas & Hellemans, Simon, 2025, An integrative revision of the genus Isognathotermes (Termitidae: Cubitermitinae) with description of seven new species and four new subspecies, European Journal of Taxonomy 1024, pp. 1-197 : 81-87

Isognathotermes magniplanifrons Josens & Deligne sp. nov.

urn:lsid:zoobank.org:act:

Figs 26–31, 46, distribution map: Fig. 47; Table 7

Diagnosis

The worker has a finitimus EVA and is among the large workers of the genus Isognathotermes (WHdW = 1.30–1.42 mm, Fig. 30) but rather difficult to distinguish from that of other species.

The soldier has generally a recognizable finitimus EVA ; it is, on average, and with the soldier of I. bulbifrons , the largest of the Isognathotermes species with a finitimus EVA (SHdL = 2.98–3.77 mm, Fig. 28), with more curved mandibles (SMlc = 0.24–0.36 mm, Fig. 29), as in I. planifrons ; its head is slightly bulbous (SHdC = 0.0– 0.07 mm), less than that of I. bulbifrons and similar to I. planifrons .

The imago is, on average, and with the imago of I. bulbifrons , the largest in the genus Isognathotermes with a finitimus EVA (IHdW = 1.62–1.78 mm, Fig. 26); but its mandibular apico-marginal distance is generally smaller (IMlAmD = 0.20–0.24 mm, Fig. 27) than in I. bulbifrons (IMlAmD = 0.20–0.30 mm in I. bulbifrons ).

Isognathotermes magniplanifrons sp. nov., is therefore morphologically close to I. bulbifrons but their chorology is different: to date, I. magniplanifrons is only known from the north-east of the DRC (Haut-Uele and Kivu provinces).

Etymology

The name magniplanifrons is from the Latin magnus (large) and the species name planifrons , referring to the resemblance with I. planifrons but with larger individuals in all castes.

Material examined

Twenty-four samples from two locations. Of the 24 old museum samples, one was initially labelled as C. minitabundus , one as C. speciosus , and 22 as Cubitermes sp.

Holotype

DEMOCRATIC REPUBLIC OF THE CONGO • soldier; Irangi ; 1°54′ S, 28°27′ E; 7 Sep. 1970; A. Wabo leg.; study code: DJ 0920; initially Cubitermes sp. in RMCA; BE RMCA INS. Iso. 059253.

Paratypes

DEMOCRATIC REPUBLIC OF THE CONGO • soldier, worker, ♂ (alate), ♀ (queen); same data as for holotype; BE RMCA INS.Iso.059935 .

Other material examined

DEMOCRATIC REPUBLIC OF THE CONGO • soldier, worker; Moto ; 3°2′ N, 29°30′ E; 1923; L. Burgeon leg.; study code: DJ 0070; initially C. speciosus in RMCA; BE RMCA INS.Iso.059258 •

soldier, worker; Irangi; 1°54′ S, 28°27′ E; 10 Apr. 1952; A. Wabo leg.; study code: DJ 0896; initially C. minitabundus in RMCA; BE RMCA INS.Iso.059256 • soldier, worker, ♂ (alate); Irangi; 1°54′ S, 28°27′ E; 4 Sep. 1970; A. Wabo leg.; study code: DJ 0894; initially Cubitermes sp. in RMCA; BE RMCA INS.Iso.059252 • soldier, worker, ♂ (king); Irangi; 1°54′ S, 28°27′ E; 4 Sep. 1970; A. Wabo leg.; study code: DJ 0919; initially Cubitermes sp. in RMCA; BE RMCA INS.Iso.059251 • soldier, worker, ♂ (king), ♀ (queen); Irangi; 1°54′ S, 28°27′ E; 6 Sep. 1970; A. Wabo leg.; study code: DJ 0929; initially Cubitermes sp. in RMCA; BE RMCA INS.Iso.059254 • soldier; Irangi; 1°54′ S, 28°27′ E; 21 Sep. 1970; A. Wabo leg.; study code: DJ B262; initially Cubitermes sp. in RMCA; BE RMCA INS.Iso.059238 • soldier; Irangi; 1°54′ S, 28°27′ E; 21 Sep. 1970; A. Wabo leg.; study code: DJ B263; initially Cubitermes sp. in RMCA; BE RMCA INS.Iso.059239 • soldier; Irangi; 1°54′ S, 28°27′ E; 21 Sep. 1970; A. Wabo leg.; study code: DJ B264; initially Cubitermes sp. in RMCA; BE RMCA INS.Iso.059240 • soldier; Irangi; 1°54′ S, 28°27′ E; 21 Sep. 1970; A. Wabo leg.; study code: DJ B265; initially Cubitermes sp. in RMCA; BE RMCA INS.Iso.059241 • soldier; Irangi; 1°54′ S, 28°27′ E; 20 Sep. 1970; A. Wabo leg.; study code: DJ B267; initially Cubitermes sp. in RMCA; BE RMCA INS.Iso.059236 • soldier; Irangi; 1°54′ S, 28°27′ E; 20 Sep. 1970; A. Wabo leg.; study code: DJ B268; initially Cubitermes sp. in RMCA; BE RMCA INS.Iso.059237 • soldier; Irangi; 1°54′ S, 28°27′ E; 20 Sep. 1970; A. Wabo leg.; study code: DJ B269; initially Cubitermes sp. in RMCA; BE RMCA INS.Iso.059243 • soldier; Irangi; 1°54′ S, 28°27′ E; 25 Jan. 1972; A. Wabo leg.; study code: DJ B272; initially Cubitermes sp. in RMCA; BE RMCA INS.Iso.059246 • soldier; Irangi; 1°54′ S, 28°27′ E; 28 Feb. 1972; A. Wabo leg.; study code: DJ B303; initially Cubitermes sp. in RMCA; BE RMCA INS.Iso.059249 • soldier; Irangi; 1°54′ S, 28°27′ E; 13 Mar. 1972; A. Wabo leg.; study code: DJ B304; initially Cubitermes sp. in RMCA; BE RMCA INS.Iso.059250 • soldier; Irangi; 1°54′ S, 28°27′ E; 31 Mar. 1972; A. Wabo leg.; study code: DJ B261; initially Cubitermes sp. in RMCA; BE RMCA INS.Iso.059235 • soldier; Irangi; 1°54′ S, 28°27′ E; 13 Mar. 1972; A. Wabo leg.; study code: DJ B274; initially Cubitermes sp. in RMCA; BE RMCA INS.Iso.059248 • soldier; Irangi; 1°54′ S, 28°27′ E; 1 Apr. 1972; A. Wabo leg.; study code: DJ B273; initially Cubitermes sp. in RMCA; BE RMCA INS.Iso.059247 • soldier; Irangi; 1°54′ S, 28°27′ E; 9 May 1972; A. Wabo leg.; study code: DJ B270; initially Cubitermes sp. in RMCA; BE RMCA INS.Iso.059244 • soldier, ♀ (alate); Irangi; 1°54′ S, 28°27′ E; 1972?; A. Wabo leg.; study code: DJ B316; initially Cubitermes sp. in RMCA; BE RMCA INS.Iso.059255 • soldier, ♀ (alate); Irangi; 1°54′ S, 28°27′ E; 1972?; A. Wabo leg.; study code: DJ B317; initially Cubitermes sp. in RMCA; BE RMCA INS.Iso.059257 • soldier; Irangi; 1°54′ S, 28°27′ E; 11 Sep. 1972; A. Wabo leg.; study code: DJ B266; initially Cubitermes sp. in RMCA; BE RMCA INS.Iso.059242 • soldier; Irangi; 1°54′ S, 28°27′ E; 15 Sep. 1972; A. Wabo leg.; study code: DJ B271; initially Cubitermes sp. in RMCA; BE RMCA INS.Iso.059245 .

Historical review

This species is described here. It was collected in 1923 in the Haut-Uele Province, DRC (and misidentified), and in 1970 in Kivu, DRC. This species is known from 24 samples, 23 of which come from the same locality.

Description

Imago

COLOUR. Head capsule: well sclerotised, dark, C6–C7; fontanelle concolorous or almost so with head capsule. Postclypeus C5–C7 concolorous or slightly paler (one level) than head capsule. Antennae C4– C6 without any difference between proximal and distal articles. Thorax: pronotum C5–C6, as head capsule or slightly paler (one level); meso- and metanotum C4–C6, as pronotum or slightly paler. Legs C4–C5. Wings hyaline with brown to grey tinge (Cf3), anterior veins darker. Abdomen: tergites C4–C6. Sternites appreciably paler in middle (C3–C4) with both sides darker (C4–C6); posterior sternites darker (C4–C6) than anterior.

SETATION. Head capsule with some prominent setae, mainly near the eyes, and a higher density of shorter, finer setae everywhere. Labrum and postclypeus with some prominent setae mixed with shorter ones. Antennae with some prominent setae, some more numerous smaller setae and, mainly distally on most articles, a bunch of very fine, bent setae (visible only at magnification 50× or more). Thorax: pronotum with prominent setae mainly on margins and many shorter ones in middle; meso- and metanotum without any visible setae or with some fine, pale setae, arranged in a medio-longitudinal strip, visible at 40 ×; generally three to four larger setae on metanotum. Legs very pilose, furnished (among numerous fine setae) with some fine spines: 6–10 on the carina of fore coxa and 0–2 on the ventral side; tibia pilose; fore, mid, and hind tibia furnished with 20–30 spines and bearing 3, 2, 2 apical spurs and 0, 2, 0 subapical spurs respectively. Abdomen: tergites with many large and small setae. Sternites with long setae, erect or directed slightly forward, and many long and smaller setae directed backwards.

STRUCTURE (measurements in Table 7, Fig. 46). Size: the imagines of I. magniplanifrons sp. nov. are, on average, rather large (but not the largest of the genus Isognathotermes ) (IHdW = 1.62–1.78 mm). Head capsule: compound eyes nearly round; fontanelle generally a tiny elongate marking; ocelli nearly round to oval removed from eyes by a distance about equal to 0.7–1.1 ocellus small diameter. Antennae: 16 articles on alate individuals, shortened by amputation by five to six articles in queens and kings. Labrum: cupola shaped. Left mandible with mandibular apico-marginal distance clearly smaller (IMlAmD = 0.20–0.24 mm) than in I. bulbifrons ( Fig. 27); apical tooth longer and more prominent than first marginal; marginal teeth three in number but second one only suggested by a slight undulation of edge between first and third marginal teeth; only the apical tooth is acute in unworn specimens; premolar tooth with proximal end obscured by molar prominence in dorsal view; molar tooth bearing a rounded molar prominence dorsally and ending posteriorly in a tiny acute apophysis. Right mandible with apical tooth longer and more prominent than first marginal; marginal teeth two in number; first marginal tooth well developed with a sharp tip when fresh; second marginal tooth smaller and with a blunt tip even when fresh; molar tooth bearing a ventral rounded flange and ending posteriorly in a kind of heel. Thorax: pronotum appreciably wider than long and slightly narrower than head width (including the eyes), straight to very weakly sellate with anterior lobe short and very slightly elevated. Fore coxa flanged ventrally resulting in a sharp carina. Wings: R1 fused entirely with costal margin, sclerotised; Rs simple, sclerotised; M and Cu not or weakly sclerotised with 2–3 and 12–13 branches, respectively.

Soldier

COLOUR. Head capsule generally C6–C7, paler (C5) in a long-preserved sample; with a gradient from a darker frons to a paler back (e.g., C6 → C4). Gulamentum concolorous with head. Antennae and labrum somewhat paler (1–2 levels) than head capsule. Mandibles dark (C8) with or without a slight clearing on their bases (one palette level) which is generally the same colour as frons. Thorax, nota and legs paler than head capsule (C4–C5). Abdomen grey to red-brown owing to digestive bolus, sometimes with a yellow tinge on tergites.

SETATION. Head capsule with few scattered setae; on frons a dense bunch of hair-like setae surrounds and overhangs fontanelle. Antennae with some prominent setae, more numerous smaller setae and at distal extremity of distal articles, a bunch of fine, bent setae (visible only at high magnification, 50× or more). Labrum always with 5–7 large setae on each lobe. Thorax: pro- and mesonotum with some setae located mainly on margins. Legs: fore coxa furnished with 1–2 spines on carina and not any one on ventral side; trochanter generally with some long lined-up setae, sometimes with two spines; fore, mid, and hind tibia bearing 3, 2, 2 apical spurs and 0, 2, 0 subapical spurs respectively; all tibiae furnished with a row of 6–15 spines. Abdomen: tergites with some large setae, mainly or only on their posterior margins. Sternites with long setae, erect or slightly directed forward, often coloured, and smaller setae directed backwards.

STRUCTURE (measurements in Table 7; Fig. 46). Size: the soldiers of I. magniplanifrons sp. nov. are, on average, the largest of the genus Isognathotermes ( Fig. 28). Head capsule: always clearly sclerotised and appreciably longer than wide. Dorsal view: lateral sides mostly subparallel with a narrowing near posterior third or fourth; from antennal sockets sides converge more or less clearly towards bases of mandibles. In profile: upper profile slightly concave (as in I. planifrons , much less than in I. bulbifrons ); frons with no hump overhanging the fontanelle. Gulamentum in ventral view always more or less constricted in its posterior half, with sides of anterior part either forming an acute widening or even a kind of ear on each side; generally, with a flat posterior part from side view. Antennae: of 15 articles. Labrum: always deeply bifurcate and wider than long, with lyre-shaped sides; lobes angular, with fine, whitish, or translucent tips; anterior margin concave. Mandibles: sabre-like; inner edges smooth with one small marginal tooth, near molar tooth on each mandible; mandibles clearly shorter than head; entire surface of both mandibles smooth and glossy. Right mandible generally slightly more curved than left. Thorax: pronotum sellate, as wide as 57–63% of head width, with generally entire anterior and posterior margins. Fore coxa flanged ventrally resulting in a carina. Gut: enteric valve seating on left side, best seen in ventral view, situated in posterior half of abdomen. Arrangement of enteric valve cushions showing trilateral symmetry: the odd cushions are on average 14% longer than the even cushions, generally without any hump or with humps weakly developed; however, the pilosity becoming abruptly very dense shows the place where a hump is expected ( Fig. 46); secondary cushions wide at the upstream end narrowing noticeably downstream with a homogeneous spine scattering. Caecum always rather small, best seen in ventral view, near centre of abdomen, lobed (2–4 small lobes).

Worker

COLOUR. Head capsule pale (C1–C3) turning grey in long preserved samples. Antennae: proximal articles pale (C2–C3), distal articles always one to two levels darker (C4–C5). Thorax, nota and legs pale (C1–C3). Abdomen grey to red-brown owing to digestive bolus.

SETATION. Head capsule and postclypeus with few, erect scattered setae. Labrum with few, robust scattered setae. Antennae with some prominent setae, some more numerous smaller setae and at distal extremity of distal articles, a bunch of fine, bent setae (visible only at high magnification, 50 × or more). Thorax: nota with some scattered setae. Legs: fore coxa always carinated, bearing one fine seta and furnished with 3–5 spines on carina and 1–2 on ventral side; fore trochanter with 6–7 spines; fore, mid, and hind tibia bearing 3, 2, 2 apical spurs and 0, 2, 0 subapical spurs respectively and a row of spines. Abdomen: tergites with scattered setae. Sternites with long setae, erect or slightly directed forward, often coloured, and smaller setae directed backwards.

STRUCTURE (measurements in Table 7, Fig. 46). Size: the workers of I. magniplanifrons sp. nov. are, on average, among the largest of the genus Isognathotermes (but with large overlapping on several other species: Fig. 30). Fore coxa flanged ventrally resulting in a sharp carina. Head capsule: weakly sclerotised (except mandibles). Antennae: 14.5 articles. Labrum: cupola shaped. Left mandible: apical tooth well developed with a sharp tip when fresh; marginal teeth three in number, first marginal well developed but with a blunt tip even when fresh, second marginal faint (visible as an undulated edge), third marginal with a blunt tip; premolar tooth with its proximal end hidden under molar prominence; molar tooth bearing a rounded molar prominence dorsally and ending posteriorly in a tiny acute apophysis. Right mandible: apical tooth well developed with a sharp tip when fresh; marginal teeth two in number; first marginal well developed with a sharp tip when fresh; second marginal smaller and with a blunt tip even when fresh; molar tooth bearing a ventral rounded flange and ending posteriorly in a kind of heel. Thorax: pronotum sellate, as wide as 70% of head width. Gut: enteric valve seating on left side, best seen in ventral view, situated in posterior half of abdomen. Arrangement of enteric valve cushions of the finitimus pattern with triradial symmetry: the odd PCs, in their downstream part, are wide and bear at that place a high density of rather short bristles on a globular bulge; supporting bristles are generally numerous: 20–38 on each side of the odd PCs; secondary cushions are wide at the upstream end, narrowing noticeably downstream with a homogeneous spine scattering. Caecum always rather small, visible in ventral view, near centre of abdomen, shortly lobed (3–4 small lobes).

Chorology-ecology

The geographic distribution of I. magniplanifrons sp. nov. is linked with the northeastern Congolian lowland forests ecoregion ( Fig. 47).

Molecular data

No genetic sequence is currently available.