Cubitermes, Josens & Deligne, 2019

Josens, Guy & Deligne, Jean, 2019, Species groups in the genus Cubitermes (Isoptera: Termitidae) defined on the basis of enteric valve morphology, European Journal of Taxonomy 515, pp. 1-72 : 47-49

7. The sankurensis valve pattern group

The worker within this pattern has an enteric valve with two primary cushions, normally PC3 and PC4, ending downstream in two yellow to brown sclerotised spatulae which look like two jaws (“valvule à mâchoires” in Bouillon & Vincke 1971; fig. 11G) sticking out of the valve ( Fig. 18 E–F); the jawlike spatulae may as an exception be borne either by PC4 and PC5 (two occurrences on 148 workers examined) or by PC5 and PC6 (one occurrence). The other primary cushions are roughly triangular: their largest width is generally located near the upstream fourth, and their lateral margins converge gradually downstream. PC1 is often clearly longer than PC2, PC5 and PC6 (and may be longer or shorter than PC3 and PC4 depending on the species), not resulting in any kind of symmetry. Unopened, the valve seen in profile is more or less strongly concave on the side ( Fig. 18E ); on a microscope slide, it is sometimes difficult to flatten this kind of valve.

A PC1 is made of (a) an upstream spiny part of variable length (13–49% of total length) with relatively strong spines, (b) a middle spiny part (18–48% of total length) with somewhat weaker spines and with 9–24 lateral supporting bristles on each side, and (c) a bristly part (24–43% of total length) with 40–110 straight, curved and hooked bristles ( Fig. 18A ).

A PC ending in a spatula (PC3 or PC4) is made of (a) an upstream spiny part (12–37% of total length) with relatively strong spines, (b) a middle spiny part (18–49% of total length) with somewhat weaker spines and with 10–23 lateral supporting bristles on each side, (c) a bristly part (12–36% of total length) with 35–80 straight bristles on a low bulge, and (d) an asymmetric, sclerotised spatula (15–33% of total length) with a rounded side bearing a few short curved bristles and an almost straight side with numerous short tooth-like spines; in situ, the two spatulae are close together and their denticulate sides face each other ( Fig. 18F ). The other PCs are similar to the PCs of a basic enteric valve.

The secondary cushions, in their upstream, spiny parts are generally not wider than the primary cushions; if they are somewhat wider, they do not exceed the PC width by more than 20%. Their largest width is sometimes located near the upstream fourth or third and they narrow gradually downstream; however, in many cases they widen in their downstream, bristly, fuzzy parts ( Fig. 18A ). In some species SC12

and/or SC61 are weakly developed ( Fig. 18A ) and fuzzy: they can be wider than PC1 but bear very few scattered spines and/or bristles.

In the soldier’s enteric valve, the two spatulae on PC3 and PC4 are always present, but sometimes weakly developed; the primary cushions are more slender than in the worker, but PC1 is frequently widened between the first third and the middle ( Fig. 18B ). The secondary cushions are like those of workers but bear less developed spines.

In the imago’s enteric valve, the two spatulae on PC3 and PC4 are either absent or simply indicated; unopened, the valve is slightly curved at its downstream end ( Fig. 18 C–D).

This valve pattern is therefore characterised by two spatulae in the workers’ and soldiers’ valves and by the high elongation index of the workers’ SCs ( Table 5 ); most species are small.

Material examined

Seventeen known species and varieties and probably two unknown species have such enteric valves:

Figures

Fig. 18. A. Enteric valve of the “sankurensis valve pattern”, from a worker of Cubitermes sankurensis Wasmann, 1911: note the narrowness of the secondary cushions in their upstream thirds; B. Idem from a soldier of C. sankurensis; C. Idem from an imago, unopened and seen in profile, of C. orthognathus (Emerson, 1928); D. The same as C, opened: the spatula on PC3 is only sketched (arrow), PC4 is lacking (damaged); E. Idem from a worker of C. proximatus Silvestri, 1914, unopened and seen in profile, the spatulae stick out of the valve into the second paunch, the contour of which is marked as a dotted line; F. The same as E unopened and seen from behind; A to F at the same scale; G. Geographical distribution of species with the sankurensis valve pattern.