Cubitermes, Wasmann, 1906, Wasmann, 1906

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 : 63-68

Key to valve pattern groups : imagines

The imagines of the genus Cubitermes can be recognized by the presence of two marginal teeth on the right mandible and the presence of three marginal teeth on the left mandible, the second one only suggested by an undulation of the edge between the first and third marginal teeth, and by the fore, mid and hind tibiae bearing 3, 2, 2 apical spurs and 0, 2, 0 subapical spurs, respectively (but the latter sometimes weakly developed). The gut generally contains a little soil and the weakly developed enteric valve bears six tiny primary cushions.

The identification of Cubitermes imagines as belonging to a valve pattern group is not always possible without observing associated workers or soldiers from the same sample. As an aid to identification, Fig. 23 gives a comparison of the ranges of variation of the most discriminatory measures and indices.

1. Fontanelle in a rather deep, large, conspicuous depression, at least 10% of IHdW; large species: 1.23 mm ± IHdL ± 1.54 mm, 1.58 mm ± IHdW ± 1.87 mm ……………… sulcifrons valve pattern

– Fontanelle not in a conspicuous depression of the head capsule …………………………………2

2. Large species: 1.38 mm ± IHdL ± 1.58 mm; 1.75 mm ± IHdW ± 1.91 mm … oblectatus valve pattern

– Smaller species: 0.82 mm ± IHdL ± 1.39 mm; 1.10 mm ± IHdW ± 1.82 mm …………3

3. Compound eye bulging weakly: 0.08 mm ± IEyW ± 0.14 mm; compound eye prominence index low: 0.06 ± IEyW/IHdW ± 0.095 ………………………………………………………………4

– Compound eye bulging strongly: 0.14 mm ± IEyW ± 0.23 mm; compound eye prominence index high: 0.095 ± IEyW/IHdW ± 0.13 ……………………………………………………5

4. Smaller eyes: 0.23 mm ± IEy D ± 0.33 mm and shorter mandibles: 0.44 mm ± IMlL ± 0.58 mm ………………………………………………………………………… bilobatus valve pattern + bilobatodes valve pattern (part) + muneris valve pattern (part) + sankurensis valve pattern (part)

– Larger eyes: 0.37 mm ± IEy D ± 0.56 mm and longer mandibles: 0.60 mm ± IMlL ± 0.72 mm …………………………………………………………………… fungifaber valve pattern (part) + bilobatodes valve pattern (part) + muneris valve pattern (part) + sankurensis valve pattern (part)

5. Eye to ocellus minimal distance index low: 0.24 ± IEyOcD/IOc D ± 0.35; left apico-marginal index small: 0.91 ± IMlAmD/IMlmmD ± 1.01; small species: 0.97± IHdL ±1.05, 1.30± IHdW ±1.48; from West African savannahs ……………………………………… oculatus valve pattern

– Eye to ocellus minimal distance index generally higher: 0.21 ± IEyOcD/IOc D ± 1.37; left apico-marginal index generally higher: 0.93 ± IMlAmD/IMlmmD ± 1.87; generally larger species: 0.82± IHdL ±1.39, 1.14± IHdW ±1.82 ………………………………………………… finitimus valve pattern + fungifaber valve pattern (part) + sankurensis valve pattern (part)

Key to valve pattern groups: soldiers

The soldiers of the genus Cubitermes can be recognized by the presence of a diverticulum on the second paunch, by the presence of soil in their gut (dark abdomen), by the rectangular shape of the head capsule, bearing a dense bunch of bristles around and above the fontanelle, by the bifurcate shape of the labrum, by the fore, mid and hind tibiae bearing 3, 2, 2 apical spurs and 0, 2, 0 subapical spurs, respectively, and by their reaping mandibles from almost straight to evenly curved or even more or less hooked, each one bearing a small marginal tooth near the molar tooth. As an aid to identification, Fig. 24 gives a comparison of the ranges of variation of the most discriminatory measures and indices.

1. Soldier with a basic enteric valve (without any spatulae) ……………………………………………2

– Soldier’s enteric valve with 2 to 6 spatulae, sometimes rather small ………………………………7

2. Soldier’s valve: secondary cushions not wider than the primary cushions; PC1-bilaterality index high: 1.33 ± SVP1–Bil ± 1.88; PC1 often substantially widened between the first quarter and the middle; small species: 1.57 mm ± SHdL ± 2.05 mm with short heads: 1.09 ± SHdL/SHdW ± 1.28; from West African savannahs ……………………………………… oculatus valve pattern

– Soldier’s valve: secondary cushions clearly wider than the primary cushions; PC1-bilaterality index generally lower: 0.80 ± SVP1-Bil ± 1.40 with some higher outlying values; PC1 not widened between the first quarter and the middle; species of various sizes: 1.40 mm ± SHdL ± 3.83 mm …3

3. Small species: 1.40 mm ± SHdL ± 2.20; soldier’s valve with the PCs barely or not at all outlined; PCs with very few (0–6), short lateral supporting bristles ……………… bilobatus valve pattern

– Small to large species: 1.56 mm ± SHdL ± 3.83; soldier’s valve bearing well outlined PCs with more than 6 supporting bristles on each side ……………………………………………………4

4. Lobes of the labrum elongated, finger-like; head weakly elongate: 1.08 ± SHdL/SHdW ± 1.46; mandibles from a little shorter to a little longer than head length: 0.84 ± SMlL/SHdL± 1.11, but one species with very short hooked mandibles: SMlL/SHdL = 0.55; small to medium-sized species: 1.62 mm ± SHdL ± 2.66 mm ……………………………………………………………………5

– Lobes of the labrum either triangular or lyre-shaped; head more elongate: 1.27 ± SHdL/SHdW ± 1.68; mandibles always shorter than head length: 0.68 ± SMlL/SHdL± 0.91; medium-sized to large species: 2.37 mm ± SHdL ± 3.83 mm ……………………………………………………6

5. Soldier’s valve: all PCs fusiform, their largest width located near the middle and their lateral margins converge gradually upstream and downstream; SCs wide and sometimes tend to have the shape of spearheads; smaller species: 1.15 ± SHdW ± 1.58 ……… bilobatodes valve pattern

– Soldier’s valve: odd PCs elongated and roughly rectangular: the lateral margins almost parallel; SCs wide with homogeneous scattering of the spines; larger species: 1.30 ± SHdW ± 1.87 ……………………………………………………………………………… muneris valve pattern

6. Soldier’s valve: odd PCs generally without crests on their downstream end or with weakly developed crests bearing some long bristles; 1.58 ± SHdW ± 2.43 …… fungifaber valve pattern

– Soldier’s valve: odd PCs with low bulges on their downstream end, weakly developed, but bearing a high density of short bristles; 1.76 ± SHdW ± 2.49 ………………………… finitimus valve pattern

7. Soldier’s valve with 6 spatulae, secondary cushions somewhat wider than the primary cushions; medium-sized to large species: 2.21 mm ± SHdL ± 3.32 mm ………… sulcifrons valve pattern

– Soldier’s valve with 2 or 3 spatulae ………………………………………………………………8

8. Soldier’s valve with 2 spatulae, secondary cushions not wider than the primary cushions; PC1 sometimes substantially widened between the first quarter and the middle; small to medium-sized species: 1.56 mm ± SHdL ± 2.37 mm …………………………………… sankurensis valve pattern

– Soldier’s valve with 3 spatulae, secondary cushions wider than the primary cushions; mediumsized to large species: 2.31 mm ± SHdL ± 3.12 mm ………………… oblectatus valve pattern

Key to valve pattern groups: workers

The workers of the genus Cubitermes can be recognised by the presence of a caecum-like diverticulum on the hind paunch, by the presence of soil in their gut (dark abdomen), by the presence of two marginal teeth on the right mandible and three marginal teeth on the left mandible, with the second one suggested only by an undulation of the edge between the first and third marginal teeth, and by the fore, mid and hind tibiae bearing 3, 2, 2 apical spurs and 0, 2, 0 subapical spurs, respectively.As an aid to identification, Fig. 25 gives a comparison of the ranges of variation of the most discriminatory measures and indices.

1. Worker with a basic enteric valve (without any spatulae) ………………………………………2

– Worker’s enteric valve with 2 to 6 spatulae that stick out of the valve …………………………7

2. Worker’s valve: secondary cushions not wider than the primary cushions; small species (0.93 mm ± WHdW ± 1.17 mm; 0.93 mm ± WT3L ± 1.16 mm) from West African savannahs ……………………………………………………………………………… oculatus valve pattern

– Worker’s valve: secondary cushions clearly wider than the primary cushions; species of various sizes: 0.84 mm ± WHdW ± 1.44 mm; 0.84 mm ± WT3L ± 1.55 mm …………………………3

3. Worker’s valve without any crests or bulges on the odd PCs; smaller species: 0.84 mm ± WHdW ± 1.27 mm; 0.84 mm ± WT3L ± 1.31 mm ……………………………………………………4

– Worker’s valves with crests or bulges near the downstream end of the odd PCs; larger species: 0.94 mm ± WHdW ± 1.44 mm; 1.06 mm ± WT3L ± 1.55 mm ………………………………6

4. PC1 of the worker’s valve bearing no more than 3–6 supporting bristles on each side; alternation index generally low: 0.94 ± WVP-Alt ± 1.43; small species: 0.84 ± WHdW ± 1.14; 0.84 mm ± WT3L ± 1.12 mm ……………………………………………………… bilobatus valve pattern

– PC1 of the worker’s valve bearing 10–30 supporting bristles on each side ……………………5

5. Odd PCs of the worker’s valve fusiform, their largest width located near the middle and their lateral margins converging gradually upstream and downstream; alternation index high: 1.13 ± WVP-Alt± 1.47; small to medium-sized species: 0.8 mm ± WHdW ± 1.21 mm; 0.93 mm ± WT3L ± 1.30 mm ……………………………………………………… bilobatodes valve pattern

– Odd PCs of the worker’s valve elongate and roughly rectangular, their lateral margins almost parallel; alternation index even higher: 1.24 ± WVP-Alt ± 1.63; small to medium-sized species: 0.91 mm ± WHdW ± 1.27 mm; 0.95 mm ± WT3L ± 1.27 mm ……… muneris valve pattern

6. Odd PCs of the worker’s valve bearing crests at least as high as they are wide, with long bristles; medium-sized to large species: 0.94 mm ± WHdW ± 1.44 mm, 1.06 mm ± WT3L ± 1.51 mm …………………………………………………………………………… fungifaber valve pattern

– Odd PCs of the worker’s valve bearing bulges wider than they are high, with a high density of short bristles; medium-sized to large species: 1.06 ± WHdW ± 1.37 mm; 1.20 mm ± WT3L ± 1.55 mm ………………………………………………………………………… finitimus valve pattern

7. Worker’s valve with 6 spatulae, secondary cushions somewhat wider than the primary cushions and either fusiform or spearhead-shaped; medium-sized to large species: 1.10 mm ± WHdW ± 1.45 mm ………………………………………………………………… sulcifrons valve pattern

– Worker’s valve with 2 or 3 spatulae ………………………………………………………………8

8. Worker’s valve with 2 jaw-like spatulae, secondary cushions almost as wide as the primary cushions; small to medium-sized species: 0.85 mm ± WHdW ± 1.29 mm; 0.86 mm ± WT3L ± 1.29 mm ………………………………………………………………… sankurensis valve pattern

– Worker’s valve with 3 spatulae, secondary cushions either wider than the primary cushions, more or less outlined and fusiform, or as wide as the PCs and suggesting spearheads; large species: 1.25 mm ± WHdW ± 1.55 mm; 1.21 mm ± WT3L ± 1.48 mm …… oblectatus valve pattern

Figures

Fig. 23. Comparison of the most discriminating variables and indices between the imagines of the various valve patterns: bt = bilobatus, bd = bilobatodes, mu = muneris, fu = fungifaber, fi = finitimus, sa = sankurensis, oc = oculatus, ob = oblectatus and su = sulcifrons. All the individuals studied are plotted in these graphs. A. The head width across the eyes shows a pattern with relatively low values and four patterns with high values but with high superimpositions. B. The imagines’ compound eye bulging shows three patterns with low values in comparison with the other patterns but here also with some superimpositions. C. The imagines’ compound eye prominence index shows five patterns with low values, two patterns with high values and two patterns crossing almost the entire range. D. The left apico-marginal index shows one pattern with low values and one pattern with high values.

Fig. 24. Comparison of the most discriminating variables and indices between the soldiers of the various valve patterns: bt = bilobatus, bd = bilobatodes, mu = muneris, fu = fungifaber, fi = finitimus, sa = sankurensis, oc = oculatus, ob = oblectatus and su = sulcifrons. All the individuals studied are plotted in these graphs. A. The soldiers head length distinguishes a group (four patterns) of larger species from a group (five patterns) of smaller species. B. The soldier’s cephalic elongation index shows two patterns with elongated heads. C. The soldier’s gnatho-cephalic index shows two patterns with relatively short mandibles and one with long mandibles (the outlier point in the muneris pattern is due to C. falcifer). D. The soldier’s valve bilaterality index distinguishes the oculatus valve pattern from almost all the other patterns.

Fig. 25. Comparison of the most discriminating variables and indices between the workers of the various valve patterns: bt = bilobatus, bd = bilobatodes, mu = muneris, fu = fungifaber, fi = finitimus, sa = sankurensis, oc = oculatus, ob = oblectatus and su = sulcifrons. All the individuals studied are plotted in these graphs. A. The length of the fore tibia is used as representative of most length measurements: it distinguishes small, medium-sized and large species. B. The number of lateral supporting bristles on one side of PC1 distinguishes two patterns with very few bristles (the outlier point in the oculatus valve pattern is due to an undetermined worker). C. The workers’ valve alternation index shows two patterns with high values. D. The workers’ valve SC elongation index distinguishes the oculatus and sankurensis valve patterns from the others.