3. The muneris valve pattern group

The workers within this pattern have basic enteric valves: all six primary cushions are similar in their arrangement but not in their sizes (Fig. 14A). In the upstream and middle spiny parts, they are armed with relatively strong spines becoming gradually thinner downstream; moreover, the middle part bears some lateral supporting spindle-like bristles leaning on the funnel membrane. In the downstream bristly part, the spines are rather abruptly replaced with longer and bristle-like setae, first straight, then curved and eventually hooked. The odd primary cushions are elongate and roughly rectangular: their lateral margins are almost parallel until the bristly part, where they are narrowed (Fig. 11D). The odd PCs are clearly longer than the even PCs, giving triradial symmetry to the valve (Fig. 14A).

An odd PC is made of (a) a long upstream spiny part (42–56% of total length) with relatively strong spines, (b) a short middle, spiny part (17–31% of total length) with clearly weaker spines and with 11–18 lateral supporting bristles on each side, and (c) a bristly part (22–30% of total length) with 50–65 straight, curved and eventually hooked bristles (Fig. 11D).

The secondary cushions are wide at the upstream end, almost filling the space between the PCs, narrowing noticeably downstream with a homogeneous spine scattering (Fig. 14A).

In the soldier’s enteric valve, the PCs are even more slender than in the worker with triradial symmetry, the odd PCs being clearly longer than the even PCs (Fig. 14B). The secondary cushions are like those of workers but bear less developed spines.

This basic valve pattern is therefore characterised by high alternation indices in both workers and soldiers and by roughly rectangular odd PCs; most species are small- to medium-sized.

Material examined

Nine species have such enteric valves: