Rhizophagus dispar (Paykull, 1800)
Considered to be a mainly northern species in England with a recent southwards expansion to at least south Devon (Peacock). Occurs under bark or in and around bark fungi, often in large numbers. Common in Pinus, especially fallen trunks before the bark dries out and becomes loose. During March 2007 samples of moss and grass tussocks growing on decaying timber throughout Whippendell wood were found to harbour the species, both males and females. Also from Oak (Quercus) and Beech (Betula), less commonly from Sycamore (Acer), Elm (Ulmus) and Poplar (Populus).

2.5-4.5mm. Usually distinctly coloured, pale reddish brown with a well developed dark mark across the elytra and often on disc of pronotum but entirely pale specimens occur. Elytra distinctly shaped, smoothly rounded and strongly tapering apically, second interstice of uniform width throughout and without punctures except occasionally one or two towards base. Appendages pale, outer edge of mid-tibiae straight (cf R.nitidulus, where it is distinctly curved) and with one or two small subapical spines. Head large with strongly convex eyes, as broad as the broadest part of pronotum, and frons with two distinct oblique depressions. Antennae with third segment short, as long as fourth and fifth together, club rounded at apex. Pronotum elongate, broader apically and with front angles rounded, not produced forward. Entire surface punctate, punctures on disc tending to be larger, up to twice the diameter of lateral edges.

Description from 4 Watford species at X20