CRUSTACEA > MALACOSTRACA > ISOPODA > Oniscidea > Synocheta > Trichonisidae

This small, off-white to buff-coloured, soil-dwelling species is no more than 4mm long and is very easy to overlook. The longitudinal dorsal ridges and continuous pereion to pleon outline are characteristic of the genus, but the ridges are much less distinct in Haplophthalmus danicus making it a little easier to identify. It has eyes consisting of a single black ocellus and antennal flagella looking like a tapered cone terminating in a tiny bristle.

The male apparently has a characteristic upwardly directed spur on the carpus of the last leg and I would guess that that's the feature giving the species its common name of the Spurred Ridgeback.

The two closely related species, Haplophthalmus mengii and Haplophthalmus montivagus, differ in having a more defined dorsal ridge coupled with a pair of prominent projections on the third pleonite. They are extremely difficult to distinguish even with close examination.

Haplophthalmus danicus is typically associated with damp well-vegetated habitats including damp woodland, gardens and farmyards particularly where there's rotting wood or peaty debris. Although common across much of the south, it becomes increasingly rare further north. It's a poorly recorded species with only four records from Dorset at the time of writing. It may be small and hard to find but, once located, you should be able to photograph them as they are far more sluggish than the larger surface species. That said, they are tiny and invariably inhabit dark places, which means that getting good well-focused photos is never easy.