Trogulus tricarinatus is a large distinctive harvestman with a markedly dorso-ventrally flattened body and relatively very short legs. The body and legs are normally covered in soil particles. There is no ocularium - the two widely spaced eyes lay directly on the cephalothorax behind a shield covering the mouthparts. When covered by soil particles, the shield looks like a single structure, but actually consists of two semi-circular projections connected by spines.
Trogulus tricarinatus is only likely to be confused with Anelasmocephalus cambridgei, but the latter is much smaller (around 4 mm compared to 10 mm for Trogulus tricarinatus). The hoods are different - that of Anelasmocephalus cambridgei is bifurcate with radiating spines. The tarsi of legs 1 and 2 have two segments in Trogulus tricarinatus, but three segments in Anelasmocephalus cambridgei.
Trogulus tricarinatus has a mainly southern, and most particularly far south-eastern, distribution in the UK - see the distribution map of the Spider and Harvestman Recording Scheme . It also occurs in many mid-European countries and extends as far south as Spain and Greece.
Trogulus tricarinatus is strongly associated with calcareous soils in low vegetation, leaf litter and under wood and stones where it feeds on snails. A characteristic place to find it is between beech leaf litter and the soil. Sieving is a good way to find it, but great care is needed because it may feign death for several minutes and is very well camouflaged.
There is little information is available on phenology, but it is said to be found all year and adults can live for up to three years.
Hillyard, P. D., & Sankey, J. H. P. 2005. Synopses of the British Fauna (New Series) No. 4: Harvestmen. Third Edition.Field Studies Council, Shrewsbury.
Richards, P. 2010. Guide to Harvestmen of the British Isles. Field Studies Council, Shrewsbury.
Richards, P. 2017. Tabular key for Identification of British Harvestmen (Opiliones). Unpublished.
Wijnhoven, H. 2009. De Nederlandse hooiwagens (Opiliones). Nederlandse Entomologische Vereniging.