ARACHNIDA > ARANEAE > Lycosidae > Xerolycosa, Trochosa and Pirata

The remaining species are placed in eight genera; Alopecosa (4), Arctosa (5), Aulonia (1), Hygrolycosa (1), Pirata (3), Piratula (3), Trochosa (4) and Xerolycosa (2). The majority are either uncommon, nationally scarce or rare.

To date, I've only seen four of these species.

The two nationally scarce Xerolycosa spiders are very similar in appearance to the previously featured Pardosa species except for the shape of the head, which is not as elevated or straight-sided. Both species could potentially be encountered locally; Xerolycosa miniata has scattered distribution throughout Britain and is almost exclusively restricted to coastal dune systems, whereas Xerolycosa nemoralis is primarily a southern and south-east species occurring in various sparsely vegetated areas such as woodland clearings, chalk grasslands and heathland. The carapace of both sexes is dark brown, almost black, with a wide, slightly tapering median band of pinkish-white hairs. The abdomen is mottled pinkish-grey in the female except for a pinkish-white patch at the front between a pair of dark shoulder markings. The male is similar apart from having two rows of white spots on the rear half that converge towards the spinnerets.  

The Trochosa genus includes four relatively large robust spiders that are generally brown in colour with a characteristic paler median band that is wider towards the front of the carapace and contains two short dark stripes. The band continues onto the abdomen producing a cardiac mark that is very useful when trying to determine the species as these four are very similar. For official recording purposes they'd require close examination, but for personal records they can be separated into two groups, which fortunately places one of the common species in each group with one of the much rarer ones.

Trochosa ruricola and Trochosa rubusta are distinguished by the cardiac mark being paler than the ground colour of the abdomen, whereas in Trochosa terricola and Trochosa spinipalpis it is pretty much the same colour.

Trochosa ruricola and Trochosa terricola are the two common species. The former is widespread across the south and most central areas, but becoming less frequent further north. It can often be found under stones or logs in damp grassland, marshland or ditch margins. The latter is abundant and well distributed throughout Britain. It occurs in a wide range of habitats including woodland, grassland and heathland where it may be found in similar places as Trochosa ruricola such as under deadwood.     

The Pirata genus used to include six species, but three were moved to the new British genus Piratula in the revised checklist (Lavery, 2019). They occur in wetland habitats, hence the collective group name of 'otter spiders'. They are superficially similar to Pardosa species, but are distinguished by a Y-shaped median mark on the carapace.

The common form is Pirata piraticus, which can be found in a wide range of wetland areas just about anywhere across the country. It usually remains hidden away in cooler weather, but when it's warmer and the sun is out, it becomes active and may be seen on low vegetation or, as with the individual I found at Fishlake Meadows, actually on the water surface, which in this case was no more than a flooded footpath. The other individual, labelled Pirata sp. is interesting as it was photographed in damp woodland, well away from any known water source. The general appearance, and colour are characteristic of the species, but the markings are not that well defined. The general habitat and the fact that it was on Sphagnum moss point to the distinct possibility that it could be the smaller, nationally scarce Pirata tenuitarsis.

Pirata piscatorius is much darker with a clear white marginal band on the carapace. It favours very wet areas and is known as the Fishing Otter Spider. It's another scarce species with widespread, although very patchy distribution but, as with Pirata tenuitarsis, it has been recorded from my general area, albeit not for some while.   

Looking through all the other lycosids, there are three rather attractive species that I would really like to find and photograph; Arctosa perita known as the Sand Bear Spider, and then two uncommon species, Alopecosa barbipes and Arctosa leopardus.

Updated, Jan.25 (v.3)