The spider family Pisauridae includes 336 described species (Platnick 2014), just 14 of which occur in North America north of Mexico. Several of the North American species are common east of the 100th meridian. Pisaurids somewhat resemble lycosids (wolf spiders), but the eyes of pisaurids are typically arranged in a pattern that is distinct from that seen in lycosids. Many pisaurids are quite large.
Pisaurids often hunt on vegetation, on tree trunks, or even on water, but (in contrast to lycosids) they are rarely found on bare ground. Some Dolomedes are known to capture small fish, tadpoles, aquatic insects, and large invertebrate larvae from ponds and slow-moving streams (a habit that accounts for the one of the common names for the family, "fishing spiders"). These spiders can skate over the water surface or plunge into the water to capture prey. When disturbed, they may climb down emergent aquatic vegetation and hide underwater.
Some or all pisaurids exhibit extended parental care. The female carries her egg case under her body, holding it in her chelicerae, while it is also attached to the spinnerets by a thread. When the young are ready to emerge from the egg sac, the female builds a nursery web for the young. She typically uses a folded leaf or similar structure as a roof and fills the space below with a sturdy tangle of threads, suspending the egg sac near the center and guarding the nursery from a nearby perch. When the young emerge, they remain in the nursery for a week or more, molt, then disperse.
In North America north of Mexico, there are just three pisaurid genera: Dolomedes (including the classic "fishing spiders"), Pisaurina, and Tinus.Pisaurina are found in herbaceous vegetation and small shrubs, typically in the ecotone between grasslands and woods or at stream and pond margins. Bruce and Carico (1988) studied mating behavior in Pisaurina mira and found that copulation occurs while the spiders are suspended from a dragline after the female is bound by a veil of the male's silk. Carico (1985) found that juveniles of Pisaurina mira construct silken retreats. Tinus peregrinus is found along the margins of streams in habitat similar to that of Dolomedes.
A phylogenetic analysis of the family was undertaken by Santos (2007). All the North American pisaurid genera were revised by Carico (1972, 1973, 1976), who also revised a number of Neotropical genera. Genitalic structure in the family was analyzed by Sierwald (1989, 1990). Trechalea, formerly considered a pisaurid, is now placed in the related family Trechaleidae (Carico 2005).
Some European Dolomedes are known to be of conservation concern (Iorio and Villepoux 2012).
(Carico 2005; Bradley 2013)
