The Euphrosinidae is a family of polychaetous annelids consisting of five genera with about 70 species.They are reported from sandy to silt/mud sediments world wide, most commonly in cold shelf to abyssal habitats and polar seas.All species are thought to be carnivorous.They are cryptic within their environment, having short, stout, oval bodies with few segments.
The Euphrosinidae is related to the family Amphinomidae; sometimes the two groups are considered as one family, the Amphinomidae sensu lato (Day 1967). Unlike the Amphinomidae, which are known as fire worms for their painful sting, euphrosinid worms do not have hollow, venom-filled chaetae, though their chaetae are carcarious, sometimes heavily so.Euphrosinid worms generally move faster than amphinomid worms.They have tufts of long chaeta as the dorsal branch of their biramous parapodia; these chaetae are used to diagnose species.The polychaetes in this family are poorly known, as are rarely encountered and collected, so have not been well characterized.
The name is Euphrosinidae comes from Greek meaning merriment.
(Hutchings and Johnson 2000; Borda and Kudenov 2013, Wikipedia 2014)