Intertidal populations of
Diopatra from Spanish, Portuguese and French Atlantic beaches have traditionally been identified as
D. neapolitana. This species is present, mainly in Spain and Portugal. However, at least some French beaches are occupied by a distinct species,
D. biscayensis, here described as new. In addition, in Portugal and Spain, a third species, here described as new,
D. cryptornata, will also key out as
D. neapolitana using standard keys, but is morphologically distinct. The three species can be separated not only on traditional characters, but also on obvious differences in anterior morphology not usually considered in descriptions. The French habitats now occupied by
D. biscayensis, previously had populations of
D. neapolitana alone as documented by collections in the Paris Museum made by Quatrefages and Saint-Joseph in the mid-late 1800s.
Diopatra marocensis has recently been reported from Atlantic waters, from both intertidal and subtidal areas. Since this species can be confused with the three species named above, a partial re-description based on paratype material is included here. Finally, a fifth species,
D. micrura, has recently been described from the area and is here briefly characterized based on the original description. A key to all five species has been constructed.
