Sternaspidae

Sternaspidae, commonly known as mud owls, are a family of marine polychaete worms with short swollen bodies. They have a global distribution and live buried in soft sediment at depths varying from the intertidal zone to .

==Description== Members of this family have oval or dumbbell-shaped bodies with a small number of segments, the prostomium often being separated from the rest of the body by a narrower segment. The peristomium is reduced to lips. The first segment of the prostomium, bears the mouth but no antennae, palps or nuchal organ. The first three segments bear rows of chaetae (bristles) and the next seven segments bear lateral bundles of tiny chaetae. The parapodia present on each segment are biramous except for those near the posterior end of the body which are uniramous. On the ventral side of the posterior of the body there are two chitinised calcareous plates forming a shield, the margins of which are rimmed with bundles of capillary chaetae. A number of long, semi-coiled, thread-like gills arise from the base of the shield. The deep yellow or reddish hard shield distinguishes members of this family from other worm groups.