Sternaspidae, commonly known as mud owls, are a family of

marine Marine is an adjective meaning of or pertaining to the sea or ocean. Marine or marines may refer to: Ocean * Maritime (disambiguation) * Marine art * Marine biology * Marine debris * Marine habitats * Marine life * Marine pollution Military * ...

polychaete Polychaeta () is a paraphyletic class of generally marine annelid worms, commonly called bristle worms or polychaetes (). Each body segment has a pair of fleshy protrusions called parapodia that bear many bristles, called chaetae, which are ...

worms with short swollen bodies. They have a global distribution and live buried in soft sediment at depths varying from the

intertidal zone The intertidal zone, also known as the foreshore, is the area above water level at low tide and underwater at high tide (in other words, the area within the tidal range). This area can include several types of habitats with various species ...

to .

Description

Members of this family have oval or

dumbbell The dumbbell, a type of free weight, is a piece of equipment used in weight training. It can be used individually or in pairs, with one in each hand. History The forerunner of the dumbbell, halteres, were used in ancient Greece as lifting ...

-shaped bodies with a small number of segments, the

prostomium The prostomium (From Ancient Greek, meaning "before the mouth"; plural: prostomia; sometimes also called the "acron") is the cephalized first body segment in an annelid worm's body at the anterior end. It is in front of (but does not include) th ...

often being separated from the rest of the body by a narrower segment. The

peristomium The peristomium is the first true body segment in an annelid worm's body in the anterior end. It is directly behind the prostomium and contains the mouth, tentacular cirri, and sometimes feeding palps, which may instead occur on the prostomium. If ...

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

chaeta A chaeta or cheta (from Greek χαίτη “crest, mane, flowing hair"; plural: chaetae) is a chitinous bristle or seta found in annelid worms, (although the term is also frequently used to describe similar structures in other invertebrates such ...

e (bristles) and the next seven segments bear lateral bundles of tiny chaetae. The

parapodia In invertebrates, the term parapodium ( Gr. ''para'', beyond or beside + ''podia'', feet; plural: parapodia) refers to lateral outgrowths or protrusions from the body. Parapodia are predominantly found in annelids, where they are paired, unjointed ...

present on each segment are

biramous The arthropod leg is a form of jointed appendage of arthropods, usually used for walking. Many of the terms used for arthropod leg segments (called podomeres) are of Latin origin, and may be confused with terms for bones: ''coxa'' (meaning hip, plu ...

except for those near the posterior end of the body which are

uniramous The arthropod leg is a form of jointed appendage of arthropods, usually used for walking. Many of the terms used for arthropod leg segments (called podomeres) are of Latin origin, and may be confused with terms for bones: ''coxa'' (meaning hip, plur ...

. On the ventral side of the posterior of the body there are two

chitin Chitin ( C8 H13 O5 N)n ( ) is a long-chain polymer of ''N''-acetylglucosamine, an amide derivative of glucose. Chitin is probably the second most abundant polysaccharide in nature (behind only cellulose); an estimated 1 billion tons of chit ...

ised 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.

Behaviour

This worm lives submerged, head-down in the sediment, with its thread-like gills on the surface, presumably to facilitate oxygen take-up. It is a

deposit feeder Detritivores (also known as detrivores, detritophages, detritus feeders, or detritus eaters) are heterotrophs that obtain nutrients by consuming detritus (decomposing plant and animal parts as well as feces). There are many kinds of invertebrates, ...

and the

pharynx The pharynx (plural: pharynges) is the part of the throat behind the mouth and nasal cavity, and above the oesophagus and trachea (the tubes going down to the stomach and the lungs). It is found in vertebrates and invertebrates, though its ...

is eversible. It is presumed that the worm scoops up dollops of sediment with the pharynx and then extracts the nutrients from what is swallowed as the main bulk passes through the long, coiled gut.

Genera

The

World Register of Marine Species The World Register of Marine Species (WoRMS) is a taxonomic database that aims to provide an authoritative and comprehensive list of names of marine organisms. Content The content of the registry is edited and maintained by scientific speciali ...

lists the following genera:- * '' Caulleryaspis'' Sendall & Salazar-Vallejo, 2013 * '' Petersenaspis'' Sendall & Salazar-Vallejo, 2013 * '' Sternaspis'' Otto, 1820 * '' Schreiberius'' Otto, 1821

References

{{Taxonbar, from=Q16725967 Terebellida Annelid families