Palpata is a subclass

Class (biology)

In biological classification, class is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, order, family, genus, and species, with class fitting between phylum and order...

 of polychaete

Polychaete

The Polychaeta or polychaetes are a class of annelid worms, generally marine. Each body segment has a pair of fleshy protrusions called parapodia that bear many bristles, called chaetae, which are made of chitin. Indeed, polychaetes are sometimes referred to as bristle worms. More than 10,000...

 worm. Members of this subclass are mostly deposit feeders

Detritivore

Detritivores, also known as detritophages or detritus feeders or detritus eaters or saprophages, are heterotrophs that obtain nutrients by consuming detritus . By doing so, they contribute to decomposition and the nutrient cycles...

 on marine detritus or filter feeder

Filter feeder

Filter feeders are animals that feed by straining suspended matter and food particles from water, typically by passing the water over a specialized filtering structure. Some animals that use this method of feeding are clams, krill, sponges, baleen whales, and many fish and some sharks. Some birds,...

s.

Characteristics

Palpata includes the majority of genera and species of polychaete worms and is subdivided into the orders

Class (biology)

In biological classification, class is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, order, family, genus, and species, with class fitting between phylum and order...

 Aciculata

Aciculata

Aciculata is an order of polychaete worms. These worms are found worldwide in marine environments and brackish water.-Families:Suborder Eunicida*Amphinomidae Savigny in Lamarck, 1818 *Diurodrilidae Kristensen and Niilonen, 1982...

 and Canalipalpata

Canalipalpata

Canalipalpata, also known as bristle-footed annelids or fan-head worms, is an order of polychaete worms, with 31 families in it including the Sabellida and the Alvinellidae, a family of deep-sea worms associated with hydrothermal vents.The Canalipalpata have no teeth or jaws. Most are filter feeders...

. The prostomium

Prostomium

Prostomium is the first body segment in annelid worms. It is in front of the mouth, being usually a small shelf- or lip-like extension over the dorsal side of the mouth. It sometimes bears antennae and eyes. It often functions like a kind of overlip when the animal is feeding...

 is characterised by a pair of sensory palps which gives the subclass its name and which are lacking in the other main taxon

Taxon

|thumb|270px|[[African elephants]] form a widely-accepted taxon, the [[genus]] LoxodontaA taxon is a group of organisms, which a taxonomist adjudges to be a unit. Usually a taxon is given a name and a rank, although neither is a requirement...

 of polychaetes, the Scolecida

Scolecida

Scolecida is a subclass of polychaete worm. Scolecids are mostly unselective deposit feeders on marine detritus.-Characteristics:Scolecids have parapodia with rami that are all alike....

.

Aciculata is a large group including about half of all existing polychaete species and is equivalent to the old taxonomic group "Errantia", worms that can move about freely by crawling or swimming. These worms are characterised by having internal supporting chaeta

Chaeta

A chaeta or cheta is a chitinous bristle or seta found on an insect, arthropod or annelid worms such as the earthworm, although the term is also frequently used to describe similar structures in other invertebrates. The plural form is chaetae or chetae.In the Polychaeta, they are located on the...

e in their parapodia

Parapodium

Parapodia , singular parapodium, are paired, un-jointed lateral outgrowths from the bodies of two different invertebrate groups, which are primarily marine in habitat...

. Aciculata is divided into suborders Eunicida and Phyllodocida

Phyllodocida

Phyllodocida is an order of polychaete worms in the subclass Aciculata. These worms are mostly marine though some are found in brackish water. Most are active benthic creatures, moving over the surface or burrowing in sediments, or living in cracks and crevices in bedrock. A few construct tubes in...

.

Canalipalpata is equivalent to the old taxonomic group "Sedentaria", worms that stay in one place, living in a self-made tube composed of mud or sand cemented together with mucus. Members of Canalipalpata are worms with elongated grooved palp structures used for feeding and the order is divided into suborders Sabellida

Sabellida

Sabellida is a suborder of annelid worms in the class Polychaeta. They are filter feeders with no buccal organ. The prostomium is fused with the peristomium and bears a ring of feathery feeding tentacles...

, Spionida

Spionida

Spionida is a suborder of marine polychaete worms in the order Canalipalpata. Spionids are cosmopolitan and live in soft substrates in the littoral or neritic zones.-Characteristics:...

 and Terebellida

Terebellida

Terebellida make up a suborder of the Polychaeta class, commonly referred to as "bristle worms". Together with the Sabellida, the Spionida and some enigmatic families of unclear taxonomic relationship , they make up the order Canalipalpata, one of the three main clades of polychaetes...

.

Taxonomy

Further research is likely to result in changes to the cladistics

Cladistics

Cladistics is a method of classifying species of organisms into groups called clades, which consist of an ancestor organism and all its descendants . For example, birds, dinosaurs, crocodiles, and all descendants of their most recent common ancestor form a clade...

 of the annelids, the monophyly

Monophyly

In common cladistic usage, a monophyletic group is a taxon which forms a clade, meaning that it contains all the descendants of the possibly hypothetical closest common ancestor of the members of the group. The term is synonymous with the uncommon term holophyly...

 of which is in doubt. The World Register of Marine Species considers Palpata a "nomen dubium" and divides the polychaetes into three subclasses, Aciculata, Canalipalpata and Scolecida

Scolecida

Scolecida is a subclass of polychaete worm. Scolecids are mostly unselective deposit feeders on marine detritus.-Characteristics:Scolecids have parapodia with rami that are all alike....

.