What is the difference between Errantia and Sedentaria?
A few are parasitic. The mobile forms (Errantia) tend to have well-developed sense organs and jaws, while the stationary forms (Sedentaria) lack them, but may have specialized gills or tentacles used for respiration and deposit or filter feeding, e.g., fanworms.
What characteristics do Polychaetes have?
Class Polychaeta
- Metamerically segmented.
- Bilateral symmetry.
- Chitinous setae called parapodia.
- Schizocoelic.
- Closed circulatory system.
- Complete digestive system.
- Respiration through skin, gills or parapodia.
- Nephridia for excretion.
What do sedentary polychaetes feed on?
Sedentary polychaetes have greatly modified head regions for specialized feeding habits. Many are adapted for feeding on organic matter deposited on the ocean floor. For example, the lugworms have a simple, thin-walled, jawless proboscis, which is used to draw sand into the gut, where organic matter is removed.
Does Hirudinea have setae?
All Oligochaetes bear bristles called “setae” on most segments. In the earthworms, setae are very short and can be best seen under the microscope. Leeches, ( Hirudinea), are also Clitellates.
Are Errantia predators?
Errantia (scaleworms, sea mice; phylum Annelida, class Polychaeta) A subclass of polychaete worms which have a large number of body segments, those of the head and posterior differing from the rest. The mouth often has several paired jaws. Most are vagile predators, others adopt a burrowing mode of life.
What is a polychaete in biology?
polychaete. / (ˈpɒlɪˌkiːt) / noun. any marine annelid worm of the class Polychaeta, having a distinct head and paired fleshy appendages (parapodia) that bear bristles (chaetae or setae) and are used in swimming: includes the lugworms, ragworms, and sea mice.
Are earthworms Errantia?
Based on these results, Annelida was split into two major clades, one clade (the Errantia) adapted to an errant mobile life and the other (the Sedentaria) which includes earthworms and leeches, to a more sessile, sedentary one.
Are Errantia predatory?
The mouth often has several paired jaws. Most are vagile predators, others adopt a burrowing mode of life. They are first recorded from the Cambrian.
What type of worms are Polychaetes?
Polychaetes, which include rag worms, lugworms, bloodworms, sea mice, and others, are marine worms notable for well-defined segmentation of the body. Unique among annelids, most polychaete body segments bear a pair of parapodia (flat, lobelike outgrowths) with setae, or tiny bristles.
Is Hirudinea a class?
ClitellataLeech / Class
What does sedentaria stand for?
Nereis, Eunice, Glycera. Clade (Class) Sedentaria (sed-en-ter’iah) Marine, freshwater, and terrestrial annelids; parapodia with reduced lobes or parapodia lacking; setae associated with the stiff body wall to facilitate anchoring in tubes and burrows; palps reduced. Includes the clade Clitellata, echiruans, and siboglinids.
What is the difference between sedentary and migratory species?
Sedentary species show a diversity of testicular cycles and greater variation than migratory species in their onset of reproduction, depending on whether they are paired and maintain year-round territories or defend territories only during the breeding period (Small et al., 2007;
What is clade sedentaria?
Clade (Class) Sedentaria (sed-en-ter’iah) Marine, freshwater, and terrestrial annelids; parapodia with reduced lobes or parapodia lacking; setae associated with the stiff body wall to facilitate anchoring in tubes and burrows; palps reduced. Includes the clade Clitellata, echiruans, and siboglinids. Arenicola, Riftia, Lumbricus, Hirudo