Oligochaetes, which range in length from a few millimetres (a fraction of an inch) to more than 3 m (10 feet), are notable for the absence of a head and parapodia, the flat, lobelike outgrowths used by many polychaete annelids (class Polychaeta) for locomotion. They have few setae, or bristles, on the body.

What are the characteristics of oligochaeta?

Characteristics of Oligochaeta

Oligochaete worms have long, segmented, tubular bodies, giving them the appearance of a piece of thick spaghetti. They can range in length from just a few millimeters to over 10 feet!

How are oligochaeta different from other annelids?

Oligochaetes are another subclass of the phylum Annelida that compose earthworms. In comparison to polychaetes, oligochaetes have few bristles on their outer surface of the body with no parapodia. Generally, earthworms are either aquatic or terrestrial, and the terrestrial earthworms burrow into the soil.

Do all annelids have parapodia?

Nearly all polychaetes have parapodia that function as limbs, while other major annelid groups lack them. Parapodia are unjointed paired extensions of the body wall, and their muscles are derived from the circular muscles of the body. They are often supported internally by one or more large, thick chetae.

Do all polychaetes have parapodia?

The known species of polychaetes share only a few characteristics. Each has a head, a tail and a segmented body, and typically each body segment has a pair of leg-like parapodia with spiny bristles sticking out. ... Since there is an exception to every rule, some polychaetes have no parapodia at all.

The Amazing World of Polychaetes

35 related questions found

How do polychaetes operate parapodia?

Polychaetes' locomotion traits, which involve extension/retraction of parapodia and chaetae, are burrowing, slow creeping (six to eight segments in one 'wavelength'), fast crawling (14 segments), and swimming. Some Aeolosoma species swim with the aid of beating the cilia at the head end of the body.

Are all polychaetes Marine?

The Polychaeta /ˌpɒlɪˈkiːtə/, also known as the bristle worms or polychaetes, are a paraphyletic 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.

Are annelids invertebrates?

annelid, phylum name Annelida, also called segmented worm, any member of a phylum of invertebrate animals that are characterized by the possession of a body cavity (or coelom), movable bristles (or setae), and a body divided into segments by transverse rings, or annulations, from which they take their name.

Are annelids Monoecious or dioecious?

Annelids may be either monoecious with permanent gonads (as in earthworms and leeches) or dioecious with temporary or seasonal gonads that develop (as in polychaetes). However, cross-fertilization is preferred in hermaphroditic animals.

Which annelid group has parapodia?

The largest class of annelids is polychaeta. Polychaetes have parapodia, fleshy, paddlelike lobes on each segment. Parapodia function in locomotion and gas exchange. Setae are located on the parapodia.

Is Oligochaeta Monoecious?

Testes and ovaries usually develop, though not invariably, in many body segments; and the sperm and eggs, often in enormous numbers, are stored in the coelom. Fertilization is external. In oligochaetes (all of which are monoecious) on the other hand, the gonads develop in a few specific segments.

Which of the following animal is belongs to class Oligochaeta?

Earthworms are members of phylum Annelida and class Oligochaeta, living in different strata of soil.

Is Oligochaeta terrestrial?

Terrestrial oligochaetes are commonly known as earthworms and burrow into the soil. ... They burrow into the sediment or live among the vegetation mostly in shallow, freshwater environments. Some are transitional between terrestrial and aquatic habitats, inhabiting swamps, mud or the borders of water bodies.

How do you identify an Oligochaete?

Oligochaetes are hermaphrodites so have male and female genitalia. Examination of the genitalia is normally required for genus or species level identifications, with the notable exception of the Naidinae. Clitellum: The easiest way to determine whether a worm is mature is to look for the clitellum.

Why are earthworms classified as Oligochaeta?

The 'Oligo' in Oligochaeta means 'few' just as the 'Poly' in Polychaeta means 'many'. Thus the Oligochaeta are the animals with few chaetae, or few bristles. Normally, as in the common earthworms, Oligochaetes have 8 small chaetae per body segment. These are usually arranged in four groups of two around the body.

How do Oligochaeta reproduce?

All oligochaetes are hermaphroditic, and nearly all cross-fertilize by copulation. Male and female reproductive organs are located in separate segments. ... The worm then secretes a cocoon into which it deposits the eggs and the sperm; fertilization and development of the eggs occur in the cocoon.

Is this worm Monoecious or dioecious?

BREEDING: Little is known about the reproduction of this species in particular. Earthworms are monoecious, meaning that both female and male organs are present within the same worm.

Do annelids have an exoskeleton?

The exoskeleton is composed of a thin, outer protein layer, the epicuticle, and a thick, inner, chitin-protein layer, the procuticle. ... Annelids have a thin chitinous cuticle covering their bodies but it is not as well developed as in arthropods.

Is an arthropod a vertebrate or invertebrate?

Arthropods are invertebrates with jointed legs. They make up about 75% of all animals on Earth and have a major role in maintaining ecosystems as pollinators, recyclers of nutrients, scavengers and food for other animals.

Are molluscs vertebrates or invertebrates?

mollusk, also spelled mollusc, any soft-bodied invertebrate of the phylum Mollusca, usually wholly or partly enclosed in a calcium carbonate shell secreted by a soft mantle covering the body.

Is an amphibian a vertebrate or invertebrate?

Vertebrates such as mammals, fish, birds, reptiles and amphibians all have a backbone, whereas invertebrates, such as butterflies, slugs, worms, and spiders, don't. ... Invertebrates can be found in land, marine and freshwater habitats, and live on every continent.

Do polychaete worms have an exoskeleton?

No, bristle worms do not have exoskeletons. They also do not have endoskeletons, the term given to animals whose skeletal structure is located within...

Do bristle worms have legs?

Bristle worms are segmented worms, usually less than 10 cm long. Each segment has pairs of legs (parapodia) usually used to move around. On each leg there are the bristles, tiny hair-like structures, that have named the class. Other than that, a wide range of body shapes are displayed among the bristle worms.

Does a bristle worm have tentacles?

Other bristleworms feed harmlessly on algae, others are scavengers. Yet others feed on detritus. They may swallow sand and mud and process these for the edible bits, others have tentacles and other appendages on their heads to sweep the surface for detritus or collect detritus suspended in the water.