Search results
Results From The WOW.Com Content Network
However, it lacks some typical annelid features and has features which are not usually found in annelids and some of which are associated with other phyla. [58] Then Simon Conway Morris and John Peel reported Phragmochaeta from Sirius Passet , about 518 million years old , and concluded that it was the oldest annelid known to date. [ 1 ]
The annelids, collectively called Annelida, are a large phylum of animals, comprising the segmented worms, with about 15 000 modern species including the well-known earthworms and leeches The main article for this category is Annelid .
Pleistoannelida is a group of annelid worms that comprises the vast majority of the diversity in phylum Annelida.Discovered through phylogenetic analyses, it is the largest clade of annelids, comprised by the last common ancestor of the highly diverse sister groups Errantia and Sedentaria (Clitellata and related polychaetes) and all the descendants of that ancestor.
The Spiralia are a morphologically diverse clade of protostome animals, including within their number the molluscs, annelids, platyhelminths and other taxa. [4] The term Spiralia is applied to those phyla that exhibit canonical spiral cleavage, a pattern of early development found in most members of the Lophotrochozoa.
This list of prehistoric annelids is an attempt to create a comprehensive listing of all genera that have ever been included in Annelida which have been found preserved as fossils. This list excludes purely vernacular terms.
The body is muscular and relatively solid; the coelom, the spacious body cavity found in other annelids, is reduced to small channels. The majority of leeches live in freshwater habitats, while some species can be found in terrestrial or marine environments.
Leeches can be found in nearly every part of the world, in freshwater, terrestrial, and marine habitats. The subclass Oligochaeta, which includes the earthworms as the largest members of the group, mostly live on land, burrowing in damp soil. Smaller freshwater species burrow in mud or live among aquatic vegetation.
The genus Glycera is a group of polychaetes (bristle worms) commonly known as bloodworms.They are typically found on the bottom of shallow marine waters, and some species (e.g. common bloodworms) can grow up to 35 cm (14 in) in length.