Siboglinidae is a family of polychaete annelid worms whose members made up the former phyla Pogonophora and Vestimentifera. The family is composed of around 100 species of vermiform creatures which live in thin tubes buried in sediment (Pogonophora) or in tubes attached to hard substratum (Vestimentifera) at ocean depths ranging from 100 to 10,000 m. They can also be found in association with hydrothermal vents, methane seeps, sunken plant material, and whale carcasses.
Any worm that lives in a marine environment is considered a water worm. Marine worms are found in several different phyla, including the Platyhelminthes, Nematoda, Annelida, Chaetognatha, Hemichordata, and Phoronida. For a list of marine animals that have been called "sea worms", see sea worm.
The Trochozoa are a proposed Lophotrochozoa clade that is a sister clade of Bryozoa. The clade would include animals in five phyla: the Nemertea, the Annelida, the Mollusca, and the two Brachiozoan phyla, Brachiopoda and Phoronida.
Segmentation in biology is the division of some animal and plant body plans into a linear series of repetitive segments that may or may not be interconnected to each other. This article focuses on the segmentation of animal body plans, specifically using the examples of the taxa Arthropoda, Chordata, and Annelida. These three groups form segments by using a "growth zone" to direct and define the segments. While all three have a generally segmented body plan and use a growth zone, they use different mechanisms for generating this patterning. Even within these groups, different organisms have different mechanisms for segmenting the body. Segmentation of the body plan is important for allowing free movement and development of certain body parts. It also allows for regeneration in specific individuals.
Lophotrochozoa is a clade of protostome animals within the Spiralia. The taxon was established as a monophyletic group based on molecular evidence. The clade includes animals like annelids, molluscs, bryozoans, brachiopods, and platyhelminthes.
The lophophore is a characteristic feeding organ possessed by four major groups of animals: the Brachiopoda, Bryozoa, Hyolitha, and Phoronida, which collectively constitute the protostome group Lophophorata. All lophophores are found in aquatic organisms.
A trochophore (;) is a type of free-swimming planktonic marine larva with several bands of cilia.
The ParaHox gene cluster is an array of homeobox genes from the Gsx, Xlox (Pdx) and Cdx gene families.
The Serpulidae are a family of sessile, tube-building annelid worms in the class Polychaeta. The members of this family differ from other sabellid tube worms in that they have a specialized operculum that blocks the entrance of their tubes when they withdraw into the tubes. In addition, serpulids secrete tubes of calcium carbonate. Serpulids are the most important biomineralizers among annelids. About 300 species in the family Serpulidae are known, all but one of which live in saline waters. The earliest serpulids are known from the Permian.
A metatrochophore (;) is a type of larva developed from the trochophore larva of a polychaete annelid.
The Spiralia are a morphologically diverse clade of protostome animals, including within their number the molluscs, annelids, platyhelminths and other taxa. 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.
Serpula is a genus of sessile, marine annelid tube worms that belongs to the family Serpulidae. Serpulid worms are very similar to tube worms of the closely related sabellid family, except that the former possess a cartilaginous operculum that occludes the entrance to their protective tube after the animal has withdrawn into it. The most distinctive feature of worms of the genus Serpula is their colorful fan-shaped "crown". The crown, used by these animals for respiration and alimentation, is the structure that is most commonly seen by scuba divers and other casual observers.
Branchiostoma floridae, the Florida lancelet, is a lancelet of the genus Branchiostoma. The genome of this species has been sequenced, revealing that among the chordates, the morphologically simpler tunicates are actually more closely related to vertebrates than lancelets. An embryo of a Florida amphioxus has a larval pharynx with gill slits that is asymmetrical. The gill slits in the larval pharynx form in the center of the embryo when it is in its earliest stage of development (primordial) meaning the thick layer of endoderm is overlapped by a thin layer; which aids into making the B. floridae asymmetrical from left to right. The lancelet Branchiostoma floridae maintains a high level of Fox transcription factor gene diversity, with 32 distinct Fox genes in its genome, and 21,229 clusters of cDNA clones, making it very useful to the research community.
Pomatoceros triqueter is a species of tube-building annelid worm in the class Polychaeta. It is common on the north eastern coasts of the Atlantic Ocean and in the Mediterranean Sea.
James A. Lake is an American evolutionary biologist and a Distinguished Professor of Molecular, Cell, and Developmental Biology and of Human Genetics at UCLA. Lake is best known for the New Animal Phylogeny and for the first three-dimensional structure of the ribosome. He has also made significant contributions to understanding genome evolution across all kingdoms of life, including discovering informational and operational genes, elucidating the complexity hypothesis for gene transfer, rooting the tree of life, and understanding the early transition from prokaryotic to eukaryotic life.
Platynereis dumerilii is a species of annelid polychaete worm. It was originally placed into the genus Nereis and later reassigned to the genus Platynereis. Platynereis dumerilii lives in coastal marine waters from temperate to tropical zones. It can be found in a wide range from the Azores, the Mediterranean, in the North Sea, the English Channel, and the Atlantic down to the Cape of Good Hope, in the Black Sea, the Red Sea, the Persian Gulf, the Sea of Japan, the Pacific, and the Kerguelen Islands. Platynereis dumerilii is today an important lab animal, it is considered as a living fossil, and it is used in many phylogenetic studies as a model organism.
Biomineralising polychaetes are polychaetes that produce minerals to harden or stiffen their own tissues (biomineralize).
The annelids, also known as the segmented worms, are a large phylum, with over 22,000 extant species including ragworms, earthworms, and leeches. The species exist in and have adapted to various ecologies – some in marine environments as distinct as tidal zones and hydrothermal vents, others in fresh water, and yet others in moist terrestrial environments.
Olev Vinn is Estonian paleobiologist and paleontologist.
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 and all the descendants of that ancestor. Most groups in the Clade find their ancestors within the Cambrian explosion when Annelid diversity expanded dramatically. The Pleistoannelida clade covers a variety of traits. However, the evolution of simple to complex eyes, developed papillae for burrowing, and for some specialized radioles for feeding can be seen universally across every species. New findings have discovered the range of Annelid diversity have led to uncertainty if groups with developed ancestral traits should remain within the clade. Furthermore There's been a lack of recently discovered Annelid traits being used in the categorization of groups within the clade, leading to many hypothesis on how to do so and which should remain within the clade. Currently three smaller clades that were originally a part of the groups Errantia and Sedentaria have been proven to fall outside while still being connected to the basal groups.
