Phylum

In biology, a phylum (plural

Plural

Plural, commonly abbreviated pl., is a grammatical number, typically referring to more than one of the referent in the real world. In the English language, singular and plural are the only grammatical numbers.-English:...

: phyla)"Phylum" is adopted from the Greek phylai, the clan-based voting groups in Greek city-states. is a taxonomic rank

Taxonomic rank

In biological classification, rank is the level in a taxonomic hierarchy. The most basic rank is that of species, the next most important is genus, and then family...

 below Kingdom

Kingdom (biology)

In biological taxonomy, kingdom and/or regnum is a taxonomic rank in either the highest rank, or the rank below domain. Each kingdom is divided into smaller groups called phyla...

 and above Class

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...

. "Phylum" is equivalent to the botanical term division.

Although a phylum is often spoken of as if it were a hard and fast entity, no satisfactory definition of a phylum exists. In fact, a phylum is perhaps best described as a statement of taxonomic ignorance. Consequently the number of phyla varies from author to author. The relationship between different phyla is increasingly well known, and larger clades can be erected to contain many of the phyla.

General description and familiar examples

Informally, phyla can be thought of as grouping animals based on general body plan

Body plan

A body plan is essentially the blueprint for the way the body of an organism is laid out. An organism's symmetry, its number of body segments and number of limbs are all aspects of its body plan...

, as well as developmental or internal organizations. For example, though seemingly divergent, spiders and crabs both belong to Arthropoda, whereas earthworms and tapeworms, similar in shape, are from Annelida and Platyhelminthes, respectively. Although the International Code of Botanical Nomenclature

International Code of Botanical Nomenclature

The International Code of Botanical Nomenclature is the set of rules and recommendations dealing with the formal botanical names that are given to plants. Its intent is that each taxonomic group of plants has only one correct name that is accepted worldwide...

 allows the use of the term "phylum" in reference to plants, the term "Division" is almost always used by botanists.

The best known animal phyla are the Mollusca, Porifera, Cnidaria

Cnidaria

Cnidaria is a phylum containing over 10,000 species of animals found exclusively in aquatic, mostly marine, environments. Their distinguishing feature is cnidocytes, specialized cells that they use mainly for capturing prey...

, Platyhelminthes, Nematoda, Annelida, Arthropod

Arthropod

An arthropod is an invertebrate that has an exoskeleton , a segmented body, and jointed attachments called appendages. Arthropods are animals belonging to the Phylum Arthropoda , and include the insects, arachnids, crustaceans, and others...

a, Echinodermata, and Chordata

Chordate

Chordates are animals which are either vertebrates or one of several closely related invertebrates. They are united by having, for at least some period of their life cycle, a notochord, a hollow dorsal nerve cord, pharyngeal slits, an endostyle, and a post-anal tail...

, the phylum to which humans belong. Although there are approximately 35 phyla, these nine include over 96% of animal species. Many phyla are exclusively marine, and only one phylum, the Onychophora (velvet worms) is entirely absent from the world's ocean

Ocean

An ocean is a large body of saline water, and a principal component of the hydrosphere. Approximately 75% of the Earth's surface is covered by ocean, a continuous body of water that is customarily divided into several principal oceans and smaller seas.More than half of this area is over 3,000...

s–although ancestral onycophorans were marine.

Earliest known phyla

The origin of phyla has traditionally been interpreted as a sudden and rapid event early in the Cambrian period, known as the Cambrian explosion

Cambrian explosion

The Cambrian explosion or Cambrian radiation was the seemingly rapid appearance of most major groups of complex animals around , as evidenced by the fossil record. This was accompanied by a major diversification of other organisms, including animals, phytoplankton, and calcimicrobes...

. However, this interpretation stemmed from an incomplete knowledge of the fossil record, and a circular definition of a phylum; organisms of the time were mainly similar to, but not strictly members of, modern phyla. The significance of this event depends on two factors:

1. How long did modern phyla exist prior to the Cambrian fossil embryos
   Fossil embryos
   Many fossils of the Doushantuo formation have been interpreted as fossil embryos; embryos are also common throughout the Cambrian fossil record.-Preservation:...
   
   ? New interpretations of the pre-Cambrian Ediacara biota
   Ediacara biota
   The Ediacara biota are ancient life-forms of the Ediacaran Period, which represent the earliest known complex multicellular organisms.Simple multicellular organisms such as red algae evolved at least . They appeared soon after the Earth thawed from the Cryogenian period's...
   
    suggest that there could have been an origin for some phyla earlier than the Cambrian.
2. How soon did phyla appear in the Cambrian? This factor depends on both the definition of a phylum and on interpretation of early fossils, which may not display characteristics needed to determine membership in a modern phylum – non-mineralised parts of organisms are rarely preserved.

The magnitude of the event was also overestimated as early authors felt it necessary to erect a new phylum for any organism that could not be accommodated in modern phyla. This approach is misleading and unhelpful; by one definition, such organisms do not fall into any phylum, but are classified as "aunts" of a phylum.

Defining a phylum

At the most basic level, a phylum can be defined in two ways: as a group of organisms with a certain degree of morphological or developmental similarity (the phenetic definition), or a group of organisms with a certain degree of relatedness (the phylogenetic definition). Attempting to define a level of the Linnean hierarchy without referring to relatedness is an unsatisfactory approach, but the phenetic definition is more useful when addressing questions of a morphological nature – such as how successful different body plans were.

Definition based on genetic relation

The largest objective measure in the above definitions is the "certain degree" – how unrelated do organisms need to be to be members of different phyla? The minimal requirement is that all organisms in a phylum should be related closely enough for them to be clearly more closely related to one another than to any other group. However, even this is problematic, as the requirement depends on our current knowledge about organisms' relationships: As more data becomes available, particularly from molecular studies, we are better able to judge the relationships between groups. So phyla can be merged or split if it becomes apparent that they are related to one another or not; for example, since the onychophora and the tardigrada have now been accepted as stem groups of the arthropod

Arthropod

An arthropod is an invertebrate that has an exoskeleton , a segmented body, and jointed attachments called appendages. Arthropods are animals belonging to the Phylum Arthropoda , and include the insects, arachnids, crustaceans, and others...

s, these three phyla should be combined.

This changeability of phyla has led some biologists to call for the concept of a phylum to be abandoned in favour of cladistics

Cladistics

Cladistics is a form of biological systematics which classifies living organisms on the basis of shared ancestry...

, a method in groups are placed on a "family tree" without any formal ranking of group size. So as to provide a handle on the size and significance of groups, a "body-plan" based definition of a phylum has been proposed by paleontologists Graham Budd and Sören Jensen. The definition was posited by paleontologists because it is extinct organisms that are typically hardest to classify, because they can be extinct off-shoots that diverged from a phylum's history before the characters that define the modern phylum were all acquired.

Definition based on body plan

By Budd and Jensen's definition, phyla are defined by a set of characters shared by all their living representatives. This has a couple of small problems – for instance, characters common to most members of a phylum may be secondarily lost by some members. It is also defined based on an arbitrary point of time (the present). However, as it is character based, it is easy to apply to the fossil record. A more major problem is that it relies on an objective decision of which group of organisms should be considered a phylum.

Its utility is that it makes it easy to classify extinct organisms as "stem groups" to the phyla with which they bear the most resemblance, based only on the taxonomically important similarities. However, proving that a fossil belongs to the crown group of a phylum is difficult, as it must display a character unique to a sub-set of the crown group.
Further, organisms in the stem group to a phylum can bear all the aspects of the "body plan" of the phylum without all the characters necessary to fall within it. This weakens the idea that each of the phyla represents a distinct body plan.

Based upon this definition, which some say is unreasonably affected by the chance survival of rare groups, which vastly increase the size of phyla, representatives of many modern phyla did not appear until long after the Cambrian – as late as the Carboniferous

Carboniferous

The Carboniferous is a geologic period and system that extends from the end of the Devonian period, about 359.2 ± 2.5 Ma , to the beginning of the Permian period, about 299.0 ± 0.8 Ma ....

 in the case of the Priapulids.

Animal phyla

Phylum	Meaning	Common Name	Distinguishing characteristic	Species described
Acanthocephala Acanthocephala The Acanthocephala is a phylum of parasitic worms known as acanthocephales, thorny-headed worms, or spiny-headed worms, characterised by the presence of an evertable proboscis, armed with spines, which it uses to pierce and hold the gut wall of its host...	Thorny headed worms	Thorny-headed worms	Reversible spiny proboscis Proboscis In general, a proboscis is an elongated appendage from the head of an animal, either a vertebrate or an invertebrate..-Etymology:...	about 750
Acoelomorpha Acoelomorpha The Acoelomorpha are a disputed phylum of animals with planula-like features and formerly considered to belong to the phylum Platyhelminthes, but recently classified by Jaume Baguñà and Marta Riutort as a separate phylum, basal among the Bilateria....	Without gut	Acoels	No mouth or alimentary canal
Annelida	Little ring	Segmented worms	Multiple circular segment	about 16,300 modern
Arthropoda	Jointed foot	Arthropods	Chitin Chitin Chitin n is a long-chain polymer of a N-acetylglucosamine, a derivative of glucose, and is found in many places throughout the natural world. It is the main component of the cell walls of fungi, the exoskeletons of arthropods, such as crustaceans Chitin...  exoskeleton Exoskeleton An exoskeleton is an external skeleton that supports and protects an animal's body, in contrast to the internal endoskeleton of, for example, a human. Some animals, such as the tortoise, have both an endoskeleton and an exoskeleton...	1,134,000+
Brachiopoda	Arm foot	Lamp shells	Lophophore Lophophore The lophophore is a characteristic feeding organ possessed by three major groups of animals: the Brachiopoda, Bryozoa, and Phoronida . All lophophores are found in aquatic organisms.-Characteristics:...  and pedicle Pedicle Pedicle or pedicel may refer to:*Pedicle of vertebral arch, the segment between the transverse process and the vertebral body, and is often used as a radiographic marker and entry point in vertebroplasty and kyphoplasty procedures...	between 300 and 500 extant
Bryozoa Bryozoa The Bryozoa, also known as Ectoprocta, are a phylum of aquatic animals, typically about long, that sieve food particles out of the water using a retractable lophophore, a "crown" of tentacles lined with cilia. Most marine species live in tropical waters, but a few occur in oceanic trenches and...	Moss animals	Moss animals, sea mats	Lophophore, no pedicle, ciliated tentacle Tentacle Tentacles can refer to the elongated flexible organs that are present in some animals, especially invertebrates, and sometimes to the hairs of the leaves of some insectivorous plants. Usually, they are used for feeding, feeling and grasping... s	about 5,000 living species
Chaetognatha Chaetognatha Chaetognatha, meaning hair-jaws, is a phylum of predatory marine worms that are a major component of plankton worldwide. About 20% of the known species are benthic and can attach to algae or rocks. They are found in all marine waters from surface tropical waters and shallow tide pools to the deep...	Longhair jaw	Arrow worms	Chitin Chitin Chitin n is a long-chain polymer of a N-acetylglucosamine, a derivative of glucose, and is found in many places throughout the natural world. It is the main component of the cell walls of fungi, the exoskeletons of arthropods, such as crustaceans Chitin... ous spines either side of head, fins	about 100 modern species
Chordata	Cord	Chordates	Hollow dorsal nervous chord Nervous system The nervous system is a network of specialized cells that communicate information about an organism's surroundings and itself. It processes this information and causes reactions in other parts of the body. It is composed of neurons and other specialized cells called glial cells that aid in the... , notochord Notochord The notochord is a flexible, rod-shaped body found in embryos of all chordates. It is composed of cells derived from the mesoderm and defines the primitive axis of the embryo. In some chordates, it persists throughout life as the main axial support of the body, while in most vertebrates it is... , pharyngeal slit Pharyngeal slit Pharyngeal slits, characteristic of both hemichordata and chordata, are used by organisms in feeding. The wall of the pharynx is perforated by up to 200 vertical slits, which are separated by stiffening rods.... s, endostyle Endostyle An endostyle is a longitudinal ciliated groove on the ventral wall of the pharynx which produces mucus to gather food particles. It is found in urochordates and cephalochordates, and in the larvae of lampreys. It aids in transporting food to the esophagus. It is also called the hypopharyngeal groove... , post-anal Anus The anus is an opening at the opposite end of an animal's digestive tract from the mouth. Its function is to expel feces, unwanted semi-solid matter produced during digestion, which, depending on the type of animal, may be one or more of: matter which the animal cannot digest, such as bones; food...  tail Tail The tail is the section at the rear end of an animal's body; in general, the term refers to a distinct, flexible appendage to the torso. It is the part of the body that corresponds roughly to the sacrum and coccyx in mammals and birds...	about 100,000+
Cnidaria Cnidaria Cnidaria is a phylum containing over 10,000 species of animals found exclusively in aquatic, mostly marine, environments. Their distinguishing feature is cnidocytes, specialized cells that they use mainly for capturing prey...	Stinging nettle	Coelenterates	Nematocysts (stinging cells)	about 11,000
Ctenophora	Comb bearer	Comb jellies	Eight "comb rows" of fused cilia	about 100 modern species
Cycliophora	Wheel carrying	Symbion Symbion Symbion is the name of a genus of aquatic animals, less than ½ mm wide, found living attached to the bodies of cold-water lobsters. They have sac-like bodies, and three distinctly different forms in different parts of their two-stage life-cycle...	Circular mouth surrounded by small cilia	at least 3
Echinodermata	Spiny skin	Echinoderms	Five-fold radial symmetry Symmetry Symmetry generally conveys two primary meanings. The first is an imprecise sense of harmonious or aesthetically pleasing proportionality and balance; such that it reflects beauty or perfection...  in living forms, mesodermal calcified spines	about 7,000 extant and 13,000 extinct species
Echiura Echiura The Echiura, or spoon worms, are a small group of marine animals. They are often considered to be a group of annelids, although they lack the segmented structure found in other members of that group, and so may also be treated as a separate phylum...	Spine tail	Spoon worms	Set of hooks at posterior end	about 140
Entoprocta Entoprocta Entoprocta, whose name means "anus inside", is a phylum of mostly sessile aquatic animals, ranging from long. Mature individuals are goblet-shaped, on relatively long stalks. They have a "crown" of solid tentacles whose cilia generate water currents that draw food particles towards the mouth,...	Inside anus Anus The anus is an opening at the opposite end of an animal's digestive tract from the mouth. Its function is to expel feces, unwanted semi-solid matter produced during digestion, which, depending on the type of animal, may be one or more of: matter which the animal cannot digest, such as bones; food...	Goblet worm	Anus inside ring of cilia	about 150
Gastrotricha	Hair stomach	Meiofauna	Two terminal adhesive tubes	about 690
Gnathostomulida	Jaw orifice	Jaw worms		about 100
Hemichordata Hemichordata Hemichordata is a phylum of worm-shaped marine deuterostome animals, generally considered the sister group of the echinoderms. They date back to the Lower or Middle Cambrian and include an important class of fossils called graptolites, most of which became extinct in the...	Half cord	Acorn worms, pterobranchs	Stomochord Stomochord The stomochord is an flexible, hollow tube found in hemichordates. Stomochords were initially considered a variant of a primitive notochord, but are now recognized to not share histological composition to that of the notochord found in chordates....  in collar, pharyngeal slit Pharyngeal slit Pharyngeal slits, characteristic of both hemichordata and chordata, are used by organisms in feeding. The wall of the pharynx is perforated by up to 200 vertical slits, which are separated by stiffening rods.... s	about 100 living species
Kinorhyncha Kinorhyncha Kinorhyncha is a phylum of small marine pseudocoelomate invertebrates that are widespread in mud or sand at all depths as part of the meiobenthos. They are also called mud dragons.They are segmented, with a body consisting of a head, neck, and a trunk of eleven segments...	Motion snout	Mud dragons	Eleven segments, each with a dorsal plate	about 150
Loricifera Loricifera Loricifera is a small phylum of marine sediment-dwelling animals with twenty-two described species, in eight genera. Aside from these described species, there are approximately 100 more that have been collected and not yet described. Their size ranges from 100 µm to ca. 1 mm...	Corset bearer	Brush heads	Umbrella-like scales at each end	about 122
Micrognathozoa	Tiny jaw animals	—	Accordion Accordion The accordion is a portable box-shaped musical instrument of the hand-held bellows-driven free-reed aerophone family, sometimes referred to as a squeezebox...  like extensible thorax Thorax The thorax is a division of an animal's body that lies between the head and the abdomen.In mammals, the thorax is the region of the body formed by the sternum, the thoracic vertebrae and the ribs. It extends from the neck to the diaphragm, and does not include the upper limbs. The heart and the...	1
Mollusca Mollusca MolluscsSpelled mollusk in the USA, see reasons given in Rosenberg's ; for the spelling "mollusc" see the reasons given by . are animals belonging to the phylum Mollusca. There are around 93,000 recognized extant species, making it the largest marine phylum with about 23% of...	Thin shell	Mollusks / molluscs	Muscular foot and mantle Mantle (mollusc) The mantle is a significant part of the anatomy of molluscs: it is the dorsal body wall which covers the visceral mass....  round shell	112,000
Nematoda	Thread like	Round worms	Round cross section, keratin Keratin Keratins are a family of fibrous structural proteins; tough and insoluble, they form the hard but un-mineralized structures found in reptiles, birds, amphibians, and mammals...  cuticle Cuticle A cuticle , or cuticula, is any of a variety of tough but flexible, non-mineral outer coverings of an organism, or parts of an organism, that provide protection. Cuticles are non-homologous, differing in their origin, structure and chemical composition.-Human anatomy:In human anatomy, cuticle ...	80 000 – 1 million
Nematomorpha Nematomorpha Nematomorpha are a phylum of parasitic animals that are morphologically and ecologically similar to nematode worms, hence the name. They range in size from 1 cm to 1 meter long, and 1 to 3 millimetres in diameter...	Thread form	Horsehair worms		about 320
Nemertea Nemertea Nemertea is a phylum of invertebrate animals also known as ribbon worms or proboscis worms. Most of the 1,400 or so species are marine, with a few living in fresh water and a small number of terrestrial forms; they are found in all marine habits, and throughout the world's oceans...	A sea nymph	Ribbon worms		about 1200
Onychophora	Claw bearer	Velvet worms	Legs tipped by chitinous claws	about 200 modern
Orthonectida Orthonectida Orthonectida is a small phylum of poorly-known parasites of marine invertebrates that are among the simplest of multi-cellular organisms. Members of this phylum are known as orthonectids.-Characteristics:...	Straight swim		Single layer of ciliated cells surrounding a mass of sex cells	about 20
Phoronida	Zeus's mistress	Horseshoe worms	U-shaped gut	20
Placozoa	Plate animals			1
Platyhelminthes	Flat worms	Flat worms		about 25,000
Porifera	Pore bearer	Sponges	Perforated interior wall	over 5,000 modern
Priapulida Priapulida Priapulida are a phylum of marine worms with an extensible spiny proboscis. Priapulid fossils are known at least as far back as the Middle Cambrian. Their nearest relatives are probably Kinorhyncha and Loricifera with which they constitute the taxon Scalidophora...	Penis	Priapulid worms	Retractable proboscis surrounded by papillae	17
Rhombozoa Rhombozoa Rhombozoa, or Dicyemida, is a phylum of tiny parasites that live in the renal appendages of cephalopods. Although the name Dicyemida precedes Rhombozoa in usage, and is preferred by most contemporary authors, Rhombozoa still enjoys much popular support.Classification is controversial...	Lozenge animal	—	Single axial Axial Axial has different meanings:* In geometry, it means: along the same line as an axis or centerline: parallel , contrary to radial, perpendicular or tangential* In anatomy, it relates to an anatomical direction of animals and humans...  cell Cell (biology) The cell is the basic structural and functional unit of all known living organisms. It is the smallest unit of an organism that is classified as living, and is often called the building block of life. The Alberts text discusses how the "cellular building blocks" move to shape developing embryos...  surrounded by ciliated cells	75
Rotifera	Wheel bearer	Rotifers	Anterior crown of cilia	about 2000
Sipuncula Sipuncula The Sipuncula or Sipunculida, sipunculid worms or peanut worms, are a phylum containing 144-320 species of bilaterally symmetrical, unsegmented marine worms...	Small tube	Peanut worms	Mouth surrounded by invertible tentacles	144–320
Tardigrada	Slow step	Water bears	Four segmented body and head	1,000+
Xenoturbellida	Strange flatworm	—	Ciliated deuterostome	2
TOTAL: 36				2,000,000-

Groups formerly ranked as phyla

Name as phylum	Common name	Current consensus
Aschelminthes	Pseudocoelomates	Divided into several pseudocoelomate phyla.
Craniata Craniata Craniata is a proposed clade of chordate animals that contains the Myxini , Petromyzontida , and Gnathostomata as living representatives. Craniata includes all animals with a skull, or cranium, as the name suggests.Craniata as an unranked taxon replaces the former use of Vertebrata...	—	Subgroup of phylum Chordata; perhaps synonymous with Vertebrata.
Cephalochordata Cephalochordata Cephalochordata is a chordate subphylum defined by the presence of a notochord that persists throughout life. It is represented in the modern oceans by the lancelets. Fossil species are also known from the Chengjiang biota....	Lancelets	Subphylum of phylum Chordata.
Cephalorhyncha	—	Superphylum Scalidophora Scalidophora Scalidophora is a group of marine pseudocoelomate invertebrates, consisting of the three phyla Kinorhyncha, Priapulida, and Loricifera. The members of the group share a number of characteristics, including introvert larvae and moulting of the cuticle... .
Enterepneusta	Acorn worms	Class of phylum Hemichordata Hemichordata Hemichordata is a phylum of worm-shaped marine deuterostome animals, generally considered the sister group of the echinoderms. They date back to the Lower or Middle Cambrian and include an important class of fossils called graptolites, most of which became extinct in the... .
Gephyra	Peanut worms and spoon worms	Divided into phyla Sipuncula Sipuncula The Sipuncula or Sipunculida, sipunculid worms or peanut worms, are a phylum containing 144-320 species of bilaterally symmetrical, unsegmented marine worms...  and Echiura Echiura The Echiura, or spoon worms, are a small group of marine animals. They are often considered to be a group of annelids, although they lack the segmented structure found in other members of that group, and so may also be treated as a separate phylum... .
Mesozoa Mesozoa The Mesozoa are enigmatic, minuscule, worm-like parasites of marine invertebrates. It is still unclear as to whether they are degenerate platyhelminthes or truly-primitive, basal metazoans. Generally, these tiny, elusive creatures consist of a somatoderm of ciliated cells surrounding one or...	Mesozoans	Divided into phyla Orthonectida Orthonectida Orthonectida is a small phylum of poorly-known parasites of marine invertebrates that are among the simplest of multi-cellular organisms. Members of this phylum are known as orthonectids.-Characteristics:...  and Rhombozoa Rhombozoa Rhombozoa, or Dicyemida, is a phylum of tiny parasites that live in the renal appendages of cephalopods. Although the name Dicyemida precedes Rhombozoa in usage, and is preferred by most contemporary authors, Rhombozoa still enjoys much popular support.Classification is controversial... .
Myxozoa Myxozoa The Myxozoa are a group of parasitic animals of aquatic environments. Over 1300 species have been described and many have a two-host lifecycle, involving a fish and an annelid worm or bryozoan. The average size of a Myxosporea spore usually ranges from 10μm to 20μm and Malacosporea up to 2mm...		Severely modified Cnidarians.
Pentastomida Pentastomida The Pentastomida are an enigmatic group of parasitic invertebrates commonly known as tongue worms due to the resemblance of the species of the genus Linguatula to a vertebrate tongue....	Tongue worms	Subclass of Maxillopoda Maxillopoda Maxillopoda is a class under the phylum Arthropoda, subphylum Crustacea, and is characterised by a reduction of the abdomen and its appendages. The most species-rich groups are the barnacles and copepods....  of phylum Arthropoda.
Pogonophora Pogonophora There are two taxa with the name Pogonophora:*Pogonophora - an obsolete animal phylum, now treated as part of the family Siboglinidae*Pogonophora - a genus in the Euphorbiaceae...	Beard worms	Part of family Siboglinidae Siboglinidae Siboglinidae, also known as the beard worms, is a family of polychaete annelid worms whose members made up the former phyla Pogonophora and Vestimentifera. They are composed of about 100 species of vermiform creatures and live in thin tubes buried in sediments at ocean depths from 100 to 10,000 m...  of phylum Annelida.
Pterobranchia Pterobranchia Pterobranchia is a clade of small, worm-shaped animals. They belong to the hemichordata, and live in secreted tubes on the ocean floor. Pterobranchia feed by filtering plankton out of the water with the help of cilia attached to tentacles. There are about 30 known living species in the group.The...	—	Class of phylum Hemichordata Hemichordata Hemichordata is a phylum of worm-shaped marine deuterostome animals, generally considered the sister group of the echinoderms. They date back to the Lower or Middle Cambrian and include an important class of fossils called graptolites, most of which became extinct in the... .
Symplasma	Glass sponges	Class Hexactinellida of phylum Porifera.
Urochordata	Tunicates	Subphylum of phylum Chordata.
Vestimentifera	Vent worms	Part of family Siboglinidae Siboglinidae Siboglinidae, also known as the beard worms, is a family of polychaete annelid worms whose members made up the former phyla Pogonophora and Vestimentifera. They are composed of about 100 species of vermiform creatures and live in thin tubes buried in sediments at ocean depths from 100 to 10,000 m...  of phylum Annelida.

Plant divisions

Division	Meaning	Common name	Distinguishing characteristics
Anthocerotophyta	Flower-horn plants	Hornworts	Horn-shaped sporophyte Sporophyte All land plants, and some algae, have life cycles in which a haploid gametophyte generation alternates with a diploid sporophyte, the generation of a plant or alga that has a double set of chromosomes. A multicellular sporophyte generation or phase is present in the life cycle of all land plants... s, no vascular system
Bryophyta Moss Mosses are small, soft plants that are typically 1–10 cm tall, though some species are much larger. They commonly grow close together in clumps or mats in damp or shady locations. They do not have flowers or seeds, and their simple leaves cover the thin wiry stems...	Moss plants	Mosses	Persistent unbranched sporophyte Sporophyte All land plants, and some algae, have life cycles in which a haploid gametophyte generation alternates with a diploid sporophyte, the generation of a plant or alga that has a double set of chromosomes. A multicellular sporophyte generation or phase is present in the life cycle of all land plants... s, no vascular system
Marchantiophyta Marchantiophyta The Marchantiophyta are a division of bryophyte plants commonly referred to as hepatics or liverworts. Like other bryopeos, they have a gametophyte-dominant life cycle, in which cells of the plant carry only a single set of genetic information....	Marchantia plants	Liverworts	Ephemeral unbranched sporophyte Sporophyte All land plants, and some algae, have life cycles in which a haploid gametophyte generation alternates with a diploid sporophyte, the generation of a plant or alga that has a double set of chromosomes. A multicellular sporophyte generation or phase is present in the life cycle of all land plants... s, no vascular system
Lycopodiophyta Lycopodiophyta The Division Lycopodiophyta is a tracheophyte subdivision of the Kingdom Plantae. It is the oldest extant vascular plant division at around 420 million years old, and includes some of the most "primitive" extant species...	Wolf foot plants	Clubmosses & Spikemosses	Microphyll Microphyll The terminology of fossil plants is in places a little confusing. In the discipline's 200+ year history, certain concepts have become entrenched, even though improved understanding has threatened the foundations upon which they are based...  leaves Leaf In botany, a leaf is an above-ground plant organ specialized for photosynthesis. For this purpose, a leaf is typically flat and thin. There is continued debate about whether the flatness of leaves evolved to expose the chloroplasts to more light or to increase the absorption of carbon dioxide. In... , vascular system
Pteridophyta	Fern plants	Ferns & Horsetails	Prothallus gametophyte Gametophyte In plants and algae that undergo alternation of generations, a gametophyte is the multicellular structure, or phase, that is haploid, containing a single set of chromosomes:... s, vascular system
Pteridospermatophyta Pteridospermatophyta The term Pteridospermatophyta refers to several distinct groups of extinct seed plants . The oldest fossil evidence of plants of this type is of late Devonian age, and they flourished particularly during the Carboniferous and Permian periods...	Fern with seeds plant	Seed ferns	Only known from fossils, mostly Devonian Devonian The Devonian is a geologic period and system of the Paleozoic era spanning from . It is named after Devon, England, where rocks from this period were first studied.... , ranking in dispute
Pinophyta Pinophyta The conifers, division Pinophyta, also known as division Coniferophyta or Coniferae, are one of 13 or 14 division level taxa within the Kingdom Plantae. Pinophytes are gymnosperms. They are cone-bearing seed plants with vascular tissue; all extant conifers are woody plants, the great majority...	Sap/pitch plants	Conifers	Cones containing seeds and wood composed of tracheids
Cycadophyta	Palm plants	Cycads	Seeds, crown of compound leaves
Ginkgophyta	Ginkgo plants	Ginkgo, Maidenhair	Seeds not protected by fruit (single species)
Gnetophyta Gnetophyta The plant division Gnetophyta or gnetophytes comprise three related families of woody plants grouped in the gymnosperms. The gnetophytes differ from other gymnosperms in having vessel elements as in the flowering plants....		Gnetophytes	Seeds and woody vascular system with vessels
Anthophyta Flowering plant The flowering plants or angiosperms are the most diverse group of land plants. The flowering plants and the gymnosperms are the only extant groups of seed plants...  (or Magnoliophyta Flowering plant The flowering plants or angiosperms are the most diverse group of land plants. The flowering plants and the gymnosperms are the only extant groups of seed plants... )	Flower plant	Flowering plants	Flowers and fruit, vascular system with vessels

Fungal divisions

Phylum	Meaning	Common name	Distinguishing characteristics
Chytridiomycota Chytridiomycota Chytridiomycota or chytrids is a division of the Fungi kingdom. The name is derived from the Greek chytridion, meaning "little pot", describing the structure containing unreleased spores...	Little pot mushroom	Chytrids	Cellulose in cell walls, flagellated gametes
Deuteromycota	Second mushroom	Imperfect fungi	Unclassified fungi; only asexual reproduction observed
Zygomycota Zygomycota Zygomycota, or zygote fungi, is a phylum of fungi. The name comes from zygosporangia, where resistant spherical spores are formed during sexual reproduction. Approximately 1060 species are known. They are mostly terrestrial in habitat, living in soil or on decaying plant or animal material...	Yolk mushroom	Zygomycetes	Blend gametangia Gametangia A gametangium is an organ or cell in which gametes are produced that is found in many multicellular protists, algae, fungi, and the gametophytes of plants...  to form a zygosporangium
Glomeromycota Glomeromycota Glomeromycota is one of seven currently recognized phyla within the kingdom Fungi, with approximately 200 described species. Members of the Glomeromycota form arbuscular mycorrhizas with the roots or thalli of land plants. Geosiphon pyriformis forms an endocytobiotic association with Nostoc...	Ball mushroom	None	Form arbuscular mycorrhizae with plants
Ascomycota Ascomycota The Ascomycota are a Division/Phylum of the kingdom Fungi, and subkingdom Dikarya. Its members are commonly known as the Sac Fungi. They are the largest phylum of Fungi, with over 64,000 species...	Bag/Wineskin Mushroom	Sac fungi	Produce spores in an 'ascus Ascus An ascus is the sexual spore-bearing cell produced in ascomycete fungi. On average, asci normally contain 8 ascospores, produced by a meiotic cell division followed, in most species, by a mitotic cell division. However, asci in some genera or species can number 1 , 2, 4, or multiples of four... '
Basidiomycota Basidiomycota Basidiomycota is one of two large phyla that, together with the Ascomycota, comprise the subkingdom Dikarya within the Kingdom Fungi...	Basidium Mushroom	Club Fungi	Produce spores from a 'basidium Basidium thumb|right|200px|Schematic showing a basidiomycete mushroom, gill structure, and spore-bearing basidia on the gill margins.A basidium is a microscopic, spore-producing structure found on the hymenophore of fruiting bodies of basidiomycete fungi. The presence of basidia is one of the main... '

External links

• Are phyla "real"? Is there really a well-defined "number of animal phyla" extant and in the fossil record?
• Major Phyla Of Animals

Etymology

Etymology

Etymology is the study of the history of words and how their form and meaning have changed over time.For languages with a long written history, etymologists make use of texts in these languages, and texts about the languages, to gather knowledge about how words were used at earlier stages, and...

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• American Heritage Dictionary: New Latin phylum, from Greek phūlon, class.
• Online Etymological Dictionary: from Gk. phylon "race, stock," related to phyle "tribe, clan," and phylein "bring forth" of physikos "pertaining to nature," from physis "nature"