Chordata Temporal range: Early Cambrian – Recent, 540–0 Ma PreЄ Є O S D C P T J K Pg N
The X-ray tetra (Pristella maxillaris), is one of the few chordates with a visible backbone. The spinal cord is housed within its backbone.
Scientific classification
Kingdom:	Animalia
Superphylum:	Deuterostomia
Phylum:	Chordata Bateson, 1885
Classes
See below

The Chordates are animals that comprise the phylum Chordata. Taxonomically the phylum Chordata includes three subphyla: Tunicata; Cephalochordata, comprising the lancelets; and the Craniata, or Vertebrata. The common attributes of the Chordata include having, for at least some period of their life cycles, a notochord, a hollow dorsal nerve cord, pharyngeal slits, an endostyle, and a post-anal tail. The phylum Hemichordata has been presented as a fourth chordate subphylum, but it now is usually treated as a separate phylum.

Overview of affinities[link]

Tunicate larvae have both a notochord and a nerve cord which are lost in adulthood. Cephalochordates have a notochord and a nerve cord (but no brain or specialist sensory organs) and a very simple circulatory system. Craniates are the only subphylum whose members have skulls. In all craniates except for hagfish, the dorsal hollow nerve cord is surrounded with cartilaginous or bony vertebrae and the notochord is generally reduced; hence, hagfish are not universally regarded as vertebrates, though recent DNA comparisons suggest that they are in fact vertebrates. The chordates and three sister phyla, the Hemichordata, the Echinodermata and the Xenoturbellida, make up the deuterostomes, one of the two superphyla that encompass all fairly complex animals.

Attempts to work out the evolutionary relationships of the chordates have produced several hypotheses. The current consensus is that chordates are monophyletic, meaning that the Chordata include all and only the descendants of a single common ancestor which is itself a chordate, and that craniates' nearest relatives are cephalochordates. All of the earliest chordate fossils have been found in the Early Cambrian Chengjiang fauna, and include two species that are regarded as fish, which implies they are vertebrates. Because the fossil record of chordates is poor, only molecular phylogenetics offers a reasonable prospect of dating their emergence. However, the use of molecular phylogenetics for dating evolutionary transitions is controversial.

It has also proved difficult to produce a detailed classification within the living chordates. Attempts to produce evolutionary "family trees" give results that differ from traditional classes because several of those classes are not monophyletic. As a result, vertebrate classification is in a state of flux.

Definition[link]

1 = bulge in spinal cord ("brain")

2 = notochord

3 = dorsal nerve cord

4 = post-anal tail

5 = anus

6 = digestive canal

7 = circulatory system

8 = atriopore

9 = space above pharynx

10 = pharyngeal slit (gill)

11 = pharynx

12 = vestibule

13 = oral cirri

14 = mouth opening

15 = gonads (ovary / testicle)

16 = light sensor

17 = nerves

18 = metapleural fold

19 = hepatic caecum (liver-like sack)

Anatomy of the cephalochordate Amphioxus. Bolded items are components of all chordates at some point in their lifetimes, and distinguish them from other phyla.

Chordates form a phylum of creatures that are based on a bilateral body plan,^[1] and is defined by having at some stage in their lives all of the following:^[2]

• A notochord, in other words a fairly stiff rod of cartilage that extends along the inside of the body. Among the vertebrate sub-group of chordates the notochord develops into the spine, and in wholly aquatic species this helps the animal to swim by flexing its tail.
• A dorsal neural tube. In fish and other vertebrates this develops into the spinal cord, the main communications trunk of the nervous system.
• Pharyngeal slits. The pharynx is the part of the throat immediately behind the mouth. In fish the slits are modified to form gills, but in some other chordates they are part of a filter-feeding system that extracts particles of food from the water in which the animals live.
• Post-anal tail. A muscular tail that extends backwards behind the anus.
• An endostyle. This is a groove in the ventral wall of the pharynx. In filter-feeding species it produces mucus to gather food particles, which helps in transporting food to the esophagus.^[3] It also stores iodine, and may be a precursor of the vertebrate thyroid gland.^[2]

Subdivisions[link]

Craniata[link]

Craniate: Hagfish

Craniates, one of the three subdivisions of chordates, have distinct skulls - including hagfish, which have no vertebrae. Michael J. Benton comments, "craniates are characterized by their heads, just as chordates, or possibly all deuterostomes, are by their tails." ^[4]

Most are vertebrates, in which the notochord is replaced by the spinal column. ^[5]

This consists of a series of bony or cartilaginous cylindrical vertebrae, generally with neural arches that protect the spinal cord and with projections that link the vertebrae. Hagfish have incomplete braincases and no vertebrae, and are therefore not regarded as vertebrates,^[6] but as members of the craniates, the group from which vertebrates are thought to have evolved.^[7] The position of lampreys is ambiguous. They have complete braincases and rudimentary vertebrae, and therefore may be regarded as vertebrates and true fish.^[8] However, molecular phylogenetics, which uses biochemical features to classify organisms, has produced both results that group them with vertebrates and others that group them with hagfish.^[9]

Cephalochordata: lancelets[link]

Cephalochordate: Lancelet

Cephalochordates are small, "vaguely fish-shaped" animals that lack brains, clearly defined heads and specialized sense organs.^[10] These burrowing filter-feeders may be either the closest living relatives of craniates or surviving members of the group from which all other chordates evolved.^[11][12]

Urochordata: tunicates[link]

Tunicates: sea squirts

Most tunicates appear as adults in two major forms, both of which are soft-bodied filter-feeders that lack the standard features of chordates: "sea squirts" are sessile and consist mainly of water pumps and filter-feeding apparatus;^[13] salps float in mid-water, feeding on plankton, and have a two-generation cycle in which one generation is solitary and the next forms chain-like colonies.^[14] However, all tunicate larvae have the standard chordate features, including long, tadpole-like tails; they also have rudimentary brains, light sensors and tilt sensors.^[13] The third main group of tunicates, Appendicularia (also known as Larvacea) retain tadpole-like shapes and active swimming all their lives, and were for a long time regarded as larvae of sea squirts or salps.^[15] Because of their larvae's long tails tunicates are also called urochordates ("tail chordates").^[13]

Closest nonchordate relatives[link]

Hemichordates[link]

Enteropneust hemichordate: Balanoglossus

Hemichordates ("half (½) chordates") have some features similar to those of chordates: branchial openings that open into the pharynx and look rather like gill slits; stomochords, similar in composition to notochords, but running in a circle round the "collar", which is ahead of the mouth; and a dorsal nerve cord — but also a smaller ventral nerve cord.

There are two living groups of hemichordates. The solitary enteropneusts, commonly known as "acorn worms", have long proboscises and worm-like bodies with up to 200 branchial slits, are up to 2.5 metres (8.2 ft) long, and burrow though seafloor sediments. Pterobranchs are colonial animals, often less than 1 millimetre (0.039 in) long individually, whose dwellings are interconnected. Each filter feeds by means of a pair of branched tentacles, and has a short, shield-shaped proboscis. The extinct graptolites, colonial animals whose fossils look like tiny hacksaw blades, lived in tubes similar to those of pterobranchs.^[16]

Echinoderms[link]

Echinoderm: starfish

Echinoderms differ from chordates and their other relatives in three conspicuous ways: instead of having bilateral symmetry, they have radial symmetry, meaning their body pattern is shaped like a wheel; they have tube feet; and their bodies are supported by skeletons made of calcite, a material not used by chordates. Their hard, calcified shells keep their bodies well protected from the environment, and these skeletons enclose their bodies, but are also covered by thin skins. The feet are powered by another unique feature of echinoderms, a water vascular system of canals that also functions as a "lung" and are surrounded by muscles that act as pumps. Crinoids look rather like flowers, and use their feather-like arms to filter food particles out of the water; most live anchored to rocks, but a few can move very slowly. Other echinoderms are mobile and take a variety of body shapes, for example starfish, sea urchins and sea cucumbers.^[17]

Origins[link]

The majority of animals more complex than jellyfish and other Cnidarians are split into two groups, the protostomes and deuterostomes, and chordates are deuterostomes.^[18] It seems very likely the 555 million-year-old Kimberella was a member of the protostomes.^[19][20] If so, this means the protostome and deuterostome lineages must have split some time before Kimberella appeared — at least 558 million years ago, and hence well before the start of the Cambrian 542 million years ago.^[18] The Ediacaran fossil Ernietta, from about 549 to 543 million years ago, may represent a deuterostome animal.^[21]

Haikouichthys, from about 518 million years ago in China, may be the earliest known fish.^[22]

Fossils of one major deuterostome group, the echinoderms (whose modern members include starfish, sea urchins and crinoids), are quite common from the start of the Cambrian, 542 million years ago.^[23] The Mid Cambrian fossil Rhabdotubus johanssoni has been interpreted as a pterobranch hemichordate.^[24] Opinions differ about whether the Chengjiang fauna fossil Yunnanozoon, from the earlier Cambrian, was a hemichordate or chordate.^[25][26] Another fossil, Haikouella lanceolata, also from the Chengjiang fauna, is interpreted as a chordate and possibly a craniate, as it shows signs of a heart, arteries, gill filaments, a tail, a neural chord with a brain at the front end, and possibly eyes — although it also had short tentacles round its mouth.^[26] Haikouichthys and Myllokunmingia, also from the Chengjiang fauna, are regarded as fish.^[22][27] Pikaia, discovered much earlier but from the Mid Cambrian Burgess Shale, is also regarded as a primitive chordate.^[28] On the other hand fossils of early chordates are very rare, since non-vertebrate chordates have no bones or teeth, and only one has been reported for the rest of the Cambrian.^[29]

The evolutionary relationships between the chordate groups and between chordates as a whole and their closest deuterostome relatives have been debated since 1890. Studies based on anatomical, embryological, and paleontological data have produced different "family trees". Some closely linked chordates and hemichordates, but that idea is now rejected.^[3] Combining such analyses with data from a small set of ribosome RNA genes eliminated some older ideas, but open the possibility that tunicates (urochordates) are "basal deuterostomes", surviving members of the group from which echinoderms, hemichordates and chordates evolved.^[31] Some researchers believe that, within the chordates, craniates are most closely related to cephalochordates, but there are also reasons for regarding tunicates (urochordates) as craniates' closest relatives.^[3][32] One other phylum, Xenoturbellida, appears to be basal within the deuterostomes, closer to the original deuterostomes than to the chordates, echinoderms and hemichordates.^[30]

Since chordates have left a poor fossil record, attempts have been made to calculate the key dates in their evolution by molecular phylogenetics techniques - by analysing biochemical differences, mainly in RNA. One such study suggested deuterostomes arose before 900 million years ago and the earliest chordates around 896 million years ago.^[32] However, molecular estimates of dates often disagree with each other and with the fossil record,^[32] and their assumption that the molecular clock runs at a known constant rate has been challenged.^[33][34]

Classification[link]

Taxonomy[link]

The following schema is from the third edition of Vertebrate Palaeontology.^[35] The invertebrate chordate classes are from Fishes of the World.^[36] While it is structured so as to reflect evolutionary relationships (similar to a cladogram), it also retains the traditional ranks used in Linnaean taxonomy.

• Phylum Chordata
  • Subphylum Tunicata (Urochordata) — (tunicates; 3,000 species)
    • • • Class Ascidiacea (sea squirts)
        • Class Thaliacea (salps)
        • Class Appendicularia (larvaceans)
        • Class Sorberacea
  • Subphylum Cephalochordata (Acraniata) — (lancelets; 30 species)
    • • • Class Leptocardii (lancelets)
  • Subphylum Vertebrata (Craniata) (vertebrates — animals with backbones; 57,674 species)
    • • • Class 'Agnatha' paraphyletic (jawless vertebrates; 100+ species)
          • Subclass Myxinoidea (hagfish; 65 species)
          • Subclass Petromyzontida (lampreys)
          • Subclass Conodonta†
          • Subclass Pteraspidomorphi (Paleozoic jawless fish)
            • Order Anaspida
            • Order Thelodonti (Paleozoic jawless fish)
    • Infraphylum Gnathostomata (jawed vertebrates)
      • • • Class Placodermi (Paleozoic armoured forms)
          • Class Chondrichthyes (cartilaginous fish; 900+ species)
          • Class Acanthodii (Paleozoic "spiny sharks")
          • Class Osteichthyes (bony fish; 30,000+ species)
            • Subclass Actinopterygii (ray-finned fish; about 30,000 species)
            • Subclass Sarcopterygii (lobe-finned fish: 8 species)
      • Superclass Tetrapoda (four-limbed vertebrates; 28,000+ species)
        • • Class Amphibia (amphibians; 6,000 species)
          • Class Sauropsida (reptiles; 18,000+ species)
            • Subclass Anapsida (extinct "proto-reptiles" and turtles)
            • Subclass Diapsida (majority of reptiles, progenitors of birds)
          • Class Aves (birds; 8,800–10,000 species)
          • Class Synapsida/Mammalia (mammal-like "reptiles"; 5,800+ species)

Phylogeny[link]

See also[link]

• List of chordate orders

References[link]

External links[link]

Wikispecies has information related to: Chordata

The Wikibook Dichotomous Key has a page on the topic of Chordata

• Complete details about Phylum Chordata at thebigger.com
• Chordate at the Encyclopedia of Life
• Chordate on GlobalTwitcher.com
• Chordate node at Tree Of Life
• Chordate node at NCBI Taxonomy

Venetian Snares
Background information
Birth name	Aaron Funk
Born	(1975-01-11) January 11, 1975 (age 37)
Origin	Winnipeg, Manitoba, Canada
Genres	Breakcore Glitchcore IDM Orchestral music Noise Drum & Bass
Instruments	Guitar, drums, percussion, kazoo, bass guitar, harpsichord, piano, violin, viola, cello, drum machine, synthesizer, sampler, softsynth
Years active	1992–present
Labels	Hymen Records Planet Mu Sublight Records
Associated acts	Last Step, Speed Dealer Moms, Stunt Rock, Bong-Ra, Speedranch, Cex, Doormouse, Fanny, John Frusciante
Website	venetiansnares.com

Venetian Snares is the main performing alias of Canadian electronic musician Aaron Funk (born January 11, 1975).

From Winnipeg, Manitoba, Canada, Funk is known for making electronic music often in odd numbered time signatures (mostly 7/4). Up until 2007, he was very prolific, releasing as many as eight recordings a year for such record labels as History of the Future, Isolate/DySLeXiC ResPonSe, Addict, Zod, Distort, Sublight, Low-Res, Planet Mu and Hymen.

Funk debuted on a record label in 1999 with the 12" vinyl EP, Greg Hates Car Culture. Prior to this, he self-released material on cassette tape as early as 1992.^[1]

Biography[link]

Funk's first release was the EP Greg Hates Car Culture released on History of the Future, followed by Salt on Zhark International and Fuck Canada/Fuck America with Stunt Rock for CLFST. When Mike Paradinas heard Greg Hates Car Culture he immediately signed Funk for Planet Mu. The first Venetian Snares LP on Planet Mu, Making Orange Things (a co-production with Speedranch), was released in early 2001, followed in short order by five more releases, all before the end of 2002. Funk continued producing for a variety of labels, including Hymen Records, Peace Off Records, Addict Records, and Sublight Records. He has also produced albums under the names Last Step and Vsnares, produced singles under the names Last Step, Snares Man! and Snares, appeared on compilations under the names Ventriloquist Snakes, Last Step, Puff, and Senetian Vnares, and did a split with Fanny under the name BeeSnares.^[2]

His style has been critically acclaimed, notably by the late British radio disc jockey John Peel.^[3] Venetian Snares is said to have reinvented breakcore^[4] and set the stage for many other artists such as UndaCova, Xanopticon, Enduser and Datach'i.

Venetian Snares composes much of his music with trackers. Before he began to release his music commercially, he worked primarily with OctaMED on an Amiga 500.^[1] At some point prior to 2000 he began using a PC and the Windows port of OctaMED, MED Soundstudio.^[5] During 2003 and 2005 he also used Cubase in addition to MED. Venetian Snares currently uses Renoise and has uploaded a video of his track "Vache" (from Cavalcade of Glee and Dadaist Happy Hardcore Pom Poms) playing in Renoise on YouTube.^[6]

In a February 2003 interview, Funk was asked a question regarding the diverse mix of genres he draws upon in his music, a property which the interviewer labelled "eclecticism". Funk replied: "I prefer to call it Surrealism."^[7]

In other interviews he discusses how his early experiments in sound influenced his aethetics and use of samples: "When I was a kid I'd use a bunch of ghetto blasters playing all at once to play different sounds I'd recorded with some other shitty ghetto blasters. A turning point was when I somehow came across this looping delay pedal that held a 2 second sample. This pedal coupled with the ghetto blaster experiments really changed my life."^[8] In another interview regarding his early musical upbringing he claimed "I did start with traditional instruments, piano when I was very young. Grew up at my grandparent’s home and they had an upright piano I plunked away on since before I can remember. Of course a sampler is a musical instrument as well as a production tool. It allows you control over any sound. You can make music out of a toilet and a Zamfir record with a sampler!" ^[9]

Discography[link]

As Venetian Snares[link]

Albums[link]

• Eat Shit And Die (1998, split with DJ Fishead, self-release)
• Spells (1998, self-release)
• Subvert! (1998, self-release)
• Fuck Canada // Fuck America (1999, CLFST, split with Stunt Rock)
• printf("shiver in eternal darkness/n"); (2000, Isolate Records)
• Making Orange Things (2001, Planet Mu, collaboration with Speedranch)
• Songs About My Cats (2001, Planet Mu)
• Doll Doll Doll (2001, Hymen Records)
• Higgins Ultra Low Track Glue Funk Hits 1972–2006 (2002, Planet Mu)
• Winter in the Belly of a Snake (2002, Planet Mu)
• Find Candace (2003, Hymen Records)
• The Chocolate Wheelchair Album (2003, Planet Mu)
• Huge Chrome Cylinder Box Unfolding (2004, Planet Mu)
• Winnipeg Is a Frozen Shithole (2005, Sublight Records)
• Rossz csillag alatt született (2005, Planet Mu)
• Meathole (2005, Planet Mu)
• Cavalcade of Glee and Dadaist Happy Hardcore Pom Poms (2006, Planet Mu)
• Hospitality (2006, Planet Mu)
• My Downfall (Original Soundtrack) (2007, Planet Mu)
• Detrimentalist (2008, Planet Mu) ^[10]
• Filth (2009, Planet Mu)
• My So-Called Life (2010, Timesig) ^[11]

12″s, 7″s, EPs, and mini-releases[link]

• Fake:Impossible (1997, self-release)
• Greg Hates Car Culture (1999, History of the Future)
• Salt (2000, Zhark International)
• 7 Sevens.med EP (2000, Low Res)
• White Label (2001, Hangars Liquides)
• Defluxion / Boarded Up Swan Entrance (2001, Planet Mu)
• Shitfuckers!!! (2001, Dyslexic Response)
• The Connected Series #2 (collaboration with Cex) (2001, Klangkrieg)
• A Giant Alien Force More Violent & Sick Than Anything You Can Imagine (2002, Hymen Records)
• Badminton (2003, Addict Records)
• Einstein-Rosen Bridge (2003, Planet Mu)
• Nymphomatriarch (2003, Hymen Records, collaboration with Hecate)
• Podsjfkj Pojid Poa (2003, Double H Noise Industries, split with Phantomsmasher)
• Skelechairs (2004, Addict Records, collaboration with Doormouse)
• Moonglow / This Bitter Earth (2004, Addict Records)
• Horse and Goat (2004, Sublight Records)
• Infolepsy EP (2004, Coredump Records)
• Pink + Green (2007, Sublight Records)
• Miss Balaton (2008, Planet Mu)
• Horsey Noises (2009, Planet Mu)
• Cubist Reggae (2011, Planet Mu)
• Affectionate (2012, self-release)
• Fool the Detector (2012, Timesig)

As Snares Man![link]

• Clearance Bin/Breakbeat Malaria (2001, History of the Future)

As Vsnares[link]

• 2370894 (2002, Planet Mu)

As BeeSnares[link]

• Leopards Of Mass Destruction (2003, Death$ucker Records, split with Fanny)

As Last Step[link]

Albums[link]

• Last Step (2007, Planet Mu)
• 1961 (2008, Planet Mu)
• Sleep (2012, Planet Mu)

12″s, 7″s, EPs, and mini-releases[link]

• You're A Nice Girl (2005, Planet Mu)
• Bhavani (2006, Project 168)

As Snares[link]

• Sabbath Dubs (2007, Kriss Records)

As Speed Dealer Moms[link]

• Speed Dealer Moms EP (2010, Timesig, collaboration with John Frusciante and Chris McDonald)^[12]

References[link]

External links[link]

• Official website
• Venetian Snares / Aaron Funk at Discogs
• Venetian Snares at Last.fm
• Last Step's page on Discogs