Hallucigenia is an extinct genus of animal found as fossils in the Middle Cambrian-aged Burgess Shale formation of British Columbia, Canada. It was named by Simon Conway Morris when he re-examined Charles Walcott's Burgess Shale genus Canadia in 1979. Morris found that what Walcott had called one genus in fact included several quite different animals. One of them was so unusual that nothing about it made much sense. Since the species clearly was not a polychaete worm, Morris had to provide a new generic name to replace Canadia. Morris named the species Hallucigenia sparsa because of its "bizarre and dream-like quality" (like a hallucination). The Middle Cambrian is an geological epoch that is part of the Cambrian Era. ... Hallucigenia Daugerrotype fossil http://grokhovs2. ... The conservation status of a species is an indicator of the likelihood of that species continuing to survive either in the present day or the future. ... FOSSIL is a standard for allowing serial communication for telecommunications programs under DOS. FOSSIL is an acronym for Fido Opus Seadog Standard Interface Layer. ... Scientific classification or biological classification is a method by which biologists group and categorize species of organisms. ... “Animalia” redirects here. ... Genera Peripatus . ... Type specimens When a new species is discovered, more important than creating a new and unique name for the species is developing a reasonably detailed description. ... In biology and ecology, extinction is the ceasing of existence of a species or group of species. ... For other uses of the word, please see Genus (disambiguation). ... “Animalia” redirects here. ... The Cambrian is a major division of the geologic timescale that begins about 542 ± 1. ... Hallucigenia sparsa, one of the organisms unique to the Burgess Shale. ... Motto: Splendor Sine Occasu (Latin: Splendour without diminishment) Capital Victoria Largest city Vancouver Official languages English Government - Lieutenant-Governor Iona Campagnolo - Premier Gordon Campbell (BC Liberal) Federal representation in Canadian Parliament - House seats 36 - Senate seats 6 Confederation July 20, 1871 (6th province) Area  Ranked 4th - Total 944,735 km... Simon Conway Morris is a British paleontologist. ... Charles Doolittle Walcott (March 31, 1850 _ February 9, 1927) was an eminent American invertebrate paleontologist. ... Canadia is an extinct polychaete annelid known from fossils found in the Burgess Shale formation of British Columbia. ... Orders Amphinomida Capitellida Chaetopterida Cirratulida Cossurida Ctenodrillidae Eunicida Flabelligerida Magelonida Myzostomida Nerillida Opheliida Orbiniida Orweniida Phyllodocida Pisionidae Polygordiida Protodrilida Psammodrilidae Sabellida Spionida Spintheridae Sternaspida Terebellida The Polychaeta or Polychaetes are a class of annelid worms, generally marine, with a pair of fleshy protrusions on each body segment called parapodia that... Canadia is an extinct polychaete annelid known from fossils found in the Burgess Shale formation of British Columbia. ... A hallucination is a sensory perception experienced in the absence of an external stimulus, as distinct from an illusion, which is a misperception of an external stimulus. ...

The 0.5 to 3 cm-long animal is wormlike — that is, long and narrow — with a poorly defined blob, or stain, on one end. This "blob" was arbitrarily designated the 'head' even though it had none of the features generally associated with heads: mouth, eyes, or other sensory organs. According to Morris' original interpretation, the animal has seven pincher-tipped tentacles lined up on one side and seven pairs of jointed spines on the other. Six of the tentacles are paired with spines, while one is in front of the spines. There are also six smaller tentacles which may be configured in three pairs behind the seven larger ones. In addition, there is a flexible, tube-like, tail-like body extension behind the tentacles.

Faced with an animal that had no obvious head and two types of appendages, neither of which seemed appropriate for any reasonable form of locomotion, Morris assigned the blob as the head and hypothesized that the spines were legs and that the tentacles were feeding appendages. Morris was able to demonstrate a workable if improbable method of walking on the spines. Only the forward tentacles can easily reach to the 'head,' meaning that a mouth on the head would have to be fed by passing food along the line of tentacles. Morris suggested that a hollow tube within each of the tentacles might be a mouth. This is a less-than-satisfactory reconstruction, but it was accepted as the best available. A picture of the animal as reconstructed by Morris can be found at [1].

An alternative interpretation once favored by some paleontologists was that Hallucigenia is actually an appendage of some larger, unknown animal. Given the uncertainty of its taxonomy, Hallucigenia was tentatively placed within the phylum Lobopodia, a catch-all clade containing numerous odd "worms with legs." A paleontologist carefully chips rock from a column of dinosaur vertebrae. ... Lobopodia are a collection of poorly understood animals from the Early Cambrian -- the beginning of well fossilized animal life. ... A clade is a term belonging to the discipline of cladistics. ...

In 1991, Lars Ramskold and Hou Xianguang, working with additional specimens of a "hallucigenid," Microdictyon, from the lower Cambrian Maotianshan shales of China, reinterpreted Hallucigenia as an Onychophore. They inverted it, interpreting the tentacles, which they believe to be paired, as walking structures and the spines as protective. Interestingly, none of the 30 or so known Burgess Shale specimens shows any sign of pairing in the large tentacles; nor do their Chinese counterparts. The pairing is based on a dissection of the actual fossil, which revealed what is probably a second tentacle structure. Ramskold and Hou also believe that the 'head' is actually a stain that appears in many specimens, not a preserved portion of the anatomy. Microdictyon is an extinct armored worm coated with dot-like scleritic scales, known from the Early Cambrian Maotianshan shale of Yunnan China. ... The Cambrian is a major division of the geologic timescale that begins about 542 ± 1. ... The Maotianshan shale is a lower Cambrian (Atdabanian) rock formation, of ca 522 Mya, now lying exposed in the Yunnan Province of China in the villages of Ercaicun and Chengjiang near the city of Kunming. ... Genera Peripatus . ...

Though Ramskold and Hou's is the accepted modern interpretation, it is far from problem-free. Unlike its contemporary Aysheaia, Hallucigenia has very little resemblance to modern Onychophora. The elongated, and clawed legs bear little resemblance to the paired annulated legs of the Onychophora. It is unknown what the spines were made of and how much 'protection' they offered. They do not seem to be preserved independent of the soft-shelled animals as carbonate or chitinous shells would probably be. It is not easy to explain why 30 or more specimens — each hypothesized to have seven pairs of rather long, flexible legs — do not show even one example of paired legs. But at least this reconstruction of the animal can plausibly walk, and the spines serve a reasonable purpose. A picture of this reconstruction as well as a photograph of an actual fossil can be seen at [2]. Aysheaia pedunculata is a soft-bodied, caterpillar-shaped organism average body length of 1-6 cm. ... Genera Peripatus . ... Genera Peripatus . ... In organic chemistry, a carbonate is a salt of carbonic acid. ... Structure of the chitin molecule, showing two of the N-Acetylglucosamine units that repeat to form long chains in beta-1,4 linkage. ...

Some paleontologists accept Ramskold and Hou's interpretation of the animal's legs, spines, and head, but also believe that Hallucigenia might be an "armored lobopod" related to Anomalocaris, rather than, or also being related to the Onychophora. Species  ? Image of the first complete Anomalocaris fossil found, residing in the Royal Ontario Museum Anomalocaris (unusual shrimp) is an extinct genus of anomalocarids, which are, in turn, thought to be closely related to the Arthropoda. ... Genera Peripatus . ...

Hallucigenia in popular culture

The detailed description of a Jart in Greg Bear's science fiction novel Eon is a scaled-up version of the original, incorrect reconstruction of Hallucigenia as walking on its spines.^[1] Science fiction is a form of speculative fiction principally dealing with the impact of imagined science and technology, or both, upon society and persons as individuals. ... Look up eon, Eon, EON in Wiktionary, the free dictionary. ...

Hallucigenia served as the model for the conceptual cosmic entity Anomaly in issue #20 of the Marvel Comics Quasar series. Image and description available at this link --> [3]

External links

• http://www.nmnh.si.edu/paleo/shale/phallu.htm - (Internet Archive)