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A genus of small, translucent, fishlike chordates found in warm marine waters. Members are structurally similar to vertebrates in having a notochord, gills, digestive tract, and nerve cord, but they lack paired fins, vertebrae, ribs, or a skull for example, Branchiostoma lanceolatum.
[amphi- + G. oxys, sharp]


See lancelet.


the disused scientific, though better-known, name for Branchiostoma (the lancet), a PROTOCHORDATE found in many parts of the world. Its embryonic development has been extensively studied and is used in texts as an example of a link between invertebrates and vertebrates. It feeds by ciliary action, trapping food particles in mucus.
References in periodicals archive ?
The research  appeared in the journal PLOS ONE under the title "Molecular regionalization of the developing amphioxus neural tube challenges major partitions of the vertebrate brain.
The researchers propose that if a critical function were performed by a single protein, as in amphioxus, then its loss or mutation would likely be lethal, resulting in no disease.
Biology of the amphioxus, Branchiostoma belcheri in the Ariake Sea, Japan.
The fossils, named Myllokunmingia and Haikouichthys, also have a more complex arrangement of gills than the simple slits used by amphioxus, according to the team's report in the Nov.
The amphioxus genome illuminates vertebrate origins and cephalochordate biology.
The present study is concerned with two cephalochordates representing different genera: namely, the Florida amphioxus, Branchiostoma floridae Hubbs, 1922, and the Bahamas lancelet, Asymmetron lucayanum Andrews, 1893.
20-22) On the other hand, homologs of Bcl11a are already present in the genomes of amphioxus and sea lamprey.
It's a long way from amphioxus, it's a long way to us.
A neurotropic herpesvirus infecting the gastropod, abalone, shares ancestry with oyster herpesvirus and a herpesvirus associated with the amphioxus genome.
Nurpl homologs have been obtained and characterized in many species of vertebrates and invertebrates, including mice, halibut, urchins, amphioxus, and frogs (Vasseur et al.
The number and locations of hox genes and their DNA sequences in a wormlike, seemingly headless creature called amphioxus place this animal as a missing link -- genetically speaking -- between animals with backbones and animals without.