These are openings that connect the pharynx or throat to the outside of the neck. In some primitive species, the slits are used to filter food out of the water. In other species, like fish, the pharyngeal slits have gills. In other species, like mammals, the pharyngeal slits are only present during the embryonic stage. Chordates also have a dorsal nerve cord that runs down the length of the organism.
The dorsal nerve cord has pairs of nerves that connect to the organism's muscles. The creature is called Mediterranean amphioxus, or amphy for short the scientific name is Branchiostoma lanceolatum. Amphy normally lives buried in the sand in the Mediterranean, in the Black Sea and along coastal beaches of the European Atlantic. Amphioxus looks like a vertebrate an animal with a backbone, like humans and other mammals but lacks the specialisations of animals like us, such as a complex brain and limbs.
It shares with vertebrates a basic body plan, and has some comparable organs and structures in its body. So amphy is used in research as an example of one of the simplest animals with a backbone that has some features in common with more complex lifeforms. For this work we sequenced the amphy genome all of its DNA and generated data required to study its genes.
This study gives us an overview of layers and control mechanisms that work around genes, and how these play a role in building more complex animals.
The mucous membrane of the gill basket catches food particles in the water and passes them to the gut where they are exposed to various enzymes that initiate digestion. Lancelet Amphioxus Pharynx The amphioxus is a small, slender fish-like organism that spends the majority of its time buried in gravel or mud on the ocean floor. Share this page:. The body is segmented and flattened dorsoventrally with a membranous flipper along the dorsal side.
The tail end has a lance-like flipper. It grows up to 8 cm in length and is semi-transparent pink in colour. The head is a mere continuation of the body. Multiple cirri project from the mouth. Most records are found off the southern coasts of Britain and Ireland as far north as Anglesea and Liverpool Bay, and along the southern North Sea, with scattered records around Scotland, and north east coast of England.
The lancelet inhabits the sandy sublittoral zone at depths down to 30 m. It prefers sand mixed with shells rather than more muddy bottoms as it is not suited to penetrate ground with small particles.
Gans, C. The lancelets Cephalochordata : a new look at some old beasts. Filter feeding in lancelets amphioxus , Branchiostoma lanceolatum.
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