Loricifera
Microscopic marine animals with a protective lorica.
Loricifera, also known as corset animals, is a phylum of very small to microscopic marine scalidophoran sediment-dwelling animals. They are characterized by a protective outer case called a lorica and inhabit the spaces between marine gravel, to which they attach themselves firmly.
- discoverer
- R.M. Kristensen
- field
- Marine zoology
- habitat
- Spaces between marine gravel
- known_for
- First multicellular organisms found to spend entire lives in anoxic environments
Lore & Background
Loricifera have a head, mouth, digestive system, and a lorica composed of six plates. The head contains the mouth and brain, and scalids are individually connected to the brain by nerves. They lack a circulatory system and endocrine system. Many larvae are acoelomate, while some adults are pseudocoelomate and others remain acoelomate. Development is generally direct, though there are Higgins-larvae with toes and hair-like structures. Most adults are gonochoric, but a few species are hermaphroditic. Fossils have been dated to the late Cambrian.
Reader's Guide
Their firm attachment to substrate explains why they remained undiscovered for so long. They are found at all depths, in different sediment types, and in all latitudes. Three species have been found in the oxygen-free sediments of the L'Atalante basin in the Mediterranean Sea, more than 3,000 meters down, making them the first multicellular organisms known to spend their entire lives in an anoxic environment. Their evolutionary history is difficult to trace due to a scarce fossil record, but they are believed to be miniaturized descendants of a larger organism, possibly resembling the Cambrian fossil Sirilorica.
Did You Know?
- Three species have been found living in completely anoxic, sulphidic sediments in the Mediterranean Sea.
- Their name comes from Latin 'lorica' (corselet) and 'fero' (to carry).
- Fossils of Loricifera have been dated to the late Cambrian.
More in Other Invertebrates 1-22
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