Loricifera (from
Latin, , corselet (armour) +
ferre, to bear) is a
phylum of very small to microscopic marine sediment-dwelling animals with twenty-two described species, in eight genera. Aside from these described species, there are approximately 100 more that have been collected and not yet described. Their sizes range from 100 µm to ca. 1 mm. They are characterised by a protective outer case called a
lorica and their habitat, which is in the spaces between marine gravel to which they attach themselves. The phylum was discovered in 1983 by
Roberto Ramos, in
Roscoff,
France. They are among the most recently discovered groups of
Metazoans. They attach themselves quite firmly to the substrate, and hence remained undiscovered for so long. The first specimen was collected in the 1970s, and later described in 1983. They are found at all depths, in different sediment types, and in all latitudes.