Loricifera

Loricifera
Pliciloricus enigmatus
Scientific classification
Kingdom:	Animalia
(unranked):	Cycloneuralia
Phylum:	Loricifera Kristensen, 1983
Order:	Nanaloricida

Loricifera ^[1] is a recently discovered ecdysozoan phylum of marine animals. The phylum includes the first animals known to exist in a completely anoxic environment (no oxygen at all).^[2] The phylum was described in 1983 by Reinhardt Kristensen.^[3]

They are a phylum of very small animals which live in sediment. There are now twenty-two described species, in eight genera.^[4][5] In addition, there are about 100 more species which have been collected, but not yet described.^[4] Their size ranges from 100 µm to about 1 mm.^[6]

Their habitat is in the spaces between marine gravel to which they attach themselves. They are among the most recently discovered groups of Metazoans.^[7] They attach themselves quite firmly to the gravel, and this explains why they remained undiscovered for so long.^[5] The first specimen was collected in the 1970s, and later described in 1983.^[7] They are found at all depths of water, in different sediment types, and in all latitudes.^[5] They have not yet been found in the fossil record.

1. ↑ from Latin, lorica, corset + ferre, to bear
2. ↑ Cite error: The named reference Nature was used but no text was provided for refs named (see the help page).
3. ↑ Heiner I. & Kristensen R.H. 2005. Two new species of the genus Pliciloricus (Loricifera, Pliciloricidae) from the Faroe Bank, North Atlantic. Zoologischer Anzeiger. 243: 121–138.
4. ↑ ^{4.0 4.1} Gad G. 2005. Successive reduction of the last instar larva of Loricifera, as evidenced by two new species of Pliciloricus from the Great Meteor Seamount (Atlantic Ocean). Zoologischer Anzeiger. 243: 239–271.
5. ↑ ^{5.0 5.1 5.2} Ruppert, Edward E., Richard S. Fox, and Robert D. Barnes. 2004. Invertebrate zoology. 7th ed. Toronto: Brooks/Cole—Thomson. p776.
6. ↑ Heiner I. 2005. Preliminary account of the loriciferan fauna of the Faroe Bank (NE Atlantic). Biofar Proceedings 2005: 213–219.
7. ↑ ^{7.0 7.1} Kristensen, R.M. 2002. An introduction to Loricifera, Cycliophora, and Micrognathozoa. Integrative and Comparative Biology. 42: 641–651.