Marine Phyla Pages -- Coastal Carolina University
LORICIFERA
Loricifera
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http://www.meiofauna-marina.com/contents/html/startseite.html |
Defining Characteristics
The Loricifera are minute invertebrates, rarely attaining 0.5 mm in size.
Systematics
The anterior of the body comprises a discrete ‘head’ and ‘neck’ surrounded by spines and scalids, reminiscent of those seen in the Kinorhyncha. Like Kinorhyncha, the head houses an introvert with a ring of eight stylets surrounding its base, and a mouth at its apex. The cone-shaped introvert has. A substantial brain lies within the loriciferan introvert.
The lorica is a specialized cuticular structure that gives the phylum its name. It comprises a system of hardened dorsal, ventral and lateral plates that surround the trunk of the animal, affording it a considerable degree of protection. Where necessary the entire anterior portion of the animal can be withdrawn into the lorica.
Loricifera are dioecious animals that have paired gonads. Little is known about the process of fertilization, but larval stages have been discovered. These resemble the adult forms, except in their reduced number of spines, and the presence of a bizarre pair of posterior swimming ‘feet’.
Feeding
The diet and physiology of these invertebrates are basically unknown. However, food substances pass from the mouth to the buccal tube, pharynx and then gut, before being expelled from the rectum via the posterior anal cone. Protonephridia carry out additional excretory processes.
Habitat
They live firmly attached to rocky and shelly marine substrata. Since the initial discovery of Nanaloricus mysticus off the French coast in 1983, a further eight species of Loriciferan have been identified. The range for this phylum has also been extended to include the coastal regions of North America, and a global distribution seems likely.
Loricifera Links
http://www.teaching-biomed.man.ac.uk/bs1999/bs146/biodiversity/loricif.htm