Mystacocarida
Ctenocheilocaris sp.
Scientific classification
Kingdom:	Animalia
Phylum:	Arthropoda
Subphylum:	Crustacea
Class:	Maxillopoda
Subclass:	Mystacocarida Pennak & Zinn, 1943
Order:	Mystacocaridida Pennak & Zinn, 1943
Family:	Derocheilocarididae Pennak & Zinn, 1943
Genera
Ctenocheilocaris Derocheilocaris

Mystacocarida are interstitial crustaceans, part of the meiobenthos. Their taxonomy is extremely conservative, superficially all mystacocarids look alike. There are only 12 described species divided between two genera, Derocheilocaris and Ctenocheilocharis. They are found along the coasts of South and North America, southern Africa, and the western Mediterranean.

Mystacocarids are tiny crustaceans, around 0.5 millimetres (0.02 in) in length, and live in the spaces between sand grains on intertidal beaches. They have a cylindrical body, with five thoracic and five abdominal segments. There are four pairs of small thoracic appendages.^[1]

The head is relatively large and divided into two by a stricture, so that the latter part gives the appearance of being a part of the thorax. This region bears a pair of maxillipeds, and the head also has two pairs of maxillae, a pair of limb-like mandibles, and two pairs of long antennae. The appendages on the head are much longer than those on the thorax, and have a number of fine hairs that the animal uses to strain detritus from the water to feed on. They have a single, nauplius eye.^[1]

After mating, mystacocarids lay tiny eggs which hatch into a nauplius larva.

[edit] South American specimens

The mystacocarid pictured (right) was found in the zone of retention at Playa Ritoque in Region V, Chile. All the Mystacocarida from South America reported so far have been of the genus Ctenocheilocaris (Hessler, 1988), so it is assumed that this is the genus of the individual pictured. Mystacocarida have been observed in samples from Playa Grande (Las Cruces) and Curiñanco (near Valdivia).

[edit] References

• Hessler, R.R. (1988): Mystacocarida In: Higgins, R.P. & Thiel, H. Introduction to the study of meiofauna. Smithsonian Institution Press. ISBN 0-87474-488-1
• Zinn, D.S., Found, B.W. & Kraus, M.G. (1982): A bibliography of the Mystacocarida. Crustaceana, 43:270-274.