Mystacocarida

Mystacocarida
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 is a subclass of crustaceans, that form part of the meiobenthos. They are less than long, and live interstitially in the intertidal zones of sandy beaches.

Taxonomy

The taxonomy of Mystacocarida is extremely conservative, since all mystacocarids look superficially alike. As of October 2012, there are 13 described species divided between two genera, Derocheilocaris (8 species) and Ctenocheilocharis (5 species). The first mystacocarids to be found were discovered on a beach in southern New England in 1939.

Distribution

Mystacocarids occur along the coasts of South and North America, southern Africa, and the western Mediterranean. The lack of records from other parts of the world is "almost certainly" due to a lack of appropriate sampling, rather than a true absence.

Description

Mystacocarids are tiny crustaceans, less than long, that 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.

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 naupliar eye. After mating, mystacocarids lay tiny eggs which hatch into a nauplius or metanauplius larva.