Overview
Rotifera (Latin: rota, wheel; fera, to bear) is a phylum within Kingdom Animalia. The rotifers are microscopic aquatic psuedocoelomates.
Description
The rotifers have a ciliated mouth called a corona, which they use
to collect food and for locomotion. The beating of the cilia gives
the illusion that this animal has a wheel attached to its jaw. The
corona creates a water current into the mastax, which is composed of
several sets of jaws called trophi. From there food passes to the
stomach, is digested by enzymes, and exits the anus.
Rotifera Classes and Orders differ in the way in which they
reproduce. In Bdelloidea males are completely absent and reproduce by
parthenogenesis. Members of Seisonidea produce haploid eggs which
must be fertilized. Monogononta produces two types of eggs:
- Amictic: Diploid eggs formed by mitosis, which develop directly into females without fertilization.
- Mictic: Haploid eggs which, if unfertilized, develop into males.
If they are fetilized these eggs will encyst themselves and await
hatching in the spring.
Characteristics
Classes within Rotifera
Characterized by paired ovaries.
Only two species, both of which are Epizoic (living on the outside
of an organism) to crustaceans; reduced corona. Males and
females are both needed to produce offspring.
More than five hundred species. Mastax is used for grinding, males absent.
More that a thousand species. Mastax not used for grinding; males
are less numerous, females produce Mictic and Amictic eggs.
Contains the orders Collothecacea, Flosculariacea, and Ploimida
Sources:
Campbell & Reece. "Biology" Benjamin Cummings. 6th Edition, 654
Introduction to Rotifera
Miller & Harley. "Zoology" McGraw Hill. 7th Edition, 176-179
Rotifer Systematic Database