Key to the Great Lakes Rotifers

Class Monogonata

Relatively rigid, often (but not always) with a lorica. Some species secrete or construct a tube which they inhabit. Not telescopic. 0-2 toes (toes may have basal spines as well). (A)

Class Digonata - Order Bdelloida

Soft bodied and capable of telescopic movements including retraction of the corona into the mouth. 3-4 small toes (plus possible spurs and papillae). (B)

Very large corona with no cilia (may have setae). No toes.

Order Collothecacea

Corona a double wreath in which the cilia of the inner circle are longer than those of the outer, with a ciliated furrow between. No toes.

Order Floscularidae (most)

Long moveable spines attached like arms. No foot or toes.

Order Floscularidae
Family Testudinellidae
Genus Filinia

Corona not especially large. No foot or toes. Lorica flat or 4-lobed in cross-section. Plates confluent at edges.

Order Floscularidae
Family Testudinellidae
Genus Pompholyx

Round with foot ending in a tuft of cilia rather than toes.

Order Floscularidae
Family Testudinellidae
Genus Testudinella

Corona reduced to a subequatorial fringe. No foot or toes.

Order Floscularidae
Family Testudinellidae
Genus Trochosphaera

Photo NA

Corona not especially large, and not a double wreath. 1-2 toes.

Order Ploima
(most)

Corona not especially large. No foot or toes. With rigid, immobile spines oriented anterior and posterior

Order Ploima (in part)

Corona not especially large. Sac shaped with no foot or toes.

Order Ploima (in part)

Corona not especially large. No foot or toes. Lorica ventral plate flate and dorsal arched. Plates separated by an infolded cuticle.

Order Ploima (in part)
Family Brachionidae
Genus Anuraeopsis

12 moveable paddlelike appendages. No foot or toes.

Order Ploima
Family Synchaetidae
Genus Polyarthra