Great Lakes Water Life Photo Gallery

Zooplankton - Waterfleas

Cladoceran Field Guide

Alonella

Under Construction!

Genus Alonella

For morphological terms see: Cladocera Anatomy

The Genus Alonella is a group of very small waterfleas including just 2 Great Lakes species. Fine features of the carapace and postabdomen are used to distinguish among species - necessitating use of a high-powered light microscope at a minimum.

to 0.5mm
Elongate body. Rostrum extending only slightly if at all beyond the tips of the olfactory setae. Postabdomen angled at the apex. Postabdominal claw with 2 major basal spines. Posterior margin may be notched or may have 1-2 carapace teeth forming a tail.
Alonella excisa

0.2-0.3mm
Spherical or broadly ellipsoid body. Valves striated. Long rostrum extending well beyond the tips of the terminal olfactory setae, only slightly recurved. Postabdomen without a prominent preanal angle and without lateral dentricles. Postabdominal claw with 1 major basal spine. With a spine at the ventroposterior angle or a small tooth at the inferoposterior angle (tail).
Alonella nana