Zooplankton of the open Baltic: Extended Atlas - IOW

Polymorphism is a common phenomenon to many rotifer species.
Individuals of the same species collected from one locality over a period of
time often show changes in one or more characteristics from one generation to
another (e.g. length of spines, or proportions of the body). In some localities
these variations are season-specific: a phenomenon known as cyclomorphosis
which is most common in some loricate rotifers (e.g. Keratella and
Brachionus), but also can be observed in the illoricates (e.g. Asplanchna).
Figure 5.1.5. Morphology of a rotifer Brachionus calyciflorus: female
on the left (dorsal view, modified from Pontin, 1978), male on the right
(lateral view, modified from Koste, 1978). H – head, B – body, F – extended
foot, A – anus position, BR – brain, CC – coronal cilia, CV – contractile
vesicle, DA – dorsal antenna, EYE – eye, EGG – egg, FB – flame bulb, GG –
gastric gland, I – intestine, J – jaws, L – lorica, LA – lateral antenna, M –
muscle, P – pharynx, PE – penis, PG – pedal gland, PR – prostate, PT –
protonephridium, S – spine, SC – sensory cirry, ST – stomach, T – toes, TE –
testis, YG – yolk gland (after Telesh & Heerkloss, 2002).
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