Eurycercus on thread algae
AN REAL ELEPHANT AMONG THE WATER FLEAS, up to 4 mm !
click to enlarge
on spider thread
click to see total picture
But a very light footed elephant: most of the time this water fleas hangs on filament algae
and water plants with its little legs. This very common water flea is a fast swimmer and has not the
hopping movements of other water flea. Eurycercus also crawls in the detritus(waste) layer on the
water bottom. Bacteria and freshly died material in the detritus layer are probably the main
nutrient. Research has shown that Eurycercus chooses the bottom especially when there are predators
present in the water that eat Eurycercus. And they do seem an easy an easy prey when stationary on
the water plants, like "sitting ducks". Ironically for ducks like the Tufted Duck and the Scaup they
are an important meal. Many fish eat Eurycercus and the water measurer can catch them as
this photo shows. Eurycercus is a genus in the
Chydoridae
family, named after the also common
Chydoris sphaericus, all species which sit most of thee
time on water plants or crawl on the water bottom. Even on a water spiders thread the walk with ease
as you see on the picture at the right. All the the pictures show that the lower forward corners of
the shell halves hang over the thread (algae) from which Eurycercus hangs, a bit like a monorail
train.
The female specimen on the left shows clearly the (normal) eggs in the breeding pouch. This pouch is
large, the water flea itself isn't really that big! The twisted intestine is remarkable, also on the
picture on the right.
Like all Chydorides, Eurycercus is able to sit in any position on the water plants.
click on the picture for more
On the pictures on the left a specimen is hanging upside down on a leaf, and so the legs the
opening of the shell are visible. The picture on the right shows a specimen sitting straight up on a
water plant, and links to more photo's
Finally a picture of a smaller specimen (0.8
mm). This could be a male, they grow no bigger than 1.5 mm.
More nice pictures of Eurycercus lamellatus (and other) on GRAHAM MATTHEWS'
page
click to enlarge
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Eurycercus lamellatus
COPYRIGHT:
All pictures on this site were made by
Gerard Visser (Aadorp,
Netherlands), unless stated otherwise. All rights remain with him. These pictures may not be used
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