Water flea ID please

Images made through a microscope. All subject types.

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Olympusman
Posts: 5090
Joined: Sun Jan 15, 2012 12:31 pm

Water flea ID please

Post by Olympusman »

My references don't provide an ID for this water flea. It is notable for the fairly flat dorsal aspect wherein most Daphnia are more rounded.

Image

Three stacks combined in Microsoft Picture Editor
Michael Reese Much FRMS EMS Bethlehem, Pennsylvania, USA

merrimoles
Posts: 8
Joined: Sun Feb 16, 2014 2:21 am
Location: Calgary, Canada

Post by merrimoles »

This is definitely Simocephalus sp, as indicated by the ventral margin of the head. Older texts will give you S. vetulus, but there seems to be a consensus that this species doesn't actually occur in N America (which is where I assume you found this). There isn't full agreement as to what to call this taxon in N America, but S. mixtus seems to be the most popular.

Olympusman
Posts: 5090
Joined: Sun Jan 15, 2012 12:31 pm

Water flea

Post by Olympusman »

Merrimoles,
Thanks for the ID.

Mike
Michael Reese Much FRMS EMS Bethlehem, Pennsylvania, USA

Clado
Posts: 98
Joined: Mon Feb 13, 2012 12:07 pm
Location: The Netherlands

Post by Clado »

Hello Olympusman and merrimoles,

May be there is another possibility, Simocephalus expinoses lives in North America too. The posterior margin of the carapace is rather straight and S. mixtus is more convex. A claer image of the postabdomen would solve this problem because S. expinoses has a comb of spines on the base of the furca.

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