Well, if you ever end up near a source of freshwater (e.g. a pond, lake, canal, creek, or even roadside-ditches) be on the lookout for tiny bivalves in the Euglesa genus. The rest of the Sphaeriidae family is also under-observed, but it’s Euglesa and a few similar genera that are the least understood and observed (see this collection project I made)
(Image of a
Euglesa compressa valve)
Euglesa is fairly common and very widespread. However, every continent that’s not North America or Europe has less than a dozen observations. Africa has only 2. Europe and North America are still missing observations from a lot of locations.
Although they are small they aren’t too difficult to find. You can usually find empty shells in the substrate of a water body like this:
They are about the size of a large grain of dirt. But, most of the time, the interior is a bright white, and makes them stand out. Make sure to note the substrate type in the comments (e.g. “Found in a mud-bottomed semi-temporary pond,” “Found in a sandy, artificial swimming beach,” or “Found in a gravel-bottomed pond full of algae”). Usually you don’t have to be too specific, just note the habitat type and substrate.
Most of the time, all you have to photograph is the exterior and interior. If possible, take a clear shot of the cardinal teeth.
^ Exterior shot
^ Interior shot
^ Cardinal teeth (the two squiggly lines at the middle of the hinge. It’s not always squiggly and they aren’t always thin lines, depending on the species).
Here’s what a live adult Euglesa looks like. This one is on the larger side at 4mm. They are usually around 2-3mm, depending on the species. There are some species that can get up to more than 10mm but anything above 5mm is considered large. They are usually somewhat translucent and a yellow or beige color. Sometimes they are encrusted with red/brown as this individual is.
TLDR; look for very tiny bivalves in freshwater. Note the habitat and substrate. Take a photo of the outside and inside if possible
