Unionidae identification pictures

Nature Talk
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So I’ve been getting into river mussels lately and I’ve been taking ID pictures solely of the top and inside of the shell above a ruler. Should I also include a frontal view of river mussel specimens or is this not necessary?

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A friend who is an expert on freshwater mussels in Texas always recommends getting flat outer and inner photos of a shell along with a dorsal image showing the depth of the shell(s) and the beak or umbo…all with a ruler in view.

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I see, thank you!

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Here are a couple of my examples:
https://www.inaturalist.org/observations/34703733
https://www.inaturalist.org/observations/34703729

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Here are some of my observations: https://www.inaturalist.org/observations?taxon_id=51903&user_id=tcriley&verifiable=any

I always try to get a top and inside photo, as well as a front, back, and side view. Depending on the genus, different photos will be needed (some need the structure of the connection point, some need the depth of the inner cavity, how inflated the shell is), but it’s always better to have more than enough photos than not enough.

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Hey there! Lots of posters here with great advice. I’d like to add as someone who does a lot of work with these guys currently. Generally, a mussel observation will need at least three up-close photos to ensure a research grade ID. Depending on where you live, there can be dozens of species possible, so good photos are a must to distinguish between many species.

  1. a photo of the outside (sideways view to clearly see the entire outline from one side of the shell)
  2. For empty shells (the vast majority of mussel observations are of empty shells that wash onto shore), an entire interior photo to get a good view of the interior colour and any pseudocardinal or lateral “teeth”, which are not teeth in a typical sense but help the mussel hold itself closed. Note: Some species have 2 sets of teeth, some have only one set, and some have none at all. No matter what, an interior photo is always helpful regardless of whether or not the mussel has these teeth.
  3. a “top-down” view of the beak (where the two shells come together). the pattern of how the shell grows there is often an identifying feature.

An example from my own collection is this Fatmucket observation which shows the exterior, interior, and dorsal view of the beaks. Note that this species has both sets of teeth present.

For live mussels, don’t try to open them up. Just get what photos you can without the interior. If you see a live mussel and can sneak up on it without disturbing it, you can sometimes get good photos of the siphon or foot, too. here’s a White Heelsplitter I observed where you can see the siphons of an actively feeding mussel.

A ruler or other item that you can use to estimate size is always helpful, too!

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