Wednesday, July 15, 2015

Pocketbook, Pigtoe, or Spike?

For the first week or so (and a little bit even now), looking at the big pile of our collected mussels on the shore was completely overwhelming. How on earth was I supposed to know whether the mussel I was holding was a Round or a Wabash pigtoe? Which one was A. Lig? And are pocketbooks and L. card the same thing? Every scientific name sounded the same, and even worse, all the mussels looked the same. They looked like roundish, flatish rocks.
But! There is hope! Only a couple of weeks in and we can all identify way more species than I thought possible. Here is a quick list of the most common species we are encountering in our fieldwork:

Spike (Elliptio dilatata): This mussel is easy to identify because of its elongated shape, much more exaggerated than most mussels.

Elliptio dilatata

Ligumia recta: Looks extremely similar to E. dil, except that the raised line on each shell starting from the hinge of the mussel, called the posterior ridge, ends on the side of the shell instead of the bottom (in other words, it ends medially instead of ventrally).

Three-ridge (Amblema plicata): By far the easiest mussel to identify-- just look for those ridges! Sometimes there are more than three, however.

Wabash pigtoe (Fusconaia flava): My favorite, it has a wonky shape but is overall much more round than mussels that have a slightly elongated shape. It also has a bright orange foot!

Fusconaia flava

Pocketbook (Lampsilis cardium): Very fat. Very, very fat. So fat. Definitely the most curious- they are the first to open their shells to explore their new surroundings when we gather on the riverbank to sort our catch.

Lampsilis cardium (center) and Amblema plicata (right)

Pink heelsplitter (Potamilus alatus): Named the heelsplitter because of its shark fin-like appendage on its top, which you would definitely not want to step on! They’re also usually much larger than other mussels.

Potamilus alatus

White heelsplitter (Lasmigona complanata): Looks exactly like the pink version, except that its sides are much flatter and not inflated. It can be hard to distinguish between the two. Both heelsplitters can be a bit of a jokester and squirt you with water when you hold them up in the air.

Mucket (Actinonaias ligamentina): If it has no real distinguishing characteristics and just kinda looks like a mussel, I would bet you’re holding a good old mucket.

Leptodea fragilis: Just like the mucket, but really light. Extremely light. Suspiciously light.

Photo credit:
Macalester promotional material

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