Some Freshwater Mussels from Maryland

Picture synopsis of some of my work over the last month...

These photos have been taken as part of mussel surveys or when I've run acrossed something interesting in the field across the State of Maryland. I make no attempt to identify these Lampsilis to species and currently no one I know of from an agency working in the Potomac drainage does, with any success. Since at least 1900, a non-native to the drainage, Lampsilis cardium, has been present and every indication is that it has displace and potentially hybridized with the native L.cariosa. Based on gross shell morphology and the confounding nature of mussels being over named and highly synonomized, there is a growing notion that some specimens could be another non-native Lampsilis, L. ovata. So while out on various surveys I have been taking as many pictures as I can, unfortunatley not in the most sensical order upon review or of the best quality. What is very exciting is the Potomac is very low, crystal clear, and female Lampsilis are displaying mantle lures. So when possible I've tried to photograph the lure and then the shell. Some non-Potomac pictures also snuck there way in...

Two Lampsilis
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Lampsilis in substrate
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Same Lampsilis removed from substrate
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Elliptio complanata in substrate
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Same E. complanta removed from substrate
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Another Lapmsilis...
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Alasmidonta undulata in substrate (not from Potomac)
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Same A. undulata, note the orange foot, which only a few species have.
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Jackpot on E. fisheriana (Potomac drainage - formerly E. producta). Collected these to measure L, W, H, and kept several for tissue sample request.
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And we're back to Lampsilis in the Potomac
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I've got a 10 second video, but it exceeds max file size to upload....

I grew up outside of D.C., and the thought that the Potomac can be described as clear is astonishing. But I'm glad for it!

Oh wow, that's awesome. I've never been interested in (or really known about) freshwater mussels until joining this site. I didn't know that us on the eastern slope had any mussel diversity or any cool species with lures like that. I will have to pay much closer attention to see if I can spot some of these guys while I'm out sampling from now on. Thanks, Matt.

Vahry nice-ah!

What a mess in the lampsilis. The lure really looks like the ovata lures I've seen in French Creek. That third picture almost screams "I'm ovata". The fisheriana really are long little dudes huh?

Todd

Bruce, it is actually very clear and more so in the upper reaches. I was up around the Monocacy River, which actually makes it a little turbid, and further up west of Hagerstown. When you get that far upstream there is a good 10 ft vertical visibility especially this time of year. Macrophyte growth in the upper and lower reaches has really taken off.

Derek - diversity not really, but just as cool. We still have things with lures and Atlantic slope even has things with spines. Puts a pustule to shame!

Todd, funny you say that. I played a little game last winter called how many species are in front of you with people around the office and the agency. I put a L. ovata from French Creek, a L. cardium from the Potomac, and a L. cariosa from the Potomac (Potomac specimens were identified by Art Bogan and confirmed my initial ID) and asked how many species are there...and then the fun started. The original records L. ventricosa cohongorata and was follwed by just L. ventricosa. Given that whole mess of synonomy it is no wonder there could be multiple species. All that coincided with (no big surprise!) major gamefish transportation and stocking by the U.S. Fish Commission. You should have seen the specimens I was pulling up last week. Some were dead ringers for topotype L. cardium or that found on any poster or book right next to something completely rayless, waxy, and a different shade of yellow. I am becoming more and more convinced that L. ovata is also in the Potomac. The lanceolate Elliptios are like dilata but sharper and spikier. Not very thick, not very tall, growth is all in the length.

I need to resize the pictures from Wednesday...tidal-fresh mussels, a whole nother can 'o worms right in the heart of snakehead central!

Edited by ashtonmj, 25 September 2009 - 08:28 PM.

Nice finds! In the last three pics the bodys of the clam look like a fish head almost! really cool

As promised, some mussels from the tidal-fresh area of the Potomac. This location is about 2km wide, but we were surveying a strip along the shoreline approximately 25-m-wide. This is really the only snorkelable habitat. Further out in the water there is a wall of hydrilla, milfoil, eelgrass/val, and muck and depth increased pretty rapidly except for a few of mud flats that are in areas between points. Shoreline varies from cement walls, rip rap, to completely natural sand and forested. In general, tidal-fresh habitats are pretty poorly sampled for mussels, which means VERY little in the grand scheme of things. It is a really unique habitat because sand, silt, and muck is often the dominant natural substrate and you have a very mixed fish community from the normal Coastal Plain community to the anadramous species like shads, herrings, temperate basses, etc. It is one of the most diverse mussel assemblages in Maryland as represents a near complete shift from the Potomac community upstream of Great Falls (Fall Line). Onto the pictures....

Ligumia nasuta (Eastern pondmussel)
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Ligumia nasuta in substrate
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Same mussel...
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A view of the general habitat we were sampling
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Lampsilis radiata radiata in substrate
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Same mussel...
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Another L. r. radiata amongst the vegetation
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Same mussel...
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Variety of L. r. radiata
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Can't find the picture, but there were plenty of Elliptio complanata.

That's good. I realize I never knew what was in the Potomac downstream from D.C. in terms of molluscs. My unthinking thought would be, well, you hit Point Lookout and there are probably oysters somewhere...