Despite some flirtation with the freezing mark the past few days that is looking to put my Friday trip to Arkona on hold, on the whole spring is definitely showing itself. This one is just a short post to highlight some river finds, and show off my newest Russian asaphid. UPDATE: actually, two.
On Monday I went back to the river on campus, remembering this time to bring my trusty rock hammer. There was not much to be had among the dull, plain, river-worn rock and the plentiful limestone only filled with tiny shell hash, but closer to the end of my time there before having to teach, I pulled out these odd beasts. Once I got confirmation of what they were, and that they are somewhat rare, I went back to collect the rest the next morning.
So what are they? I've seen these before and just dismissed them as some kind of wacky brachiopod. Not so! They are somewhat related to bivalves but occupy a place all their own as being rostroconches. These planktic, valved creatures would more resemble a taco than a clam. Their hinges are somewhat weak, and they have a long rostrum (the piece on the far left, centre shows it best - the striations that appear like someone scraped it). Looking at the comparable species in the general strata, it may be a Conocardium cuneus. It is a first for me ... at least the first time I've kept one. It was interesting to learn that finding these is far from common, and yet I pulled all of this from a single rock.
This is another lovely Russian asaphid, the fifth that has arrived in my collection, and with five more to come. This would be a nice, prone Asaphus plautini from the Mid-Ordovician, Aseri Stage, collected from the Gostilitsy Quarry near St Petersburg, Russia. It is about 62 mm long, so about average for this species. Here is the evolutionary sequence chart from thefossilmuseum.net:
But wait, there's more! Today I welcome species #6 to the family, Asaphus kotlukovi: