RCFossils Posted March 9, 2012 Share Posted March 9, 2012 I wanted to share a fossil that I recently collected with everyone here on the Fossil Forum. It is a huge example of a bizzare bivalved arthropod known as Concavicaris sinuala. I believe this species is the largest known Thylacocephala (flea shrimp). They range from the Cambrian to Cretaceous. Little work has been done with them although most were believed to be active predators. This specimen was collected from a black shale site in Lasalle County Illinois. The shale is similar in age to the Mecca Quarry Shale of Indiana (Pennsylvannian). I have collected quite a few Concavicaris from the nearby Mazon Creek deposit that preserve soft parts (appendages and eyes). They are much smaller with most measuring well under an inch in length. This specimen of Concavicaris sinuala measures 8.2 centimeters. The fossil is pyritized and the gold color really stands out from the black shale. I collected this specimen when we has a break in the weather in early January. It was still partially covered with matrix and I had a friend of mine do the prep. It took him nine hours but the results were fantastic. The carapace is covered with scale like structures which is unique to this species. There also might be portions of appendages preserved in the lower left edge. I am also including a reconstruction of C. georgeorum from Mazon Creek. It has a similar body plan with a large eye set in the notch in the carapace. It also had large raptorial appendages to grab its prey. I have only found a few relatively complete examples over the years. This is my best to date. Link to comment Share on other sites More sharing options...
RCFossils Posted March 9, 2012 Author Share Posted March 9, 2012 Here is a reconstruction of the similar Concavicaris georgeorum from the Mazon Creek deposit. Link to comment Share on other sites More sharing options...
Kehbe Posted March 9, 2012 Share Posted March 9, 2012 Wow, the diversity of life on this planet, both past and present, just baffles me! This creature is amazing! Great find Rc! Realizing what it was would have been my downfall and the piece would probably still be lying where i found it! Glad you rescued it! It is not the strongest of the species that survives, nor the most intelligent that survives. It is the one that is the most adaptable to change. Charles Darwin Link to comment Share on other sites More sharing options...
Auspex Posted March 9, 2012 Share Posted March 9, 2012 What a spectacularly odd creature! Congratulations on your "best to date"! "There has been an alarming increase in the number of things I know nothing about." - Ashleigh Ellwood Brilliant “Try to learn something about everything and everything about something.” - Thomas Henry Huxley >Paleontology is an evolving science. >May your wonders never cease! Link to comment Share on other sites More sharing options...
trilobiteruss Posted March 9, 2012 Share Posted March 9, 2012 Awesome, never knew these existed in our Penn rocks, and I looked at alot of black shales in Illinois over years. Thanks for sharing this awesome specimen! Link to comment Share on other sites More sharing options...
oilshale Posted March 9, 2012 Share Posted March 9, 2012 (edited) Wow, what a beautiful monster! Here are some others from the Jurassic: http://www.thefossil...__fromsearch__1 Thomas Edited March 9, 2012 by oilshale Be not ashamed of mistakes and thus make them crimes (Confucius, 551 BC - 479 BC). Link to comment Share on other sites More sharing options...
Auspex Posted March 9, 2012 Share Posted March 9, 2012 Wow, what a beautiful monster! Here are some others from the Jurassic: http://www.thefossil...__fromsearch__1 Thomas Now I remember where I heard of them! "There has been an alarming increase in the number of things I know nothing about." - Ashleigh Ellwood Brilliant “Try to learn something about everything and everything about something.” - Thomas Henry Huxley >Paleontology is an evolving science. >May your wonders never cease! Link to comment Share on other sites More sharing options...
pleecan Posted March 9, 2012 Share Posted March 9, 2012 Congratulations on that spectacular find!!!! Link to comment Share on other sites More sharing options...
Lloyd Posted March 9, 2012 Share Posted March 9, 2012 Wow, very nice find. Congratulations! Link to comment Share on other sites More sharing options...
Roz Posted March 9, 2012 Share Posted March 9, 2012 What an amazing and unusual find! Congratulations! This is new to me.. Almost looks like some kind of scales on it.. I hope you can stabilize that pyrite so it doesn't ever get compromised.. Welcome to the forum! Link to comment Share on other sites More sharing options...
piranha Posted March 9, 2012 Share Posted March 9, 2012 Magnificent fossil and prep... Top-Shelf... Congrats Rob Link to comment Share on other sites More sharing options...
Missourian Posted March 10, 2012 Share Posted March 10, 2012 (edited) We come across those here in Kansas City from time to time. A fellow forumer found one (I think) in black shale just last Sunday. But your has all of ours beat by far. I have a thread on some of mine here: http://www.thefossil...__fromsearch__1 Here's a couple images for your convenience.... Carapace: Telson: Edited March 10, 2012 by Missourian Context is critical. Link to comment Share on other sites More sharing options...
RCFossils Posted March 13, 2012 Author Share Posted March 13, 2012 Thanks for the nice compliments! Russ, I too was surprised that these can be found in Illinois. I occasionally come across partials but complete specimens are quite rare. Most are not well preserved so this is really a stunning example. Thomas, thanks for the link i remember seeing your post a while back. Great specimens Missourian! The telson appears to be a phyllocarid but the others are definately thylacocephala. Link to comment Share on other sites More sharing options...
Missourian Posted March 13, 2012 Share Posted March 13, 2012 Great specimens Missourian! The telson appears to be a phyllocarid but the others are definately thylacocephala. Cool. It's always nice to add another class to my list, let alone another genus. Now then what does a Concavicaris carapace look like?.... Context is critical. Link to comment Share on other sites More sharing options...
Plantguy Posted April 21, 2012 Share Posted April 21, 2012 Hi RC, thanks for sharing photos/info on this unusual little guy. That scale like pattern is very intriguing indeed. Awesome! Regards, Chris Link to comment Share on other sites More sharing options...
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