Kram Posted April 3, 2010 Share Posted April 3, 2010 Can anyone offer me a suggestion as to what type of trilobite this is? Trilobites are rather hard to find in Minnesota, and i'd be interested in your ideas? Link to comment Share on other sites More sharing options...
Auspex Posted April 3, 2010 Share Posted April 3, 2010 Order Phacopida; Family ?Calmoniidae? (Wait for someone who actually knows something, though!) Where (roughly) in MN was it found? "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...
FrozenInTime Posted April 3, 2010 Share Posted April 3, 2010 (edited) It could belong to the genus Calyptaulax? Judging from it being found in Minnesota, and because it's looking very Ordovician! cheers, Mark Edited April 3, 2010 by FrozenInTime Link to comment Share on other sites More sharing options...
FrozenInTime Posted April 3, 2010 Share Posted April 3, 2010 Check out this website for possible related fossils: www.midwestpaleo.com Link to comment Share on other sites More sharing options...
Rob Russell Posted April 3, 2010 Share Posted April 3, 2010 In my opinion it looks to be Calyptaulax Fredricki. Just a guess however...http://midwestpaleo.com/Photo_Gallery/Maquoketa%20Photos/index.htm. Take a look at this Kram. This was found in the northeast corner Iowa.... Not sure of your exact location im Minnesota.... Finding my way through life; one fossil at a time. Link to comment Share on other sites More sharing options...
FrozenInTime Posted April 3, 2010 Share Posted April 3, 2010 Rob, it hasn't got as much to do with the location in Minnesota, as it does with whether this was an in-situ find, and if so, in what formation, as you may have seen on the Midwest Paleo website, these specific formations (the top one being Maquekota) are apparently sometimes stacked on top of eachother. In all likelihood the genus is indeed Calyptaulaux, but this genus apparently occurs in all 4 formations described on this website, with different species in each formation! Defining the species will probably be a bit harder than taking a best guess. And we've already been assuming this fossil was found in one of the formations, shame on us. I guess Kram will have to enlighten us with some more information before we may start crossing out possibilities! cheers, Mark Link to comment Share on other sites More sharing options...
Kram Posted April 4, 2010 Author Share Posted April 4, 2010 In my opinion it looks to be Calyptaulax Fredricki. Just a guess however...http://midwestpaleo.com/Photo_Gallery/Maquoketa%20Photos/index.htm. Take a look at this Kram. This was found in the northeast corner Iowa.... Not sure of your exact location im Minnesota.... Thanks for your reply, I've only found two trilobites in Minnesota in my life. And the one you showed me looks like a dupe of what I have. Very impressed by you guys. Why are they so hard to find here? Was the sea too deep, too shallow? or were trilobites simply on the way out 400 million years ago, which is what I've been told is the age of the limestone in and around St. Paul. Thanks Much. Kram Link to comment Share on other sites More sharing options...
Kram Posted April 4, 2010 Author Share Posted April 4, 2010 Rob, it hasn't got as much to do with the location in Minnesota, as it does with whether this was an in-situ find, and if so, in what formation, as you may have seen on the Midwest Paleo website, these specific formations (the top one being Maquekota) are apparently sometimes stacked on top of eachother. In all likelihood the genus is indeed Calyptaulaux, but this genus apparently occurs in all 4 formations described on this website, with different species in each formation! Defining the species will probably be a bit harder than taking a best guess. And we've already been assuming this fossil was found in one of the formations, shame on us. I guess Kram will have to enlighten us with some more information before we may start crossing out possibilities! cheers, Mark The trilobite was found in St. Paul, Minnesota. I've been told that the limestone here is 400 million years old. The trilobite is a little one, About 1 cm across. Thanks for your time. Kram Link to comment Share on other sites More sharing options...
FrozenInTime Posted April 4, 2010 Share Posted April 4, 2010 (edited) Why are they so hard to find here? You think they are hard to find, because they are so much easier to find elsewhere, but the hard reality for many trilobite collectors is that many localities will only yield scarcely yield complete examples. The sites where one would find massive amounts of trilobites often are the result from natural disasters, but in less turbulent times, sediment was also deposited! I think you should be able to find complete trilobites too at the same locality where you found this cephalon, the only way is to dig some more and find out, which I highly encourage!! I know I would spend a few days to find a complete one, and the occurence of parts often means there are articulated fossils to be found, so keep the hopes up!! Was the sea too deep, too shallow? Judging from the finds you are able to make there, the sediments were once deposited in a relatively shallow sea. In any case, I think judging from the fauna we will be able to exclude deep water sediments, because they would yield other trilobites such as Cyclopygids, which were pelagic trilobites, living in the deeper parts of the sea far from any shoreline. As you can see they look a lot different! (Below a linedrawing of a Cyclopyge pelagic trilobite by Dr. Sam Gon III) or were trilobites simply on the way out 400 million years ago Trilobites were definitely not on their way out in the Ordovician (490-440 mya), it was actually the peak time in trilobite diversity!! 400 million years is in the right direction, I am not aware of the exact age of these formations, but would reckon your fossil to be more in the direction of 460 million years old! Hope this answers at least part of your questions! cheers, Mark Edited April 4, 2010 by FrozenInTime Link to comment Share on other sites More sharing options...
cousin it Posted April 4, 2010 Share Posted April 4, 2010 Rob, it hasn't got as much to do with the location in Minnesota, as it does with whether this was an in-situ find, and if so, in what formation, as you may have seen on the Midwest Paleo website, these specific formations (the top one being Maquekota) are apparently sometimes stacked on top of eachother. In all likelihood the genus is indeed Calyptaulaux, but this genus apparently occurs in all 4 formations described on this website, with different species in each formation! Defining the species will probably be a bit harder than taking a best guess. And we've already been assuming this fossil was found in one of the formations, shame on us. I guess Kram will have to enlighten us with some more information before we may start crossing out possibilities! cheers, Mark An Ordovician invert geek worthy of the the title, he is. http://soliussymbiosus.wordpress.com/ Link to comment Share on other sites More sharing options...
Shamalama Posted April 4, 2010 Share Posted April 4, 2010 Judging from the finds you are able to make there, the sediments were once deposited in a relatively shallow sea. In any case, I think judging from the fauna we will be able to exclude deep water sediments, because they would yield other trilobites such as Cyclopygids, which were pelagic trilobites, living in the deeper parts of the sea far from any shoreline. As you can see they look a lot different! (Below a linedrawing of a Cyclopyge pelagic trilobite by Dr. Sam Gon III) Lookit the eyes on that bugger! I'm guessing he was a tiny, plankton sized trilobite? -Dave __________________________________________________ Geologists on the whole are inconsistent drivers. When a roadcut presents itself, they tend to lurch and weave. To them, the roadcut is a portal, a fragment of a regional story, a proscenium arch that leads their imaginations into the earth and through the surrounding terrain. - John McPheeIf I'm going to drive safely, I can't do geology. - John McPheeCheck out my Blog for more fossils I've found: http://viewsofthemahantango.blogspot.com/ Link to comment Share on other sites More sharing options...
FrozenInTime Posted April 4, 2010 Share Posted April 4, 2010 Well, plankton sized, not necessarily.... This is also a Cyclopygid, a Novakella, you just need a little bit of imagination to see what gargantuan eyes this huge Cyclopygid must have had. recently shown here: The Trilobites from Shropshire, UK, Topic on DiscussFossils Cyclopygids are surrounded by myth and legend in any case, their huge eyes rarily preserve, and they are generally rare occurrences. I even heard someone speculate they could have had some kind of bioluminescent organ.. What I do know for a fact is that some of them preserve two symmetrical horizontal dots on what I believe to remember was the uppermost thorax segment.... What the function of this was (or what was attached to these dots!) remains a mystery, as far as I know... Guess we just gotta keep looking and hope to find one "complete" one day! Sorry for hijacking the topic, Kram, but I hope it was informative.. cheers, Mark Link to comment Share on other sites More sharing options...
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