Missourian Posted January 18, 2013 Share Posted January 18, 2013 (edited) I'm hoping someone here can id these -- at least at the generic level.... Body is 16 mm long: Body is 8 mm long: Body is 10 mm long: They are all from the upper Cherokee Group (Desmoinesian / upper Moscovian) at Knob Noster, Missouri. I believe they are close to the level of the Mazon Creek deposits. Edited January 19, 2013 by Missourian Context is critical. Link to comment Share on other sites More sharing options...
piranha Posted January 18, 2013 Share Posted January 18, 2013 The ventral specimen reminds me of the Mazon Creek genus: Architarbus. Link to comment Share on other sites More sharing options...
Fossildude19 Posted January 19, 2013 Share Posted January 19, 2013 Can't help on the ID front, but man, those are cool! Regards, Tim - VETERAN SHALE SPLITTER VFOTM --- APRIL - 2015 __________________________________________________ "In every walk with nature one receives far more than he seeks." John Muir ~ ~ ~ ~ ><))))( *> About Me Link to comment Share on other sites More sharing options...
AgrilusHunter Posted January 19, 2013 Share Posted January 19, 2013 (edited) Hi Missourian, These are some wicked cool Trigonotarbids! Great pictures of them too! 1) Looks like Phalangiotarbus. 2) I'd agree with a ventral Architarbus. 3) ??? I'll try hard for that third one but these guys are tough. There just isn't a lot known about them. Edited January 19, 2013 by AgrilusHunter "They ... savoured the strange warm glow of being much more ignorant than ordinary people, who were only ignorant of ordinary things." -- Terry Pratchett Link to comment Share on other sites More sharing options...
Missourian Posted January 19, 2013 Author Share Posted January 19, 2013 (edited) The ventral specimen reminds me of the Mazon Creek genus: Architarbus. Hi Missourian, These are some wicked cool Trigonotarbids! Great pictures of them too! 1) Looks like Phalangiotarbus. 2) I'd agree with a ventral Architarbus. 3) ??? I'll try hard for that third one but these guys are tough. There just isn't a lot known about them. Thanks for the id's. Because these guys are so diverse and hard to track down in the literature, I figured I just let the fellow forum members have all the fun. AgrilusHunter, I'm glad you can't yet id #3. That means it must be rare. It is my best spider, after all. Edited January 19, 2013 by Missourian Context is critical. Link to comment Share on other sites More sharing options...
Wrangellian Posted January 19, 2013 Share Posted January 19, 2013 Nice ones! Those must be pretty rare (valuable)... Link to comment Share on other sites More sharing options...
AgrilusHunter Posted January 19, 2013 Share Posted January 19, 2013 ... AgrilusHunter, I'm glad you can't yet id #3. That means it must be rare ... Oh dear! I don't know about that, I sure hope it's something special though. It is an amazing specimen but I've only seen a few of these guys at the Field Musuem, online, and in manuscripts. I'm far from an expert on the group. RCfossils or fiddlehead have likely seen many more, they may recognize features in the last specimen and be able to give you a good identification. You may also want to contact Dr. Russel Garwood in the UK. Your images are very good and he may be able to give you much more information about these particular fossils. I have to say Trigonotarbids are my favorite fossils in nodules, even beyond the insects. So little is known about these early land predators and I find them just fascinating! If anyone wants to see what these guys likely looked like check out the basal order of arachnids Ricinulei. These guys have the same three divisions in the dorsal segmentation as the Trigonotarbids. "They ... savoured the strange warm glow of being much more ignorant than ordinary people, who were only ignorant of ordinary things." -- Terry Pratchett Link to comment Share on other sites More sharing options...
lissa318 Posted January 19, 2013 Share Posted January 19, 2013 Inspirational.... Those are fabulous. Link to comment Share on other sites More sharing options...
Missourian Posted January 19, 2013 Author Share Posted January 19, 2013 Oh dear! I don't know about that, I sure hope it's something special though. It is an amazing specimen but I've only seen a few of these guys at the Field Musuem, online, and in manuscripts. I'm far from an expert on the group. I didn't mean to put you on the spot. I was just sayin'. Context is critical. Link to comment Share on other sites More sharing options...
AgrilusHunter Posted January 19, 2013 Share Posted January 19, 2013 (edited) No worries. Those really are some rare and exquisite fossils! Thanks for showing them here on the Forum. I hope you can get identifcations for all of them as your images are easily some of the nicest available for Trigonotarbids anywhere online. Edited January 19, 2013 by AgrilusHunter "They ... savoured the strange warm glow of being much more ignorant than ordinary people, who were only ignorant of ordinary things." -- Terry Pratchett Link to comment Share on other sites More sharing options...
Missourian Posted January 19, 2013 Author Share Posted January 19, 2013 Edit: Oops.... forgot the scale. I added the body length in mm to each image Context is critical. Link to comment Share on other sites More sharing options...
Eero59 Posted January 19, 2013 Share Posted January 19, 2013 Beautiful things, it's easy to imagine them alive... Link to comment Share on other sites More sharing options...
Terry Dactyll Posted January 19, 2013 Share Posted January 19, 2013 Very nice specimens... Ive sent you a contact... Cheers Steve... And Welcome if your a New Member... Link to comment Share on other sites More sharing options...
ckmerlin Posted January 19, 2013 Share Posted January 19, 2013 Very nice specimens... Ive sent you a contact... all I can say is wow!! excellent specimens "A man who stares at a rock must have a lot on his mind... or nothing at all' Link to comment Share on other sites More sharing options...
Roz Posted January 19, 2013 Share Posted January 19, 2013 Beautiful and unusual to me! Did you find those recently? Welcome to the forum! Link to comment Share on other sites More sharing options...
Missourian Posted January 19, 2013 Author Share Posted January 19, 2013 Beautiful and unusual to me! Did you find those recently? I acquired them from the landowner several years ago. I'd love to stumble across a deposit like that. Context is critical. Link to comment Share on other sites More sharing options...
tohicknH2o Posted January 21, 2013 Share Posted January 21, 2013 beauties!!! Link to comment Share on other sites More sharing options...
RCFossils Posted January 21, 2013 Share Posted January 21, 2013 Great specimens and great pictures! I love your Knob Noster material and wish i had purchased more fauna from the deposit when i had the opportunity. All three specimens appear to me to be Phalangiotarbids. I cannot make out any defiing characteristics to identify them to the genus level. Perhaps an arachnid expert will be able to go further with them. Thanks for sharing Link to comment Share on other sites More sharing options...
hitekmastr Posted January 23, 2013 Share Posted January 23, 2013 I keep reading that insects from this period were so large but these are closer to modern insects in size. I'm wondering, when we look at St. Clair and other Carboniferous/Pennsylvanian sites, are we looking for foot long dragonflies, or 8 mm arachnids? Link to comment Share on other sites More sharing options...
AgrilusHunter Posted January 23, 2013 Share Posted January 23, 2013 I keep reading that insects from this period were so large but these are closer to modern insects in size. I'm wondering, when we look at St. Clair and other Carboniferous/Pennsylvanian sites, are we looking for foot long dragonflies, or 8 mm arachnids? Hi hitekmastr, Look for both. Technically, these are not insects and they have a very different respiration system. Insects use an internal network of thin tubes connected to openings (spiracles) along their body for respiration. Spiders, and their past relatives the trigonotarbids, use a modified gill like respiratory system called book lungs. These morphological differences may or may not have produced a different effect in the higher oxygen environment (if that was even the cause of the insect gigantism). Regardless, there was a whole range of terrestrial arthropod body sizes on display in the Pennsylvanian, one should be open for just about anything. "They ... savoured the strange warm glow of being much more ignorant than ordinary people, who were only ignorant of ordinary things." -- Terry Pratchett Link to comment Share on other sites More sharing options...
Missourian Posted January 23, 2013 Author Share Posted January 23, 2013 I keep reading that insects from this period were so large but these are closer to modern insects in size. I'm wondering, when we look at St. Clair and other Carboniferous/Pennsylvanian sites, are we looking for foot long dragonflies, or 8 mm arachnids? The little spiders may just be the ones that were preserved in the nodules. Larger arthropods at Knob Noster, such as some eurypterids, tend to be fragmentary. Context is critical. Link to comment Share on other sites More sharing options...
AgrilusHunter Posted January 23, 2013 Share Posted January 23, 2013 (edited) The little spiders may just be the ones that were preserved in the nodules. Larger arthropods at Knob Noster, such as some eurypterids, tend to be fragmentary. Great point! Preservation bias can make all the difference. Edited February 6, 2013 by AgrilusHunter "They ... savoured the strange warm glow of being much more ignorant than ordinary people, who were only ignorant of ordinary things." -- Terry Pratchett Link to comment Share on other sites More sharing options...
hitekmastr Posted February 10, 2013 Share Posted February 10, 2013 Super cool...this is the kind of find that adds meanintfully to the fossil record!!! Really great. Link to comment Share on other sites More sharing options...
TMNH Posted February 10, 2013 Share Posted February 10, 2013 Awsome specimens! You don't see many of those around. It will be interesting to see if anyone can pin down an ID... Link to comment Share on other sites More sharing options...
Terry Dactyll Posted February 11, 2013 Share Posted February 11, 2013 Any News regarding ID's from Jason?... Cheers Steve... And Welcome if your a New Member... Link to comment Share on other sites More sharing options...
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