Pseudogygites Posted July 5, 2018 Share Posted July 5, 2018 Hello again! This post will be about some beautifully preserved Triarthrus fossils (and my first complete Trilobite finds). Some of them even have the eyes preserved! I found these at a local train station, and the site of significant construction lately. I believe most of the to be E. eotoni, and the last one to be E. rougensis or spinosus. It may not be visible in the picture, but the last one has a streak of pyrite along the side of its cephalon / upper thorax. Could this be some kind of soft body tissue preservation, similar to those of the Beecher's Trilobite bed? 3 Link to comment Share on other sites More sharing options...
ynot Posted July 5, 2018 Share Posted July 5, 2018 Nice finds! Love the multi plate. 1 Darwin said: " Man sprang from monkeys." Will Rogers said: " Some of them didn't spring far enough." My Fossil collection - My Mineral collection My favorite thread on TFF. Link to comment Share on other sites More sharing options...
caldigger Posted July 5, 2018 Share Posted July 5, 2018 Ya, that's a busy little plate. Must have been having a party when they got buried. 2 Link to comment Share on other sites More sharing options...
Kane Posted July 5, 2018 Share Posted July 5, 2018 A really lovely plate! I am thinking on the plate they are all Triarthrus eatoni (T. spinosus has a long genal spine, if memory serves). It is unlikely that this shale will preserve soft body parts like in Lagerstatte areas as the deposition and preservation conditions in this shale are not favourable to that. 1 ...How to Philosophize with a Hammer Link to comment Share on other sites More sharing options...
aek Posted July 5, 2018 Share Posted July 5, 2018 So cool to find such beautiful specimens at a temporary construction site. Congrats! 1 Link to comment Share on other sites More sharing options...
Monica Posted July 5, 2018 Share Posted July 5, 2018 Congratulations on finding such beautiful little bugs!!! I am Thanks for sharing! 1 Link to comment Share on other sites More sharing options...
Northern Sharks Posted July 5, 2018 Share Posted July 5, 2018 Great finds. They are all Triarthrus and on the last one, it does indeed look like there are genal spines, making it T.spinosus (but a clearer picture would certainly help). 1 There's no limit to what you can accomplish when you're supposed to be doing something else Link to comment Share on other sites More sharing options...
FossilsAnonymous Posted July 5, 2018 Share Posted July 5, 2018 They are all great finds 1 On The Hunt For The Trophy Otodus! Link to comment Share on other sites More sharing options...
FossilDAWG Posted July 5, 2018 Share Posted July 5, 2018 Very nice finds! I lived (and collected) in Ottawa for seven years and never saw an aggregation of Triarthus eatoni like yours. Triarthus spinosus has long genal spines, a spine on the occipital ring, and axial spines on the 8th, 9th, and 10th thoracic segments. However the spines on the axis are often broken so you may have to look for the spine bases, and often you can see the impression of the spines on the thorax exoskeleton. There is no pygidial spine, but in fairness the thoracic spines can easily be mistaken for a pygidial spine. I found an old but archived web page about the various Triarthrus species posted by forum member Trilobitologist. The Whitby Formation in southern Ontario and the Billings Shale in the Ottawa area also contain a second spiny Triarthrus species, Triarthus rougensis. T. rougensis has genal spines similar to T. spinosus and a single axial spine on the 9th thoracic segment, but it lacks the occipital spine and spines on the 8th and 10th thoracic segment. However as these spines are often difficult to see on T. spinosus care must be taken to distinguish the species. Don 5 Link to comment Share on other sites More sharing options...
Pseudogygites Posted July 5, 2018 Author Share Posted July 5, 2018 1 hour ago, FossilDAWG said: Very nice finds! I lived (and collected) in Ottawa for seven years and never saw an aggregation of Triarthus eatoni like yours. Triarthus spinosus has long genal spines, a spine on the occipital ring, and axial spines on the 9th, 10th, and 11th thoracic segments. However the spines on the axis are often broken so you may have to look for the spine bases, and often you can see the impression of the spines on the thorax exoskeleton. There is no pygidial spine. Don Wow! I had no idea this was so rare! Though not visible in the picture, the last Triarthrus does have a pygidial spine. Would that make it a T. rougensis? I believe it is the only other species with genial spines. Also, are the Triarthrus in the aggregation moults that were washed together, or the living animals that were killed in an event, such as a mudslide? Feeling really lucky! Link to comment Share on other sites More sharing options...
Pseudogygites Posted July 5, 2018 Author Share Posted July 5, 2018 This is unrelated, but could someone please tell me how to make that walking Triarthrus emoji-thing? I'd really like to put it at the end of these posts. Link to comment Share on other sites More sharing options...
Monica Posted July 5, 2018 Share Posted July 5, 2018 @Pseudogygites Do you mean this one: ? If so, click on the happy face at the top of your reply box - this trilo is one of the many "Fossil Emoticons" available 2 Link to comment Share on other sites More sharing options...
Pseudogygites Posted July 5, 2018 Author Share Posted July 5, 2018 3 minutes ago, Monica said: @Pseudogygites Do you mean this one: ? If so, click on the happy face at the top of your reply box - this trilo is one of the many "Fossil Emoticons" available Thank you! 1 1 Link to comment Share on other sites More sharing options...
Northern Sharks Posted July 5, 2018 Share Posted July 5, 2018 3 hours ago, Pseudogygites said: Wow! I had no idea this was so rare! Though not visible in the picture, the last Triarthrus does have a pygidial spine. Would that make it a T. rougensis? I believe it is the only other species with genial spines. Also, are the Triarthrus in the aggregation moults that were washed together, or the living animals that were killed in an event, such as a mudslide? Feeling really lucky! Triarthrus do not have a spine on the pygidium, in any species from the area. The spines are on the thoracic segments. Each species has 12 segments, T. spinosus has spines on the 8th, 9th and 10th with the 9th being the longest. T.rougensis has at least a long spine on the 9th. The big difference is that T.spinosus has a spine on the occipital ring (back of the cephalon) and T.rougensis does not. I learned something new looking that up. 2 There's no limit to what you can accomplish when you're supposed to be doing something else Link to comment Share on other sites More sharing options...
Pseudogygites Posted July 5, 2018 Author Share Posted July 5, 2018 3 minutes ago, Northern Sharks said: Triarthrus do not have a spine on the pygidium, in any species from the area. The spines are on the thoracic segments. Each species has 12 segments, T. spinosus has spines on the 8th, 9th and 10th with the 9th being the longest. T.rougensis has at least a long spine on the 9th. The big difference is that T.spinosus has a spine on the occipital ring (back of the cephalon) and T.rougensis does not. I learned something new looking that up. Whoops! The spine I'm seeing must be from one of the lower thoracic segments (9th, most likely), near the pygidium. Link to comment Share on other sites More sharing options...
FossilDAWG Posted July 5, 2018 Share Posted July 5, 2018 16 minutes ago, Northern Sharks said: Triarthrus do not have a spine on the pygidium, in any species from the area. The spines are on the thoracic segments. Each species has 12 segments, T. spinosus has spines on the 8th, 9th and 10th with the 9th being the longest. T.rougensis has at least a long spine on the 9th. The big difference is that T.spinosus has a spine on the occipital ring (back of the cephalon) and T.rougensis does not. I learned something new looking that up. BTW Northern Sharks posted this info as I was editing my post above, so he was actually ahead of me by a couple of minutes posting the information about T. rougensis. Credit where credit is due! Don 1 Link to comment Share on other sites More sharing options...
Pseudogygites Posted July 5, 2018 Author Share Posted July 5, 2018 Upon closer examination, I have realized that the first Triarthrus also has a genial spine. This means that the only T. eotoni are located on the aggregation plate. Link to comment Share on other sites More sharing options...
Tidgy's Dad Posted July 26, 2018 Share Posted July 26, 2018 Lovely finds! 1 Life's Good! Tortoise Friend. Link to comment Share on other sites More sharing options...
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