rew Posted March 8, 2020 Author Share Posted March 8, 2020 8 hours ago, piranha said: The photo is tricky to my eyes... ...if I change the viewing angle they also look like pits. Are they granules or pits? They seem to be pits, not bumps. Link to comment Share on other sites More sharing options...
rew Posted March 8, 2020 Author Share Posted March 8, 2020 Here's a close up of the front of the head of the Cernuolimbus ludvigseni. The light is coming only from the right. You can see that the trilobite is in a shallow pit dug out by the preparator, the side of that pit is dark because it is in shadow. The red arrow points to a row of dots. You can see that they are dark as you would expect for pits, not lit up as you would expect for bumps. So they're pits. 3 Link to comment Share on other sites More sharing options...
Huntonia Posted March 8, 2020 Share Posted March 8, 2020 Definitely looks like pits. Very cool indeed, and incredibly striking photo as well, I'm a sucker for dynamic lighting. Link to comment Share on other sites More sharing options...
rew Posted March 8, 2020 Author Share Posted March 8, 2020 Normally I use diffuse light on opposite sides of a trilobite to minimize shadow. But when deciding whether something is a pit or a bump, directional lighting to create shadows is just what you need. That picture was made with a magnifying macro lens. A series of pictures was taken, each with a very narrow strip in focus. The stack of photos was processed by Helicon Focus to make that image. You can't get the sort of pictures I have on this thread without photo stacking. (Well, maybe with a pinhole camera and exposure times in the hours.) Link to comment Share on other sites More sharing options...
Ruger9a Posted March 8, 2020 Share Posted March 8, 2020 On 3/7/2020 at 1:03 AM, rew said: And now for #105, the official trilobite of the week. This is Cernuolimbus ludvigseni, of late Cambrian age, from the McKay Group, near Cranbrook, British Columbia. Here we see another good example of how photographing your bugs can show you things you didn't know were there (hopefully more interesting than dust). I noticed that on the front lip of the head, just in front of the glabella, is a row of small dots. These aren't really visible with the naked eye. I suspect they served a sensory function, maybe they had hairs to detect vibrations. Beautiful example!!!! I am so envious. Link to comment Share on other sites More sharing options...
rew Posted March 9, 2020 Author Share Posted March 9, 2020 Just for fun here's a typical image from my magnifying macro lens before photo stacking. Only a narrow strip is in focus. 1 Link to comment Share on other sites More sharing options...
rew Posted March 11, 2020 Author Share Posted March 11, 2020 Midweek bonus trilobite, #106, is Cedaria minor. This Middle Cambrian Ptychoparid is from the Weeks Formation in the House Range in Millard County, Utah. 5 Link to comment Share on other sites More sharing options...
rew Posted March 15, 2020 Author Share Posted March 15, 2020 Trilobite of the week #107 is the Silurian Encrinurus tuberculatus from the Much Wenlock Limestone Formation of Malvern, Worcestershire, England. This is twice as long as my Encrinurus macrourus, and has a big axial spine. 5 1 Link to comment Share on other sites More sharing options...
Huntonia Posted March 15, 2020 Share Posted March 15, 2020 Woah, just wow! What an incredible bug, I think this one's gotta be my favorite so far 1 Link to comment Share on other sites More sharing options...
rew Posted March 19, 2020 Author Share Posted March 19, 2020 Now for mid week bonus trilobite #108. This is a small Middle Cambrian Ptychoparid trilobite Menomonia semele, from the Weeks Formation in the House Range, Millard County, Utah. 5 Link to comment Share on other sites More sharing options...
rew Posted March 22, 2020 Author Share Posted March 22, 2020 Trilobite of the week #109 is another Northeastern member of the Homalonotidae, but of Middle Devonian rather than Silurian age, Dipleura dekayi from the Mahantango Formation in Seven Stars, Pennsylvania. This trilobite has some differences from Trimerus delphinocephalus, such as a more rounded pygidium, but the basic design is the same. Like other members of the family these trilobites burrowed through the mud. 4 Link to comment Share on other sites More sharing options...
rew Posted March 25, 2020 Author Share Posted March 25, 2020 Today's mid-week bonus trilobites are two species of Brachyaspidion, both Middle Cambrian in age and from the Wheeler Formation of Millard County, Utah. The first bug, #110, is the diminutive Brachyaspidon microps, about 7 mm long. The second, #111, is Brachyaspidion sulcatum, and is 11 mm long. 5 Link to comment Share on other sites More sharing options...
piranha Posted March 25, 2020 Share Posted March 25, 2020 3 hours ago, rew said: Today's mid-week bonus trilobites are two species of Brachyaspidion, both Middle Cambrian in age and from the Wheeler Formation of Millard County, Utah. The first bug, #110, is the diminutive Brachyaspidon microps, about 7 mm long. The second, #111, is Brachyaspidion sulcatum, and is 11 mm long. These are both Brachyaspidion microps. B. sulcatum does not have genal spines. If you look closely at the first specimen a break is evident at the left genal angle. Robison, R.A., Babcock, L.E., Gunther, V.G. 2015 Exceptional Cambrian Fossils from Utah: A Window Into the Age of Trilobites. Utah Geological Survey Miscellaneous Publication, 15-1:1-97 6 Link to comment Share on other sites More sharing options...
rew Posted March 25, 2020 Author Share Posted March 25, 2020 Well, I have to admit that my second trilobite matches that bug on the left, not the one on the right. In fact, it matches it better than the smaller trilobite does. My only defense is that the second trilobite was dug up and identified by a well known paleontologist and trilobite hunter. Link to comment Share on other sites More sharing options...
piranha Posted March 25, 2020 Share Posted March 25, 2020 25 minutes ago, rew said: Well, I have to admit that my second trilobite matches that bug on the left, not the one on the right. In fact, it matches it better than the smaller trilobite does. My only defense is that the second trilobite was dug up and identified by a well known paleontologist and trilobite hunter. To elaborate more precisely: The difference in the smaller specimen is the missing free cheeks. There is also variable glabellar effacement in Brachyaspidion microps as noted in Robison 1971. Robison, R.A. 1971. Additional Middle Cambrian Trilobites from the Wheeler Shale of Utah. Journal of Paleontology, 45(5):796-804 2 Link to comment Share on other sites More sharing options...
rew Posted March 27, 2020 Author Share Posted March 27, 2020 Trilobite #112 is another Middle Devonian scutellid. This is Scabriscutellum lahceni from the Timrhanrhart Formation at Foum Zguid, Morocco. There are lenses visible in both eyes, with the left eye particularly well preserved. The hypostome is visible and slightly detached. There is an occipital spine, short stubby spines over the eyes, and prominent axial spines. 6 Link to comment Share on other sites More sharing options...
rew Posted March 27, 2020 Author Share Posted March 27, 2020 Here's a close up of the left eye. 6 Link to comment Share on other sites More sharing options...
piranha Posted March 28, 2020 Share Posted March 28, 2020 7 hours ago, rew said: Trilobite #112 is another Middle Devonian scutellid. This is Scabriscutellum lahceni from the Timrhanrhart Formation at Foum Zguid, Morocco. There are lenses visible in both eyes, with the left eye particularly well preserved. The hypostome is visible and slightly detached. There is an occipital spine, short stubby spines over the eyes, and prominent axial spines. This one is now classified: Scabriscutellum (Rheiscutellum) lahceni Basse, M., Müller, P. 2016 Trilobiten aus dem Ober-Emsium und Frühen Eifelium der Südlichen Lahnmulde (Rupbach-Schiefer, Leun-Schiefer und Ballersbach-Kalk). [Trilobites from the Upper Emsian and the Early Eifelian of the Southern Lahn Syncline (Rupbach Shale, Leun Shale, and Ballersbach Limestone).] Abhandlungen der Senckenberg Gesellschaft für Naturforschung, 572:1-329 4 Link to comment Share on other sites More sharing options...
rew Posted March 28, 2020 Author Share Posted March 28, 2020 "This one is now classified: Scabriscutellum (Rheiscutellum) lahceni " Isn't that what I called it? Link to comment Share on other sites More sharing options...
piranha Posted March 28, 2020 Share Posted March 28, 2020 3 hours ago, rew said: "This one is now classified: Scabriscutellum (Rheiscutellum) lahceni " Isn't that what I called it? Where did you call it that? Scabriscutellum lahceni is distinctly different than Scabriscutellum so a new subgenus (Rheiscutellum) was established. Currently the correct name combination is: Scabriscutellum (Rheiscutellum) lahceni (Chatterton et al. 2006) Link to comment Share on other sites More sharing options...
rew Posted April 2, 2020 Author Share Posted April 2, 2020 Mid week bonus trilobite #113 is Solenopleura sp. of Middle Cambrian age from the Spence Shale in Box Elder County, Utah. I have the genus for this one, but not the species. 4 Link to comment Share on other sites More sharing options...
piranha Posted April 2, 2020 Share Posted April 2, 2020 19 hours ago, rew said: Mid week bonus trilobite #113 is Solenopleura sp. of Middle Cambrian age from the Spence Shale in Box Elder County, Utah. I have the genus for this one, but not the species. This one is still awaiting a formal description. Very nice example! Robison, R.A., Babcock, L.E., Gunther, V.G. 2015 Exceptional Cambrian Fossils from Utah: A Window Into the Age of Trilobites. Utah Geological Survey Miscellaneous Publication, 15-1:1-97 4 Link to comment Share on other sites More sharing options...
rew Posted April 4, 2020 Author Share Posted April 4, 2020 Trilobite of the week #114 is of Early Cambrian age from the Anti-Atlas Mountains near Jbel Ougnate, Morocco. The genus is Hamatolenus and I believe, but am not certain, that the species is Hamatolenus marocanus. This is a large bug, about 13 cm long. 4 Link to comment Share on other sites More sharing options...
rew Posted April 8, 2020 Author Share Posted April 8, 2020 Bonus mid-week trilobite #115 is another Chinese bug, Shergoldia laevigata, of Late Cambrian age and from the Sandu Formation at Jingxi, Guangxi, China. It's not particularly pretty, but it's the only bug I have in the Tsinaniidae. 4 Link to comment Share on other sites More sharing options...
piranha Posted April 8, 2020 Share Posted April 8, 2020 6 hours ago, rew said: It's not particularly pretty, but it's the only bug I have in the Tsinaniidae. I respectfully disagree ... this is a very aesthetic textbook example! Interesting extra info: Early holaspides of Shergoldia laevigata had a pair of anterolateral pygidial spines that disappeared in later holaspides. Zhu, X.J., Hughes, N.C., Peng, S.C. 2007 On a New Species of Shergoldia Zhang & Jell, 1987 (Trilobita), the Family Tsinaniidae and the Order Asaphida. Memoirs of the Association of Australasian Palaeontologists, 34:243-253 PDF LINK 5 Link to comment Share on other sites More sharing options...
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