LabRatKing Posted November 6, 2020 Share Posted November 6, 2020 So...I have some questions about sclerotic rings. In addition to supporting large eyes, resisting pressure, etc. how do they work? I ask as I see four basic forms across species, extant and extinct. the first is a fixed ring fused to the frontal and zygomatics. the second looks to be a fused or partially fused ring that is around the iris the third is a ring of small plates held together by connective tissue and the fourth looks like a camera iris Where my confusion arises is with the third and fourth and some birds and fossils. Do these function as part of the actual muscles of the iris sliding/flexing the sclera, or are they purely support for the overall structure? For those unfamiliar: 2 Link to comment Share on other sites More sharing options...
LabRatKing Posted November 6, 2020 Author Share Posted November 6, 2020 I should add that the visual is a web steal and other, more trustworthy references give data that is contradictory and/or confusing to me. Link to comment Share on other sites More sharing options...
Rhiguita Posted November 7, 2020 Share Posted November 7, 2020 From what I am able to gather they appear to help support the eye and prevent movement of the eye in the socket, and the shape and structure the of the ring is related to the lifestyle of the animal that had them, as the shape can determine what time of day it was most active, as changing the structure and distance of parts of the eyes allows the animal to have the advantage in either diurnal or nocturnal life. I found a paper that talks about them which might do a better job at explaining then me. https://onlinelibrary.wiley.com/doi/full/10.1111/j.1469-7580.2008.00897.x 1 Link to comment Share on other sites More sharing options...
LabRatKing Posted November 7, 2020 Author Share Posted November 7, 2020 So I’m asking this as I’m working on an Archaeopteryx project on the side, and pointed out that the fossil morphology is nearly identical to extant chameleon morphology...and there is an oft ignored bone on the Berlin specimen that correlates to turret eyes and extensible tongue on extant insectivores... yeah, heresy, but I’m not a paleomorphologist, just a scrub with an eye for details... hence some of the other posts I’ve made today...feelers... tomorrow, I’ll start what will become the controversial post on the first physical Archaeopteryx reconstruction based off all available research. these eye rings are the wild card... but, I’ll start with a 2x scale and work into a 1:1 but I believe I can support a claim about the Berlin specimen that is way outside the box... building an automata to support my wild claims... but the comparative data indicates chameleon-like turret eyes...and an extensible tongue do to ignited fossil evidence....on lithographica... Link to comment Share on other sites More sharing options...
Rhiguita Posted November 7, 2020 Share Posted November 7, 2020 That sounds really interesting and I want to see how the reconstruction comes out. Link to comment Share on other sites More sharing options...
LabRatKing Posted November 7, 2020 Author Share Posted November 7, 2020 12 minutes ago, Rhiguita said: That sounds really interesting and I want to see how the reconstruction comes out. Me too, I have pretty solid references for the structure, but the eyes are the wild card. Archaeopteryx has what I call “type4”. ill save the rest of the details for a separate thread...hoping the heavy hitters will chime in Link to comment Share on other sites More sharing options...
jpc Posted November 7, 2020 Share Posted November 7, 2020 30 minutes ago, LabRatKing said: tomorrow, I’ll start what will become the controversial post on the first physical Archaeopteryx reconstruction based off all available research. Not sure what you mean by the first... this has been done several times.... Link to comment Share on other sites More sharing options...
LabRatKing Posted November 7, 2020 Author Share Posted November 7, 2020 17 minutes ago, jpc said: Not sure what you mean by the first... this has been done several times.... Absolutely. But I’m going to try something a bit different...okay really different... But back to sclerotics... chameleon vs bird vs amphibians vs reptile turret eyes on gape limited insectivores? shutter effect or anchor? Link to comment Share on other sites More sharing options...
LordTrilobite Posted November 7, 2020 Share Posted November 7, 2020 Well if it's Archaeopteryx info you're looking for. I made a detailed skull reconstruction a while ago. And I did include the sclerotic rings. It might be helpful as reference. I mostly used the proportions from Peter Wellnhofer's 2d skull reconstruction. But there were a number of inaccuracies due to when that reconstruction was made. Since then there have been studies on the braincase using CT data from the London specimen. So I used that to correct the posterior half of the braincase. I also made extensive use of highly detailed photos of several of the specimens, mainly London, Eichstatt and Thermopolis but also Berlin and Munich. Some of them have the sclerotic ring mostly intact, but none of them have a good view of the medial side. So in my reconstruction I just left the medial sides of the rings blank. I'm quite confident in that I got most of the anatomy correct on the skull. But perhaps the sclerotic rings I'm less confident in simply because I don't know enough about how those work. So I've mostly followed Wellnhofer in reconstructing those. I highly recommend getting the book "Archaeopteryx: The Icon of Evolution" by Peter Wellnhofer. It's an absolutely fantastic book. It's where I got most of my reference. The only thing is that it's slightly out of date by now as some things have changed in Archaeopteryx research. Such as the a fore mentioned London CT scan, but also the melanosome research on the feather and the reclassification of some of the specimens like the Haarlem specimen. But even so, it's a great resource and an absolute must have. You can view my reconstruction here. 3 Olof Moleman AKA Lord Trilobite Link to comment Share on other sites More sharing options...
Ruger9a Posted November 7, 2020 Share Posted November 7, 2020 That 3D video is fantSTIC!! Link to comment Share on other sites More sharing options...
ynot Posted December 17, 2022 Share Posted December 17, 2022 On 11/6/2020 at 6:28 PM, LabRatKing said: ill save the rest of the details for a separate thread.. Did You doo this? Where is the thread? 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...
Recommended Posts