michele 1937 Posted August 31, 2018 Share Posted August 31, 2018 Interesting ? Protaster sp. Ordovician Morocco bought in Tucson in 2018 4 Link to comment Share on other sites More sharing options...
ynot Posted August 31, 2018 Share Posted August 31, 2018 Very nice one. Link to comment Share on other sites More sharing options...
Tidgy's Dad Posted August 31, 2018 Share Posted August 31, 2018 Looks a pretty good specimen to me! Nice acquisition. Life's Good! Tortoise Friend. Link to comment Share on other sites More sharing options...
oilshale Posted August 31, 2018 Share Posted August 31, 2018 42 minutes ago, Tidgy's Dad said: Looks a pretty good specimen to me! Nice acquisition. Great specimen with 6 arms - congrats! Be not ashamed of mistakes and thus make them crimes (Confucius, 551 BC - 479 BC). Link to comment Share on other sites More sharing options...
Tidgy's Dad Posted August 31, 2018 Share Posted August 31, 2018 4 minutes ago, oilshale said: Great specimen with 6 arms - congrats! Indeed. The rest of it looks real to me, so why on Earth did they add the 6th arm? As Michele said, it's interesting, and a nice example of this kind of thing. 1 Life's Good! Tortoise Friend. Link to comment Share on other sites More sharing options...
oilshale Posted August 31, 2018 Share Posted August 31, 2018 Now and then starfish with 6 arms are found. This Furcaster from the Devonian of Bundenbach also has 6 arms: I think the sixth arm is real. 3 Be not ashamed of mistakes and thus make them crimes (Confucius, 551 BC - 479 BC). Link to comment Share on other sites More sharing options...
Tidgy's Dad Posted August 31, 2018 Share Posted August 31, 2018 Yes, sometimes modern starfish have 6 arms, too. But I'm not sure about the arm that is top right. It doesn't seem to have the same detail as the others, I would like to see a closer piccie, but it seems like it may have been added to fill a space. Edit : Actually, looking at an enlarged image, you are right, it does look real. Life's Good! Tortoise Friend. Link to comment Share on other sites More sharing options...
Plantguy Posted September 3, 2018 Share Posted September 3, 2018 Nice addition! Regards, Chris Link to comment Share on other sites More sharing options...
siteseer Posted September 6, 2018 Share Posted September 6, 2018 On 8/31/2018 at 4:04 PM, Tidgy's Dad said: Yes, sometimes modern starfish have 6 arms, too. But I'm not sure about the arm that is top right. It doesn't seem to have the same detail as the others, I would like to see a closer piccie, but it seems like it may have been added to fill a space. Edit : Actually, looking at an enlarged image, you are right, it does look real. Yes, I think it's real too. The other possibility would be that there is another starfish beneath it with that arm the only part showing on the surface. Could it be the same gene that gives the occasional human a sixth finger? Link to comment Share on other sites More sharing options...
Tidgy's Dad Posted September 6, 2018 Share Posted September 6, 2018 5 hours ago, siteseer said: Yes, I think it's real too. The other possibility would be that there is another starfish beneath it with that arm the only part showing on the surface. Could it be the same gene that gives the occasional human a sixth finger? Well, the chordates and echinoderms belong to the same superphylum, we are both deuterostomes, so we have some genetic similarities. We have 5 fingers and toes, 5 lobes in our lungs etc. Some think chordates may have evolved from echinoderms, though this is out of favour at the moment. My dad had six fingers. Life's Good! Tortoise Friend. Link to comment Share on other sites More sharing options...
Johannes Posted September 6, 2018 Share Posted September 6, 2018 8 minutes ago, Tidgy's Dad said: Well, the chordates and echinoderms belong to the same superphylum, we are both deuterostomes, so we have some genetic similarities. We have 5 fingers and toes, 5 lobes in our lungs etc. Some think chordates may have evolved from echinoderms, though this is out of favour at the moment. My dad had six fingers. Echinoderms and chordates have completely different body symmetries. The "5-Rule" evolves in both groups at different times in the palaeozoic. Before these evolutionary events there were echinoderms with >5-radial-symmetry and chordates (bliateral symmerty with left-right-anomaly) with more than "5-fingers". (remembering: graptolites are some of our nearest invertebrate cousins... ) Link to comment Share on other sites More sharing options...
Tidgy's Dad Posted September 6, 2018 Share Posted September 6, 2018 2 hours ago, Johannes said: Echinoderms and chordates have completely different body symmetries. The "5-Rule" evolves in both groups at different times in the palaeozoic. Before these evolutionary events there were echinoderms with >5-radial-symmetry and chordates (bliateral symmerty with left-right-anomaly) with more than "5-fingers". (remembering: graptolites are some of our nearest invertebrate cousins... ) I was being funny. And I'm quite aware of the hemichordates. But these three groups do appear to share a closer common ancestor and are more closely related to each other than to other phyla. Life's Good! Tortoise Friend. Link to comment Share on other sites More sharing options...
doushantuo Posted September 6, 2018 Share Posted September 6, 2018 E.g. Soluta and Cincta are not pentaradial. At some point in the future i might start reading: From David/Mooi(evoDevo) on HOX genes and deuterostome phylogeny 2 Link to comment Share on other sites More sharing options...
michele 1937 Posted September 6, 2018 Author Share Posted September 6, 2018 I'm glad I opened a discussion. And interested Link to comment Share on other sites More sharing options...
fifbrindacier Posted September 17, 2018 Share Posted September 17, 2018 Nice piece Michele, and an interesting discussion. "On ne voit bien que par le coeur, l'essentiel est invisible pour les yeux." (Antoine de Saint-Exupéry) "We only well see with the heart, the essential is invisible for the eyes." In memory of Doren Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now