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PA Ordovician Starfish


historianmichael

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For Father's Day Weekend my dad and I drove into Pennsylvania yesterday to collect Ordovician fossils at a location I read about with access to the Salona Formation. With rain in the forecast I was a little worried the trip would be a total wash. Instead, we experienced beating sun, and, having left our hats at home, we quickly began to overheat. My dad also found two snakes while overturning some large rocks. To say the least my dad was ready to leave after an hour. Luckily I was able to convince him that if he wanted to stop he should at least let me poke around for another 30 minutes. While I was poking around my dad decided that it would be safer for him to remove and examine new material than to work in the talus. We worked for another hour before calling it a day. When we got home I went to work washing off the many hash plates my dad exposed while removing new material. The plates were covered in a fine layer of dust so it was incredible to see what they fully held after washing them off. As I was washing one plate I had to stop myself in the middle. I could not believe my eyes. In the bottom corner of one plate there was a rather familiar shape that I was not expecting to see. I immediately knew what it had to be. In all of the literature I have seen no mention of starfish fossils being found at this site. Given that my dad was ready to leave after an hour I consider this find even more lucky. Although I did not have anything to go on, I believe that the starfish is Promopalaester bellulus. It certainly made for an exciting and memorable Father's Day Weekend!

 

IMG_1142.thumb.jpg.5c6315b223c44c3a3aee2e0ca6a99620.jpg  IMG_1140.thumb.jpg.12518ccc5f5e8f0837bf219b62ef1434.jpg

 

 

Here are some of our other exciting finds:

 

Hash Plates with Bits of Cryptolithus

IMG_1143.thumb.jpg.7ff3b7c3cfe0eaa7a4e3b91da6bf7f00.jpg 

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IMG_1147.thumb.jpg.0b1d352140df9221da889c646a78908b.jpg 

 

 

Ventral Ceraurus Cephalon

IMG_1155.thumb.jpg.58f20b34f35890ba9a49a9a56711202b.jpg

 

 

Pygidial Spine of Ceraurus

IMG_1151.thumb.jpg.6534f3350046cdb2a325664477d1394f.jpg

 

 

Ventral Isotelus Thorax

IMG_1157.thumb.jpg.645c765d0aeab2d326a82baa05db88e6.jpg

 

 

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Follow me on Instagram (@fossil_mike) to check out my personal collection of fossils collected and acquired over more than 15 years of fossil hunting!

 

 

 

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On 6/21/2020 at 11:28 AM, historianmichael said:

Thorax Cross Section of Ceraurus

IMG_1155.thumb.jpg.58f20b34f35890ba9a49a9a56711202b.jpg

Pygidial Spine of Ceraurus

IMG_1151.thumb.jpg.6534f3350046cdb2a325664477d1394f.jpg

 

 

Very nice finds ... Congrats! http://www.twcenter.net/forums/images/smilies/emoticons/happy0144.gif  The specimen labeled thorax is a ventral cheirurid cephalon.

 

The next one is a genal spine of Cryptolithus.  The arrows highlight some pits and a partial outline of the girder.

image.thumb.png.3a1601e0c3f393b6f1fe786291884200.png

 

Hughes, C.P., Ingham, J.K., Addison, R. 1975

The Morphology, Classification and Evolution of the Trinucleidae (Trilobita). Philosophical Transactions of the Royal Society of London, B 272:537-604  PDF LINK

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@piranha Thank you so much! I have edited the post with the update on the Ceraurus cephalon. Is the last photo at least a thorax cross section of Isotelus? It is about 65 mm across.

 

My initial thought on the other photo was Cryptolithus as well, but this fossil is much larger than any other Cryptolithus fossil I have ever seen. It measures about 47 mm. That is why I thought Ceraurus

 

IMG_1151.jpg.aa6d9721a5de6ea7c203a099ceb55a4a.jpg.bbc19d17446a239be9308a888ecd9330.jpg

Follow me on Instagram (@fossil_mike) to check out my personal collection of fossils collected and acquired over more than 15 years of fossil hunting!

 

 

 

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I agree the large size is a match for Isotelus.  The morphology of the spine is incorrect for Ceraurus

 

With a 10x loupe can you confirm the presence of any pits or is it just an optical illusion?

image.png.a84de26dad44fb03836a743755df237c.png

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@piranha I think it is just an optical illusion. What looks like pits are more like tiny holes. They lack the ordered pattern of the pits in Cryptolithus. Perhaps it is an area before the pits began. Here are some other photos of that spot under magnification. 

 

5eefc92faa0e1_ScreenShot2020-06-21at4_50_57PM.png.ab4566420b600359a72ba10896f324dc.png  5eefc930ae862_ScreenShot2020-06-21at4_51_10PM.png.06f4c66efa8dea56f9894d84402a5ab7.png

 

 

Follow me on Instagram (@fossil_mike) to check out my personal collection of fossils collected and acquired over more than 15 years of fossil hunting!

 

 

 

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WOW!!!  That starfish is an AMAZING find - congratulations to you and your dad!!!

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Very nice finds! 

The good thing about science is that it's true whether or not you believe in it.  -Neil deGrasse Tyson

 

Everyone you will ever meet knows something you don't. -Bill Nye (The Science Guy)

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  I'm not into hash plates, but I will make an exception for the starfish one.  Very cool find indeed!!!

 

RB

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  • 2 weeks later...

That really is fantastic! I was out poking around the Salona myself last weekend. Haven't sorted it all out yet, but pretty much all brachiopods. I did find a sweet little crinoid stem, which for some odd reason are rather rare in the Salona, or at least the site I was at. Everything else was brachiopods and a couple trilo-bits. Someone took over my brachiopod spot when I gave up sorting through a bed of all the same species and - lo and behold- found a p[late with to very nice trilobites that I was probably sitting on! I also met a friendly milk snake. IMG_6087-a.thumb.jpg.9280de9c56547bf65c67f84677c89d0d.jpg

I refuse to give up my childish wonder at the world.

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  • 4 months later...

UPDATE:

 

Earlier this week I received the sea star back from a professional preparer. He did an incredible job at exposing the full morphology of the sea star. Since then I have had conversations with several people who study extinct asteroids and received confirmation that this sea star is likely actually Macroporaster matutinus (?). I have been told that this is a rare find. Even though everyone I spoke with was amazed with the preservation of this sea star, I was encouraged to put a question mark next to the name due to several pieces of incomplete information. Given the size of this sea star, I was also told that it is likely immature but that it is hard to be sure due to the same limitations.

 

5fb68d970ef14_Photo1.thumb.jpg.3f266ab8502d0ff30e37fa657edac172.jpg

 

5fb68d98a0bca_Photo2withScale.thumb.jpg.7e280f2401e01906df02e24674442ad4.jpg

 

5fb68d9a01c65_Photo3.thumb.jpg.1dce2c4b573bed79493034dce572df0d.jpg

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Follow me on Instagram (@fossil_mike) to check out my personal collection of fossils collected and acquired over more than 15 years of fossil hunting!

 

 

 

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