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Showing results for tags 'crinoid'.
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From the album: Mahantango Formation
Crinoid Calyx Schuylkill County, Pennsylvania- 2 comments
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Hello to all. Found this sample few years ago. Place of discovery: Ukraine, Donetsk region, Dobropolsky district. The age of it is the Kasimovian stage of the Carboniferous period (307 Ma). Have a nice day 3.mp4 6.mp4
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A Pirasocrinid Crinoid from the Pennsylvanian Holdenville Formation
Mochaccino posted a topic in Member Collections
I would like to share a beautiful and possibly important crinoid in my collection from the Pennsylvanian Holdenville Formation of Oklahoma, USA. This specimen is best identified as Plaxocrinus sp. aff. P. dornickensis as originally described by Harrell Strimple in his 1961 paper "Late Desmoinesian crinoid faunule from Oklahoma", and confirmed by Pennsylvanian crinoid expert Peter Holterhoff. It was prepared masterfully by Mike Meacher. It is a member of the family "Pirasocrinidae", which is a prevalent group of crinoids especially in the Pennsylvanian. They are characterized by a low, saucer-shaped cup with three anal plates, axillary first primibrachials and various spinosity on the arms, and most notably a prominent highly-specialized "umbrella-like" anal sac that terminates as a platform of plates surrounded by a circlet of laterally-projecting spines. Aside from simply wanting to show off one of my favorite fossils, there are a couple of reasons I think sharing this publicly could be useful. First off, articulated pirasocrinids are generally very rare in the fossil record, especially of this genus. It is thought that these crinoids had weak sutures between plates which made them highly-vulnerable to disarticulation. The vast majority of remains are found as loose anal/brachial spines and occasional calyxes, as shown below. https://snr.unl.edu/data/geologysoils/fossils/nebrinverthughes.aspx Likely because of this, formal descriptions and pictures of pirasocrinid crowns are scarce in the literature and it is difficult to find public references on what articulated specimens look like, especially of how the spines of the arms and anal sac are configured. Though on my specimen the arms are not 100% complete all-around, enough is preserved to describe the full structure of the arms and the nature of the spinose primibrachials. Moreover, the exceptionally-preserved and prepared anal sac shows nearly the full extent of its articulation. Note the couple of near-complete brachial and anal sac spines, whose extraordinary lengths exceed the width of the calyx. The second reason this specimen could be important is more specific. In Strimple 1961, Plaxocrinus sp. aff. P. dornickensis was described on just a single specimen; the calyx shown below: Atypically for the genus, this calyx has a very smooth outline owing to flat, non-bulbous basals and nonimpressed, almost imperceptible sutures. Strimple concluded this species to be closely-related to but not conspecific with true Plaxocrinus dornickensis (which is a slightly older species than the Holdenville fauna, according to Dr. Holterhoff); hence the "aff." in the identification. Essentially, as far as formal description in the literature is concerned, the full crown of this crinoid is unknown. I have also not personally seen any other confirmed crowns of this species from the Holdenville Formation. All-in-all, this specimen could be quite significant for showing the previously-unknown arms and anal sac of Plaxocrinus sp. aff. P. dornickensis on an articulated crown, which might help further its description.- 11 replies
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Aglaocrinus crinoid? and tiny trilobite pygium
Bonehunter posted a topic in General Fossil Discussion
Hi all! Very excited to find this crinoid on the very edge of a cliff and cleaned it just a little to reveal this tiny 4mm wide trilobite pygium right next to it. Using Missourian's key, I think the crinoid is Aglaocrinus ? The trilobite doesn't look exactly like the pygidiums I have of Ameura so not sure on that one - thoughts? Am I close? Should I try to clean more of the crinoid? The piece is only another inch or two thick. Thanks for any help!! Bone -
Hi all, I’m new to this forum! And maybe this is nothing, but thought I’d get your opinions. I found this stone in Sand Banks, Ontario. Any ideas as to what it is?
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Hoooooooooooorrrrrrrrrrrraaaaaaayyyyyyyyyyy!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! Here we are at last, into Adam's Silurian. Thanks for looking. First up is the Lower Silurian or Llandovery and I begin with a problem. I posted this one incorrectly in Adam's Ordovician as it had got it's label muddled up with an Ordovician Favosites I had that has vanished in the move here, but is being replaced by kind forum member @Herb Anyway, this, I remember now I've found the correct label, is from the greenish Browgill Formation, part of the Stockdale Group from a cutting near Skelgill (Skelghyll) in Cumbria, Northern England. It seems to be a tabulate coral, but I can't find any listed for this location, only mentions of small, rare, rugose corals. It has the star shaped corallites of a Heliolitidid, but seems to be tightly packed together like a Favositidid. A couple of species of Palaeofavosites seem to be close and are a bit star-shaped,, but anyone know any better? @TqB@piranha hmm who else? The coral bit, an external mold, is a maximum of 3.5 cm across and each corallite up to 2 mm.
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Hello, I found this during my last trip to a NJ Cretaceous stream. I sometimes find Devonian coral fragments but have never found something like this. I believe the round parts to be remnants of crinoid stems but I’m unsure about the star shapes. Any help is appreciated, thanks!
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Location: Tankerton, Kent, UK Epoch and Age: Eocene; Ypresian Geology: London Clay formation Date visited: 3 March 2024 This is written with an intent to help other people visiting Tankerton, rather than to brag about all the great finds I had (of which there were none). We decided to try out this location as prior in the week there had been substantial rain storms with high winds, so I thought perhaps scouring conditions may occur to reveal the clay. I was wrong. At roughly an hour before low tide there was a great deal of shingle/pebbles on the beach, but also a fair amount of silt. I trekked out as far as I could go while my daughter and husband went to play in the sandy part of the upper foreshore, but met with no luck. We were about 200m west of Long Rock, as the UK Fossils website <https://ukfossils.co.uk/2012/01/24/tankerton/> had said that was the best area. Perhaps the low tide also wasn’t low enough? I also don’t have any experience looking for nodule beds, whereas someone else may have been able to locate them amongst the pebbles. Everything looked more or less the same to me, apart from a couple of ‘rivers’ running from the foreshore into the sea, which I did investigate to no avail. Upon further reading, it seems that scouring conditions are difficult to predict and really require substantial winds at the time of the visit, creating that ‘wavy’ pattern on the sediment of the beach. I looked at some picture of ‘scouring conditions’, and it definitely was not like that when we went. Unfortunately, this meant that the finds were thin and far between. I only found one nodule of the correct type – that light brown ‘milky tea’ colour, and unfortunately it was empty. My daughter really likes ‘sea treasure’, and I did find a few pieces of old pottery, so she was delighted with those bits. One is in her bed to keep it safe and didn’t make it into the photo as I dare not remove it. As far as other finds go, the only thing I’m pleased with is a tiny fragment of pyritised crinoid stem. I thought it was a stick when I went to pick it up, but couldn’t break it with my fingernail, and upon closer inspection the rings around the outside are visible. It doesn’t have a star pattern, though, just round. I've attached my reference image, too. I found a couple of things that might be lobster burrows (B and C); I noticed the presence of an outer ring around a central core, so that’s where I got my identification. I would be grateful if someone could confirm/correct this guess. D and E have interesting shapes. D appears to have some small pores at the top of what looks like branch stems, so perhaps some sort of coral structure? E is a very smooth long oval shape, and has a tiny section of pattern. Not sure, but thought the shape might be suggestive (of what, I couldn’t say). F has a nice colour and perhaps an imprint on the inside? That could certainly be a geologic formation, but didn’t want to rule it out. G (on main photo) I think is half of the outside of a worm burrow. It could be man-made, but the material does seem to be rock rather than concrete. H (on main photo) appears to have a number of tiny worm burrows digging into the material. I found a few pieces like this, so just took one as an example. My other that was that it was more recent sea creatures digging into it as there was a fair amount of seaweed growing on it stuck fast – is there a way to tell? I is another interesting one, and not sure if it’s geologic in nature. The round circles in the middle are of a different quality from the rest of the matrix, and I’m hoping that someone can indicate whether it’s fossil material or just a different mineral inside. Regardless, it looks cool and is the only one of its type I found. A few neat stones, some larger worn shell pieces, and a few shells my daughter picked up round out the collection. My improvement points would be to definitely make sure the conditions are correct in order to not be met with disappointment and frustration. Perhaps if someone is really experienced in spotting the cream-coloured nodules they would do fine in just a low tide, but it proved beyond my capacities. We still had a great time as the wind was very mild, particularly in the first hour, and it wasn’t raining (about all you could ask for in early March). It’s a lot of fun to check out new locations, and at the very least you learn something for the next trip! Cheers!
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Crinoid Delocrinus vulgatus Pennsylvanian Texas
JamieLynn posted a gallery image in Member Collections
From the album: Texas Pennsylvanian: Echinoderms (Crinoids and Echinoids)
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Crinoid Paragassizocrinus tarri Pennsylvanian Texas
JamieLynn posted a gallery image in Member Collections
From the album: Texas Pennsylvanian: Echinoderms (Crinoids and Echinoids)
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From the album: Texas Pennsylvanian: Echinoderms (Crinoids and Echinoids)
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From the album: Texas Pennsylvanian: Echinoderms (Crinoids and Echinoids)
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From the album: Texas Pennsylvanian: Echinoderms (Crinoids and Echinoids)
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From the album: Texas Pennsylvanian: Echinoderms (Crinoids and Echinoids)
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Crinoid Calyx Allegecrinus bassleri Pennsylvanian Texas
JamieLynn posted a gallery image in Member Collections
From the album: Texas Pennsylvanian: Echinoderms (Crinoids and Echinoids)
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From the album: Texas Pennsylvanian: Echinoderms (Crinoids and Echinoids)
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From the album: Texas Pennsylvanian: Echinoderms (Crinoids and Echinoids)
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Traumatocrinus from Guanling Biota of China: Aboral and Oral Calyx Surfaces
Biotalker posted a topic in General Fossil Discussion
There are a lot of crinoid fossils coming out of China these days, particularly this good sized and photogenic species. I believe it is called Traumatocrinus, perhaps named after a famed paleontologist who was killed during WWII. By far, most available fossils are a side view of the calyx and arms. I was interested in acquiring specimens that clearly show the echinoderm geometry on the aboral surface of the calyx. I was also interested in some view of the oral surface, which is usually hidden behind a blizzard of arms and branching pinnules. The crinoid has a pentaradial symmetry with two arms on each for a total of 10 arms. The green outline shows one of the five structures that make a five pointed "star". The oral surface is less visible. One can see plate-like structures in the center but I can't detect a mouth, hydropore or anus.- 2 replies
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Crinoid Calyx Paramphicrinus Texas Pennsylvanian
JamieLynn posted a gallery image in Member Collections
From the album: Texas Pennsylvanian: Echinoderms (Crinoids and Echinoids)
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From the album: Texas Pennsylvanian: Echinoderms (Crinoids and Echinoids)
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Crinoid Ethelocrinus tuberculatus Texas Pennsylvanian
JamieLynn posted a gallery image in Member Collections
From the album: Texas Pennsylvanian: Echinoderms (Crinoids and Echinoids)
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Crinoid Primibrachial axillary Texas Pennsylvanian
JamieLynn posted a gallery image in Member Collections
From the album: Texas Pennsylvanian: Echinoderms (Crinoids and Echinoids)
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Crinoid Primibrachial axillary Texas Pennsylvanian
JamieLynn posted a gallery image in Member Collections
From the album: Texas Pennsylvanian: Echinoderms (Crinoids and Echinoids)
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- crinoid
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