Al Dente Posted July 21, 2014 Share Posted July 21, 2014 I have been searching the Castle Hayne Formation (Mid to Late Eocene) for crinoids for many years. Here are a few that I wanted to share. All but one species of crinoid in the Castle Hayne Formation are comatulid crinoids. Comatulids are stalkless and are better known today as "feather stars". Here is a picture of a modern comatulid from Wikipedia- Here is a view of a dried comatulid showing the underside - referred to as the dorsal side even though in life it faces downward- In the center of this dried specimen is an ossicle known as the centrodorsal. There are cirri that grow out of the centrodorsal that act as legs and there are 5 plates known as radials that are attached to the centrodorsals in living comatulids that are frequently still attached on the fossil comatulids. Circular scars are found on the centrdorsals where cirri were once attached. These scars can be important for identification. The first Castle Hayne comatulid was identified by Ebenezer Emmons in 1858. He named it Microcrinus conoideus. Here is his drawing and one of my examples. Microcrinus are easy to identify. They have 5 paired columns of cirri scars with smooth areas in between. No other comatulids in the Castle Hayne have this feature. My example has 4 of the 5 radials present. Emmons' drawing is missing the radials and you can see 5 partitions inside. This is typical for Microcrinus. Here are two more. The one on the left is missing the radials and you can see the 5 partitions inside. 14 Link to comment Share on other sites More sharing options...
Al Dente Posted July 21, 2014 Author Share Posted July 21, 2014 Here is an unidentified comatulid that has similar partitions as Microcrinus but is much larger, more bowl shaped and instead of the 5 paired columns of cirri scars, this is completely covered with cirri scars. A paper published in 2004 by Ciampaglio and Weaver identifies comatulid crinoids from the Castle Hayne Formation. They listed seven species from seven genera. I've tried to match my fossils with theirs and have a few that are pretty good matches (including Microcrinus already shown above). The first is Amphorometra parva. A. parva have 10 columns of vertically stacked cirri scars and a nice star pattern on top- The second is Placometra veniti. It also has the vertically stacked columns of cirri scars but has a truncated dorsal side (bottom of cup) and 5 prominent ridges located between the pairs of stacked cirri scars- 12 Link to comment Share on other sites More sharing options...
Al Dente Posted July 21, 2014 Author Share Posted July 21, 2014 The Ciampaglio and Weaver paper has several tiny comatulids that I can match to some of my specimens but I think there is a possibility that some might be variations of the same species. Studies on modern comatulids have shown a lot of variation in the centrodorsals within a single species. This includes shape and number of cirri scars present. There is a paper on the Cretaceous comatulids from Texas by Peck and Watkins that demonstrates changes in the centrodorsals with size within a species. Here's a picture from their paper demonstrating this variability- Here is one of my specimens that looks very much like Hertha plana from the Ciampaglio and Weaver paper- H. plana is one of the comatulids that I think may be a small stage of the common Himerometra bassleri. Here is what the larger ones look like. The first example lacks the 5 radials and the second has the 5 radials. Here is a group of comatulids that may be different species but I suspect they are all H. bassleri- 11 Link to comment Share on other sites More sharing options...
Al Dente Posted July 21, 2014 Author Share Posted July 21, 2014 Here is another unidentified comatulid. This one is different in having large alternating cirri scars instead of parallel columns. The first is lacking the radials, the second has them. Along with the centrodorsals, I find a lot of pieces of cirri and arms of teh crinoids but they aren't diagnostic. Here are a few pieces- 10 Link to comment Share on other sites More sharing options...
Al Dente Posted July 21, 2014 Author Share Posted July 21, 2014 Stalked Crinoids- There is a single species of stalked crinoid in the Castle Hayne Formation. It is Decmocrinus simmsi (Ciampaglio et al. 2007). It is a type of crinoid known as a bourgueticrinid. They are tiny but very common in some Castle Hayne sediment. The crowns are plain- The columns are unusual for crinoids. They don't have the typical pentameral symmetry of a lot of crinoids but are more bilaterally symmetrical- Here is what a nearly complete bourgueticrinid crown and stem would look like- References: Ciampaglio, C.N., Weaver, P.G., 2004. Comatulid Crinoids from the Castle Hayne Limestone (Eocene), Southeastern North Carolina. Southeastern Geology, 42 (3), 179-187. Ciampaglio, C.N., Donovan, S.K., Weaver, P.G., 2007. Gracile bourgueticrinids (Crinoidea) from the Castle Hayne Formation (Eocene), Southeastern North Carolina, USA. Swiss Journal of Geosciences, 100: 243-249. Emmons, E., 1858. Report of the North Carolina Geological Survey, Agriculture of the Eastern Counties; together with Descriptions of the Fossils of the Marl Beds. Peck, R.E., Watkins, W.T., 1972. Comatulid Crinoids from the Lower Cretaceous of Texas. Journal of Paleontology, v. 46, No. 3, p. 410-414. 12 Link to comment Share on other sites More sharing options...
MarcoSr Posted July 21, 2014 Share Posted July 21, 2014 Eric Really interesting. Looks like most of your specimens would be caught for sure by window screen. You mention that some species are common. Are all the species that you show common in the Castle Hayne Formation? With all the limestone debris, I would imagine that these are difficult to spot in the matrix especially the smaller specimens. Marco Sr. "Any day that you can fossil hunt is a great day." My family fossil website Some Of My Shark, Ray, Fish And Other Micros My Extant Shark Jaw Collection Link to comment Share on other sites More sharing options...
Al Dente Posted July 21, 2014 Author Share Posted July 21, 2014 You mention that some species are common. Are all the species that you show common in the Castle Hayne Formation? With all the limestone debris, I would imagine that these are difficult to spot in the matrix especially the smaller specimens. Marco Sr. Marco One of the Castle Hayne outliers that I used to collect almost completely lacked crinoids but all the other sites have numerous crinoids. Democrinus is the most common with Microcrinus second and Himerometra third. When I sort though Castle Hayne material I go very slowly and look at every grain. Not many shark teeth found this way but a good variety of invertebrates. I use a 1 mm. screen. I've tried smaller but it is too tedious. 1 Link to comment Share on other sites More sharing options...
JohnJ Posted July 21, 2014 Share Posted July 21, 2014 Excellent presentation, Eric. I can appreciate your efforts in the photography of small finds. I occasionally find pieces of the Cretaceous comatulids here in Texas, and your topic has improved my understanding of them. The human mind has the ability to believe anything is true. - JJ Link to comment Share on other sites More sharing options...
squalicorax Posted July 21, 2014 Share Posted July 21, 2014 Great thread on uncommon fossils!! My Flickr Page of My Collection: http://www.flickr.com/photos/79424101@N00/sets Link to comment Share on other sites More sharing options...
fossilized6s Posted July 21, 2014 Share Posted July 21, 2014 Very nice thread sir. This will definitely help others with IDs. Pretty cool little crinoids. I have yet to get my hands on Castle Hayne matrix. ~Charlie~ "There are those that look at things the way they are, and ask why.....i dream of things that never were, and ask why not?" ~RFK ->Get your Mosasaur print ->How to spot a fake Trilobite ->How to identify a CONCRETION from a DINOSAUR EGG Link to comment Share on other sites More sharing options...
Ludwigia Posted July 21, 2014 Share Posted July 21, 2014 Thanks very much for this informative post! Greetings from the Lake of Constance. Roger http://www.steinkern.de/ Link to comment Share on other sites More sharing options...
siteseer Posted July 22, 2014 Share Posted July 22, 2014 Al Dente, Interesting. I don't think I've seen crinoid specimens from NC before - particularly Eocene ones. I used to see Eocene ones from Oregon at shows. Jess Link to comment Share on other sites More sharing options...
Al Dente Posted July 23, 2014 Author Share Posted July 23, 2014 Thanks for all the nice comments. Link to comment Share on other sites More sharing options...
thair Posted July 24, 2014 Share Posted July 24, 2014 Those are really neat. Dont have any off those around here. Link to comment Share on other sites More sharing options...
Plax Posted March 5, 2015 Share Posted March 5, 2015 Just read this now Eric. I need to start looking in the member collections section! I received a thorough education from this. Thanks for enlightening us. Link to comment Share on other sites More sharing options...
MikeR Posted April 3, 2015 Share Posted April 3, 2015 Ditto! "A problem solved is a problem caused"--Karl Pilkington "I was dead for millions of years before I was born and it never inconvenienced me a bit." -- Mark Twain Link to comment Share on other sites More sharing options...
sixgill pete Posted April 1, 2016 Share Posted April 1, 2016 I wanted to give this thread a bump. I search for it every now and then when I come across crinoids from the N.C. Castle Hayne. Wonder moderators, could we pin this? 1 Bulldozers and dirt Bulldozers and dirt behind the trailer, my desert Them red clay piles are heaven on earth I get my rocks off, bulldozers and dirt Patterson Hood; Drive-By Truckers May 2016 May 2012 Aug 2013, May 2016, Apr 2020 Oct 2022 Link to comment Share on other sites More sharing options...
CAtoPA Posted July 22, 2016 Share Posted July 22, 2016 I think I might have some crinoids, so now I have a way to verify! Thanks so much, Al, for this amazing collection of fossils with descriptors, etc... awesome help for laymen! Link to comment Share on other sites More sharing options...
Mitchu Posted October 7, 2017 Share Posted October 7, 2017 Very interesting article. I've been to the Castle Hayne quarry multiple times, but only recently hit upon my liking of the micro world. Wish I would have discovered that area a little sooner. Thanks for the great info, when I make it back there I know one of the items that I will certainly be looking for (besides echinoids of course). Link to comment Share on other sites More sharing options...
Malone Posted March 30, 2018 Share Posted March 30, 2018 Absolutely fascinating! The preservation, presentation, and the addition of knowledge is truly praiseworthy. Generations, hopefully, will benefit greatly! Link to comment Share on other sites More sharing options...
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