Cgs928 Posted March 14, 2018 Share Posted March 14, 2018 Hello all, I am working on my thesis covering fossils of the lower Glen Rose Formation. Could anyone possibly help me identify these specimens? These are heart urchins which I suspect to be Epiaster whitei... Could these be heteraster instead? They range from 3 to 5 cm in diameter and are mostly crushed or broken... Link to comment Share on other sites More sharing options...
erose Posted March 15, 2018 Share Posted March 15, 2018 On left: Pliotoxaster comanchei On right: Heteraster (Enallaster) obliquatus 5 Link to comment Share on other sites More sharing options...
Herb Posted March 15, 2018 Share Posted March 15, 2018 I agree with Eric. "Absence of evidence is not evidence of absence"_ Carl Sagen No trees were killed in this posting......however, many innocent electrons were diverted from where they originally intended to go. " I think, therefore I collect fossils." _ Me "When you have eliminated the impossible, whatever remains, however improbable, must be the truth."__S. Holmes "can't we all just get along?" Jack Nicholson from Mars Attacks Link to comment Share on other sites More sharing options...
bone2stone Posted March 15, 2018 Share Posted March 15, 2018 6 hours ago, Herb said: I agree with Eric. I do too. You should be finding Loriolia texana as well which can be found in the walnut stuff too. 1 Link to comment Share on other sites More sharing options...
Uncle Siphuncle Posted March 15, 2018 Share Posted March 15, 2018 There are 2 main spatangoids you find in that horizon, correctly ID'd by our esteemed colleague, erose. They are easy to distinguish at a glance based on macro features. Heteraster has a single depressed ambulacrum, the posterior amb. Pliotoxaster has all 5 ambs depressed. Keep in mind that keying out similar echs often entails examination of details on the micro level, with species sometimes distinguished by single vs. double rows of pores, shape of pores (round vs. slits), tubercle count per row, etc. We got off easy this time. 6 Grüße, Daniel A. Wöhr aus Südtexas "To the motivated go the spoils." Link to comment Share on other sites More sharing options...
erose Posted March 15, 2018 Share Posted March 15, 2018 3 hours ago, Uncle Siphuncle said: There are 2 main spatangoids you find in that horizon, correctly ID'd by our esteemed colleague, erose. They are easy to distinguish at a glance based on macro features. Heteraster has a single depressed ambulacrum, the posterior amb. Pliotoxaster has all 5 ambs depressed. Keep in mind that keying out similar echs often entails examination of details on the micro level, with species sometimes distinguished by single vs. double rows of pores, shape of pores (round vs. slits), tubercle count per row, etc. We got off easy this time. Thanks Dan. And you are absolutely correct that these two were easy. Sometimes the possible choices are much harder to sort out. Link to comment Share on other sites More sharing options...
erose Posted March 15, 2018 Share Posted March 15, 2018 8 hours ago, bone2stone said: I do too. You should be finding Loriolia texana as well which can be found in the walnut stuff too. Loriolia rosana is what you are thinking of. Link to comment Share on other sites More sharing options...
bone2stone Posted March 18, 2018 Share Posted March 18, 2018 On 3/15/2018 at 12:40 PM, erose said: Loriolia rosana is what you are thinking of. By golly you're right. Link to comment Share on other sites More sharing options...
Txfossilmom Posted March 18, 2018 Share Posted March 18, 2018 We were recently in that area and found several similar fossils. Link to comment Share on other sites More sharing options...
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