Florida Echinoid Help Needed

[Plantguy]

Hi Gang,

So we had an aborted Peace River trip yesterday and Jeff and I winded up in some nearby feeder creeks which was just fine with me. With Jeff leading the way I snagged this precious little invertebrate beauty from the first creek venture...my prize for the day by far!

Since I'm no expert in echys, the best guess I have going thru some online photos is Oligopygus as a possible ID. Having said that it appears the ones from Florida are from further north and are Eocene. There is alot of road construction in the area so I'm wondering where that fill might have come from and how it might have ended up in this part of the creek and so well preserved when much of the other shell material was broken....

Well enough speculation, maybe its simply something else from the local younger Peace River Hawthorne formation aged sediments and it is not some lost wanderer from further north in the state.

Any ID help is much greatly appreciated.

Regards, Chris

[Plantguy]

Any one else clicking on these images seeing them rotated???

Going to try attaching again.

Hmm...I reposted and no change...

Regards, Chris

Edited April 20, 2014 by Plantguy

[Al Dente]

It looks like Oligopygus haldemani. It is Eocene.

[Plantguy]

Thanks Al dente. I had seen photos of that species....the Univ of Florida link has one that is a bit larger than mine...wondering if mine was a juvenile...

http://www.flmnh.ufl.edu/invertpaleo/display.asp?catalog_number=64401&gallery_type=Florida%20Echinoidea

Still amazes me how tiny it is and that it was in very good shape and intact being in the creek with all of the other gravel. I did also find this chunk of whale vertebra

and rather fragile turtle shell fragment in the same digging hole. Both showed some wear and were broken but not really water worn too bad at all.

Thanks again for the ID help.

Regards, Chris

Edited April 21, 2014 by Plantguy

[dozer operator]

Really strange you found an Eocene echnoid in a peace river feeder creek. As far as I thought theres no exposed Eocene around there and comming from a construction back ground I can tell you fill cost a lot of money to haul, usually doesnt come from to far away. In anycase its still a super cool find!

[prem]

Echinoid-bearing Eocene limestone is often used as fill all over Florida. I've seen it all over.

---Prem

[dozer operator]

Doubt you would find any eocene material south of okeechobee

[Plantguy]

Doubt you would find any eocene material south of okeechobee

Yeah, I started with the county geologic maps and then had looked at the state geologic map...and was wondering....

Nothing Eocene aged down south. We were in Charlotte county and you got to go all the way north up into Polk county to get into that older age stuff (colored in blue)....at least 50-80 miles....

and who knows if there is even a quarry in that area.

The Echy traveled a bit however it got there!

Regards, Chris

[Plantguy]

Here's the state geologic map legend and the attached map to give you the full perspective.

ms146_geology_of_fl.pdf

[Harry Pristis]

That echinoid certainly is the right size to be Oligopygus phelani Kier 1967. I haven't dabbled in echinoids for some time, so I don't know if this taxon is still valid. Google it to see.

[dozer operator]

That one sure is a tiny bugger maybe its a juvenile that could be a reason making difficult for positive ID right? Heres a photo of one I found a couple hours east of the peace from a much more recent age pleis or plio ill have to look it up

[Plantguy]

That echinoid certainly is the right size to be Oligopygus phelani Kier 1967. I haven't dabbled in echinoids for some time, so I don't know if this taxon is still valid. Google it to see.

Hi Harry, thanks for the additional feedback. I believe the 3 species haldemeni, phelani and wetherbyi are all valid, but i'm way out of my league and will defer to others expertise. I should probably bug Dr. Portell to verify the species and age and ask about what others they have found that far south.

As a side note, here's a neat little one page cheat sheet on Common Echinoids from Florida that I found that shows their relative sizes and the other echinoids to be had in the state.

Regards, Chris

[Plantguy]

That one sure is a tiny bugger maybe its a juvenile that could be a reason making difficult for positive ID right? Heres a photo of one I found a couple hours east of the peace from a much more recent age pleis or plio ill have to look it up

Screenshot_2014-04-24-19-20-04.png

Yep, as I was just replying to Harry above I'm guessing I should bug Dr. Portell and see what he thinks.

Yours is a keeper too!

Regards, Chris

[MikeR]

Hi Chris

Your echinoid is indeed Oligopygus haldemani (Conrad, 1850). It is too large to be O. phelani and is a quite normal size for O. haldemani. The largest O. haldemani that I have ever found is 33 mm, a monster compared to all others in my collection and in general it can be separated from O. wetherbyi by its much smaller size. As an immature O. wetherbyi could be of the same size as mature O. haldemani, the defining characteristic is the position of periproct (anus) in relation to the peristome (mouth). In O. haldemani the periproct is along the bottom edge of the test (as in yours) where in O. whetherbyi it is half way between the bottom edge of the test and the peristome.

As to how it got there, most likely accidently dropped by someone who collects the Ocala. In a relatable story, early last year Dan Woehr graciously hosted me at his Corsicanna Marl site in South Texas. As Dan had to leave for a business trip that day, I was by myself for sometime afterwards. I came across a Salenia which is common in Texas' Lower Cretaceous and not found (as far as I know) in the Upper Cretaceous. When Dan later asked if I found any thing unusual I sent him a pic which he immediately told me he had tossed it out of his apron but obviously not far enough for me to find it later on.

Mike

Edited April 29, 2014 by MikeR

[Harry Pristis]

Mike . . .

Human transport certainly can be a problem. I've collected hundreds, perhaps thousands of these Oligopygus echinoids over the years, but I plead 'not guilty' to salting a creek in South Florida.

The difference between O. wetherbyi and O. haldemani is obvious to even the casual observer. What I'd like to know is the difference between O. haldemani and O. phelani.

For example, this specimen is about 15mm long (guesstimate), and you say that this is too large for O. phelani. What is the size range of O. phelani? ...The maximum size?

What is the 'normal size' for O. haldemani? I may need to correct some labels.

[MikeR]

Hi Harry

Both Kier and Portell/Oyen restrict O. phelani to the lower Ocala (aka Inglis) and O. wetherbyi and O. haldemani to the Upper Ocala (aka Crystal River). Like O. wetherbyi, the periproct is closer to the peristome in O. phelani . Kier does the best description in comparing O. phelani and O. haldemani in regards to characteristics and size.

"Specimens of this species have previously been referred to Oligopygus haldemani which occurs in the higher Crystal River Formation. Although O. phelani is very similar to O. haldemani in shape, having the same length to width and height ratios, and similar petals, it is easily distinguished from it by its lack of a deep peristomal trough and its more anteriorly situated periproct. In O. haldemani the peristome is in a deep transverse trough, whereas in O. phelani the test is only depressed in the area immediately around the opening. In O. phelani the periproct is located between 54 and 73 percent the distance from the center of the peristome to the posterior margin, whereas in O. haldemani it is located at 76 to 84 percent of this distance. Furthermore, O. phelani is a smaller species, the largest specimen being 18.5 mm long, whereas in O. haldemani the largest specimen is 37 mm long."

[MikeR]

As an addenum to my previous message, Chris' specimen does fit within the size range for O. phelani. My statement about his being too large to be O. phelani was based on my experiences of ~20mm for O. haldemani and under 10mm for O. phelani. Since stratigraphy cannot be used on a specimen out of context, the easiest way to discern the two would be how I would differentiate O. haldemani and O. wetherbyi which occur together. The position of the periproct in O. phelani would be on the bottom away from the edge of the test as in O. wetherbyi.

Mike

Edited April 29, 2014 by MikeR

[Harry Pristis]

That's good . . . thank you, Mike.

From what you've quoted here, I'd say that there are two useful characters to look for in distinguishing smaller O. haldemani from larger O. phelani (~0.73 inches). Those characters are:

1. For haldemani, the peristome (area of the mouth opening) is located in a pronounced trough, while phelani lacks such a 'deep peristomal trough.' (This trough seems evident in the specimen in this thread.)

2. In phelani the periproct is located between 54 and 73 percent the distance from the center of the peristome to the posterior margin, whereas in haldemani it is located at 76 to 84 percent of this distance.

This second character seems less reliable for a collector because, in making these calculations for equivalent size examples, the difference between 73% (phelani) and 76% (haldemani) would be very, very small.

I just did the calculation for a small haldemani:

7.9 mm peristome to posterior margin

.76 min. distance of peristome to periproct

6.004 mm location of periproct from peristome

And, if this echinoid were a phelani:

7.9 mm peristome to posterior margin

.73 max. distance of peristome to periproct

5.767 mm location of periproct from peristome

The difference is 0.297mm in this minimum-maximum comparison.

On several small specimens in front of me, the actual peristome - periproct distance is a much-higher percentage of the peristome - posterior margin distance than the minimum 76% used above. Each of these has a deep peristomal trough. They are young haldemani, no doubt.

Great! I feel like I've learned something.

Edited April 29, 2014 by Harry Pristis

[Plantguy]

Hi Chris

Your echinoid is indeed Oligopygus haldemani (Conrad, 1850). It is too large to be O. phelani and is a quite normal size for O. haldemani. The largest O. haldemani that I have ever found is 33 mm, a monster compared to all others in my collection and in general it can be separated from O. wetherbyi by its much smaller size. As an immature O. wetherbyi could be of the same size as mature O. haldemani, the defining characteristic is the position of periproct (anus) in relation to the peristome (mouth). In O. haldemani the periproct is along the bottom edge of the test (as in yours) where in O. whetherbyi it is half way between the bottom edge of the test and the peristome.

As to how it got there, most likely accidently dropped by someone who collects the Ocala. In a relatable story, early last year Dan Woehr graciously hosted me at his Corsicanna Marl site in South Texas. As Dan had to leave for a business trip that day, I was by myself for sometime afterwards. I came across a Salenia which is common in Texas' Lower Cretaceous and not found (as far as I know) in the Upper Cretaceous. When Dan later asked if I found any thing unusual I sent him a pic which he immediately told me he had tossed it out of his apron but obviously not far enough for me to find it later on.

Mike

Hi Mike, thanks for all the details and reasoning. I appreciate the explanations. I certainly learned a great deal! I'm hoping anyone possibly tossing things in there will some how see this post and let me know. If they've thrown lots of them in there I'd love to go back and find some more without having to drive all the way up north! FYI, I did shoot Roger a note before you responded and if I hear anything I'll add it...I did ask about the species distribution as I was curious.

That's good . . . thank you, Mike.

From what you've quoted here, I'd say that there are two useful characters to look for in distinguishing smaller O. haldemani from larger O. phelani (~0.73 inches). Those characters are:

1. For haldemani, the peristome (area of the mouth opening) is located in a pronounced trough, while phelani lacks such a 'deep peristomal trough.' (This trough seems evident in the specimen in this thread.)

2. In phelani the periproct is located between 54 and 73 percent the distance from the center of the peristome to the posterior margin, whereas in haldemani it is located at 76 to 84 percent of this distance.

This second character seems less reliable for a collector because, in making these calculations for equivalent size examples, the difference between 73% (phelani) and 76% (haldemani) would be very, very small.

I just did the calculation for a small haldemani:

7.9 mm peristome to posterior margin

.76 min. distance of peristome to periproct

6.004 mm location of periproct from peristome

And, if this echinoid were a phelani:

7.9 mm peristome to posterior margin

.73 max. distance of peristome to periproct

5.767 mm location of periproct from peristome

The difference is 0.297mm in this minimum-maximum comparison.

On several small specimens in front of me, the actual peristome - periproct distance is a much-higher percentage of the peristome - posterior margin distance than the minimum 76% used above. Each of these has a deep peristomal trough. They are young haldemani, no doubt.

Great! I feel like I've learned something.

Hi Harry, thanks for the inquisitiveness and info as I did also learn alot from this little echy find....From more about the geology of the state to echinoid anatomy.

Welcome back to the forum! Regards, Chris