A cidaroid (and sexual) enigma

[Quer]

Hi everyone. I would expose a paleontological ID question that intrigues me. Let me do it in a storytelling style.

 

 

Prologue

 

 

Last November I found this beautiful bug in a limestone Upper Campanian /Lower Maastrichtian strata in the SE of Pyrenees, Catalonia (Spain). So, I start a little detective process... which turned not to be so little.

 

 

 

This cidaroid specimen is almost complete, retaining even its plates, which is rather rare. In fact, its plates are of most importance in this story.

 

 

Chapter 1

 

 

In 1933 French paleontologist Jules Lambert found some cidaroid specimens in the Pyrenees, in a place not far from I live, called Falgars (a Holy Mary sanctuary surrounded by meadows and woods, a very nice place). He described the species as Typocidaris falgarsensis, designing a holotype. He donated –among others- the holotype to the Museu Geologic del Seminari de Barcelona (Seminary’s –catholic- of Barcelona Geological Museum).

 

 

But during the turmoil of revolutionary events of Spanish Civil War the Seminary’s was sacked in 1936 and the holotype was lost.

 

 

In 1997 paleontologist J.J.Carrasco did a revision of the species and fixed a neotype, a specimen found some 4 km west of Falgars, in strata continuity, near the little village of Sant Julià de Cerdanyola. He reclassified it as Temnocidaris (Stereocidaris) falgarsensis (Lambert 1933). He did it in this paper (in Spanish) (The exact site where the original holotype was found is now forgotten)

 

Sant Julià de Cerdanyola village

 

I went to the MGSB museum, where director Dr. Calzada kindly allowed me to compare my specimen with the neotype, and as far as I know they are the same.

 

ID solved? Not entirely

 

In 1991 North-American paleontologists D.B.Blake and W.J.Zinsmeister described a new genus and new species of cidaroid echinoid from the Maastrichtian of Seymour Island, Antarctic Peninsula: Almucidaris durhami. As they said here The species is unique in that the plates of the female expanded and hollowed to form marsupia.

 

Maybe not so unique, though, as during the last 90’s (I don’t know when exactly) some specimens of cidaroid echinoids forming marsupia were found around... Sant Julià de Cerdanyola. You can see them in this thread of the Spanish Foro Nautilus (my specimen is the last one, and was found some 15 km. west of Sant Julià, not far from the town of Berga. Note that it has no marsupia, so it is arguably male).

 

Andrew B. Smith took the view that Pyrenean Upper Cretaceous cidaroids showing marsupia should be classed in the genus Almucidaris, as he stated in The Echinoid Directory. In fact A.B.Smith made for the first time this statement in: Smith, A.B. & Jeffery, C.H. 2000. Maastrichtian and Palaeocene echinoids: a key to world faunas. Special Papers in Palaentology 63, 1-406. Unfortunately, I have no access to this paper. I have sent some messages to TED, with no answer.

 

 

Unsolved enigmas

 

 

So, we Spanish amateur or professional paleontologists have assumed Andrew B. Smith’s view, calling our specimens Almucidaris falgarsensis. But some questions remain unresolved.

 

 

a) If specimens with marsupia are females, what about the male ones (as mine)? The belonging of arguably male specimens of Temnocidaris (Stereocidaris) falgarsensis to the genus Almucidaris can’t be stated? This would lead to a very paradoxical situation, with females of one species belonging to a genus and male ones remaining in another (a bizarre sort of sexual discrimination ).

 

 

b-  Are Almucidaris durhami and Almucidaris falgarsensis the same species or only belong to the same genus?

 

 

c) Have been found specimens in other places, apart from Antarctica and Pyrenees, of cidaroid echinoids having developed large brood chambers in the plates?

 

 

I highly appreciate any information and suggestions, and I hope I have not bored you.

 

 

[daves64]

Maybe they were gender neutral & became one sex or the other as needed. Or even completely neutral & able to reproduce without mating. 

[KimTexan]

Not boring at all. Thought provoking.

 

I have a cidarid I found years ago that to my knowledge is a one of a kind and has not been ID’d. At the time no cidarids had been described in the formation it was found in. It had something protruding from the top which appeared to be coming from within, but it was amorphous so in prep I removed it. This makes me wonder if it could have been remnants of a female attribute.

@erose and @Bill Thompson may find this of interest.

[Coco]

Hi,

 

The difference between male marsupial sea urchins and female is only at the level of the hollow apical which was of use to females to keep and to protect their babies.

Kim, if you removed something which exceeded, it is possible that it was a part of Aristote's lantern (jaw) on the lower face, doubtless 5 teeth.

 

Coco

[KimTexan]

8 minutes ago, Coco said:

Hi,

 

The difference between male marsupial sea urchins and female is only at the level of the hollow apical which was of use to females to keep and to protect their babies.

Kim, if you removed something which exceeded, it is possible that it was a part of Aristote's lantern (jaw) on the lower face, doubtless 5 teeth.

 

Coco

It honestly looked like rock. I am familiar with the jaw. It didn’t look like that. Sometimes in prep you have to make the choice to keep or not keep matrix or other stuff for esthetic purposes.

[Tidgy's Dad]

Very interesting. 

I will be following this thread with, er, interest.

[daves64]

4 minutes ago, Tidgy's Dad said:

Very interesting. 

I will be following this thread with, er, interest.

The things some people do for thrills... err .. pleasure..  uummm.. enjoyment...  out of boredom ..  

[Tidgy's Dad]

1 minute ago, daves64 said:

The things some people do for thrills... err .. pleasure..  uummm.. enjoyment...  out of boredom ..  

My life is empty.

I am a very sad individual. 

But this is interesting.

[erose]

4 hours ago, KimTexan said:

Not boring at all. Thought provoking.

 

I have a cidarid I found years ago that to my knowledge is a one of a kind and has not been ID’d. At the time no cidarids had been described in the formation it was found in. It had something protruding from the top which appeared to be coming from within, but it was amorphous so in prep I removed it. This makes me wonder if it could have been remnants of a female attribute.

@erose and @Bill Thompson may find this of interest.

There are quite a number of yet to be properly described species of ancient marine life in various collections, both amateur and museum.  If possible you should consider donating it to a museum or university so that it can be studied and described by professionals.  

 

[Quer]

6 hours ago, daves64 said:

Maybe they were gender neutral & became one sex or the other as needed. Or even completely neutral & able to reproduce without mating. 

As far as I know cidaroids are dioecious, having separate male and female sexes from the start, although no distinguishing features are visible externally in most cases.

 

5 hours ago, Coco said:

The difference between male marsupial sea urchins and female is only at the level of the hollow apical which was of use to females to keep and to protect their babies.

So, the belonging of a male specimen to the genus Almucidaris should be established from other morphologic characteristics. It seems it is very difficult.

 

6 hours ago, KimTexan said:

I have a cidarid I found years ago that to my knowledge is a one of a kind and has not been ID’d. At the time no cidarids had been described in the formation it was found in. It had something protruding from the top which appeared to be coming from within, but it was amorphous so in prep I removed it. This makes me wonder if it could have been remnants of a female attribute

Blake & Zinsmeister consider that "The incidence of brooding in invertebrates, including echinoderms, increases with latitude and apparent stress; stressful conditions might have contributed tot the evolution of A. durhami". Discarding latitude (latitude of Antarctica and Pyrenees hardly can be more different), they were plenty of stressful conditions in the Maastrichtian.

 

So, if more cidaroid specimens having developed -plate marsupia were found in distant places, it could be explained as a recurring -but not often successful- evolutionary response to increase reproduction rate in difficult times.  

[Coco]

Hi,

 

I’ve seen marsupial sea urchins, but never cidaridae.

 

1 hour ago, Quer said:

As far as I know cidaroids are dioecious, having separate male and female sexes from the start, although no distinguishing features are visible externally in most cases.

 

In some species of cidaridae, males are distinguished from females by the size of gonopores : females ones are larger to let the eggs pass. For example recent Stereocidaris granularis var. rubra. I will try to do pic tomorrow if I find time and if the weather is good.

 

Coco

[Coco]

Here is the pic, on the left one you can see bigger gonopores (female) than on the right one (male).

 

 

Coco

[KimTexan]

On 2/1/2019 at 8:29 AM, erose said:

There are quite a number of yet to be properly described species of ancient marine life in various collections, both amateur and museum.  If possible you should consider donating it to a museum or university so that it can be studied and described by professionals.  

 

Bill Thompson called me one day expressing interest in it. He said he’d be up in my area and he’d like to see it, but I never heard back from him. 

I find it very hard to part with the most beautiful echinoid I have ever found. They’re so rare. I doubt I’ll ever find another cidarid.

[sixgill pete]

26 minutes ago, KimTexan said:

Bill Thompson called me one day expressing interest in it. He said he’d be up in my area and he’d like to see it, but I never heard back from him. 

I find it very hard to part with the most beautiful echinoid I have ever found. They’re so rare. I doubt I’ll ever find another cidarid.

The rarest fossil i have ever found. A one of a kind (for N.C.) Oligocene Eosqualodon tooth is now sitting in a display at the Mace Brown Museum in Charleston. It was the right thing to do for science to learn more about the evolution of squalodontids. 

But the decision is yours. My only advice would be that if you do donate this, make sure it goes to someone who will write it up scientifically with peer review and publication. Not just named and put in a book.

[JohnJ]

Well said, Don.

[The Amateur Paleontologist]

This is a rather interesting thread  I like the "detective" work you're doing in trying to ID your specimen!

-Christian

[Quer]

4 hours ago, Coco said:

Here is the pic, on the left one you can see bigger gonopores (female) than on the right one (male).

 

Thank you very much. This is a form of sexual dimorphism in cidaroids I did not know.

2 hours ago, The Amateur Paleontologist said:

This is a rather interesting thread  I like the "detective" work you're doing in trying to ID your specimen!

-Christian

 

Thanks for your interest, Chistian.

 

I would add something. This specimen is the only one I've found almost complete (test and plates, but no spines attached or around), but spare pieces and spines are not so rare.

 

In TED is said that "Primary spines (are) unkown", but those are spines found around pieces of likely Almucidaris falgarsensis:

 

This one shows a well-preserved base and neck:

 

 

Unfortunately, silicification has changed its ornamentation in a sort of Beekite rings  (@abyssunder will love this):

 

For ornamentation better see those ones:

 

 

 

Finally, this one remains very close to the tubercle:

 

Summarizing: primary spines seem to be cylindrical rather than fusiform, ornamented with thorns. Lenght can't be stated.

[KimTexan]

4 hours ago, sixgill pete said:

The rarest fossil i have ever found. A one of a kind (for N.C.) Oligocene Eosqualodon tooth is now sitting in a display at the Mace Brown Museum in Charleston. It was the right thing to do for science to learn more about the evolution of squalodontids. 

But the decision is yours. My only advice would be that if you do donate this, make sure it goes to someone who will write it up scientifically with peer review and publication. Not just named and put in a book.

I have no problem letting someone borrow it for study. But honestly many of the holotypes end up in storage somewhere where nobody sees or enjoys them for decades on end. 

The urchin has a lot of sentimental value to me. I found it near where I found my first ammonites and gastropods and regular urchins and other fossils in college. I have many happy memories of that place. It is a symbol and memento of a different bygone era of my life. I don’t have that first ammonite, but I have the urchin.

If I found it in some random place I think it would have very different value to me.

[sixgill pete]

@KimTexan no worries. We all do indeed have special fossils. I have parted ways with many megs. But i still have my first. I'm not sure there is anyone who would write up a new species, have it peer reviewed and then published without it going into a museums collection. And yes many do sit in drawers. But, there are researchers out there who periodically study them for further undetstanding. 

[abyssunder]

1 hour ago, Quer said:

Unfortunately, silicification has changed its ornamentation in a sort of Beekite rings  (@abyssunder will love this):

Wow, beautiful beekite ring formation!

Thank you for showing this.

[abyssunder]

Guys, gals, do you want to provoke a heart attack to me with those mamelons?
(Hope my wife doesn't see this) 

[Coco]

 

Coco

[Plax]

23 hours ago, Coco said:

Here is the pic, on the left one you can see bigger gonopores (female) than on the right one (male).

 

 

Coco

thanks for the education Coco!

[Sagebrush Steve]

21 hours ago, KimTexan said:

I have no problem letting someone borrow it for study. But honestly many of the holotypes end up in storage somewhere where nobody sees or enjoys them for decades on end. 

The urchin has a lot of sentimental value to me. I found it near where I found my first ammonites and gastropods and regular urchins and other fossils in college. I have many happy memories of that place. It is a symbol and memento of a different bygone era of my life. I don’t have that first ammonite, but I have the urchin.

If I found it in some random place I think it would have very different value to me.

Can we see a photo of it, or did I miss one you already posted?