Preservation of colour in fossil shells

[pachy-pleuro-whatnot-odon]

Hi all,

 

Some time ago I found this shell in (what I believe to be) the French Upper Muschelkalk (Triassic). Now I'm not into shells myself, but to judge from the remains of operculum on the underside of it, the specimen concerns an oyster. Most strikingly, however, the shell has a pattern of darker-coloured lines that do not correspond to any three-dimensional/elevational differences on the shell surface - which is, in fact, entirely flat. I haven't seen this on a fossil shell before.

 

Now when doing a Google search for my response on whether it would be possible for crustacean carapaces to retain traces of their original colour, I bumped into an article that described that molluscs may incorporate melanin in the calcite of their shells to create the colour patterns we see (e.g., here). This got me wondering: could the lines I'm seeing indeed be traces of the original melanin pigmentation of this shell? And, if so, how common is this phenomenon? Does anybody else have examples of such shells? I'd also be very happy if someone could furnish me with a genus or species name to go with my specimen. But here I'd like to primarily raise the topic of ancient colour reconstruction in shells.

 

[hadrosauridae]

Yes, they can.  I watched a video topic on the very thing.  The researcher noticed the exact thing you are and then began research and studying thousands of examples and found that it is very common for some formations to allows the shells to retain their coloration patterns and sometimes, remnants of the actual color.

 

edit to add.... The speaker of the lecture also compared those patternations to extant family members and found the identical markings in some.

 

Edited May 19, 2021 by hadrosauridae

[sharkdoctor]

Perhaps this will be a useful resource in regards to this question?:

https://phys.org/news/2015-02-million-year-old-mollusk-protein.html

 

[pachy-pleuro-whatnot-odon]

2 hours ago, sharkdoctor said:

Perhaps this will be a useful resource in regards to this question?:

https://phys.org/news/2015-02-million-year-old-mollusk-protein.html

 

Thanks! This definitely makes for an interesting read and indeed seems to support the preservation of shell colour through time - including the corresponding proteins! Makes you wonder whether my specimen would still have any protein attached to it, although my guess, just from touch (and there goes the sample's purity anyway!), would be not. Still, as the article mentioned preservation of shell proteins - and with it colour - of 15 million years being some of the oldest known, I'd say that my specimen may be particularly old...!

 

2 hours ago, hadrosauridae said:

Yes, they can.  I watched a video topic on the very thing.  The researcher noticed the exact thing you are and then began research and studying thousands of examples and found that it is very common for some formations to allows the shells to retain their coloration patterns and sometimes, remnants of the actual color.

 

edit to add.... The speaker of the lecture also compared those patternations to extant family members and found the identical markings in some.

 

That's pretty amazing! You don't happen to have a link to the video or remember the name of the researcher in question, do you?

[Coco]

Jean-Michel Pacaud (Museum National d'Histoire Naturelle, Paris, France) has written several articles on the methods used to make appear traces of color on certain tertiary shells, But he may have written on shells that naturally have some residual color. I have Naticidae (I think) that present checkerboards of color, coming from a French site but I do not know which one. I’d have to look into it.

 

Coco

Motifs colorés Ampullinidae.pdf motifs colorés APF.pdf Motifs colorés Roumanie.pdf Motifs colorés RST.pdf Motifs colorés stratotype Lutetien.pdf

[hadrosauridae]

14 minutes ago, pachy-pleuro-whatnot-odon said:

 

That's pretty amazing! You don't happen to have a link to the video or remember the name of the researcher in question, do you?

 

I'm sorry, it was a zoom meeting last year and I dont remember the name of the speaker.

[Ludwigia]

I recieved these small Vitta picta gastropods out of the Austrian Miocene Florianer Schichten a while ago from @FranzBernhard which I believe still have their original pigment.

 

 

[pachy-pleuro-whatnot-odon]

16 hours ago, hadrosauridae said:

I'm sorry, it was a zoom meeting last year and I dont remember the name of the speaker.

 

No worries! With the information others have posted by now, I've got plenty to go from

 

14 hours ago, Ludwigia said:

I recieved these small Vitta picta gastropods out of the Austrian Miocene Florianer Schichten a while ago from @FranzBernhard which I believe still have their original pigment.

 

 

Oh wow! That's a stunning batch of shells!

 

It seems very likely that they preserve their original colours, as I can't really imagine the patterns they exhibit being the result of patterns mineralization or microbial mats, or things like that. Besides, it looks like the colour pattern has partially stripped away from the top left shell, which suggests that most of the colouration is present in the top layer of the shell exterior. They also shine beautifully. Is that the result of some sort of consolidation or rather mineralisation?

 

16 hours ago, Coco said:

Jean-Michel Pacaud (Museum National d'Histoire Naturelle, Paris, France) has written several articles on the methods used to make appear traces of color on certain tertiary shells, But he may have written on shells that naturally have some residual color. I have Naticidae (I think) that present checkerboards of color, coming from a French site but I do not know which one. I’d have to look into it.

 

Coco

 

Thanks for all the literature, Coco! I didn't know this has already received such attention. But it's quite spectacular to find out that the colour of shells preserves so well, and seemingly all over the world too! I mean, if you look at the residual colours exposed under UV on the Cosiocoliisia laevigata specimen below (from Merle et al., 2009), it's stunning how close of a match it is to my specimen...!

 

 

Interesting, though, all information I've seen so far only describes the phenomenon for the Cenozoic, starting with the Eocene. My find, with dates to the Triassic, is significantly older than that. Anybody know if the same findings have also been made that far back in time?

[Ludwigia]

1 hour ago, pachy-pleuro-whatnot-odon said:

They also shine beautifully. Is that the result of some sort of consolidation or rather mineralisation?

 

I must admit, I did give them a thin coat of a beeswax finish called Rember.

[FranzBernhard]

 

2 hours ago, pachy-pleuro-whatnot-odon said:

it looks like the colour pattern has partially stripped away from the top left shell, which suggests that most of the colouration is present in the top layer of the shell exterior.

Correct! During weathering, the top layer with the pattern is spalling off.

 

2 hours ago, pachy-pleuro-whatnot-odon said:

They also shine beautifully

They come out naturally with a very high gloss from the outcrops when fresh. Also no mineralization involved, just the original shell.

 

 

Here are some more from the same site as above (Fuggaberg-3), untreated.

 

 

Another one from another site in that area (Höllerkogel-21), a very large one, about 6 mm high:

And a batch from site Höllerkogel-21, field of view is about 4 cm:

 

And a matrix specimen from site Höllerkogel-21, about 10 cm wide and completely untreated:

 

And here a link to a plate on my personal homepage, you can see various stages of weathering. Everything is uncoated.

Vitta picta - Langhian - Florianer Schichten, Styria, Austria

 

Franz Bernhard

[pachy-pleuro-whatnot-odon]

Spectacular shells! The variety and preservation are just stunning!  Makes me reconsider wanting to add some fossil shells to my collection...!

[Crusty_Crab]

On 5/20/2021 at 7:55 AM, FranzBernhard said:

 

Correct! During weathering, the top layer with the pattern is spalling off.

 

They come out naturally with a very high gloss from the outcrops when fresh. Also no mineralization involved, just the original shell.

 

 

Here are some more from the same site as above (Fuggaberg-3), untreated.

 

 

Another one from another site in that area (Höllerkogel-21), a very large one, about 6 mm high:

And a batch from site Höllerkogel-21, field of view is about 4 cm:

 

And a matrix specimen from site Höllerkogel-21, about 10 cm wide and completely untreated:

 

And here a link to a plate on my personal homepage, you can see various stages of weathering. Everything is uncoated.

Vitta picta - Langhian - Florianer Schichten, Styria, Austria

 

Franz Bernhard

Wow, that is very unique. Miocene in age with the original shell preserved, no mineralization. There must be some very interesting taphonomy going on.  

[FranzBernhard]

3 hours ago, Crusty_Crab said:

Wow, that is very unique. Miocene in age with the original shell preserved, no mineralization. There must be some very interesting taphonomy going on.

Well, I think, I have misunderstood or misinterpreted the word "mineralization". Aragonitic shells in that formation are mostly composed of calcite now, as usual. At some spots, though, olive snails, for example, also still have a high gloss. This kind of preservation depends more on the type of organism, I think. These Theodoxus/Vitta/Nerita/Agapilia gastropods have a quite special and stable surface layer, as far as I know.

There are no studies of taphonomy in that formation, but these Vitta usually occur in quite permeable sandy layers, like in the hand specimen shown above.

 

They occur also in another, slightly younger (Serravallian) formation around me, but in a clayey sediment:

 

Some individuals, field of view is 38 mm. These snails are about 3 Million years younger than the one from the "Florianer Schichten". They don´t show that much variation in pattern, they are all sticking to the same style :

Franz Bernhard

[pachy-pleuro-whatnot-odon]

It looks like similar preservation of residual colour might also be present in echinoids, such as these Hemipneustes striatoradiatus sea urchins from the Maastrichtian of Eben-Emael.

 

[Thomas.Dodson]

While it isn't possible for me to say if these are actual protein-pigment complexes or some method of taphonomy that preserves the bands and rays through different minerals or replacement, color banding like your specimen isn't rare in the Fox Hills Formation. It is especially notable on the common bivalve Tellinimera (Tellina) scitula. Still not Triassic but these Maestrichian fossils are moving closer to the age of your specimen.

 

 

[pachy-pleuro-whatnot-odon]

 Wow, that's pretty amazing! From the sites I've visited - whether they be Triassic, Jurassic, Cretaceous or Eocene - I never expected to see so much, in some cases true-to-life, colour preserved on ancient shells...! It doesn't even seem to matter whether they're marine or terrestrial. Quite the eye-opener! 

[siteseer]

I think one of the Barton Beds sites (mid-late Eocene) in Hampshire, England has mollusk shells that have retained some color.  Somewhere, I think I have a Venus shell from a French or English site that still has some.

[Missourian]

I just found this thread.

 

Euconospira sp.

Winterset Limestone, Missourian/Kasimovian, Pennsylvanian

Kansas City, Missouri, USA

 

 

 

 

Edit: I adjusted each image to show a more natural appearance

 

Edited June 2, 2022 by Missourian
Placed Genus & sp. in italics; edited images

[rocket]

incredible stuff

I was happy with my Natica tigrina millepunctata (posted it here: color patterns - General Fossil Discussion - The Fossil Forum), but when I see this ones, wow.... 

 

[Coco]

Hi,

 

A French scientist from the Museum National d'Histoire Naturelle in Paris, Jean-Michel Pacaud, has written several articles on the residual colours of shells revealed by ultraviolet light.

 

To make the residual colors appear on some shells, I seem to remember that he uses bleach before passing the shells under UV.

 

Coco

[pachy-pleuro-whatnot-odon]

12 minutes ago, Coco said:

Hi,

 

A French scientist from the Museum National d'Histoire Naturelle in Paris, Jean-Michel Pacaud, has written several articles on the residual colours of shells revealed by ultraviolet light.

 

To make the residual colors appear on some shells, I seem to remember that he uses bleach before passing the shells under UV.

 

Coco

 

Yeah, I think you already mentioned it somewhere above, Jean-Michel Pacaud Very interesting stuff!

[JBkansas]

It's not that hard to believe now that we've identified residual pigmentation in preserved dinosaur soft tissues (such as psittacosaurus cloaca pigments). 

 

The world had a colorful past.

[Coco]

2 hours ago, pachy-pleuro-whatnot-odon said:

 

Yeah, I think you already mentioned it somewhere above, Jean-Michel Pacaud Very interesting stuff!

You're right Each time someone speaks about residual colors on shells I speak about Jean-Michel and his publications.

 

Coco

[Missourian]

Gastropod or cephalopod with preserved color pattern (via mineralization)? The slight asymmetry of the pattern leads me to lean toward a bellerophontid gastropod.

 

Westerville Limestone, Kasimovian/Missourian Stage, Pennsylvanian, Carboniferous

Raytown, Missouri, USA

 

 

[Lone Hunter]

I was thrilled to find a big slab of colorful bivalves, a far cry from the cement colored fossils I usually find.        North Texas, Cretaceous Eagle Ford