Keichousaurus - real or fake?

[RodX]

I'm thinking about buying this Keichsosaurus, found in China, at Taiwan since 1980. Since there are so many fakes of the Keichsosaurs out there: is it real or a colorful fake? 

 

Size: 23 x 12 cm

Size Keichosaurus: about 29 cm long, male

 

 

[FranzBernhard]

There are not that many fakes out there, mostly poorly preped ones.

 

This is something different, reddish matrix, white bones. Has it gone through a fire / was it preped with fire? Its also quite an old specimen.

 

Its real but I can not judge on restoration. 

 

Franz Bernhard

[oilshale]

Real, and a good one. Almost looks like the Keichousaurs from Myanmar.

https://www.app.pan.pl/archive/published/app64/app005942019.html

[Tidgy's Dad]

No red flags that I can see. 

( 'cept it's red.) 

[RodX]

Thank you verrrrryyyyyy, verryyyyy much :-) :-) :-)

@oilshale - looks quite similar! Yeah!

Edited September 30, 2023 by RodX

[RJB]

Hey Rod, the only red flag that I can see, is that this is not sittin in my fossil cabinet. 

 

RB

[Bobby Rico]

Nice one but I would see if you can get more info on the location. As this matrix an preservation is very unusual . 

Edited September 30, 2023 by Bobby Rico

[Fossildude19]

Just a gentle reminder that the Fossil Forum Prohibits the use/copying of seller verbiage on the Forum.

Please do not post any part of the advertisement. We are discussing fossils, not advertisements here. 

[-Andy-]

It is real, and looks to be a pretty good specimen too

[RodX]

Thank you all!

The happy little swimmer will arrive in the next 3-4 weeks. I will keep you up to date.

Without you I wouldn't have dared to make the purchase.  Again: Thank you very much!

 

@Tim: sorry - no more verbiage. Can I paraphrase a sentence from a salesperson in the future? Or how should I handle this?

 

@RJB You're welcome to take a look at it when it's there and you're in my area. 

And when it's there I'll hang it invisibly on the wall using one of your methods.  Thanks for helping me with the Phareodus encaustus.

 

 

Edited October 1, 2023 by RodX

[RodX]

@-Andy-Just got a message from the seller. There was no restoration at all. Really a nice one.

[RodX]

@FranzBernhardNow I've got more information dear countryman: no it was not prepared with fire; the Matrix is like that by nature*.  The white in the bones could be - as far as I was able to find out - pyrophyllite. I got my wisdom from an article by Jayson Kowinsky "Why Do Fossils Come In So Many Colors?" He describes the fossilization in white; but it's a fern - nice picture. I can PM you the link, because I should not add an link here, if I'm remembering the forum-rules correctly - but it should be easy to find with the search engine. 

Is the additional light muted pink color play in the bones iron and something else? Unfortunately, I'm a complete beginner in this direction.

And I suspect there are also some other ways for nature to create such white-(muted pink) fossilized bones?! 

 

The white lines that run through the matrix should be quartz. But I doubt it. Let's see what it is once I have the slab with the 29 cm "long" male Keichosaurus in my hands.

 

@Bobby RicoThe answer was: Yunnan, China. I asked for more information.

*but this extremely colorful stone also irritated me. At first it was just too good to be true for me. That's why I hesitated about buying it for a week and then asked in the forum.

Edited October 2, 2023 by RodX

[FranzBernhard]

Think the bones are still apatite. Yes, orange-pink-reddish colors are due to finely divided iron compounds. Specimen may come from a weathered zone?

Franz Bernhard 

[RodX]

@FranzBernhard I just asked the seller a minute ago, if it comes from a weathered zone. Unfortunately, the responses only come in dribs and drabs.

 

Apatite (thanks for the info): I just looked it up: Collective name for a group of chemically similar but unspecified minerals. So I guess it's Hydroxylapatit or Carbonat-Fluorapatit or Carbonat-Hydroxylapatit or Hydroxylapatit-M; the latter being whiter than the more transparent other minerals. 

So no pyrophyllite?

 

Thank you for the confirmation, concerning the orange-pink-reddish colors.

 

Rod

[Crazyhen]

This specimen should be coming from Luoping of Yunnan Province, China.  The matrix there is different from the typical black plates of Keichosaurus found in Yunnan and Guizhou, it is usually colourful but brittle, the locals call the plates "colourful plate".  Keichousaurus is less commonly found at Luoping than elsewhere in Yunnan (such as Fuyuan) and Guizhou (such as the type locality Xingyi).  My rough estimate is that you would see one only in 100 specimens.  The bones/scales of Keichosaurus and fish found there are usually whitish.

 

It does not seem to be prepped, other than with covering matrix manually removed.  Because the matrix at Luoping is brittle, fossils found there are usually broken into pieces as is the case here for this specimen.

[RodX]

@CrazyhenWow! Thanks for the detailed information! If you know anything more about the fossil found at Luoping, it would be a pleasure to learn more. Especially what the composition of the matrix is would be very interesting and which minerals causes white-pink-reddish (carat) colors there.

Edited October 3, 2023 by RodX

[FranzBernhard]

11 hours ago, RodX said:

So no pyrophyllite?

I think its apatite. Don´t know of any biological apatite replaced by pyrophyllite.

Franz Bernhard

[RodX]

@FranzBernhardOkay :-) - then it's apatite. Thanks!

 

Only with ferns then? The fern on the pic was labeled among other things with pyrophyllite.

[Crazyhen]

No expert in geology but you may find relevant description from the following paper:

 

The Luoping biota comes from the Guanling Formation, a unit exposed extensively over eastern Yunnan and western Guizhou provinces (figure 1), located in the southwestern part of the Yangtze Platform between the Nanpanjiang Basin and the Yangtze Platform [11]. The Guanling Formation (figure 2) comprises carbonates and clastic rocks, and is subdivided into two members. Member I is 333 m thick, and consists of mainly mudstone and argillaceous dolomite with a volcanic ash bed (green pisolite) at the base. Member II is a 580 m thick succession composed of nodular limestone, silty limestone, micritic limestone and bands of dolomite. The overlying Yangliujing Formation comprises 1204 m of dolostone and dolomitic limestone intercalated with limestone breccias that are characterized by pseudomorphs of gypsum- and evaporite-solution breccias.

 

The Luoping biota: exceptional preservation, and new evidence on the Triassic recovery from end-Permian mass extinction

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3119007/

[FranzBernhard]

1 hour ago, RodX said:

Only with ferns then?

I don´t know. These ferns are quite a special case of preservation. Usually, plants are preserved as carbonaceous matter.

Franz Bernhard

[RodX]

@FranzBernhard I got the answer: Yes, the Keichousaurus was found in a weathered zone. That's responsible for the colors and difficult to preserve, as I was told.

 

And the white fern is really something: "(...) Over millions of years, many different minerals can seep into and out of fossils, each imparting different colors. An interesting example of multiple mineral replacements come from white plant fossils on black shales that are found in areas such as central Pennsylvania and parts of Germany. These plants fell into oxygen poor waters and were rapidly buried by fine gray sediments. The plant-filled sediments eventually subducted deep beneath the ground where heat and pressure cooked the plants, leaving an ash like black carbon film. Pyrite in the ground replaced this carbon film and created orange plant fossils. However, later, through oxidation and replacement reactions, the pyrite was replaced by a white substance called pyrophyllite and many of the orange fossils turned white. Today one can find these beautiful white fossils preserved on black shale.(...)"

Why Do Fossils Come In So Many Colors? (Jayson Kowinsky)

 

 

@Crazyhen Thank you very much for the detailed information. Very interesting; also the article. But I know just that it was found somewhere in Yunnan.

Edited October 3, 2023 by RodX