Orsten fossils

Bredocaris admirabilis

Ooooh, there’s a gorgeous gallery of Orsten fossils online. These are some very pretty SEMs of tiny Cambrian animals, preserved in a kind of rock called Orsten, or stinkstone (apparently, the high sulfur content of the rock makes it smell awful). What are Orsten fossils?

Orsten fossils in the strict sense are spectacular minute secondarily phosphatised (apatitic) fossils, among them many Crustacea of different evolutionary levels, but also other arthropods and nemathelminths. The largest fragments we have do not exceed two mm. Orsten-type fossils, on the other hand, have the great advantage in being three-dimensionally preserved with all surface structures in place and thus easier to interpret than any other fossil material. Orsten fossils are preserved virtually as if they were just critical-point dried extant organisms. Details observable range down to less than 1 µm, and include pores, sensilla and minute secondary bristles on filter setae and denticles. Orsten fossils also give an insight of meiofaunal benthic life at small scale, including preservation larval stages, and hence a life zone inhabited by the earliest metazoan elements of the food chain.

It’s a good browse over there. I think it’s useful to remember that the majority of the fauna of the world both extant and half a billion years ago is and was tiny and unfamiliar.


  1. Bill W says

    I bet using Mycodex w/ lindane as a shampoo would get rid of it.

    Seriously, I love stuff like this, being stuck in a macrobiotic field

  2. djlactin says

    at the bottom of the website, one finds this startling reference and comment:

    Xiao, Shuhai; Zhang, Yun & Knoll, Andrew H. (1998). Three-dimensional preservation of algae and animal embryos in a Neoproterozoic phosphorite. Nature 391, 553-558. Phosphorites of the late Neoproterozoic (570 ?20 MyrBP) Doushantuo Formation, southern China, preserve an exceptional record of multicellular life from just before the Ediacaran radiation of macroscopic animals. Abundant thalli with cellular structures preserved in the three-dimensional detail show that latest-Proterozoic algae already possessed many of the anatomical and reproductive features seen in the modern marine flora.

    (emphasis mine)

    Pre-Ediacaran! This should sink any creationist “cambrian explosion = sudden appearance” ship

  3. rrt says

    I had no idea fossils of this sort even existed. Jaw-dropping.

    At least once a week I learn something amazing and new from you PZ, if not more often. Once again, thanks, and wow.

  4. says

    The pictures are spectacular. I wonder if any are larval forms of things that would look completely different as adults.

  5. rrt says

    I think so, Mark. If I recall my invertebrate bio correctly, those “starlets” are a familiar form of larva even in modern critters. Could be way off, of course, that’s a distant memory.

  6. says

    BEAU-TI-FUL!!! Holy cow. Good work, oh scientists of Ulm!

    One of those larvae looks distinctly like a pentastomid, but surely it’s much too early for such a thing to exist?

  7. PaulC says

    “Get out your 3D glasses. There are some stunning 3D pics on that site.”

    Fortunately, I keep a pair handy next to the monitor at home and at work. Do I win some kind of uber-geek prize for that? It started with the pictures from the Mars rovers a few years ago. I was wondering where to get a cheap pair of red/blue glasses. I was able to get a free sample from http://www.3dglassesonline.com/ at the time. The web site is still there, but I don’t see a link for free samples. There might be some other places.