Ausich, W.I., Wilson, M.A. and Tinn, O. 2019. Kalana Lagerstätte crinoids: Early Silurian (Llandovery) of central Estonia. Journal of Paleontology doi.org/10.1017/jpa.2019.27
It was an absolutely delightful project that was thoroughly documented in this blog. Last summer Bill and I traveled to Tartu, Estonia, to work with Oive on describing the extraordinary crinoids of the Silurian Kalana Lagerstätte. A Lagerstätte is a sedimentary deposit with exceptional fossil preservation. It is a privilege as a paleontologist to work on one. As you can see from the images, the crinoids here are well preserved indeed. I’ll let the paper’s abstract tell the story:
Abstract.—The Kalana Lagerstätte of early Aeronian (Llandovery, Silurian) age in central Estonia preserves a diverse shallow marine biota dominated by non-calcified algae. This soft-tissue flora and decalcified and calcified crinoids are preserved in situ in a lens of microlaminated, dolomitized micrite interbedded in a sequence of dolomitized packstones and wackestones. Although the Lagerstätte is dominated by non-calcified algae, crinoids (together with brachiopods and gastropods) are among the most common organisms that were originally comprised of a carbonate skeleton. Two new crinoids are described from this unit, Kalanacrinus mastikae n. gen. n. sp. (large camerate) and Tartucrinus kalanaensis n. gen. n. sp. (small disparid). Interestingly, these two crinoids display contrasting preservation, with the more common large camerate preserved primarily as a decalcified organic residue, whereas the smaller disparid is preserved primarily in calcite. Preservation was assessed using elemental mapping of C, Ca, S, and Si. Columns have the highest portion of Ca, once living soft tissue is indicated by C, S was dispersed as pyrite or associated with organics, and Si is probably associated with clay minerals in the matrix. This new fauna increases our understanding of the crinoid radiation on Baltica following Late Ordovician extinctions.
The top image and that above shows the new crinoid Kalanacrinus mastikae. Look at those gorgeous arms and the carbon films in the calyx that may represent internal organs. The species is named in recognition of Viirika Mastik, an Estonian graduate student who helped us in innumerable ways, and she was very patient with the sometimes clueless Americans! The genus, of course, is named for the deposit. (Scale bar is 5.0 mm.)
Here is another specimen of Kalanacrinus mastikae. Note the small angular, twiggy fossil below the calyx. I think it may be a green alga similar to the modern Hydrodictyon but marine and with larger cells.
Say hello to the new crinoid Tartucrinus kalanaensis. It’s pretty obvious how we came up with these names. Note again a carbon film in the calyx that may be from internal organs, possibly the anal sac. (Scale bar is 5.0 mm.)
Oive does excellent geochemistry, so she handled the elemental mapping. This example shows a close view of a Kalana crinoid column, with the elements C, Ca, S, and Si mapped. As stated in the abstract, columns have the highest portion of Ca, once living soft tissue is indicated by C, S was dispersed as pyrite or associated with organics, and Si is probably associated with clay minerals in the matrix.
Thank you to our excellent Estonian colleagues!