Seirocrinus subangularis38x17x1.5 cm
Holzmaden, Lias Epsilon I/2
Delicate crinoid colony with three specimens in perfect condition. Stem, cirrus and pinnulae show excellent details.
Special feature: Original matrix, not remolded, no composite. Hard to find in this quality. A delicacy!
The colony-forming driftwood sea lily: Seirocrinus subangularis from Holzmaden
An absolute showpiece and one of the best-known fossils from the famous Posidonia shale formation (Lower Jurassic, around 180 million years ago) of Holzmaden. Contrary to their name, crinoids are not plants, but fascinating sea creatures related to starfish and sea urchins. The finds from Holzmaden are of inestimable museum value, often in the form of huge slabs called the “Swabian Medusa Head”.
Biology and lifestyle
The sea lily has the typical structure: a stalk consisting of hundreds of small “poker chips” (stalk members) and a crown with acalyx (calyx) and numerous tentacles. The animals were passive filter feeders that used their fine, feather-like arms to filter tiny food particles from the ocean current.
The outstanding feature of this genus was its pseudoplanktonic way of life. Unlike most crinoids, which were rooted to the sea floor, the animal attached itself in large colonies to driftwood logs drifting through the Jurassic Sea. In this way, they were able to use zones with stronger currents to filter feed efficiently. Specimens were found with stem lengths of over 15 meters, while the crown itself measured “only” 20 to 30 centimeters.
The special feature of the Holzmaden finds
The fossils from the fine-grained, low-oxygen shale of Holzmaden are known worldwide for their spectacular preservation. In this genus, not only the robust stem limbs but also the filigree, finely branched arms are often perfectly preserved. The unique taphonomic conditions prevented decomposition and made it possible to preserve them in detail, often together with the original driftwood on which they were hanging, which is extremely rare.
Finds of individual segments are captivating in their aesthetics and often show dozens of individuals whose arms remained arranged in parallel – an indication that the arms were held together by a kind of “Velcro mechanism” to prevent them from becoming entangled in the water. The fossils are also often partially transformed into gold-colored pyrite, which gives them a special aesthetic appeal.
Holzmaden Conservation Site: A window into prehistoric times
This detailed preservation is thanks to the unique depositional environment in the Jurassic Sea, which made Seirocrinus a “Fossil of the Year” (2018). A specimen from Holzmaden is therefore an impressive document of a unique, suspended way of life and an exquisite exhibit for any sophisticated palaeontological collection.
