Seirocrinus subangularis
18 x 17 x 1.5 cm (Matrix)
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 re-embedded, no composite, no restorations whatsoever. This level of quality is now very hard to find. A real treat!
The colony-forming driftwood sea lily
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 of Seirocrinus subangularis
The sea lily has a typical structure: a stem consisting of hundreds of small stem segments, and a corolla with acalyx and numerous tentacles. These animals were passive filter feeders that used their fine, feather-like arms to filter tiny food particles from the ocean current.
The most striking feature of this genus was its pseudoplanktonic lifestyle. Unlike most sea lilies, which were rooted to the seafloor, this animal attached itself in large colonies to driftwood logs floating through the Jurassic Sea. This allowed them to take advantage of areas with stronger currents to efficiently filter food. Specimens have been found with stalk lengths exceeding 15 meters, while the crown itself measured “only” 20 to 30 centimeters.
The Unique Characteristics of the Holzmaden Fossil Site
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.
This high level of preservation is due to the unique depositional environment of the Jurassic Sea, which led to Seirocrinus being named “Fossil of the Year” (2018). A specimen from Holzmaden is therefore a striking testament to a unique, planktonic lifestyle and an exquisite addition to any discerning paleontological collection.
