Furcaster
paleozoicus
The Devonian-aged Hunsrück Slate Lagerstätte is one of
the most famous soft-bodied fossil deposits. Hunsrück fossils have been
pyritized (replaced with pyrite/“fool’s gold” - FeS2). They
occur in a black slate matrix - the result is beautiful brassy gold colored
fossils on a black background. A diverse biota has been described,
including trilobites with preserved legs & gills, crinoids, starfish &
brittle stars, “worms”, molluscs, corals, conulariids, sponges, cnidarians,
land plants, “algae”, fish, plus various unusual arthropods & echinoderms.
The Hunsrück Slate Lagerstätte occurs in the Kaub
Formation (Hunsrück Slate Group, lower Emsian Stage, upper Lower Devonian) in
the Budenbach area of western Germany.
Preparation of Hunsrück fossils is notoriously
difficult, and many of the pyritized fossils crumble to dust from pyrite
disease over many years. Recently, a “secret” air abrasion method has
been successfully used to prepare Hunsrück fossils, using an abrasive grit
composed of metallic iron powder mixed with potato starch.
Shown below is a pyritized, complete fossil brittle
star (ophiuroid) from the Hunsrück. All five arms are bent in the same
direction, indicating current direction before final burial. This is a Furcaster
paleozoicus brittle star, a species first described by Bernhard Stürtz in
1886.
Classification: Animalia, Echinodermata, Asterozoa, Ophiuroidea,
Oegophiurida, Zeugophiurina, Furcasteridae
Furcaster paleozoicus Stürtz, 1886 (8.5 cm long) with current aligned arms
from the Hunsrück Lagerstätte (Lower Devonian) of western Germany.
Furcaster paleozoicus Stürtz, 1886 (field of view ~4.0 cm across) from the
Hunsrück Lagerstätte (Lower Devonian) of western Germany.