A diverse collection of isolated basal plates, radial plates, brachial and anal sac spines, and columnals, collectively representing multiple
crinoid taxa, is present.
This facies is bioclastic grainstone and consists of brachiopod shells, bryozoans, ostracods, gastropods,
crinoids and mollusks (Fig.
Researchers are interested in
crinoids not just because they are part of Earth's history, but because the various
crinoid species were able to survive millions of years of climate changes to become the sea lilies we know today.
The most common of these are
crinoids (sea lilies), snails, clam-like brachiopods, and ancestors of today's squids that had shells back then.
Chia, "Energetic content of eggs, larvae, and juveniles of Florometra serratissima and the implications for the evolution of
crinoid life histories," International Journal of Invertebrate Reproduction and Development, vol.
Different types of fauna, observed in the formation, include brachiopods, bryozoans,
crinoids, bivalves and foraminifera (fusulinids).
Huge (Araxilevis) and moderate productida, such as Tschernyschewia, Compresoproductus, and huge Orthotetina such as Orthotetina eusarkos (Abich), along with the coral Plentamplexus leptoconicus (Abich 1878) and the
crinoid Erisocrinus araxensis (Yakovlev and Ivanov, 1965) represent significant fossils from this biota association.
ascensionis was found, we usually observed other echinoderms, such as the
crinoid Tropiometra carinata carinata and the two-mentioned species of sea-urchins.
ICON The original Hoff SPOOKY A white sea star UNUSUAL A stalked
crinoid GRIPPING Stalked barnacles DISCOVERY A new octopus FULL FLOW Large anemone
As fish populations thrived in the Devonian,
crinoid diversity and abundance remained low despite favorable conditions.
And on the beach at Holy Island, you can pick up St Cuthbert's Beads, the little coins of
crinoid stems."
Siderite within the Barnsdall Formation of northeastern Oklahoma occurs in four varieties: (1) large nodules lacking a distinct central nucleus, concentrated in horizons bearing articulated
crinoids; (2) small concretions with distinct skeletal nuclei consisting of infaunal bivalves and inarticulate brachiopods occurring in horizons relatively lacking in articulated
crinoids and
crinoid material; (3) large sideritized burrows occurring above
crinoid horizons; and (4) concretions nucleated around former sites of soft tissue in large
crinoids and productid brachiopods.
Gahn and Baumiller examined more than 2,500
crinoid fossils for evidence of arm regeneration, focusing on specimens dating back 290 million to 490 million years.
