| In the Upper Jurassic Štramberk-type limestones of southern Poland are reported 11
cyrtocrinid taxa (Eugeniacrinites zitelli, E. alexandrowiczi, Phyllocrinus malbosianus, P.
stellaris, P. sinuatus, Sclerocrinus polonicus, Strambergocrinus cf. jurassicus, Ascidicrinus
pentagonus, Tetracrinus baumilleri, Salamonicrinus prodigiosum and Cotylederma sp.),
along with isocrinids (Isocrinus sp.) and comatulids (Notocrinidae indet.). It is
worth mentioning that Salamonicrinus is a transitional link between Hemicrinus and
Ancepsicrinus, and that all these taxa should be included into the family Sclerocrinidae.
Conducted biometric analysis evidenced that the most frequent phyllocrinids within
our test material belong to rather four, instead of the usual three, morphotypes.
Consequently they may belong to four different species. Additionally Early Jurassic genus
Eudesicrinus appears as the oldest cyrtocrinid representative, thus providing an
ancestor-rooting baseline to stemless hemibrachiocrinids and brachiomonocrinids
(Hemibrachiocrinidae; Brachiomonocrinidae), and as having reduced stem and/or reduced
number of arms (e.g., Ancepsicrinus, Cyrtocrinus, Hemicrinus, Salamonicrinus and
Strambergocrinus).
References:
Salamon Mariusz A. and Gorzelak Przemysław, 2010: Cyrtocrinids (Echinodermata,
Crinoidea) from Upper Jurassic Štramberk-type limestones in southern Poland.
Palaeontology, 53(4): 869–885. |