The youngest Mesozoic record of millericrinid crinoids (Millericrinida, Crinoidea) from Upper Cretaceous deposits of Poland
by Przemyslaw Gorzelak and Mariusz A. Salamon, Sosnowiec
GORZELAK, P. & SALAMON, M.A. (2006): The youngest Mesozoic record of millericrinid crinoids (Millericrinida, Crinoidea) from Upper Cretaceous deposits of Poland. Paläontologie, Stratigraphie, Fazies -psf (14), Freiberger Forschungshefte, C 511: 41-44; Freiberg.
full-text of short communication
According to RASMUSSEN (1978) the order Millericrinida comprises two suborders: Millericrinina and Hyocrinina. The Middle Triassic, Jurassic-Lower Cretaceous suborder Millericrinina includes four families: Dadocrinidae, Millericrinidae, Apiocrinitidae and Cyclocrinidae. One family (Hyocrinidae) belongs to the second suborder, Hyocrinina, reported from Palaeogene to Recent. Representatives of all families of the Millericrinina have been found in the Mesozoic epicratonic succession of Poland (= epicontinental, Polish Lowlands; see also appendix 1). Whereas the oldest millericrinid representatives, Middle Triassic dadocrinids, have been studied thoroughly many times (see reference list in HAGDORN, 1996), Jurassic millericrinids and Jurassic-Cretaceous apiocrinitids (Apiocrinitidae), have been mentioned only in passing and studies of their palaeoecology, taphonomy and palaeogeography have been initiated only quite recently (RADWANSKA, 2005; SALAMON & ZATON, 2005). Representatives of the Jurassic-Lower Cretaceous family Cyclocrinidae, were recently described by RADWANSKA & RADWANSKI (2003) from Poland (but see comments in HESS, 2006).
During the present fieldwork (summer 2006) in the Wolbrom-Miechów area (southern Poland; Glanów I locality), a few samples was obtained from a cleaned face of Cenomanian strata where contamination with older or younger sediments was impossible (for details concerning locality and sampling methodology see SALAMON, in press). Within the conglomerates and gravels, with small and numerous echinoderm ossicles of the late Cenomanian age (Calycoceras naviculare zone according to MARCINOWSKI, 1974; see also Fig. 1D in SALAMON, in press), four holdfasts and five pluricolumnals referred to Apiocrinites have been found (Pl. 1). The holdfasts are medium-sized, massive and irregular. The columnals and pluricolumnals are circular in outline, with maximum diameter up to 13 mm. The columnal articular faces are covered with fine, closely placed radiating crenulae that reach the lumen. The lumen of all recorded columnals is large and circular.
According to RASMUSSEN (1978), the youngest Mesozoic representatives of millericrinids (several species of family Apiocrinites; see e.g. OOSTER, 1871; RASMUSSEN, 1961, 1978) occur in Early Cretaceous sediments of Europe, Africa and North America. All columnals illustrated by RASMUSSEN (1961, pl. 22, 23) are circular (except one columnal of A. aff. neocomiensis, see pl. 22, fig. 4a), very low and with a large lumen and long and thick crenulae on the articular surfaces, similar to columnals currently noted. Also holdfasts presently recorded are very massive and irregular, similar to those of Apiocrinites figured by DE LORIOL (1879, e.g. pl. 5, fig. 6).
It is worth mentioning that FRAAS (1878) and SUJKOWSKI (1926) have previously noted millericrinid columnals from sediments younger than Albian (Cenomanian of Libanon and southern Poland). Nevertheless, RASMUSSEN (1961) discounted these reports due to the fact that they lacked illustrations in most cases, and crinoids were derived from the sediments with a high probability of contamination. In our opinion the arguments presented by RASMUSSEN (1961) are no longer valid.