Key words: Central Iran, Oligo-Miocene, Limestones, Echinoderms
1992; Hunt 1993) and reduced geographic range (Emlet 1995) in Patiriella and other echinoderms
have relatively simple nervous systems consisting of a pentaradially symmetrical nerve ring from which radiate five radial nerves, which in turn innervate the numerous tube feet and spines (Cobb, 1985).
The presence of reef forming organisms (bryozoans, foraminifers, echinoderms
, and bivalves) support this model.
The nearly equal areas of the Utah hardground were covered by bryozoans and echinoderm
holdfasts (Wilson et al.
These cells stay in the body cavity, on the coelomic fluid present in the circulatory system of adults and larvae echinoderms
. The coelomocytes mediate immune responses, performing phagocytosis and encapsulation of foreign particles, in conjunction with the release of antimicrobial molecules by degranulation (Smith et al.
Although rapid burial can happen by several processes, apparently storm deposition is the most common bottom-smothering process that commonly leads to complete preservation of crinoids and other echinoderms
(Meyer and others 1989; Ausich 2001).
(sea stars, sea urchins, sand dollars, sea cucumbers, and sea lilies) have impressive regenerative abilities.
The reefs are embedded in an echinoderm
grainstone, identical to those known from the Vasalemma and Rummu area.
Ciliary bands in echinoderm
larvae: Evidence for structural homologies and a common plan.
However, the lack of tracts of neurons along the ciliary bands is unexpected because neurons in these areas are considered to be ancestral features of echinoderm
development (Burke, 2011).