It is concluded that the study of Oligo-Miocene Echinoderms
present in the Qom formation is essential and important because, at the same time, the Central Iran Sea had a communicative role between the Indo-Pacific Ocean and the Mediterranean Sea.
Studies of larval forms intermediate between feeding and nonfeeding development suggest that the traits characteristic of feeding larvae of echinoderms
can be lost one at a time (Emlet 1986; Olson et al.
Extraocular sensitivity to polarized light in an echinoderm
The diverse bioclastic Wackstone facies (AMB 3B) is dominated by adiverse assemblage of different bioclasts including brachiopod (20%), bryozoans (12%), algae (5%), bivalve (3%), echinoderm
(5%) and fusulinid forams (2%).
stem fragment was found attached to the holdfasts.
represent an important group of invertebrates and a major component of marine communities that may be vulnerable to a variety of environmental pathogens.
A targeted search for echinoderms
in a similar stratigraphic context should yield more well-preserved echinoderms
and new taxa that required rapid burial for preservation.
This is consistent with the regeneration process in some echinoderm
The 'Saku facies', later formalized as the Saku Member (Roomusoks 1970), was first recognized in the northeastern edge of the outcrop area of the Vasalemma Formation near the Saku settlement and interpreted as a lateral continuation of the echinoderm
grainstone facies (Polma et al.
It is now known that echinoderm
pelagic larvae are principally lecithotrophic in these areas.
However, the animal was identified as a basket star, which belongs to an echinoderm
group known as brittle stars, with a disk-shaped body and five flexible arms.
The nervous system is especially interesting because it is closely associated with the continuous ciliary band in feeding echinoderm
Consequently, careful attention to disarticulated crinoids shows promise for enhancing paleoenvironmental reconstructions, improving understanding of biotic interactions, and increasing records of echinoderm
biodiversity and paleobiology.