(c) Rachaimer Gymnocidaris lestocquii (D Esor )
Oberkimeridgium
Oggenhausen 1980
collection georolf
Aboralansicht a slope regular sea urchin. Gymnocidariden are very rare. This piece was the silicified Highway construction (Oggenhausen close Nattheim) recovered almost completely covered by limestone, and etched with hydrochloric acid. This sea urchin was the occupant of fossil coral reefs. From the same reference also silicified corals have survived. The lower figure shows the structure of a recent Cidaris Cidaris (L OCCUPIED ) for comparison. georolf
(c) Rachaimer Cidaris Cidaris (L OCCUPIED )
collection
echinoids (sea urchin) are among the Echinodermata (echinoderms). They usually have a rigid, more or less spherical or flattened body, the skeleton of different plates is composed (Corona). Some of these panels sit "warts", which sit on the sea urchin spines. In the regular echinoids is the side of the mouth (oral side) and below the anus (Aboralseite) above. They have almost a five-pointed symmetry. Cidaris has 5 Ambulakralfelder from which hydraulically "feet" and "tools" emerge, as well as 5 bestzte Interambulakralfelder with spines. A Interambulakralplatte carries a Primärwarze (PW), which is surrounded by ring warts (RW). On the head (KO) who was on the cone (KE) of the wart, sits the sting.
On the oral side is a masticatory apparatus (Aristotle's lantern). With the help of five-card sharp Teeth of sea urchins may graze the substrate on the seafloor. On the Aboralseite is the madreporite (a type of sieve), which connects to the water vascular system.
ref:
H ANS H ESS : fossil echinoderms of the Swiss Jura
Publications of the Natural History Museum Basel No. 8 1975
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