Crinoid
A recent stalked crinoid in the caldera of a submarine volcano.
- Worldwide
Sea lilies and feather stars ( Crinoidea AltGr κρίνος. , Lily ') belonging to the phylum echinoderms ( Echinodermata ) and are thus related to sea urchins and starfish. In the scheme, the sea lilies and feather stars with about 620 species all other modern echinoderms ( Eleutherozoa ) are compared as a sister group Pelmatozoa.
The scheme is uncertain. All modern sea lilies and feather stars are counted for the subclass Articulata. This is, according to sources, divided into two to five orders. Often Cirrentragende ( Isocrinida ) and Cirrenlose crinoids are distinguished ( Millericrinida ). There is agreement only that the hair star ( Comatulida ) who do not live sessile and today make up the majority of the surviving species constitute a separate order.
There are only about 25 pedunculated, sessile living species that usually live in the deep sea to 6000 meters and with a maximum height of half a meter to remain much smaller than their extinct relatives.
Features
Most Seelilienarten are attached to a handle on the sea floor and wear at the top of a built-up plate with wreaths chalice, which protects the soft body of the animal. From the cup edge off first branch five arms ( five-pointed symmetry). By further dividing the arm bases accounts for 10 - or 20 -armed crowns. With the help of fiederartigen arm sets ( pinnules ) plankton is filtered and fed into the mouth. The tegmen is called tegmen.
All sea lilies and feather stars feed by filtering particles fressbare with their feathery arms from the passing water.
System
The sea lilies and feather stars are currently divided into five classes:
- Flexibilia †
- Articulata Bourgueticrinida
- Hair Stars ( Comatulida )
- Cyrtocrinida
- Encrinida †
- Hyocrinida
- Isocrinida
- Millericrinida
- Roveacrinida † Saccocomidae † Saccocoma †
Fossil crinoids
The crinoids occurred since the Ordovician, and live, with the exception of feather stars ( Comatulida ), today only in the deep-sea area south of the Equator ( " Living fossils ").
During the Middle Triassic ( Muschelkalk ) ( Germanic Basin ) the crinoid occurred in the Central European shallow sea area in such masses that it was rock-forming ( Trochitenkalk ).
In addition to the fixed forms and free-swimming crinoids occur. While the Black Jurassic ( Lias ), there was, for example, due to the hostile conditions (lack of oxygen ) in the deeper sea areas only free-swimming crinoids. They lived either in colonies attached to driftwood or as individual animals.
Another group, the buoy crinoids ( Scyphocriniten ) was (before about 400 million years ago) widely distributed in the upper Silurian and lower Devonian. The most beautiful discoveries of Scyphocrinites elegans are from Morocco to Erfoud. In addition to the cups in a spherical -like structures ( Lobolithen ) found with a diameter of 10 cm and more, originally gas-filled " buoys " on which hung the stems with the cups down. The buoy crinoids from Morocco are among the most remarkable developments of crinoids at all. As the buoys have emerged from initially small roots, is still the subject of research.
The largest Seelilienkolonie that has ever been found and prepared the world is exhibited in the prehistoric world - Museum Hauff in wood grubs. It is 18 m × 6 m tall. She grew up fast to a 12 meter long driftwood and comes from the Black Jura Epsilon (Lower Toarcian ) of wood grubs.
Locations
Fossils of crinoids are found in the peripheral regions of the ridge Elm in soft Elmkalkstein, particularly pronounced in Erkerode (in the middle of the ridge came through erosions of the harder, lower limestone to the fore ). Above all, it was the kind Encrinus liliiformis with their stocky, robust crown. Recently, whole mussel crinoid communities were detected in the Elm, the narrowly defined, reef-like structures represented. The collection Klages ( king Lutter ) has several hundred copies, including a large stone slab with 16 Seelilienkronen and stems up to 70 cm in length.
One of the classic areas of Fund fully preserved Encrinus liliiformis is the environment of Crailsheim. The Trochitenbänke are especially powerful and made in layers almost entirely of the Trochiten this type specimens from the Crailsheim area are in many museums.
Popular beliefs and customs
Particularly widespread are Trochiten, the fossilized crinoid of sea lilies that were formed from the calcareous skeletons of crinoids. Back in the Stone Age Trochitenkalk was made into necklaces. This was obvious because the tubular Trochiten served as the nerve canal of the animals. In pre-Christian times was bored free and Others in Central Europe fossil Trochiten the former nerve canal again and strung the individual links to a necklace. For the Germans the Trochiten were a sign of bravery. This significance remained long. In the course of the Christianization of the population had to leave their Trochiten ( Boniface pennies, pennies or elves witches money). Even in 1714 it was found Trochiten in pharmacies as a remedy for various diseases, such as epilepsy, melancholy, poisonous animals, nosebleeds, dizziness, and kidney disease. In addition, they should encourage bravery, facilitate the afterbirth and the owner bring a long life.
Certain fossils of crinoids as well as those of many-armed brittle stars ( Ophiuroidea ) were in a past when these fossilized forms could still arouse fear in their viewers, referred to as " Medusa ". The meeresbewohnende Medusa from Greek mythology are made by the mere sight of her covered with snake hair head people to stone.