Sea scorpions

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Sea scorpions
Specimen of Eurypterus remipes from the Obersilur of North America in the State Museum for Natural History Karlsruhe

Specimen of Eurypterus remipes from the Obersilur of North America in the State Museum for Natural History Karlsruhe

Temporal occurrence
Ordovician to Perm
461 to 258 million years
Locations
  • almost worldwide
Systematics
Molting animals (Ecdysozoa)
Arthropod (arthropoda)
Jawbearers (Chelicerata)
Hip mouths (Merostomata)
Sea scorpions
Scientific name
Eurypterida
Burmeister , 1843
Orders

As sea ​​scorpions , giant scorpions or Eurypterids (Eurypterida, from ancient Greek εὐρύς m., (Εὐρεῖα f., Εὐρύ n.) - 'wide' and πτερόν - 'wings', 'fin': "broad-finned") an extinct group of jaw- clawed bearers becomes (Chelicerata), which together with the swordtails (Xiphosura) are integrated into the taxon of the merostomats (Merostomata). This group is compared to the other chelicerates, the arachnids (Arachnida), as a separate class.

Like the swordtails, the Eurypterids were primarily sea creatures and were only recorded there from the Ordovician to the Permian . They then established themselves in brackish and fresh water, and some species may have been able to survive on the mainland for a short time. In 2005, the fossil traces of movement of a Hibbertopterus were discovered, which clearly originated on land and thus provided the evidence that sea scorpions could leave the water at least for a short time. With a body length of over two meters, some species of this group, such as Eurypterus spec. the largest known arthropods at all.

The Eurypterids had a narrow carapace with a poorly articulated head shield ( prosoma ) and an abdomen ( opisthosoma ) with twelve segments . As with today's spiders and their relatives, the legs and other limbs only start at the prosoma, the rearmost pair of legs was transformed into large swimming legs. The foremost leg links as well as the chelicerae were equipped with pincer-like structures and teeth, which enabled the prey to be held, accordingly the Eurypterids can be regarded as dangerous predators of the vertebrates and large invertebrates of that time.

Eurypterus in an artistic living reconstruction

Specimens of the genus Eurypterus , preserved in great detail, were found in 1898 from dolomite rocks of the Silurian Mountains on the island of Ösel ( Estonia ). The finest details could be observed in these animals, such as the male and female genital appendages on the second segment of the abdomen. In 1995, Eurypterids were also found in the Soom schist in South Africa, in which details of the muscles and internal organs could still be seen.

Web links

Commons : Sea Scorpions  - Collection of images, videos and audio files
Wikisource: Sea Scorpions  - Sources and Full Texts

Individual evidence

  1. Paul Selden and John Nudds: Window on Evolution - Famous Fossil Findings of the World (translated by Jens Seeling), Elsevier Spektrum Akademischer Verlag, Munich 2007, ISBN 978-3-8274-1771-8 , p. 29