Antiarchi

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Antiarchi
Pterichthyodes milleri

Pterichthyodes milleri

Temporal occurrence
Middle Devon to Upper Devon
391.8 to 376.1 million years
Locations
  • worldwide
Systematics
Chordates (chordata)
Vertebrates (vertebrata)
Placodermi
Antiarchi
Scientific name
Antiarchi
Cope , 1885

The Antiarchi (Antiarcha, Antiarchiformes) are a group of the extinct Placodermi , heavily armored fish-like vertebrates from the Devonian . They lived on the ground, especially in fresh water, and were very species-rich. They were still rare in the Lower Devonian (fossil finds in Yunnan , China) and then occur in large numbers in many fossil sites in the middle and upper Devonian. There are also some finds from the lowest Lower Carboniferous .

The peculiar scientific name is explained by the fact that the fossils were initially oriented the wrong way and that the anus was on the upper side ("Gegenärschler").

features

Tank from Bothriolepis panderi , in the Museum für Naturkunde Berlin

The Antiarchi were the most heavily armored placoderms. The head and front body of the animals were surrounded by armor, which had openings for the stalk-shaped pectoral fins, which were also encased by bone plates, and a single oval or spectacle-shaped opening for the closely spaced eyes and nostrils. The pectoral fins usually had a joint in the middle. The purpose of these arthropodies is still unclear (digging? Defense against Eurypterids ?). The head was small in relation to the torso. The mouth opening was on the underside of the head. The endoskeleton was not ossified. The back of the body and tail may have been bare (e.g. in Bothriolepis , previously called Pterichthys ) or covered by overlapping scales (e.g. in Pterichthyodes ). Most species reached a length of 20 to 30 centimeters, the largest were one meter long.

literature

Web links

Commons : Antiarchi  - collection of images, videos and audio files