Placodermi - armoured sharks
The armoured sharks - Placodermi - were a numerous group of fish which had developed real jaws. They lived in the Devonian only. In many Placoderms, the head and front part of the body was covered by a strong armour of rigid and fused bony plates. Other forms developed scales and small bony plates. The endoskeleton was made of cartilage or mineralised cartilage. The Placoderms had paired pectoral and pelvic fins. Giants of 9 metres lenght are known, others were only a few centimetres long.
Armoured arm-sharks - Antiarchi - had an armour covering the head, the front part of the body and the pectoral fins. They had a flat ventral side and a small mouth, and lived near the bottom of the sea. List of contents in the placoderm showcase
Publisert 18. mai 2011 16:00 - Sist endret 13. mai 2019 13:56