Sunday, October 10, 2010
October 10, 2010 : Sacabambaspis (Extinct)
Sacabambaspis is an extinct genus of jawless fish that lived in the Ordovician period. It is related to Astraspis.
Sacabambaspis had a head shield made from a large upper (dorsal) plate that rose to a slight ridge in the midline, and a deep curved lower (ventral) plate. Also it had narrow branchial plates which link these two along the sides, and cover the gill area. The rest of body was covered by long, strap-like scales behind the head shield. The eyes were far forward and between them are possibly two small nostrils, and the mouth was armed with very thin plates (oral plates).
The fossils of Sacabambaspis and Astraspis show clear evidence of a sensory structure (lateral line system). The arrangement of these organs in regular lines allows the fish to detect the direction and distance from which a disturbance in the water is coming.