Shenacanthus vermiformis

Shenacanthus vermiformis

The oldest complete preserved chondrichthyan

Age 

Llandovery, Silurian, 436 million years ago

Distribution 

Xiushan, Chongqing, China

Taxonomy 

Chondrichthyes, Acanthodii

Body size 

Small, approximately 22 mm from the rostrum to the anal fin

Ecology

Shenacanthus vermiformis has no teeth and may eat tiny zooplankton

Trivia 

Its discovery means that chondrichthyans originated from the "armoured" placoderms