Stensioella heintzi (Broili 1933; Emsian, late Early Devonian; 27 cm est.) is widely considered the most basal placoderm. Here it nests with Sphyrna with which it shares most traits including a flattened head with fused roofing bones and a subterminal mouth. Stensioella would have had a lifestyle like Squatina, the extant angel shark.