Pteraspis

Pteraspis is an extinct genus of armored, jawless fish that lived during the Devonian Period. Its head was covered by fused bony plates, and it lacked paired fins.

Ostracoderm: An informal name for extinct, armored jawless fishes of the Paleozoic Era. Pteraspis is one of the distinctive fossil groups commonly called ostracoderms.
Cephalaspidomorphi: A group of extinct jawless vertebrates with broad, flattened head shields. Their flattened shields differ from Pteraspis's more streamlined head armor.
Arandaspida: An extinct group of early armored jawless vertebrates known from Ordovician rocks. Arandaspids preceded Pteraspis and provide an earlier comparison for armored jawless fishes.
Pteraspis rostrata: A species of Pteraspis known from Devonian strata in Europe. It is a commonly cited species illustrating the genus's characteristic armor.
Agnatha: A traditional grouping of vertebrates that lack jaws, including living and extinct forms. Pteraspis belongs among the early jawless vertebrates.
Head shield: A protective plate or set of fused plates covering the head in some ancient fishes. Pteraspis's rigid head shield was its most conspicuous armor.
Heterostraci: An extinct group of armored jawless vertebrates characterized by distinctive bony head and trunk plates. Pteraspis is classified within this group.
Old Red Sandstone: A sequence of Devonian sedimentary rocks exposed across parts of Britain and nearby regions. Pteraspis fossils occur in rocks associated with this formation.
Vertebrate: An animal with a backbone or its evolutionary precursor, the notochord. Its armored body belongs to the early history of vertebrate anatomy.
Lateral line: A sensory system that detects water movement through pores and neuromasts along an animal's body. Canal-like sensory structures in its armor are associated with detecting water movement.

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PteraspidomorphiBroader topic: Its fossils exemplify the group’s shield-like armor and tapering body.