page_title: Pteraspidiformes
section_title: Anatomy
hierarchical_section_title: Pteraspidiformes / Anatomy
caption_attribution_description: Rhinopteraspis dunensis (formerly Pteraspis) back armour fossil at the Museum für Naturkunde, Berlin.
context_page_description: Pteraspidiformes is an extinct order of heterostracan agnathan vertebrates known from extensive fossil remains primarily from Early Devonian strata of Europe and North America, and from Upper Silurian Canada.
context_section_description: A pteraspidiform heterostracan has the cephalothorax enclosed in armor, formed from several plates, including dorsal, ventral, rostral, pineal plates, a dorsal spine derived from a scale, and a large, scale-covered tail.  Many genera were benthic, others were apparently active swimming nekton.  Delicate, finger-like components of the anterior end of the ventral plate forming the edges of the mouth suggest that pteraspidiform heterostracans were filter-feeders that selectively filtered specific sized plankton from the water column.
caption: Rhinopteraspis fossil
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