Amphiaspidida
From Wikipedia, the free encyclopedia
| Amphiaspidida Temporal range: Early Devonian | |
|---|---|
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| Amphiaspis argo reconstruction | |
Scientific classification  | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Infraphylum: | Agnatha |
| Class: | †Pteraspidomorpha |
| Subclass: | †Heterostraci |
| Order: | †Cyathaspidiformes |
| Clade: | †Amphiaspidida |
| Superfamilies and families | |
| Synonyms | |
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Amphiaspidiformes | |
Amphiaspidida is a taxon of extinct cyathaspidid heterostracan agnathans whose fossils are restricted to Lower Devonian marine strata of Siberia near the Taimyr Peninsula. Some authorities treat it as a suborder of Cyathaspidiformes,[1] while others treat it as an order in its own right as "Amphiaspidiformes."[2] In life, they are thought to be benthic animals that lived most of their lives mostly buried in the sediment of a series of hypersaline lagoons. Amphiaspids are easily distinguished from other heterostracans in that all of the plates of the cephalothorax armor are fused into a single, muff-like unit, so that the forebody of the living animal would have looked like a potpie or a hot waterbottle with a pair of small, or degenerated eyes sometimes flanked by preorbital openings, a pair of branchial openings for exhaling, and a simple, slit-like, or tube-like mouth.
