Amphiaspidida

Amphiaspidida
Temporal range: Early Devonian
Amphiaspis argo reconstruction
Scientific classification
Kingdom:
Animalia
Phylum:
Chordata
Class:
Pteraspidomorphi
Subclass:
Heterostraci
Order:
Cyathaspidiformes
(unranked):
Amphiaspidida
Superfamilies and families
Synonyms

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.

  1. ^ Lundgren, Mette, and Henning Blom. "Phylogenetic relationships of the cyathaspidids (Heterostraci)." GFF 135.1 (2013): 74-84.
  2. ^ Novitskaya, Larisse. Les amphiaspides (Heterostraci) du Devonien de la Siberie. Éditions du Centre national de la recherche scientifique, 1971.