Gabreyaspididae is a

family Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...

of extinct amphiaspidid heterostracan agnathans whose fossils are restricted to Lower Devonian marine strata of

Siberia Siberia ( ; rus, Сибирь, r=Sibir', p=sʲɪˈbʲirʲ, a=Ru-Сибирь.ogg) is an extensive geographical region, constituting all of North Asia, from the Ural Mountains in the west to the Pacific Ocean in the east. It has been a part of ...

near the Taimyr Peninsula.Novitskaya, Larisse. Les amphiaspides (Heterostraci) du Devonien de la Siberie. Éditions du Centre national de la recherche scientifique, 1971. In life, all amphiaspidids 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 cephalothoracic armor are fused into a single, muff-like unit, so that the forebody of the living animal would have looked, in the case of gabreyaspidids, vaguely like a horseshoe crab with a pair of small, or degenerated eyes, with each flanked by a preorbital opening, and a simple, slit-like mouth positioned slightly ventrally. Gabreyaspidids differ from the amphiaspidoid amphiaspids of

Amphiaspididae Amphiaspididae is a family of extinct amphiaspidid heterostracan agnathans whose fossils are restricted to Lower Devonian marine strata of Siberia Siberia ( ; rus, Сибирь, r=Sibir', p=sʲɪˈbʲirʲ, a=Ru-Сибирь.ogg) is an ex ...

primarily due to ornamentation unique to each family, and differs from amphiaspidoid amphiaspids of

Olbiaspididae Olbiaspididae is a family of extinct amphiaspidid heterostracan agnathans whose fossils are restricted to Lower Devonian marine strata of Siberia near the Taimyr Peninsula. In life, all amphiaspidids are thought to be benthic animals that li ...

in that gabreyaspidids' mouths are ventrally positioned, whereas the mouths of olbiaspidids are positioned anteriorly.

Taxonomy

''Gabreyaspis''

''Gabreyaspis tarda'' is the type species of the family, and is known from several mostly complete cephalothoracic armors. It has a woodgrain-like ornamentation over its armor, with several tesserae-like units, especially around the head-region.

''Prosarctaspis''

''Prosarctaspis taimyrica'' has a broad, flat, half-circle-shaped armor that looks vaguely like a horseshoe crab.

''Pelaspis''

''Pelaspis teres'' differs from other gabreyaspidids in its unique ornamentation, the shape of its cephalothoracic armor, which is oval-circular, and suggestive of a pizza or a cookie, and its apparent lack of a dorsal spine.

''Tareyaspis''

''Tareyaspis venusta'' is similar in size and dimensions to ''Pelaspis'', but differs in ornamentation, and the shape of the posterior region of the cephalothoracic armor, which, in ''T. venusta'', has a dorsal spine.

References

Amphiaspidida Devonian jawless fish Early Devonian fish Prehistoric jawless fish families Devonian fish of Asia Fauna of Siberia Fossils of Russia Early Devonian first appearances Devonian extinctions {{Devonian-jawless-fish-stub