Gabreyaspididae
Gabreyaspididae Temporal range: Early Devonian
| |
---|---|
![]() | |
Reconstruction of | |
Scientific classification | |
Kingdom: | |
Phylum: | Chordata
|
Class: | |
Subclass: | Heterostraci
|
Order: | |
(unranked): | |
Superfamily: | |
Family: | Gabreyaspididae
|
Genera | |
|
Gabreyaspididae is a family of extinct amphiaspidid heterostracan agnathans whose fossils are restricted to Lower Devonian marine strata of Siberia near the Taimyr Peninsula.[1] 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 primarily due to ornamentation unique to each family,[1] and differs from amphiaspidoid amphiaspids of Olbiaspididae 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
- Pteraspidomorphi stubs
- Devonian jawless fish stubs