Boreaspis
Encyclopedia
Boreaspis is an extinct genus of primitive jawless fish
that lived in the Devonian
period.
Fourteen different species of Boreaspis have been found in sandstone
of the lagoon
s and estuaries of Devonian Spitsbergen
.
Boreaspis was about 13 centimetres (5.1 in) long, with a tough shield covering its head, and extra protective spikes protruding from the cheek regions. It also had a long spike-like rostrum
on its snout, which would have enhanced the fish's hydrodynamics and was probably also used to root out food buried beneath the substrate.
Fish
Fish are a paraphyletic group of organisms that consist of all gill-bearing aquatic vertebrate animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish, as well as various extinct related groups...
that lived in the Devonian
Devonian
The Devonian is a geologic period and system of the Paleozoic Era spanning from the end of the Silurian Period, about 416.0 ± 2.8 Mya , to the beginning of the Carboniferous Period, about 359.2 ± 2.5 Mya...
period.
Fourteen different species of Boreaspis have been found in sandstone
Sandstone
Sandstone is a sedimentary rock composed mainly of sand-sized minerals or rock grains.Most sandstone is composed of quartz and/or feldspar because these are the most common minerals in the Earth's crust. Like sand, sandstone may be any colour, but the most common colours are tan, brown, yellow,...
of the lagoon
Lagoon
A lagoon is a body of shallow sea water or brackish water separated from the sea by some form of barrier. The EU's habitat directive defines lagoons as "expanses of shallow coastal salt water, of varying salinity or water volume, wholly or partially separated from the sea by sand banks or shingle,...
s and estuaries of Devonian Spitsbergen
Spitsbergen
Spitsbergen is the largest and only permanently populated island of the Svalbard archipelago in Norway. Constituting the western-most bulk of the archipelago, it borders the Arctic Ocean, the Norwegian Sea and the Greenland Sea...
.
Boreaspis was about 13 centimetres (5.1 in) long, with a tough shield covering its head, and extra protective spikes protruding from the cheek regions. It also had a long spike-like rostrum
Rostrum (anatomy)
The term rostrum is used for a number of unrelated structures in different groups of animals:*In crustaceans, the rostrum is the forward extension of the carapace in front of the eyes....
on its snout, which would have enhanced the fish's hydrodynamics and was probably also used to root out food buried beneath the substrate.