Name: Doryaspis
(Dart shield).
Phonetic: Do-re-ass-piss.
Named By: White - 1935.
Classification: Chordata, Agnatha,
Heterostraci, Pteraspidiformes, Doraspididae.
Species: D. nathorsti
(type), D. arctica.
Diet: Uncertain.
Size: About 15 centimetres long.
Known locations: Spitsbergen - Wood Bay
Formation.
Time period: Early Devonian.
Fossil representation: Individuals to represent 2
species.
Doryaspis
was a jawless fish that swam in the oceans of the early Devonian,
and one that had an unusual body shape. Like others, it had a
rounded box-like body with a long flexible tail, but it also had a
long, thin pointed snout projecting from the front, as well as two
more thin spike-like projections projecting from the sides of the back
of the main body at near right angles from the forward snout, while
also being curved slightly forward.
The
function of these three spikes is uncertain, but the rear spikes that
pointed to the sides may have acted like hydroplanes to help maintain
level swimming. The front spike may have been used to stir up soft
sediment to expose small invertebrates and morsels of organic matter
that could then be sucked into the jawless mouth.
These
spikes of Doryaspis have long been noted as being
serrated, but the
discovery and naming of a new species has brought the realisation that
not all Doryaspis had serrated spikes. The
spikes of D. arctica
are noted as being smooth, which means the serrated snout and spikes
of the type species D. nathorsti are either for
inter species
recognition, or a feature of a more specialised lifestyle.
Further reading
- The genus Doryaspis White (Heterostracti)
from the lower
Devonian of Vestspitsbergen,Svalbard, - V. I. N. C. E. NT
Noel. PERN�GRE, 2001.