''Pteraspis'' (from 'wing' or 'fin' and 'shield') is an extinct genus of pteraspidid heterostracan

jawless fish Agnatha (; ) or jawless fish is a paraphyletic infraphylum of animals in the subphylum Vertebrata of the phylum Chordata, characterized by the lack of jaws. The group consists of both extant taxon, living (Cyclostomi, cyclostomes such as hagfish ...

. It lived from the

Lochkovian The Lochkovian is one of three faunal stages in the Early Devonian Epoch. It lasted from 419.2 ± 3.2 million years ago to 410.8 ± 2.8 million years ago. It marked the beginning of the Devonian Period, and was followed by the Pragian Stage. It is ...

Eifelian The Eifelian is the first of two faunal stages in the Middle Devonian Epoch. It lasted from 393.3 ± 1.2 million years ago to 387.7 ± 0.8 million years ago. It was preceded by the Emsian Stage and followed by the Givetian Stage. North American ...

epochs of the

Devonian The Devonian ( ) is a period (geology), geologic period and system (stratigraphy), system of the Paleozoic era (geology), era during the Phanerozoic eon (geology), eon, spanning 60.3 million years from the end of the preceding Silurian per ...

period in what is now Brazil (

Maecuru Formation), Britain (

Ditton Group), Ukraine (Lochkovian Ivane Suite,

Pragian The Pragian is one of three faunal stages in the Early Devonian Epoch. It lasted from 410.8 ± 2.8 million years ago to 407.6 ± 2.8 million years ago. It was preceded by the Lochkovian Stage and followed by the Emsian Stage. The most important ...

Babin Sandstone) and Belgium.

Description

Like other heterostracan fishes, ''Pteraspis'' had a protective armored plating covering the front of its body. Though lacking fins other than its lobed tail, it is thought to have been a good swimmer due to stiff, wing-like protrusions derived from the armoured plates over its gills. This, along with the horn-like

rostrum Rostrum may refer to: * Any kind of a platform for a speaker: **dais **pulpit ** podium * Rostrum (anatomy), a beak, or anatomical structure resembling a beak, as in the mouthparts of many sucking insects * Rostrum (ship), a form of bow on naval ...

, made ''Pteraspis'' very streamlined in shape, which is good for swimming. ''Pteraspis'' also had some stiff spikes on its back, possibly an additional form of protection against predators. It is thought to have fed from shoals of

plankton Plankton are the diverse collection of organisms that drift in Hydrosphere, water (or atmosphere, air) but are unable to actively propel themselves against ocean current, currents (or wind). The individual organisms constituting plankton are ca ...

just under the ocean surface. Some records are found in association with marine fossils, while some others are found in

freshwater Fresh water or freshwater is any naturally occurring liquid or frozen water containing low concentrations of dissolved salts and other total dissolved solids. The term excludes seawater and brackish water, but it does include non-salty mi ...

environment. ''Pteraspis'' grew to an estimated length of .

Gallery

File:Pteraspis rostrata.jpg, 1908 ''P. rostrata'' reconstruction File:Pteraspis Wiki2 (cropped).png, 2024 ''P. rostrata'' reconstruction. File:Pteraspis rostrata1.jpg, 1908 illustration of ''P. rostratas dorsal shield. File:Pteraspis crouchi (fossil fish) (Lower Devonian; Herefordshire, England) (34234547416).jpg, ''P. crouchi'' from Britain, at the FMNH. File:Pteraspis rostrata 7.JPG, ''P. rostrata'' fossil File:Pteraspis rostrata recon.jpg, ''P. rostrata'' reconstruction.

References

Pteraspidiformes genera Devonian jawless fish Early Devonian fish Early Devonian genus first appearances Lochkovian life Pragian life Emsian life Eifelian life Middle Devonian genus extinctions Early Devonian fish of Europe Devonian England Fossils of England Paleozoic Ukraine Fossils of Ukraine Devonian animals of South America Devonian Brazil Fossils of Brazil Fossil taxa described in 1835 Fossil taxa described in 1847 Taxa named by Louis Agassiz {{Pteraspidomorphi-stub