| Ateleaspididae | |
|---|---|
 | |
| Ateleaspis tessellata | |
Scientific classification  | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Infraphylum: | Agnatha |
| Class: | † Osteostraci |
| Order: | † Atelaspidiformes |
| Family: | † Ateleaspididae Traquair, 1899 [1] |
| Genera | |
| |
Ateleaspididae is a prehistoric jawless fish family in the class Osteostraci. [2]
Gnathostomata are the jawed vertebrates. The term derives from Greek: γνάθος "jaw" + στόμα "mouth". Gnathostome diversity comprises roughly 60,000 species, which accounts for 99% of all living vertebrates. In addition to opposing jaws, living gnathostomes have true teeth, paired appendages, the elastomeric protein of elastin, and a horizontal semicircular canal of the inner ear, along with physiological and cellular anatomical characters such as the myelin sheaths of neurons, and an adaptive immune system that has the discrete lymphoid organs of spleen and thymus, and uses V(D)J recombination to create antigen recognition sites, rather than using genetic recombination in the variable lymphocyte receptor gene.
Cephalaspidomorphs are a group of jawless fishes named for Cephalaspis of the osteostracans. Most biologists regard this taxon as extinct, but the name is sometimes used in the classification of lampreys, because lampreys were once thought to be related to cephalaspids. If lampreys are included, they would extend the known range of the group from the Silurian and Devonian periods to the present day. They are the closest relatives of jawed fishes, who emerged from within them and they would survive if the jawed fish are included.
Heterostraci is an extinct subclass of pteraspidomorph jawless vertebrate that lived primarily in marine and estuary environments. The first identifiable heterostracans appear in the fossil record during the Early Silurian, and all, save for the Psammosteids, became extinct by the start of the late Devonian. This last group of heterostracans died out in the extinction event at the end of the Devonian.
The class Osteostraci is an extinct taxon of bony-armored jawless fish, termed "ostracoderms", that lived in what is now North America, Europe and Russia from the Middle Silurian to Late Devonian.
Galeaspida is an extinct taxon of jawless marine and freshwater fish. The name is derived from galea, the Latin word for helmet, and refers to their massive bone shield on the head. Galeaspida lived in shallow, fresh water and marine environments during the Silurian and Devonian times in what is now Southern China, Tibet and Vietnam. Superficially, their morphology appears more similar to that of Heterostraci than Osteostraci, there being currently no evidence that the galeaspids had paired fins. However, Galeaspida are in fact regarded as being more closely related to Osteostraci, based on the closer similarity of the morphology of the braincase.
The Pituriaspida are a small group of extinct armored jawless fishes with tremendous nose-like rostrums, which lived in the marine, deltaic environments of Middle Devonian Australia. They are known only by two species, Pituriaspis doylei and Neeyambaspis enigmatica found in a single sandstone location of the Georgina Basin, in Western Queensland, Australia.
Cephalaspis is a possibly monotypic genus of extinct osteostracan agnathan vertebrate. It was a trout-sized detritivorous fish that lived in the early Devonian.
Boreaspis is an extinct genus of osteostracan agnathan vertebrate that lived in the Devonian period.
Pituriaspis doylei is one of two known species of jawless fish belonging to the Class Pituriaspida, and is the better known of the two. The species lived in estuaries during the Givetian epoch of the Middle Devonian, 390 million years ago in what is now the Georgina Basin of Western Queensland, Australia.
Brindabellaspis stensioi is a placoderm with a flat, platypus-like snout from the Early Devonian of the Taemas-Wee Jasper reef in Australia. When it was first discovered in 1980, it was originally regarded as a Weejasperaspid acanthothoracid due to anatomical similarities with the other species found at the reef.
Witaaspis was an extinct genus of osteostraci fish that lived in the Wenlock and Ludlow epochs of the Silurian period.
Benneviaspidida is an order of osteostracan jawless fishes which lived in the Early Devonian. The fishes in this order have a flat headshield and are dorsoventrally depressed. The first canal to lateral sensory field bifurcates near the orbit.
Superciliaspis is an extinct genus of jawless fish which existed in what is now the Northwest Territories of Canada during the Lochkovian age. Originally identified as a species of Cephalaspis by Dineley and Loeffler in 1976, it was reassigned to Superciliaspis gabrielsi by Adrain and Wilson in 1994.
Janaspis is an extinct genus of osteostracan, that lived in the early Devonian period in Britain. It is characterised by a number of features of its armoured headshield, including the presence of raised rims around its eyes, the shape of its lateral and median fields, its prominent dorsal spine, fairly long cornual processes and ornamentation. Janaspis was fairly small compared with other osteostracans, with a headshield measuring less than 60mm.
Zenaspidida is an extinct order of osteostracans, a group of jawless stem-gnathostomes. They possessed a distinct headshield, which varied in width to length ratio by species.
Zenaspididae is an extinct family of jawless fish in the order Zenaspida.
Cephalaspidae is an extinct family of jawless fish in the class Osteostraci.
Thyestiida is an order of bony-armored jawless fish in the extinct vertebrate class Osteostraci.
Zychaspis is an extinct genus of Devonian jawless fishes. Species are from the Devonian of Ukraine.
Turiniida is an extinct order of jawless fish from the Lower Devonian of Europe.
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