Protaspididae

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Protaspididae
Temporal range: Early Devonian
Protaspis transversa.jpg
Fossil of Cosmaspis transversa in the Field Museum of Natural History, Chicago
Scientific classification Red Pencil Icon.png
Kingdom: Animalia
Phylum: Chordata
Superclass: Agnatha
Class: † Pteraspidomorphi
Subclass: † Heterostraci
Order: † Pteraspidiformes
Suborder: † Pteraspidoidei
Family: †Protaspididae
Genera

Protaspididae is an extinct family of pteraspidid heterostracan agnathans. Fossils of the various genera are found in early Devonian-aged marine strata. Protaspidids were once thought to represent a transitional form between the Pteraspididae and the Psammosteida, bearing the broad head shield shape of the latter, due to a more benthic (bottom-dwelling) existence, but recent phylogenical comparisons demonstrate that the protaspidids are actually highly derived pteraspidids, [1] and that the anchipteraspidids, the most primitive of pteraspidids, are the sister-group of the Psammosteids.

Family is one of the eight major hierarchical taxonomic ranks in Linnaean taxonomy; it is classified between order and genus. A family may be divided into subfamilies, which are intermediate ranks between the ranks of family and genus. The official family names are Latin in origin; however, popular names are often used: for example, walnut trees and hickory trees belong to the family Juglandaceae, but that family is commonly referred to as being the "walnut family".

Heterostraci subclass of fishes (fossil)

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.

Agnatha superclass of fishes

Agnatha is a superclass of jawless fish in the phylum Chordata, subphylum Vertebrata, consisting of both present (cyclostomes) and extinct species. The group is sister to all vertebrates with jaws, known as gnathostomes.

Contents

Genera

Many genera are found in Lower Devonian marine deposits of the United States, especially of Utah and Wyoming. Others are found in Lower Devonian marine strata of Europe, especially of Svalbard, Norway, and Podolia, Ukraine. [2]

Svalbard Archipelago in the Arctic Ocean

Svalbard is a Norwegian archipelago in the Arctic Ocean. Situated north of mainland Europe, it is about midway between continental Norway and the North Pole. The islands of the group range from 74° to 81° north latitude, and from 10° to 35° east longitude. The largest island is Spitsbergen, followed by Nordaustlandet and Edgeøya. Administratively, the archipelago is not part of any Norwegian county, but forms an unincorporated area administered by a governor appointed by the Norwegian government. Since 2002, Svalbard's main settlement, Longyearbyen, has had an elected local government, somewhat similar to mainland municipalities. Other settlements include the Russian mining community of Barentsburg, the research station of Ny-Ålesund, and the mining outpost of Sveagruva. Ny-Ålesund is the northernmost settlement in the world with a permanent civilian population. Other settlements are farther north, but are populated only by rotating groups of researchers.

Norway constitutional monarchy in Northern Europe

Norway, officially the Kingdom of Norway, is a Nordic country in Northern Europe whose territory comprises the western and northernmost portion of the Scandinavian Peninsula; the remote island of Jan Mayen and the archipelago of Svalbard are also part of the Kingdom of Norway. The Antarctic Peter I Island and the sub-Antarctic Bouvet Island are dependent territories and thus not considered part of the kingdom. Norway also lays claim to a section of Antarctica known as Queen Maud Land.

Podolia Historical Region

Podolia or Podilia is a historic region in Eastern Europe, located in the west-central and south-western parts of Ukraine and in northeastern Moldova. The name derives from Old Slavic po, meaning "by/next to/along" and dol, "valley".

Protaspis

This genus is known from several species from the Early Devonian-aged Beartooth Butte Formation strata of Wyoming and Utah. Europrotaspis, Cosmaspis, Lampraspis, Gigantaspis , Eucyclaspis, and Cyrtaspidithchys have been formerly placed within Protaspis as subgenera, or otherwise have been treated as species therein. [3]

Europrotaspis

Species of this genus are very similar to those of Protaspis, but, are found in Early Devonian-aged strata of Western Europe and Podolia, Ukraine.

Eucyclaspis

Species of Eucyclaspis are found in marine strata of the Water Canyon Formation, in Lower Devonian Utah. This genus differs from Protaspis by having unique processes emanating behind the eye on the orbital plate.

Cosmaspis

Cosmaspis is restricted to marine environments of Early Devonian Wyoming, and possibly of Utah, as well, where it coexisted with species of Protaspis, Lampraspis, Eucyclaspis, Oreaspis and Cyrtaspidichthys.

Lampraspis

Lampraspis is known from Early Devonian-aged marine environments of Utah and Wyoming. It is closely related to Oreaspis and Psephaspis, and the three genera were, at one time, placed together in a subfamily, "Oreaspidinae." [2]

Cyrtaspidichthys

Species of Cyrtaspidichthys, originally "Cyrtaspis," are very similar to those of Protaspis. Fossils of Cyrtaspidichthys are found in Early Devonian-aged marine strata of Beartooth Butte, Wyoming.

Oreaspis

Oreaspis differs from Protaspis in ornamentation, and that the postbranchial plate (the plate posterior to the exhalant opening of the animal's gills) forms a tiny, wing-like process. Species of Oreaspis are found in Early Devonian marine strata of Water Canyon, Utah, and Beartooth Butte of Wyoming. At one time, this genus, together with Lampraspis and Psephaspis, was placed within its own subfamily, "Oreaspidinae."

Psephaspis

Species of Psephaspis, which are restricted to Idaho and Utah, have broad, flat, rounded and heart-shaped dorsal shields, and ornamentation similar to those of psammosteids. Because of these two traits, species of this genus were originally described as being North American psammosteids closely related to Drepanaspis by Orvig. Denison then redescribed them as being pteraspidids closely related to Protaspis, noting that the overall anatomy is that of a typical pteraspidid. Denison also notes that Psephaspis is the youngest genus of pteraspidid, as specimens of P. idahoensis are found in Middle Devonian-aged strata of Lemhi County, Idaho, which are younger than the latest strata other pteraspidids are found in. [3]

Psammosteida suborder of fishes (fossil)

Psammmosteida also called as Psammosteoidei is a suborder of pteraspidid heterostracan agnathans. The psammosteids had broad, flattened bodies, suggesting a predominantly benthic habit. The earliest unequivocal psammosteid is Drepanaspis of Early Devonian Germany, which is either included in the family Psammosteidae, or placed within its own family, Drepanaspididae. If the late Silurian/Early Devonian Weigeltaspis is a psammosteid, as opposed to being a traquairaspid, then that genus, instead, would be the oldest psammosteid. However, its placement within Heterostraci remains a matter of debate. Other notable psammosteids include Psammosteus, and Obruchevia, two genera of enormous species with dorsal shields around one meter in diameter. The Psammosteids were the only heterostracans to survive to the end of the Devonian, where they finally perish during the Hangenberg event.

Rodenaspis

This genus was established by Blieck in 1984 when he elevated Protaspis (Protaspis) brevispina into a separate genus, noting its cornual processes are distinct from Protaspis. [2]

Tuberculaspis

Tuberculaspis is known from Early Devonian marine strata of Nevada, where it coexisted sympatrically with the protopteraspidid Lamiaspis , and fellow protaspid Pirumaspis in a shallow-water marine environment. It is named for tubercule-like growths that decorate the borders of its dorsal shield. [4]

Xylaspis

This Spitzbergen protaspid was originally named Spitsbergaspis , but that name was discovered to be preoccupied by an Ordovician trilobite. It is similar in form and related to Zascinaspis and Woodfjordaspis.

Zascinaspis

Species of Zascinaspis are found in Early Devonian marine strata of Spitzbergen, and are similar in form to Xylaspis, Woodfjordaspis and Gigantaspis , the former two genera being closely related.

Woodfjordaspis

Woodfjordaspis is known from an incomplete, partially articulated armor found in early Devonian-aged marine strata of Spitzbergen. It is similar in form and is closely related to Zascinaspis and Xylaspis.

Pirumaspis

This protaspid is from the Sevy Dolomite Fauna of Late Emsian-aged marine strata in Nevada, where it coexisted sympatrically with Tuberculaspis, and the protopteraspidid Lamiaspis.

Related Research Articles

Dunkleosteidae family of fishes (fossil)

Dunkleosteidae is an extinct family of arthrodire placoderms. The gigantic apex predator Dunkleosteus terrelli is the best known member of this group. While they were previously thought to be close relatives of the genus Dinichthys and grouped together in the family Dinichthyidae, more recent studies have shown that the two taxa represent two very distinct clades within Arthrodira. The reappraisal of Kiangyousteus lead to a restructuring of the family, with the inclusions of the benthic, aberrant Heterosteus as the sister taxon of Dunkleosteus, and the Late Emsian Xiangshuiosteus as the sister taxon of Eastmanosteus calliaspis, and the removal of Westralichthys from the family

<i>Jaekelopterus</i> extinct species of the Eurypterida (sea scorpions), Devonian period

Jaekelopterus is a genus of predatory eurypterid, a group of extinct aquatic arthropods. Fossils of Jaekelopterus have been discovered in deposits of Early Devonian age, from the Pragian and Emsian stages. There are two known species: the type species J. rhenaniae from brackish to fresh water strata in the Rhineland, and J. howelli from estuarine strata in Wyoming. The generic name combines the name of German paleontologist Otto Jaekel, who described the type species, and the Greek word πτερόν (pteron) meaning "wing".

<i>Homosteus</i> Genus of fossil fishes

Homosteus is a genus of flattened arthrodire placoderm from the Middle Devonian. Fossils are found primarily in Eifelian-epoch aged strata of Europe, Canada, Greenland, and Estonia. All of the species had comparatively large, flattened heads with, as suggested by the upward opening orbits, upward-pointing eyes. These adaptations suggest that the various species were benthic predators.

Protaspis is an extinct genus of pteraspidid heterostracan agnathan which lived during the Early Devonian of the United States, with fossils found in marine strata in what is now Utah, Wyoming and Idaho.

Holonematidae family of fishes (fossil)

Holonematidae is an extinct family of relatively large arthrodire placoderms from the Early to Late Devonian. Almost all fossil specimens are of armor fragments, though, all have distinctive ornamentation, often of unique arrangements and patterns of tubercles, that are diagnostic of the family. The trunkshield is very elongated, giving the armor an overall "barrel" like appearance.

<i>Buchanosteus</i> genus of fishes (fossil)

Buchanosteus is an extinct genus of arthrodire placoderm. Its fossils have been found in Early Devonian-aged marine strata throughout Asia and Australia. It contains the following species:

Homostiidae family of fishes (fossil)

Homostiidae is a family of flattened arthrodire placoderms from the Early to Middle Devonian. Fossils appear in various strata in Europe, Russia, Morocco, Australia, Canada and Greenland.

Buchanosteidae family of fishes (fossil)

Buchanosteidae is a family of arthrodire placoderms that lived from the Early to Middle Devonian. Fossils appear in various strata in Russia, Central Asia, Australia, and China.

<i>Panamintaspis</i> genus of fishes

Panamintaspis snowi is an extinct species of pteraspidid heterostracan agnathan which existed during the early Middle Devonian period of Death Valley, California. Fossils are found in Late Emsian-aged marine strata of the Lost Burro Formation. P. snowi strongly resembles Pteraspis, though while it was originally described as a member of the same family, Pteraspididae, a recent phylogenetic reassessment of the order Pteraspidiformes places P. snowi within the paraphyletic family "Protopeteraspidae," as the sister taxon of the suborder Pteraspidoidei.

<i>Cardipeltis</i> genus of fishes (fossil)

Cardipeltis is an extinct genus of heterostracan agnathan from marine strata of early Devonian of Utah, and Wyoming. Species of Cardipeltis superficially resemble those of cyathaspids in having a flattened body and indistinct head covered by a large, broad, guitar pick or heart-shaped dorsal shield, and a long, scaly tail. Unlike cyathaspids, which all have a single ventral plate, however, the ventral shield of Cardipeltis is a mosaic composed of large scales.

Pteraspidiformes order of fishes (fossil)

Pteraspidiformes is an extinct order of heterostracan agnathan vertebrates known from extensive fossil remains primarily from Early Devonian strata of Europe and North America, and from Upper Silurian Canada.

Cyathaspidiformes order of fishes (fossil)

Cyathaspidiformes is an extinct order of heterostracan vertebrates known from extensive fossil remains primarily from Silurian to Early Devonian strata of Europe, and North America, and from Early Devonian marine strata of Siberia.

<i>Blieckaspis</i> genus of fishes (fossil)

Blieckaspis priscillae is a pteraspidid heterostracan agnathan from the Middle Devonian of North America.

<i>Weigeltaspis</i> genus of fishes (fossil)

Weigeltaspis is a genus of extinct heterostracan agnathan fish known from the Late Silurian and Early Devonian periods. Fossils are known primarily from Early Devonian-aged marine strata of Europe and Canada. Fragments and disarticulated plates of what may be of Weigeltaspis are known from Late Silurian-aged marine strata of Arctic Canada. Rare articulated fossils, plus the overall anatomy of its plates suggest the living animals were, at least superficially, similar to psammosteids, some authorities, such as Tarlo, place them within Psammosteida. Because the ornamentation on the plates and scales are very similar to the ornamentation seen on the plates and scales of Traquairaspis to the point of constant confusion, other authorities follow the lead of Obruchev, and place Weigeltaspis within Traquairaspidiformes. Still other authorities remain unconvinced of either side, and, instead, follow Denison's lead to simply treat Weigeltaspis as incertae sedis.

Protopteraspididae family of fishes (fossil)

Protopteraspididae is an extinct family of pteraspidid heterostracan agnathans. Fossils of the various genera are found in early Devonian-aged marine strata. Protopteraspidids were once thought to represent a taxon of basal pteraspidids but recent evaluations demonstrate that Protopteraspididae is a paraphyletic group of various transitional forms representing a gradual transition between the more advanced Pteraspoidei, and the anchipteraspidids and the Psammosteids.

<i>Lamiaspis</i> genus of fishes (fossil)

Lamiaspis longiripa is an extinct pteraspid heterostracan agnathan vertebrate found in marine strata of Early Devonian Nevada.

Pteraspididae family of fishes (fossil)

Pteraspididae is an extinct family of heterostracan vertebrates. It is an Early Devonian-aged family that contains the stereotypical, torpedo-shaped pteraspidids, such as the type genus, Pteraspis, and its close relatives Errivaspis and Rhinopteraspis, that are popularly thought to have actively swam about in the water column. The elongated rostral plate is thought to help with their hydrodynamic ability. Various genera are found in various marine and estuarine strata of Early Devonian Europe and North America.

Anchipteraspididae is an extinct family of heterostracan vertebrates restricted to Late Silurian and Early Devonian strata of Arctic Canada.

References

  1. ↑ Pernegre, Vincent N., and David K. Elliott. "Phylogeny of the Pteraspidiformes (Heterostraci), Silurian–Devonian jawless vertebrates." Zoologica Scripta 37.4 (2008): 391-403.
  2. 1 2 3 Blieck, Alain. "Les hétérostracés Ptéraspidiformes, agnathes du Silurien-Dévonien du continent Nord-Atlantique et des blocs avoisinants: Révision systématique, phylogénie, biostratigraphie, biogéographie." (1984).
  3. 1 2 Denison, Robert Howland. Revised classification of Pteraspididae with description of new forms from Wyoming. Field Museum of Natural History, 1970.
  4. ↑ Ilyes, Robert R., and David K. Elliott. "New Early Devonian pteraspidids (Agnatha, Heterostraci) from East-central Nevada." Journal of Paleontology(1994): 878-892.
  1. Palaeos Vertebrates entry on order Pteraspidiformes
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