Citizendia
Your Ad Here

Arthrodira
Fossil range: Late Silurian? to Late Devonian
Reconstruction of the long-snouted camuropiscid Rolfosteus canningensis
Reconstruction of the long-snouted camuropiscid Rolfosteus canningensis
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Subphylum: Vertebrata
Infraphylum: Gnathostomata
Class: Placodermi
Order: Arthrodira
Suborders and infraorders

basal

  • Actinolepina

Phlyctaenioidei

  • Phlyctaeniina

Brachythoraci

and see text

Arthrodira is an order of extinct armored jawed fishes of the Placodermi class who flourished in the Devonian period before their sudden extinction, surviving for about 50 million years and penetrating most marine ecological niches. The Silurian is a geologic period and system that extends from the end of the Ordovician period about 443 The Devonian is a geologic period and system of the Paleozoic era spanning from to  million years ago. Rolfosteus canningensis is an extinct species of Arthrodire Placoderm from the late Devonian of the Gogo Reef formation in Australia Chordates ( Phylum Chordata) are a group of Animals that includes the Vertebrates together with several closely related Invertebrates Vertebrates are members of the Subphylum Vertebrata, Chordates with backbones or spinal columns The grouping sometimes includes Gnathostomata is the group of Vertebrates with Jaws The group is traditionally a superclass, including the familiar classes of Fish, The Placodermi were a class of armoured Prehistoric fishes known from Fossils which lived from the late Silurian to the end of the Devonian This article is about the taxonomic rank for the sequence of species in a taxonomic list see Taxonomic order In scientific classification used This article is about the taxonomic rank for the sequence of species in a taxonomic list see Taxonomic order In scientific classification used In Phylogenetics, a basal Clade is the earliest clade to branch in a larger clade it appears at the base of a cladogram The Brachythoraci were a Suborder of Arthrodire Placoderms armored fish most diverse during the Devonian. The Coccosteina were an Infraorder of Placoderms armored fish most diverse during the Devonian. The Placodermi were a class of armoured Prehistoric fishes known from Fossils which lived from the late Silurian to the end of the Devonian The Devonian is a geologic period and system of the Paleozoic era spanning from to  million years ago. In Ecology, a niche (pronounced nich nēsh or nish A shorthand definition of niche is how an organism makes a living

Greek for "jointed neck", the arthrodires had movable joint between armor surrounding the head and body. Armour (or armor) is protective covering most commonly manufactured from metals to prevent damage from being inflicted to an individual or a vehicle through use of direct contact The mouth is interesting because as the lower jaw moved down the head shield moved allowing for a large opening. Lacking distinct teeth, like all placoderms, they used the sharpened edges of a bony plate as a biting surface. The eye sockets are protected by a bony ring a feature shared by birds and some ichthyosaurs. Ichthyosaurs ( Greek for 'fish lizard' - ιχθυς / ichthyos meaning 'fish' and σαυρος / sauros meaning 'lizard' were giant Early arthrodires, such as the genus Arctolepis, were well-armoured fishes with flattened bodies. Arctolepis is an Extinct Genus of Placoderm fish which lived during the Early Devonian period (408 – 307 mya The largest member of this group, Dunkleosteus, was a true superpredator of the latest Devonian period, reaching 3 to as much as 9 meters in length. Dunkleosteus (From "(David Dunkle" + Greek: osteus / οστεος = bone; meaning "Dunkle's Bone" is a In contrast, the long-nosed Rolfosteus measured just 15 cm. Rolfosteus canningensis is an extinct species of Arthrodire Placoderm from the late Devonian of the Gogo Reef formation in Australia

There is a common misconception that the arthrodires (along with all other placoderms) were sluggish bottom-dwellers that were out-competed by more advanced fish. Leading to this misconception is that the arthrodire body plan remained relatively conserved (that is, the majority of arthrodires were bullet or torpedo-shaped) during the Devonian period, save for increasing in size. A body plan, or bauplan, is essentially the blueprint for the way the body of an organism is laid out A bullet is a solid Projectile propelled by a Firearm or Air gun and is normally made from metal (usually Lead) The modern torpedo (historically called an automotive automobile locomotive or fish torpedo is a self-propelled explosive Projectile weapon launched above or below However during their reign the arthrodires were one of the most diverse and numerically successful, if not the most successful, vertebrate orders of the Devonian, occupying a vast spectrum of roles from apex predator to detritus-nibbling bottom dweller. In Biology, detritus is non-living particulate organic material (as opposed to dissolved organic material Despite their success, the arthrodires were one of many groups eliminated by the environmental catastrophes of the Late Devonian extinction, allowing other fish such as sharks to diversify into the vacated ecological niches during the Carboniferous period. The Late Devonian extinction was one of five major Extinction events in the history of the Earth's Biota. Sharks ( Superorder Selachimorpha) are a type of Fish with a full cartilaginous Skeleton and a highly streamlined body The Carboniferous is a geologic period and system that extends from the end of the Devonian period about 359

The flattened, primitive arthrodire Homostius milleri
The flattened, primitive arthrodire Homostius milleri

Contents

Systematics[1]

ORDER ARTHRODIRA

Genera incertae sedis

Arthrodira of unresolved relationships

Footnotes

  1. ^ For sources, see Haaramo (2005)

References

External links

© 2009 citizendia.org; parts available under the terms of GNU Free Documentation License, from http://en.wikipedia.org
 Dapyx Software network: MP3 Explorer | Ebook Manager | Zenithic