Acanthodii
Outdated live reconstruction of Climatius macnicoli (excluding large bony plates in the head region and with exposed gill slits ) from the Lower Devonian of Scotland.
- Worldwide
The Acanthodii are a class of extinct, highly diverse fish. Systematically, they belong to the superclass gnathostomes ( gnathostomata ) and are the sister group of bony fishes ( Osteichthyes ), with whom they form the taxon Teleostomi. They are the first fossil traditional gnathostomata and lived from the Silurian to the Permian. The flower they experienced in Devon. Individual fossilized spines and scales (so-called Ichthyodorulithen ) has been found from the Untersilur, secure, well-preserved finds from this period are still unknown. The oft-used German name " dogfish sharks " means no close relationship, but only refers to the appearance of many haiähnliche Acanthodier with the typical feature that the membranous fins were supported at its front edge of a sting.
Features
The Acanthodii were 8 centimeters to 2.5 meters long and were in the sea, but mainly in freshwater before. Your inner skeleton was made of cartilage, but the braincase of a piece of bone (albeit with deep cartilage bays - in itself but without Gelenkung ). Head and body were covered with small scales. Some species had bony gill cover of " radii ". All species possessed jaw, but the teeth were often missing. When present they were often on the lower jaw. The toothless genera ( for example acanthodes ) are considered pelagic filter feeders. The hyoid arch was initially interpreted as a "normal branchial arch ", but more detailed studies ( Miles 1973) showed that he had propped up the arch, such as sharks, rays, and bony fishes; between the two was often the spray hole. In contrast, there were no Pharyngealia with pharyngeal teeth. The Unpaarflossen had no fins own carrier, but sat on the extended neural or Hämalfortsätzen (on the notochord ). The small pair of fins were sometimes independent of the ventral rows of prongs. The shoulder girdle was weak. The fins had no radiation, only scales as props. The eyes were set far forward and were provided with Scleralringen; the nasal organs must have been small, but there were already two each Narinen ( nostrils ).
Systematics ( incomplete)
The Ischnacanthiformes and Climatiiformes can already be found in the Silurian, while the Acanthodiformes are known only from the Lower Devonian.
Climatiiformes
Except for the Diplacanthides had many jaw teeth.
- Family Climatiidae Climatius Upper Silurian to Lower Devonian, Locations: Europe, North America
- Euthacanthus Lower Devonian, Locations: Europe
- Parexus Lower Devonian, Locations: Europe
- Nostolepis Upper Silurian to Lower Devonian, find spots: including Europe ( mostly based only on findings shed genus )
- Gyracanthus Lower Devonian to Upper Carboniferous Locations: North America
- Diplacanthus ( Rhadinacanthus ) Middle to Upper Devonian, Locations: Europe, North America
Ischnacanthiformes
- Family Ischnacanthidae Bracteatacanthus Upper Silurian, Locations: Europe ( Lithuania)
- Arenaceacanthus sub - Silurian, spots: only shed finds, Europe
- Ischnacanthus Lower to Upper Devonian, Locations: Europe, North America
Acanthodiformes
All Acanthodiformes had only one dorsal fin, while the Climatiiformes and Ischnacanthiformes two can be found. They were probably filter feeders, usually no teeth are present.
- Family Acanthodidae Acanthodes sub - Carboniferous to Lower Permian localities: Europe, North America, Australia, South Africa, East Asia
- Cheiracanthus Middle Devonian, Locations: Europe
- Homalacanthus Upper Devonian to Lower Carboniferous localities: North America, Europe
- Mesacanthus Lower to Middle Devonian, Locations: Europe
- Traquairichthys Upper Devonian to Lower Carboniferous, Locations: Europe, North America
- Triazeugacanthus Upper Devonian, Locations: North America
Some genera of uncertain systematic position
- Onchus sub - Silurian to Lower Devonian, Locations: North America and Europe
- Antarchtonchus Middle and Upper Devonian, Locations: Antarctic
- Monopleurodus Upper Silurian, Locations: Europe