Climatiiformes
Climatius macnicoli
- Worldwide
The Climatiiformes ( Syn: Diplacanthiformes Berg, 1940) are an extinct order of fish from the group of Acanthodii ( " dogfish sharks "). She lived from the Middle Silurian to the Mississippian ( Lower Carboniferous ). Fossils of Climatiiformes were in Europe, North and South America, Greenland, South Africa, found in Asia, Australia, New Zealand and Antarctica. They were named after Climatius from the British Old Red Sandstone.
Features
The Climatiiformes are considered primitive Acanthodii and differ from other forms mainly by the two - or multi-paired spines between pectoral and ventral fins. The spines have wide bases and were corrugated. They had two dorsal fins. Below their shoulder girdle can be found in most cases ornamented dermal bones. The scales were small, thick and hochkronig and not overlapped. The Diplacanthidae family was toothless, most of the other Climatiiformes had spirals of small teeth that were not firmly adherent to the pines. Like other " dogfish sharks " were mostly small fish with a length of 15 cm or less. Gyracanthus a common form of Carboniferous is mainly known by fossil spines, which could be up to 40 cm long. For this type a length of about 1.5 m is assumed.
Outer systematics
The Climatiiformes be counted among the Acanthodii, called in German as " dogfish sharks ." The monophyly and thus the systematic position of the Acanthodii is uncertain. Traditionally, they are regarded as sister group of bony fishes ( Osteichthyes ). This systematic position cladogram shows the following:
Placodermi
Cartilaginous fishes ( Chondrichthyes )
Acanthodiformes
Climatiiformes
Bony fishes ( Osteichthyes )
According to recent phylogenetic studies, the Climatiiformes are a poly-and paraphyletic taxon that includes different types, the basal in the Eugnathostomata (all gnathostomes to the placoderms ) must be filed, or to the root group of cartilaginous fishes ( Chondrichthyes ) and the bony fishes ( Osteichthyes ) belong.
The following diagram shows the Climatiiformes as poly-and paraphyletic taxon:
Placodermi
Climatiiformes ( Tetanopsyridae, Culmacanthidae, Diplacanthidae )
Climatiiformes ( Climatiidae, in parts )
Climatiiformes ( Climatiidae, in parts )
Cartilaginous fishes ( Chondrichthyes )
Climatiiformes ( Cassidiceps, Euthacanthus )
Acanthodiformes
Ischnacanthiformes
Bony fishes ( Osteichthyes )