Chondrostoma
Nose ( Chondrostoma nasus )
Chondrostoma is a genus of freshwater fish in the family Cyprinidae. Your striking feature is a well-developed, nose similar essay, which covers most of the upper lip. Together with fish of the genera Protochondrostoma, Pseudochondrostoma, Parachondrostoma, Achondrostoma and Iberochondrostoma that have a similarly shaped upper lip, they are referred to in the German therefore as noses.
Features
The fish of the genus Chondrostoma reach standard lengths 135-470 mm. The bodies are flattened cylindrical or laterally. The adult fish have a subscript mouth with a horny, often sharp-edged layer covering the lower lip. The upper lip wearing a nose-like attachment. In some species the mouth is bent. For more specialized types of leading edge of the lower lip is straight. The morphology of the mouth changes during ontogeny. For example, at the mouth Chondrostoma nasus in the adult fish straight while it is bent at the juvenile fish.
Way of life
Most species of the genus Chondrostoma inhabit fast-flowing waters. Their diet consists of invertebrates and algae, which they scrape from rocks or rock on the stony ground.
System
For a long time the name Chondrostoma was used for a heterogeneous group of fish that had a nose-like attachment on the upper lip together. Based on genetic analyzes of the Spanish ichthyologist Benigno Elvira could find in 1987 that these similarities are based only on convergent evolution and that these differ fish through clearly defined molecular features. Today, the following six genera are distinguished: Chondrostoma, Protochondrostoma, Pseudochondrostoma, Parachondrostoma, Achondrostoma and Iberochondrostoma. However, molecular analyzes from 2008 suggested the assumption that the genera Achondrostoma and Iberochondrostoma are indistinguishable.
Species and their distribution
Geographically, the areas of distribution of the genus Chondrostoma be divided into three regions.
The first region includes the Volga region, the Black Sea, the Caspian Sea and the inflow to the North Sea and the Baltic. Here the following taxa occur:
- Chondrostoma oxyrhynchum
- Chondrostoma kubanicum
- Nose ( Chondrostoma nasus )
- Chondrostoma variabile
The second region includes the tributaries of the Mediterranean Sea and the freshwater regions of the Balkan Peninsula, where the following species are represented:
- Chondrostoma knerii
- Chondrostoma nasus
- Chondrostoma olisiponensis
- Chondrostoma phoxinus
- Chondrostoma prespense
- Chondrostoma scodrense
- Chondrostoma soetta
- Chondrostoma vardarense
The third region includes the freshwater regions of the Caucasus, Turkey and the Middle East. Here are the distribution areas of the following ways:
- Chondrostoma angorense
- Chondrostoma holmwoodii
- Chondrostoma beysehirense
- Chondrostoma kinzelbachi
- Chondrostoma meandrense