Natricinae
Grass Snake (Natrix natrix )
The water snakes ( Natricinae ) are a species-rich subfamily of snakes ( Colubridae ) about 210 species in 32 genera. They include genera from all different parts of the world. Among other things, include the European water snakes ( Natrix ), to which ( Natrix natrix ) and the grass snake heard the American swimming snakes, the garter snakes and fish snakes on the Natricinae.
Features
The most slender snakes are non-toxic. As a food, small mammals, amphibians, fish, lizards, eggs and young birds, also taken earthworms at the smaller species, the prey spectrum of species is slightly different kind.
Most of these snakes like to live near water and are good swimmers.
A diagnostic feature of the group is the special shape of the sulcus spermaticus, a groove on the inside of hemipenis in which the sperm are introduced into the female cloaca during copulation. The sulcus of the spermatic Natricinae is single, strongly curved, forming a bare region on the middle inside of the two hemipenes. Existing in many queues calyces, small and single-cell structures that form a complex folding pattern, are missing.
Inside systematics
The internal system is, as with many Schlangentaxa, still subject to scientific debate. Within the Natricinae the American genera form a monophyletic group, the tribes Thamnophiini. The following genera are counted according to the water snakes:
- Afronatrix
- Amphiesma
- Amphiesmoides
- Anoplohydrus
- Aspidura
- Atretium
- Balanophis
- Hologerrhum
- Hydrablabes
- Hydraethiops
- Iguanognathus
- Lycognathophis
- Macropisthodon
- Natriciteres
- Natrix (European water snakes )
- Opisthotropis
- Parahelicops
- Pararhabdophis
- Paratapinophis
- Rhabdophis
- Sinonatrix
- Tropidonophis
- Xenochrophis
Tribus Thamnophiini ( New World Natricinae )
- Adelophis
- Clonophis
- Nerodia Southern swimming snake ( Nerodia fasciata )
- Brown swimming snake ( Nerodia taxispilota )
Outer systematics
The subfamily of water snakes is to the family of snakes ( Colubridae ) counted, which belongs to the order Squamata ( Squamata ).