Pusa
Caspian seal (Phoca caspica )
Pusa is a genus of true seals, which was formerly managed as a subgenus of the Real earless seals. It includes the ringed seal ( Pusa hispida ) and the two adapted to life in freshwater species Baikal Seal ( Pusa sibirica ) and Caspian Seal ( Pusa caspica ) three types, all of which occur in the northern hemisphere.
Freshwater species
In this species also the only two species of fresh water are classified: The Baikal seal ( P. sibirica ) in the Siberian Lake Baikal and the Caspian seal ( P. caspica ) on the Caspian Sea. Both species probably descended from the ringed seal ( P. hispida ), either during glaciation have reached the middle or above sea connections in the late Pleistocene these lakes and life since then isolated.
System
The genus comprises Pusa on the current state of three ways:
- Ringed seal ( Pusa hispida )
- Baikal Seal ( Pusa sibirica )
- Caspian Seal ( Pusa caspica )
These three species were originally slammed together with the harp seal ( Pagophilus groenlandicus ) of the genus of the Real earless seals, but this was resolved and today only the common seal (Phoca vitulina ) and the largha Seal (Phoca largha ) includes.
According to the cladistic analyzes of Bininda - Emonds and Russell the entire genus was paraphyletic with respect to the bearded seal ( Erignathus barbatus), to Palo Väinöla and possibly also in terms of the gray seal ( Halichoerus grypus ). The largha Seal could be as basal type, the sister species of all other representatives and the monophyly of the two freshwater species with the ringed seal is placed on the molecular level of Palo and Väinöla in question ..