This system also takes into account instances when one has more than one wife. Over a period of time name of the benefactor is also included as Gotra,as a mark of Respect.
For example, Kasyapa, Apasthara, Naithruva'
This is different from Kasyapa Gotra.
There is another Pravara for Kasyapa Gotra as well.
Kasyapa, Aavatsaara, Daivala.
The same with the other Rishis.
I am posting a list from the available resources and people may also contribute with authentication to make this List a Comprehensive one.
Each gotra takes the name of a famousRishi or sage.
Gotra is a concept of patrilineal classification, which identifies the families of a caste.
The original rishis after whom the gotras were named were just Seven in number .
Gotras were further subdivided into ganas and sub ganas.
Another concept is that of Pravar Rishis who were a few of the most learned and capable sages belonging to that gotra.
Each Brahmin was thus known by his gotra, pravar, sutra and shakha.
There are exceptions to the rule too. For example the descendents of Maharishis Bhrigu and Angirasa cannot marry, because of the same Pravara Rishis, which are common to the two individuals.
The weddings in India are fixed as per the Gotra of the bride and groom.
Gotra matching is one of the most important concerns in North indian Hindu matrimony.
Wedding in similar Gotra is strictly prohibited.
A Gotra has three Rishis.
This indicates the fact some of the Rishis had more than one wife, at different times , for example Pa