Summary
As late as the 11th c. AD, in the Gotra-Pravara-Manjari of Purusottama-Pandita, it is written as still prevalent that the gotra-pravara system applies to brahman (arsheya) lineages only: the Baudhayana-Pravara-Adhyaya mentions that the (biological) descendants of the seven rishis plus Agastya as the eighth are called gotra: this is the arsha-gotra (pita-putra parampara).
The conventional sense is used as laukika-gotra (guru-shishya parampara/which non-brahmans use). Over the centuries, during to social and cultural changes, various groups in India have adopted the gotra system, but the pravara system still applies only to brahman gotras.
Purusottama-Pandita also adds that Ksatriyas (who employ kulapurohitas) use either the gotra of their kulapurohita, or use the generic template: Manava, Aila, Paururavasa (or: Pururava, Ila, Manu).
Vaisyas, similarly, are to use the Vatsapri gotra.
However, Purushottama Pandita also points out the Tandin school’s opinion (which he seems to favor) that other than brahmans or kshatriyas with kulapurohits, the sarvasadharana usage should be Manava gotra, since (they say) we all are human beings and belong to the human gotra.
sUtra quotes
Baudhayana
Ksatriyas have a three-riShi (pravara), ‘Mānava, Aida, Paurūravasa’. Vaisyas have a three-riShi pravara, ‘bhālandana, vātsapra, mAnkila’.
Apastamba
Next, of Ksatriyas. If they recite their own, they have the one pravara, Manava, Aila, paurUravasa’, etc. Those who do not have hymn-composers should make the recitation with their purohita’s pravara; those who have hymn composers should do without their purohita’s pravara. (But the correct view is that these also) should use their purohita’s pravara, because of the logical argument.
Vaisyas have a one-rShipravara, “Vatsapra’ for the Hotr, ’like Vatsapri for the Adhvaryu.
Kātyāyana and Laugāksi
Kings have their purohita’s pravara; with this too the pravara of Vaisyas is explained. If he should recite with yi-names he should say: ‘Manava, Aila, Paurūravasa’.
Ashvalāyana
Kings have their purohita’s pravara; if they should make the pravara recitation with RShis, “Manava, Aila, Paurūravasa”.
Tribals
The gotras of Munda and Oraon tribes are based on names of birds, which were the vehicles of the people from where their gotras began.
[From the book ‘Jharkhand Ke Adivasi Aur Unke Gotra’ by Dr. Sikradas Tirki]