As I discuss in this question, every Brahmana is a descendant of sages, which is why every Gotra or clan of Brahmins has an associated list of Pravaras, a list of the sages they're descended from. For instance, I am a Brahmin belonging to Vadhula Gotra, and my Pravaras are "Bhargava, Vaitahavya, Savedasa", which means that I am descended from the sage Savedasa, who is a descendant of the sage Vitahavya (whom I discuss here), who is a descendant of the sage Bhrigu. But Brahmanas are not the only ones with Gotra Pravaras; here is what the Baudhayana Shrauta Sutras say about the Pravaras for Kshatriyas and Vaishyas:
Kshatriyas have a three-rishi (pravara) "Manava, Aida, Paururavasa" for the Hotri, "like Pururavas, Ida, Manu", for the Adhvaryu. Vaishyas have a three-rishi (pravara) "Bhalandana, Vatsapra, Mankila" for the Hotri, "like Mankila, Vatsapri, Bhalandana" for the Adhvaryus.
Now the Pravaras for Kshatriyas make some measure of sense; you have Vaivasvata Manu, then Vaivasvata Manu's son/daughter Ila, and then Ila's son Pururavas who is the ancestor of lunar dynasty kings. (Although there is still the issue of how these Pravaras would apply to solar dynasty kings.). But I'm interested in the Pravaras for Vaishyas.
I think Bhalandana and Vatsapri refer to the figures mentioned in this chapter of the Srimad Bhagavatam, who were descendants of Vaivasvata Manu's son Dishta:
Diṣṭa had a son by the name Nābhāga. This Nābhāga, who was different from the Nābhāga described later, became a vaiśya by occupational duty. The son of Nābhāga was known as Bhalandana, the son of Bhalandana was Vatsaprīti, and his son was Prāṁśu. Prāṁśu’s son was Pramati, Pramati’s son was Khanitra, Khanitra’s son was Cākṣuṣa, and his son was Viviṁśati.
But my question is, who is the third figure Mankila mentioned in the Gotra Pravaras for Vaishyas?
If it helps, the name Mankila is sometimes spelled as Manktila. Does anyone know any scriptures that mention a Vaishya named Mankila or Manktila?
EDIT: It looks like this Vaishya Rishi may be named Sankila, not Mankila; here's what this excerpt from the Matsya Purana says:
Bhalandaka, Vashashva, Sankila are the chiefs of the Vaishya clan and are the great Mantrakrits.
And this excerpt from the Anusanga Pada of the Brahmanda Purana says the same thing:
Bhalandana, Vatsa and Samkila - these three are composers of Mantras and are remembered as the most excellent ones among Vaishyas.
Also, using the Rig Veda Anukramani in my answer here, I found out that three hymns of the Rig Veda were heard by Vatsapri son of Bhalandana: Book 9 Hymn 68, Book 10 Hymn 45, and Book 10 Hymn 46. I haven't found any hymns heard by Bhalandana or Mankila/Sankila though. Finally, I found the stories of Nabhaga, Bhalandana, and Vatsapri in this excerpt from the Markandeya Purana.