Among all the progeny of Rathitara, these sons were the most prominent because, owing to their birth, they were considered brahmanas

Expressions researched:
"Among all the progeny of Rathītara, these sons were the most prominent because, owing to their birth, they were considered brāhmaṇas"

Srimad-Bhagavatam

SB Canto 9

Having been born from the womb of Rathītara's wife, all these sons were known as the dynasty of Rathītara, but because they were born from the semen of Aṅgirā, they were also known as the dynasty of Aṅgirā. Among all the progeny of Rathītara, these sons were the most prominent because, owing to their birth, they were considered brāhmaṇas.

SB 9.6.3, Translation and Purport

Having been born from the womb of Rathītara's wife, all these sons were known as the dynasty of Rathītara, but because they were born from the semen of Aṅgirā, they were also known as the dynasty of Aṅgirā. Among all the progeny of Rathītara, these sons were the most prominent because, owing to their birth, they were considered brāhmaṇas.

Śrīla Viśvanātha Cakravartī Ṭhākura gives the meaning of dvi jātayaḥ as "mixed caste," indicating a mixture of brāhmaṇa and kṣatriya.