Śatapatha Brāhmaṇa ("of a hundred paths") 8.6.2.12

8.6.2.12

pakṣau paṅktayaḥ | tā yatpaṅktayo bhavanti pāṅktau hi pakṣau pārśvata upadadhāti pārśvato hīmau pakṣau yadvarṣīyaścandastaddakṣiṇata upadadhāti dakṣiṇaṃ tadardham paśorvīryavattaraṃ karoti tasmāddakṣiṇo 'rdhaḥ paśovīryavattaraḥ

Paṅktis are the wings: and as to their being Paṅktis, it is because the wings are of Paṅkti (fivefold) nature. He places them sideways, for these wings are sideways. Whatever metre is larger that he places on the right side: he thus makes the right half of the animal the stronger, and hence the right side of an animal is the stronger.