What is the difference between Prajapati and Parameshthin Prajapatya, and which one is Brahma?

Question

The Jaiminiya Upanishad Brahmana, aka the Talavakara Upanishad Brahmana, is a confusingly named text which is actually an Aranyaka of the Sama Veda, not a Brahmana or Upanishad. It contains within it the famous Kena Upanishad which I discuss here, but my question is about a different part of the text. As I discuss in this question, the Jaiminiya Upanishad Brahmana discusses how someone rescued Brahma from demons by singing the Gayatra Saman, an important hymn of the Sama Veda.

But after that, in this excerpt it gives the Guru Parampara by which the Gayatra Saman was passed down. Here's the beginning of it:

That is the immortal gayatra[-saman]. By means of it Prajapati went unto immortality, by means of it the gods, by means of it the sages (rishi). That the same the brahman told to Prajapati; Prajapati to Parameshthin Prajapatya, Parameshthin Prajapatya to god Savitar, god Savitar to Agni, Agni to Indra, Indra to Kashyapa, Kashyapa to Rishyashringa Kashyapa, ...

As I discuss here, Rishyasringa is the priest who conducted Dasharatha's Putrakameshti Yagna. But my question is, who is the figure "Prajapati" that Brahman taught the Gayatra Saman to, and who is the figure "Parameshthin Prajapatya" that this Prajapati taught it to?

Up until now, I had assumed that Prajapati and Parameshthin were just two names of the creator god Brahma, the husband of Saraswati. For instance, this chapter of the Brihadaranyaka Upanishad gives the Guru Parampara of the Madhu Vidya (which I discuss here), and it says this:

53. Vyashti from Sanâru,
54. Sanâru from Sanâtana,
55. Sanâtana from Sanaga,
56. Sanaga from Parameshthin,
57. Parameshthin from Brahman,
58. Brahman is Svayambhu, self-existent.

Adoration to Brahman.

And this chapter of the Satapatha Brahmana of the Yajur Veda discusses the following Guru Parampara:

9. Now the line of succession (of teachers). The same as far as Sâmgîvîputra. Sâmgîvîputra (received it) from Mândûkâyani, Mândûkâyani from Mândavya, Mândavya from Kautsa, Kautsa from Mâhitthi, Mâhitthi from Vâmakakshâyana, Vâmakakshâyana from Vâtsya, Vâtsya from Sândilya, Sândilya from Kusri, Kusri from Yagñavakas Râgastambâyana, Yagñavakas Râgastambâyana from Tura Kâvasheya, Tura Kâvasheya from Pragâpati, Pragâpati from Brahman (n.). Brahman is the self-existent: reverence be to Brahman!

Until now I had assumed that "Parameshthin from Brahman" and "Prajapati from Brahman" were just two ways of saying the same thing, namely that the creator god Brahma was a disciple of Vishnu. But the Jaiminiya Upanishad Brahmana quote above seems to be treating Prajapati and Parameshthin Prajapatya as two different people. So who are these two figures, and which one of them is Brahma?

My question here about Adi Shankaracharya's use of the terms "Viraj" and "Hiranyagarbha" may be relevant to all this. Also, on a side note it's interesting that Indra taught his father Kashyapa the Gayatra Saman. Usually it's the other way around.

Answer 1

According to this chapter of the Shatapatha Brahmana, Prajapati is the one born from the golden egg:

1. Verily, in the beginning this (universe) was water, nothing but a sea of water. The waters desired, 'How can we be reproduced?' They toiled and performed fervid devotions, when they were becoming heated, a golden egg was produced. The year, indeed, was not then in existence: this golden egg floated about for as long as the space of a year.

2. In a year's time a man, this Pragâpati, was produced therefrom; and hence a woman, a cow, or a mare brings forth within the space of a year; for Pragâpati was born in a year. He broke open this golden egg. There was then, indeed, no resting-place: only this golden egg, bearing him, floated about for as long as the space of a year.

3. At the end of a year he tried to speak. He said 'bhûh': this (word) became this earth;--'bhuvah': this became this air;--'svah': this became yonder sky.

This birth of Prajapati from the golden egg and his creation of the three worlds would point towards him being Brahma as does the further creation of Devas and Asuras by him:

7. Desirous of offspring, he went on singing praises and toiling. He laid the power of reproduction into his own self. By (the breath of) his mouth he created the gods: the gods were created on entering the sky; and this is the godhead of the gods (deva) that they were created on entering the sky (div). Having created them, there was, as it were, daylight for him; and this also is the godhead of the gods that, after creating them, there was, as it were, daylight (diva) for him.

8. And by the downward breathing he created the Asuras: they were created on entering this earth. Having created them there was, as it were, darkness for him.

Coming to Parameshthhin, the text further states that he was was created by Prajapati:

14. Now, these are the deities who were created out of Pragâpati,- Agni, Indra, Soma, and Parameshthin Prâgâpatya.

Praajaapatya therefore seems to be an adjective showing that Paramesthhin was born from Prajapati.

16. They went on singing praises and toiling. Then Parameshthin, son of Pragâpati, saw that sacrifice, the New and Full-moon offerings, and performed these offerings. Having performed them, he desired, 'Would I were everything here!' He became the waters, for the waters are everything here, inasmuch as they abide in the furthest place; for he who digs here on earth finds indeed water; and, in truth, it is from that furthest place, to wit, from yonder sky that he rains, whence the name Parameshthin (abiding in the furthest, highest place).

The above verse gives us the meaning of the name Parameshthhin as One-abiding-in-the-farthest-place. The text further states that the son performed a sacrifice for the father:

17. Parameshthin spake unto his father Pragâpati, 'I have discovered a sacrifice which fulfils wishes: let me perform this for thee!'--'So be it!' he said. He accordingly performed it for him. Having sacrificed, he (Pragâpati) desired, 'Would I were everything here!' He became the breath (vital air), for breath is everything here: Pragâpati is that breath which blows here (the wind); and whatsoever knows that it is thus he blows is his (Pragâpati's) eyesight; and whatsoever is endowed with breath is Pragâpati. And, verily, whosoever thus knows that eyesight of Pragâpati becomes, as it were, manifest.

The Prajapati is so impressed by this sacrifice that he also performs it for his son Indra who then performed it for his brothers Agni and Soma. We can leave the details of the later sacrifices but another chapter of the same Brahamana mentions something interesting which could related to the sacrifice done by Prajapati:

15. And, again, as to why he lays it down by means of Parameshthin. When Pragâpati had become disjointed, the deities took him and went off in different directions. Parameshthin took his head, and kept going away from him.

16. He spake to him, 'Come to me and restore unto me that wherewith thou hast gone from me!'--'What will therefrom accrue to me?'--'That part of my body shall be sacred to thee!'--'So be it!' So Parameshthin restored that to him.

The Parameshthhin seems to be similar to the Puranic Shiva in the sense that he was born from Brahma and as mentioned in the above incident, is related with having taken away the head of Prajapati. Be that as it may, for the purpose of this question, it seems clear that Prajapti and Paramaeshthin are two different entities and out of the two Prajapati appears to be the same as Brahma.