In Varieties of Faith in the Empire, we've got the Altmeri Pantheon as:

Auri-El, Trinimac, Magnus, Syrabane, Y'ffre, Xarxes, Mara, Stendarr, Lorkhan, Phynaster.

We know basicly Auri-El can be seen as Akatosh and other aspects of Lorkhan we are too familiar with. Mara is always Mara and Stendarr is always Stendarr(Stun), while Trinimac, at least before his transformation into Malacath, shares some similarity with Tsun and by that with Zenithar. Magnus is that Magnus, and Xarxes has some relation with Hermaus Mora, so with Jhunal and maybe even with Julianos. Both Phynaster and Syrabane are ancestor gods. And at last they worship Y'ffre the Earthbone. However, in this pantheon we cannot find any trace of Kynareth and Dibella, while their planets have been observed for thousands of years, and we would be sure that the eight Aedra that forming the Spokes of the Wheel includes Kynareth(or the origin Et'Ada) and Dibella(or the origin Et'Ada), and the Wheel is an Elven concept, adapted both in Dunmeri and Ayleidoon mystic culture.

So my question is, where are these two lost Spokes in Altmeri religion, or let's take one step further, in Aldmeri religion?

Now I can think up two solutions. One is that, in the Alemeri religion both the aspect of Kynareth and Dibella have merged into that of Mara, as in the Mythic Dawn Commentaries, circles drawn by wet Dibellites: three concentric and let their lower blood fall where it may. This is also implied in the case of Almalexia, as in the Nu-Hatta Inquery Tree, Almalexia is : Hnnnh. Kyne and Mara and Dibella and sixteen Daedric elements: all contributed to the snake-faced queen when she touched the drum. Their sum? A Beauty Cala as none have seen. Cala! Wetness of Kingdom! Considering Nu-Hatta is maybe Cyrodiilic culture based, it is easy for him to say Kyne and Mara and Dibella added up, while in fact in Aldmeri culture Almalexia can just approach a single Mara to become all three, as they are one already.

The other is that, consider the connection between Kyne and Y'ffre, maybe the Kyne and Dibella the men worship are in fact what left over after some Et'Ada sacrificed themselves into the Earthbone. That is to say, the origin Et'Ada sacrificed himself to stablize the Mundus, by giving all creature and plants in Mundus a certain shape that never natrally changed. This made some parts of him an Earthbone, and this Earthbone is named Y'ffre. What was left flew into the sky and became Kyne, or the Sky Hawk that is flowing freely and without shape as the Air. The Aldmers chose to worship Y'ffre, while the ancestors of Men chose to worship the Sky Hawk, the different parts of a same Et'Ada. I say this because an Et'Ada need not to put all himself into an Earthbone to be seen asn an Earthbone. The Heart of Lorkhan is an Earthbone, while Shor and Shezarr and other aspects of Lorkhan are not. Maybe Kyne and Y'ffre is in the similar case. The problem is, by far I cannot find the Earthbone that separate Dibella from her origin Et'Ada.

So, what do you think of it?

Perhaps the're seen as goddesses who still thought Mundus was a good idea after it was created unlike Auriel. Kynareth's like the feckless mother who let herself get knocked up by Lorkhan and is indifferent to her children's quarrels and suffering. And she militantly stands by Lorkhan sending Men at the Aldmer as cannon fodder. At least Mara does what she can to comfort her children.
Meanwhile Dibella is responsible for a lot of the things that make life on Mundus enjoyable. Possibly seen as a goddess of natural beauty. Why aspire to ascending to the spirit plane, when one is too busy fixating on flowers, birdsong, wordly drama and the [censored] on the girl next door?

But that's not the reason they're not in the pantheon. I mean, Lorkhan is in the Aldmeri pantheon.

An enemy god is still a god, just the Aldmers never worship them did not mean they didn't recognize them as gods, like in the case of Lorkhan. But not in the pantheon means they are not even considered god, which is quite suspicious.

So if Aldmeri Mara had absorbed Aldmeri Kyne/Dibella into her, the goddesses of air and beauty had merged into the Mother Goddess as a Trinity, then they would have no need to show up. Or, if Kyne is what was left from Y'ffre, as the Aldmers had already worshipped Y'ffre, they had no need to recognize Kyne as a seperate goddess then.