sphinx
One of my books, The Tarot Handbook by Angeles Arrien, says that the sphinx is put on the top of the wheel to illustrate a new way of doing things.
I don't know that they share the same zodiac. I have information that the Wheel is matched with Jupiter, While the "World" or "Universe" [21] is Saturn's.
I know that the Wheel's Jupiter-size-like backing multiplies the position where it is put or it's cards near by. As in to the power of 10. If the Wheel is capable of meaning a great burden or illness if reversed, or like being under a rock, as if the wheel is made of stone. If up and isolated, can mean a great deal of relief and "fortune".
Though [21] is named Universe, I think that that is a nicety. I call it "El Fin" like at the end of an old movie. I've seen it mean death frequently, or "as big as death" like an accident or a diagnosis that was walked away from. In a relationship [21] can mean a finalization was made -- no crying involved. Reversed [21] is as whaling as a Siren, loud, emotional and needy or if you are the Siren "self expressing" needing a "fair relationship"
The Wheel will apply more to a job or one's emotional health, cheer, or toxication level. The Universe has more fate - collisions and misses and human thriumphs to it. Sometimes if the [21] is reversed it can actually be running water such as an aquaduct, gutter, flooded basement, or the tub over flowing. The Wheel does not share this direct connect with visible reality.