No need to apologize.
A third example would be Bge (F), which can be baggage camels or elephants in addition to the more typical horse-herds or pack-mules.
Similarly, mounted infantry treats some terrain differently depending on whether they ride horses, camels (some Arab lists) or light carts (Elamites, Assyrians, and presumably Kyreneans*).
* The rule specifies that kallapani treat terrain as if chariots: it doesn't say explicitly about Kyrenean carts, but it would be most strange if they somehow dealt better with rough terrain.