There’s no such thing as “Palestinian”. It’s a made-up name.
Although Jordanians identify as Arab (how and why, I do not know), they aren’t descended from Ishmael.
Oh, I knew all that. “Palestinian” is a name the Romans invented, a modern version of “Philistine.” The Arabs came along later and took the name for themselves.
As for the Arabs, they were a mixture of many tribes before the time of Mohammed. South of Mecca, the main tribe was called the “True Arabs,” and descended from Qahtan (Joktan in the Old Testament). North of Mecca there were the “Ishmaelite Arabs,” who spoke Aramaic instead of Arabic. And then there were some dark-skinned folk called the “Lost Arabs.” The Mahra of South Yemen and the Shahra of Oman are Veddoid (South Indian) in appearance, so they are probably “Lost Arabs.”