Yoruba Nigerian Chief's Pants (go with robe / thobe).
This Yoruba of Nigeria chief's garments consists of the the various components that make up traditional Yoruba men's clothing: the fila (hat), the buba (the shirt worn against the skin), the agbada (the long covering top), and the sokoto (pants). This outfit appears to be made from aso oke, the traditional handwoven Yoruban ceremonial cloth, and has been decorated with embroidery; this color of red aso oke is known as Alaari. Aso oke is hand-loomed, and the process of its fabrication involves first washing and starching the thread, then allowing it to dry in the sun before weaving is begun. Both men and women wear garments made of aso oke, but obviously the articles of clothing differ between genders.
Dr. Turner would likely have acquired this outfit of clothing during his time in West Africa in 1951 and 1952.