13543
Studies of the brain have shown the similarities with Condylarthra , The ptolemaiidans , a mysterious clade of mammals with uncertain affinities , may actually be stem-aardvarks , either as a sister clade to Tubulidentata or as a grade leading to true tubulidentates .
 None
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: location, person, organization 
Text: {0} 
Answer:
 None