It stumps our cousin: he did you? (9)

I haven't cracked this one yet — but the brilliant team at Fifteensquared have:

definition: former Guardian crossword setter, someone who would have stumped/puzzled many solvers of today's crossword the araucaria tree is known as the 'monkey puzzle tree' and therefore might stump/puzzle a monkey ('our cousin' referring to humans and monkeys categorised closely together in biological classification)