"sexually", by fusion of the genetic matter of two separate individuals.

Yeahbut©, the fusion of genetic material is not sexual in the way we normally think of sexual, i.e., genetic material from one individual introduced to the other individual, in which other individual the offspring develops. What happens in the paramecia is that genetic material is traded and each then proceeds to divide in the normal asexual manner. Biology was never my strong suit so perhaps this is defined as sexual in some technical way that I am unaware of, in which case I will stand corrected, but until then I stand fast.