"Of certain affinities" does restrict it more, though older primitive
mollusks, sponges, and cnidarians are known from many areas. I do not
remember whether other phyla are definitely known from the pre-trilobite
basal Cambrian, though there are now some summary papers on the subject.
However, if nothing of certain affinity is found below the trilobites, then
nothing is known about when taxa appeared and we cannot say whether the
trilobites appeared before, after, or simultaneously with the lobopods
except by extrapolation.
David C.