The comprehensive, open access review paper is:
Slater, B.J. and Bohlin, M.S., 2022. Animal origins: The record
from organic microfossils. Earth-Science Reviews, 232, no. 104107.
open access review paper
A related video.
Possible sponge fossils in the Tonian of northwestern Canada,
Elizabeth Turner, Laurentian University, Virtual Seminars in
Precambrian Geology
Turner's open access paper is:
Turner, E.C., 2021. Possible poriferan body fossils in early
Neoproterozoic microbial reefs. Nature, 596(7870), pp.87-91.
Yours,
Paul H.