Comment on "Fossilized nuclei and germination structures identify Ediacaran 'animal embryos' as encysting protists".

On the basis of putative nuclei and endospores, Huldtgren et al. (Reports, 23 December 2011, p. 1696) propose that embryo-like Doushantuo microfossils are nonmetazoan holozoans akin to mesomycetozoeans. However, both size and preservation preclude interpretation of internal structures as nuclei. Moreover, the authors may have conflated two different populations; some specimens display a pseudoparenchymatous organization incompatible with a mesomycetozoean comparison.