Maotianoascus octonarius is an extinct species of stem-group ctenophore, known from the Chinese Maotianshan shales of Yunnan. It is dated to Cambrian Stage 3 and belongs to late Early Cambrian strata.
The species is remarkable for its set of eight massive lobes.
A phylogenetic study of Cambrian stem-group ctenophores recovered Maotianoascus in Scleroctenophora, along with Galeactena, Thaumactena, Batofasciculus, Gemmactena and Trigoides.