The Pseudocolus Stinkhorn and the Survival of Ediacaran Architecture: A Genomic & Structural Reassessment of a Misclassified Proto-Animal
Year: 2025
Type: article
Abstract: This study presents genomic and morphological evidence challenging the classification of Pseudocolus species as terrestrial fungi and instead supports their identification as living representatives of ancient marine metazoan lineages. Using an extended BLAST alignment pipeline (REBLAST), this study identified high-confidence genomic matches between Pseudocolus and basal marine taxa, including sponges (Porifera), cnidarians, and unicellular holozoans. Alignments consistently exceeded 1,750 base pairs with >85% identity and E-values of zero, indicating deep evolutionary conservation rather than convergent similarity. The strongest matches occurred with demosponges (Axinella, Geodia) and calcareous sponges (Clathrinida), exhibiting triradial spicule arrangements, as well as with predatory flagellates (Tunicaraptor) showing 87% identity over 2,116 base pairs. Morphological analyses further demonstrate that Pseudocolus displays features inconsistent with fungal biology: triradial symmetry, manganese-rich biomineralization, hydrogel-supported modular architecture, and a volatile chemical profile resembling marine stress-response signaling rather than terrestrial spore dispersal. These traits align with Ediacaran fossil forms and suggest a scaffold-based developmental logic predating bilaterian patterning systems. Based on this converging genomic and structural evidence, we propose reclassifying Pseudocolus as Tribrachia fusiformis (Demospongiae, incertae sedis) and introduce the provisional clade Triquadrozoa, defined by triradial morphogenesis and mineral-organic scaffold formation. This lineage represents a living archive of pre-bilaterian body plan logic, offering novel insights into early metazoan evolution and the persistence of ancestral developmental architectures. Note: Translations of the article are available in Japanese and Chinese.
Author: Gjovik, Ashley Marie
Language: English
Subfield: Paleontology
Field: Earth and Planetary Sciences
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W6949769028