Figure 4. Extracellular membrane protrusions from asgard archaea.

Potential trade-off between cytosol investment between cell and protrusion. Each 1 µm increase in protrusion takes 12% cytoplasm, likely limiting total protrusion and reducing cell volume. Values in the table for the asgard archaea were calculated based on Eme et al., 2017: average asgard cell radius: 0.25 µm, average protrusion radius 50 nm, and length 1 µm. Average alphaproteobacterium radius and length were taken to be 0.5 and 3 µm, respectively.