You're quite right, GP is being mistakenly over-broad. Mimivirus (APMV) is an encapsidated virus, and the capsid is what forms that shape. Capsids[1] generally contain the DNA or RNA of the virus' genome and often appear quite geometric. Capsids have a T-number, which determines how many faces of triangles or hexagons+pentagons exist. It's a deeply mathematical field of study since these are, essentially, tiny repetitive building blocks.
Some (tobacco mosaic virus being the most famous) are helical, while others (bacteriophages) look completely different[2]. Viruses appearing spherical are generally enveloped, meaning they contain part of the cellular plasma membrane surrounding their capsid (HIV). Ebola is part of the filovirus family[3], which are characterized by, among other things, their long, filamentous shape (hence the name).
Bacteriophages are often icosahedral in the headpiece. In fact, the packing motor portion of the icosahedral bacteriophage was not solved until recently because the symmetry averaged structure washed out the stalk part in crystallography and cryo-EM techniques. (it was machine-vision-assisted cryo-EM class averaging technique that helped elucidate the structure)
Yes, there are some filamental viruses such as TMV and ebola, and the P22 bacteriophage, but most viruses, even membrane-enveloped ones, seem to have icosahedral or pseudo-icosahedral structures.
My original point being: "d20"-ness is the rule, not the exception.
the d12 ones are effectively equivalent to d20s because an icosahedron is the dual solid of the dodecahedron; depending on "how you look at it", T1 virus capsids can either be "d20s" or "d12s".
I would imagine the earliest forms of life (proto-life if we use cellular structure in the definition of life) were free-floating strands of genetic material, more similar to viruses than to fully formed cells. Or if that's on the right track, we could say the first "cells" were large bowls of the primordial soup.
Fascinating article, but it was hard for me to get past 'Immune defence'. I'm sure they meant no offence, but it coloured the rest of the text for me. (If it had been on a .co.uk, I'd have left them alone, scout's honour).