Verrucula arnoldaria is a rare species of lichenicolous (lichen-dwelling) lichen in the family Verrucariaceae.

It grows parasitically on the thallus of the rock-dwelling, crustose lichen Calogaya arnoldii.

[1] The species was formally described as new to science in 2007 by lichenologists Père Navarro-Rosinés and Claude Roux, from specimens collected in Vaucluse, France.

[3] The lichen has a thick brownish-grey, areolate thallus that roughly maintains the shape of its underlying host.

It makes ellipsoid spores that measure up to about 15 μm long.