Subgenus Spongia (Heterofibria) Cook & Bergquist, 2001

Diagnosis. Spongia species in which the dominant sub-primary fiber reticulum is clearly divisible into two different size classes, the smaller approximately 40–50% less in diameter than the larger. The meshes formed by the fiber skeleton are usually polygonal, though irregular in size and shape, and less angular than those seen in the subgenus Spongia (from Cook & Bergquist 2002: 1055).

Type species. Spongia (H.) decooki van Soest & Hooper, 2020 (in van Soest et al. 2020: 21); based on Spongia (Heterofibria) cristata Cook & Bergquist, 2001 (unaccepted).

Type locality. Leigh, Northland, New Zealand (Cook & Bergquist 2002: 1055).