There are two morphologically similar fungi on fallen wood in New Zealand that appear to be Ameghiniella/Ionomidotis-like. One of these (e.g. PDD 99209, PDD 63654) has been referred to Ameghiniella australis (ITS sequences from PDD 99209 match S American specimens identified as A. australis in GenBank). The second species has a paler (brown rather than blackish; when fresh with an olive-green hymenium and mustard yellow receptacle) receptacle that is not folded and ridged when dry (e.g. PDD 119573, 119574). An ITS sequence from the dried specimen of PDD 119573 shows this matches Ionomidotis s.s.
Both species are ionomidotic - the pigment in A. australis is red but with a yellowish tinge, the pigment in the Ionomidotis species deep purple red. The two species differ in ascospore shape and size - allantoid, 5.5-6 x 1.5 um in A. australis; oblong to short-cylindric, more or less straight, 5-6 x 2 um in the second species.

The genus Diplocarpa is accepted with five lignicolous species: D. bloxamii (type of Diplocarpa), D. constans, D. fischeri comb. nov. (type of Poloniodiscus), D. iberica sp. nov., and D. irregularis (type of Ionomidotis). The North American D. irregularis and European D. fischeri have previously been considered synonyms. Australian records under the name D. bloxamii could belong to a sixth species.