Penion maximus is the largest species of Penion siphon whelk, and is endemic to Australia.[2][3] The species could be confused with the sympatric species P. mandarinus, however P. mandarinus is typically smaller and has a smoother shell with a shorter siphonal canal.[2] Their shells are highly coveted due to the intricate designs embedded in onto the shells.
^ abcVaux, Felix; Hills, Simon F.K.; Marshall, Bruce A.; Trewick, Steven A.; Morgan-Richards, Mary (2017). "A phylogeny of Southern Hemisphere whelks (Gastropoda: Buccinulidae) and concordance with the fossil record". Molecular Phylogenetics and Evolution. 114 (2017): 367–381. doi:10.1016/j.ympev.2017.06.018. PMID28669812.
^ abVaux, Felix; Crampton, James S.C.; Trewick, Steven A.; Marshall, Bruce A.; Beu, Alan G.; Hills, Simon F.K.; Morgan-Richards, Mary (2018). "Evolutionary lineages of marine snails identified using molecular phylogenetics and geometric morphometric analysis of shells". Molecular Phylogenetics and Evolution. 127 (October 2018): 626–637. doi:10.1016/j.ympev.2018.06.009. PMID29913310. S2CID49303166.