The component subfamilies of the Delthyridoidea are critically reviewed and subjected to phylogenetic analysis. This shows the presence of two clades, assigned to the Delthyrididae and Acrospiriferidae, within the superfamily. The subfamilial categories are redefined mainly on the basis of the characters used in the phylogenetic analysis. The spiriferid, mainly delthyridide, Gaspe fauna is formally revised and redescribed. This new taxonomic treatment leads to more precise biostratigraphy and to the recognition of a new subfamily, the Gaspespiriferinae, based on the new genus Gaspespirifer. Five new species aye described: Howellella (Howellella) forillonensis, Brachyspirifer (Brachyspirifer) briseboisi, Paraspirifer desbiensi, Brevispirifer florentinus, and B. quebecensis, The occurrence of Brevispirifer species with Middle Devonian chonetaceans confirms the presence of marine Eifelian strata in the Matapedia Valley. Paraspirifer desbiensi n. sp. and two species left in open nomenclature, Vandercammenina sp. and Mucrospirifer sp., have considerable biostratigraphic and biogeographic significance in the Lower Devonian. The first occurrence in the Eastern Americas Realm of the typically Rhenish genera Brachyspirifer, Paraspirifer, and Vandercammenina are in Gaspe. This reinforces the hypothesis that Gaspe served as a stepping stone for Rhenish species invading North America in Pragian and Emsian times, as previously suggested by bivalve biogeography.