Abstract

Chonetes (Eodevonaria) primigenius Twenhofel 1914, from the Vaureal Formation (Ashgill: Richmondian) of Anticosti Island, is chosen as the type species for a new genus, Archeochonetes, the oldest chonetid brachiopod known. Specimens of Archeochonetes from the overlying Ellis Bay Formation (Ashgili: Gamachian, Himantian) are assigned to a new species, A. muirwoodae. A further, as yet unnamed, species of strophochonetid is also described and figured from the Silurian (Llandovery) Jupiter Formation. Detailed external and internal analysis of the shell reveals that the origin of Archeochonetes lies with the Strophomenacea, thus posing a new perspective to the problem of the mono- or polyphyletic origin of the chronetaceans.

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