TROPIDOLEPTIDA (BRACHIOPODA) DEVONIAN HOPEFUL MONSTERS OR MISPLACED ORPHANS

The phylogenetic placement of Tropidoleptus a common and distinctive genus of articulated brachiopod has proved difficult Tropidoleptus has, for example been related to orthides, strophomenides and terebratulides In the first edition of the Treatise, the genus was assigned to the Entele toidea largely on the basis of its general shape and the pres ence of punctation The cyrtomatodont dentition, however and complex cardinalia with crurae, apophyses and a median septum are more typical of some of the more unusual rhynchonellides for example the Uncinuloidea and more specifically the Eatonudae A punctate shell condition, none theless has not been reported in that group It is argued that Tropidoleptus, although It shares many of its features with a number of rhynchonellate orders, has characteristic and unique features justifying the elevation of the Tropidolepti dae to ordinal status and cladistic analysis places the new order in a basil position within the Rhynchonellata stem group.