Aberlemnia caledonica gen. et comb. nov., a new name for Cooksonia caledonica Edwards 1970

Cooksonia caledonica Edwards 1970 is a small Early Devonian plant, which presents some usual plesiomorphic characters for polysporangiophytes: isotomously branched axes, terminal sporangia. The plant was placed in the genus Cooksonia Lang 1937 on the basis of the “wider than high sporangium” character. The type material has been examined and is re-described. New large specimens, recently found in the Jackson de Figueiredo flora from the Paraná Basin, Brazil, are also studied. The sporangium of C. caledonica is bivalved and possesses a complex subdistal structure for dehiscence. It is different from that of the type species, C. pertoni Lang 1937, which is trumpet-shaped. The morphology of its sporangium clearly excludes the species C. caledonica from the genus Cooksonia. The sporangia of C. caledonica are comparable to those of Sporathylacium salopense Edwards et al. 2001a, which show the same organization. According to the ICBN, conspecificity of the two taxa cannot be established as they do not refer to the same biological structures. A new genus, Aberlemnia, is therefore erected for the plants formerly named C. caledonica.