Eurypterid trackways from the Table Mountain Group (Ordovician) of South Africa

Eurypterid trackways in paralic facies of the Graafwater and Peninsula Formations, lower Table Mountain Group (Ordovician) of the Western Cape Province, South Africa, are reviewed. The ichnotaxonomy of trackways preserved on the ‘Brandenburg slab’ from the Graafwater area is reassessed, with the recognition of two distinct forms: (1) Palmichnium capensis (Anderson, 1975), consisting of a series of four tracks, many accessory imprints and (usually) an intermittent bilobed medial impression; and (2) Petalichnus brandenburgensis isp. nov., a much narrower trackway with nine to ten tracks per series and no medial impression. Palmichnium capensis is interpreted as the locomotory trace of an onychopterellan eurypterid (Chelicerata: Eurypterida). Petalichnus brandenbergensis is provisionally ascribed to the Trilobita. The likely walking techniques employed by onychopterellan eurypterids are assessed from the revised ichnological evidence, comparisons with extant taxa and modelling procedures; subaqueous locomotion was achieved by a series of short hops across the substrate and on land these animals were slow-moving and cumbersome, employing an ungainly, undulatory gait.