This type of trackway was originally based on large fossils from
Pennsylvanian strata of Nova Scotia, when Sir J. W. Dawson named it in 1873. Dawson proposed that
Diplichnites were produced by a fish “walking” in shallow water on pectoral or ventral fin spines. Previous to this he had suggested that a large
crustacean,
annelid worm or
myriapod (such as a
millipede) could have made them. Subsequent evidence has supported this earlier interpretation. The fossils on which this
ichnotaxon was based are now thought to be from giant myriapods, such as
Arthropleura. The Scottish
Diplichnites cuithensis could have been the result of a 1-meter-long
arthropleurid walking. In the decades following Dawson's work, the trackways of several other arthropods were also included within
Diplichnites – particularly,
trilobites, which are known from marine
Paleozoic deposits around the world. In addition, recent evidence indicates that some
Diplichnites trackways from certain
Cambrian intertidal and subaerial deposits of North America, especially the Potsdam and Elk Mound Groups, were produced by
euthycarcinoids. In that scenario, the
Diplichnites may have been undertracks that penetrated to the underlying layer of sediment, and the fossil trackways thus produced on the top surface (preserving the impression of the dragging tail) were
Protichnites. ==References==