Footprints of the Komodo Monitor and the Trackways of Fossil Reptiles

Abstract

differs from the lateral arc of protraction in the forearm movement of crocodiles, whose manus prints are generally less distinct. The monitor's pes moves parasagittally, somewhat as in crocodiles. Tail marks were not conspicuous. The Komodo monitor tracks are similar in great detail to those of Triassic pseudosuchian thecodonts and (to a lesser extent) Early Jurassic crocodiles. Footprint faunas since the Upper Triassic are completely devoid of similar tracks. The similarities probably reflect retention in all these groups of a primitive reptilian locomotory pattern. Hence, the Komodo monitor tracks underscore the extent to which fossil footprints are classified by grade of organization and locomotion. Lacertilian tracks are uncommon in the fossil record. Similarities of Komodo monitor tracks to fossil footprints of nonlacertilians suggest that analysis of modern lacertilian footprints may provide insight into ontogenetic and functional differences underlying much of the basis of paleoichnologic taxonomy.