In actinopterygian fishes, there are three configurations of tegument: the naked body, without ossified structures on the skin, scales and bony plates. The rarer configuration of tegument in teleosts is the dermal plate, composed of interlocked ossifications that gives a great degree of body protection in exchange of flexibility. An unusual type of dermal plate is found in syngnathids, in which the whole body is encased in interlocking bony rings. Each bony ring articulates with its horizontally adjacent rings through the main keel of each bony plate, and each bony ring is formed by the connection of the bony plates with its vertically adjacent plates by interlocking secondary keels. Those structures are one of the most important taxonomic features of the family, with characters such as number of rings, configuration of bony rings, presence of scutella and other characters used to separate different genera and species within the Syngnathidae. Combining information from taxonomic descriptions found in the literature with a detailed study of cleared and stained bony rings, we discovered an outstanding diversity in size, shape and configuration of the main and secondary keels, with ornamentation of bony plates unique to each taxa, with those patterns being found also on the surface of other bones throughout the skeleton.These characters will be incorporated in an ongoing phylogenetic work based on morphology of syngnathids.