plakodermic

Plakodermic is an adjective used in biology to describe organisms whose skin is covered by plate-like dermal armor—comprising interlocking plates formed within the dermis or mineralized sheets that create a protective covering.

Etymology: from Greek plakos meaning plate and derma meaning skin, with the suffix -ic. The term is a descriptive neologism rather than a formal taxonomic designation.

In paleontological literature, plakodermic features are often discussed in relation to armored jawed vertebrates. The most prominent examples are placoderms, an extinct class of Devonian fishes with extensive dermal plates forming head shields and trunk armor. The term emphasizes the morphology of the skin surface rather than the organism’s higher-level classification.

Relation to formal taxonomy: plakodermic describes armor morphology; Placodermi is the scientific name of a taxonomic group. While placoderms are classically described as having plakodermic armor, the adjective can also be used more broadly for any organism exhibiting plate-like dermal armor, including extinct or hypothetical forms. The term is most often encountered in descriptive anatomy or evolutionary morphology discussions rather than formal taxonomy.

See also: placoderms, dermal bone, armored vertebrates.