Hypermorphosis

Hypermorphosis

 

(hyperspecialization), a type of phylogenetic development leading to disruption of the relationship of an organism to its environment as a result of hypertrophy of certain organs. Examples of hypermorphosis are the upper canine teeth of the fossil saber-toothed tiger (Machairodus), the horns of the giant reindeer, and the tusks of the contemporary boar (the babirusa). A frequent case of hypermorphosis is the general enlargement of body dimensions, resulting in disruption of the coordination of certain organs. Hypermorphosis indicates a lag in the evolution of the organism to adapt to changes in the conditions of its existence. When there is considerable manifestation of hypermorphosis, the consequence is extinction.

REFERENCE

Shmal’gauzen, I. I. Puti i zakonomernosti evoliutsionnogo prot-sessa. Moscow-Leningrad, 1940.
References in periodicals archive ?
Thus, it was suggested that populations of subalpine hay meadows are the peramorphic variants derived from populations of alpine grassland by predisplacement in vegetative gr owth and that populations of subalpine limestone grassland are peramorphic variants derived from populations of alpine grassland by hypermorphosis in vegetative growth.
Therefore, a joint effect of hypermorphosis, neoteny, and postdisplacement has resulted in the evolution of small homostylous flowers in A.
These mutants cause dramatic morphological changes by different types of heterochronic processes, including neoteny, progenesis, acceleration, and hypermorphosis.
Of the six pure classic heterochronic processes, we found neoteny (decreased developmental rate in descendant), progenesis (earlier offset), and acceleration (increased rate) to be more commonly reported than hypermorphosis (delayed offset) or predisplacement (earlier onset).
These do not represent dimensional allometry but may be the result of developmental hypermorphosis in which a developmental growth pattern is played out at the same rate (or rate of increase) over a lengthened period of time (either the entire lifespan or just the juvenile stage) (Gould, 1977).
predisplacement, postdisplacement, hypermorphosis, progenesis sensu McKinney & McNamara, 1991) cannot be ruled out.