The cuticle of lithobiomorph centipedes (Chilopoda, Lithobiomorpha) offers a special opportunity for studying cellular processes of morphogenesis during postembryonic growth. The present paper shows that in lithobiomorph centipedes the polygonal surface pattern of the cuticle can record the geometry of the external face of hypodermal cells at the stage of deposition of the very first layers of the cuticle (epicuticle). Based on this hypodermis-to-cuticle correspondence, cuticular patterns are used to study the hypodermal behaviour during growth of an area of the cephalic shield. Growth is isometric and intercalary and mitosis is the fundamental cellular process responsible for its realization, but adjustments of cell size and shape are also extensively involved in the global control of sclerite form. The observed spatial distribution of mitoses is evaluated against the statistics predicted by a null model of random distribution. The observed growth patterns show a character of local randomness, but some constraints at the level of the whole sclerite seem to be at work. No effect of lateral inhibition is observed.
Cellular processes in the growth of lithobiomorph centipedes (Chilopoda: Lithobiomorpha). A cuticular view
FUSCO, GIUSEPPE;BRENA, CARLO;MINELLI, ALESSANDRO
2000
Abstract
The cuticle of lithobiomorph centipedes (Chilopoda, Lithobiomorpha) offers a special opportunity for studying cellular processes of morphogenesis during postembryonic growth. The present paper shows that in lithobiomorph centipedes the polygonal surface pattern of the cuticle can record the geometry of the external face of hypodermal cells at the stage of deposition of the very first layers of the cuticle (epicuticle). Based on this hypodermis-to-cuticle correspondence, cuticular patterns are used to study the hypodermal behaviour during growth of an area of the cephalic shield. Growth is isometric and intercalary and mitosis is the fundamental cellular process responsible for its realization, but adjustments of cell size and shape are also extensively involved in the global control of sclerite form. The observed spatial distribution of mitoses is evaluated against the statistics predicted by a null model of random distribution. The observed growth patterns show a character of local randomness, but some constraints at the level of the whole sclerite seem to be at work. No effect of lateral inhibition is observed.
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