Ref ID : 7735
Anne Fleury and Ghislaine Fryd-Versavel; [Unite et Diversite chez les Hypotriches (Protozoaires Cilies) I. - Approche Morphogenetique par L'etude de Quelques Formes peu Differenciees]. Protistologica XX(4):525-546, 1984
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From morphological point of view, the occurrence of ventral cirri distinguishes Hypotrichs and Heterotrichs. From a morphogenetical point of view, Hypotrichs are traditionally characterized by a series of anlage positional particularities, which can define patterns (<< paysages >>); but the order can also be defined by a specific morphogenetical dynamics, involving systematic reshaping of a large cortical zone. We have morphogenetically studied four pooly differentiated species. Three of these four morphotypes, Plagiotoma lumbrici, Parastrongylidium martini n. g., n. sp., and Kahliella bacilliformis, reach the operating limits of Hypotrich morphological definition, since they possess a very low ventrodorsal differentiation. The morphogenetical study of these morphotypes shows that their morphogenetical patterns are not specific of Hypotrichs, but also shows that the morphogenetical sequences expressed by these morphotypes are typical of this Order. The fourth species, Hypotrichidium conicum, possesses a morphogenetical pattern and dynamics typical of Hypotrichs; the interest of this last morphotypes is the very strong differentiation of its caudal infraciliature, dorsal in origin, a character uncommon in Hypotrichs All these results suggest that the morphological differentiation of Hypotrichs can originate from many convergent evolutionary lines. Thus, we suggest that morphogenetical dynamics, constant in a given morphotype, is a better phylogenetic criterion than patterns, correlated to morphology. This hypothesis leads to a new rearrangement of the Hypotrich morphotypes.