Initial morphological diversity as a criterion in deciphering turbellarian phylogeny
✍ Scribed by Yu. V. Mamkaev
- Book ID
- 104622069
- Publisher
- Springer
- Year
- 1986
- Tongue
- English
- Weight
- 213 KB
- Volume
- 132
- Category
- Article
- ISSN
- 1573-5141
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✦ Synopsis
The most profound structural variety in morphofunctional systems and morphogenetic mechanisms, i .e. the highest morphological diversity, is observed in those groups where these systems and mechanisms are evolutionarily most primitive . Here, such variety can involve the basic body plan of a given phylum and the types of morphogenesis characteristic of it . This correlation provides a new criterion of evolutionary primitiveness, namely, the criterion of initial morphological diversity .
The highest morphological diversity among turbellarian groups is observed in the order Acoela . Acoel turbellarians are archaic in most of their features, apparently being a group near the base of the turbellarian phylogenetic tree. Among other turbellarians there are a few groups that also are archaic in some few features (above all, the Catenulida), although on the whole they are more advanced than the Acoela . The Turbellaria as a whole is notable for its morphological diversity in comparison with other classes of the Scolecida .