Os Turbellaria...
Because of their postion among the simplest of metazoans, the “Turbellaria” have always received considerable attention concerning thier comparative morphology and systematics and the inter-relationship of these with their phylogeny or the evolution. However, may still represented a useful facies of a predominantly freeliving flatworm with a ciliated epidermis distinguishable from the similar Gnathostomulida by, among other things, the lack of a pair of jaws and base plate in the mouth.
Turbelarians are ubiquitous forms in freshwater and marine habitats; they are very associate with other organisms to various degrees (some are parasistic). About 2/3 are small (1 – 2 mm long or less), but osme, the marine polyclads and terrestrial triclads in particular, can grow to many centimeters in length. There are three main turbellarian life cycles types: univoltine, bivoltine, and polyvoltine. Among which have either continuous or discontinuous sexual maturity throughout the year. Univoltine and bivoltine life cycles are predominantly found in all other taxa. Turbellarians are very common on and in various benthic substrates (soft bottom, sandy bottom, calcareous bottom, gravel, mussel associations, vegetation) both intertidally and subtidally. Some turbellarians live in ground waters and caves in the stygobios.
Because of their postion among the simplest of metazoans, the “Turbellaria” have always received considerable attention concerning thier comparative morphology and systematics and the inter-relationship of these with their phylogeny or the evolution. However, may still represented a useful facies of a predominantly freeliving flatworm with a ciliated epidermis distinguishable from the similar Gnathostomulida by, among other things, the lack of a pair of jaws and base plate in the mouth.
Turbelarians are ubiquitous forms in freshwater and marine habitats; they are very associate with other organisms to various degrees (some are parasistic). About 2/3 are small (1 – 2 mm long or less), but osme, the marine polyclads and terrestrial triclads in particular, can grow to many centimeters in length. There are three main turbellarian life cycles types: univoltine, bivoltine, and polyvoltine. Among which have either continuous or discontinuous sexual maturity throughout the year. Univoltine and bivoltine life cycles are predominantly found in all other taxa. Turbellarians are very common on and in various benthic substrates (soft bottom, sandy bottom, calcareous bottom, gravel, mussel associations, vegetation) both intertidally and subtidally. Some turbellarians live in ground waters and caves in the stygobios.
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