PHYLUM ROTIFERA
2001; Elsevier BV; Linguagem: Inglês
10.1016/b978-012690647-9/50009-0
AutoresRobert L. Wallace, Terry W. Snell,
Tópico(s)Isotope Analysis in Ecology
ResumoThe phylum Rotifera or Rotatoria comprises of approximately 2000 species of unsegmented, bilaterally symmetrical, pseudocoelomates, possessing two distinctive features. First, at the apical end (head), there is a ciliated region called the corona, which is used in locomotion and food gathering. In adults of some forms, ciliation is lacking and the corona is a funnel or bowl shaped structure, at the bottom of which is the mouth. Second, a muscular pharynx, the mastax, possessing a complex set of hard jaws called trophi, is present in all rotifers. Although rotifers are often confused with ciliated protozoans and gastrotrichs by beginning students, those organisms do not possess trophi and their ciliation is not distributed in the same way as in rotifers. Collectively, this phylum is widely distributed; it is found in all freshwater habitats at densities generally ranging up to about 1,000 individuals/L. However, rotifers occasionally become abundant if sufficient food is available. In general, rotifers are not as diverse or as abundant in marine environments as micro crustaceans, but they occur in many near shore marine communities and occasionally comprise the dominant portion of the biomass.
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