Chromsome polymorphism and complements in populations of Girardia species (Platyhelminths
, Tricladida, Paludicola) from southern Brazil.
Analyses of DNA sequences in the protein's codifying and non-codifying regions, have been largely used in phylogenetic studies on fish helminths parasites (Clark, 2006), with special reference to investigations on the three main Platyhelminthes
groups: Cestoda, Digenea and Monogenea.
However, there have been debates on the ultrastructural criteria of glial cells in the nervous system of the platyhelminths
, flatworms (Radojcic & Pentreath, 1979; Biserova, 2008), although the functional significance of glial cells in a way similar to that in verterbrates has been well stated in the nematode, next higher phylum to the platyhelminths
, represented by C.
Uniciliated, non-ciliated and various other types of presumed sensory receptors have been described on the body surface and haptor of monogeneans and other Platyhelminthes
Overall results showed that annelids, arthropods, nematodes, and platyhelminthes
were the most abundant taxa throughout the dataset; however, community composition showed spatial and temporal variation throughout the year (Fig.
Cestodes, a class of the phylum Platyhelminths
, are tapeworms which are flat and ribbon like.
Monogenean parasites are platyhelminths
with a direct life cycle.
Hermaphroditism is prevalent in the phylum Platyhelminthes
. Among parasitic platyhelminths
(Trematoda and Cestoda) both cross- and self-insemination have been reported (Nollen 1983), but the question of the mating system of natural populations has hardly been addressed.
Molluscs belong to the superphylum Lophotrochozoa that also includes annelids, platyhelminths
, and a range of other phyla members (Graham 2000).
A summary of the database pertaining to the phylogeny of the major groups of the parasitic platyhelminths
, with a revised classification.
Terrestrial mollusks, arthropods, and vertebrates are tolerant of desiccation and therefore are more fully terrestrial than are cryptozoic taxa such as platyhelminths
, nemerteans, annelids, and onychophorans (Little 1983).
However, many examples of reciprocal endocrine interactions between parasites and hosts have been found in insects, arthropods, and mammals, and also in parasitic platyhelminths
. For example, the platyhelminth
tapeworm Taenia crassiceps affects the serum concentration of steroid hormones and the reproductive behavior of its male mouse host (Romano et al., 2003).
, primarily represented by Digenea (flukes), were the most prevalent helminths found.
- Patterns of parasite morphological diversification were investigated using a morphological data base for the parasitic platyhelminths
comprising 1,459 characters analyzed using phylogenetic systematic methods.
The relationships among the lophotrochozoan taxa are still somewhat poorly resolved (Dunn et al., 2008; Paps et al., 2009), but the core group (lophotrochozoan sensu stricto of Paps et al., 2009) includes molluscs, annelids, nemertines, the lophophorates, platyhelminths
, and other smaller phyla).