Treść książki
Przejdź do opcji czytnikaPrzejdź do nawigacjiPrzejdź do informacjiPrzejdź do stopki
theory,thereconstructionofphylogenetictreesshouldbebasedonapomorphies
andshouldonlytakemonophyleticgroupsintoaccount,i.e.thosethathave
acommonancestor.
RotiferswereincludedintheobsoletephylumAschelminthesuntilthe1990s,
butnowtheyareclassifiedasanindependentphylum.TraditionallytheRotifera
comprisethreeclasses:theSeisonidea(bisexualectoparasites),Monogononta
(cyclicalparthenogenesisandsexualreproduction,withhaploidmales)and
Bdelloidea(onlyasexualreproduction,parthenogenetic).OriginallytheBdelloi-
deaandMonogonontawerelinkedtogetherinonegroup:Eurotatoria(mELONE
etal.1998).
WiththedevelopmentoftechniquesbasedonDNAanalysis,viewsonthepo-
sitionofrotifersinthephylogeneticanimaltreewerechanging.Originally,based
onmorphologicalcharacteristics(sperm,intracytoplasmiclamina),theRotifera
andAcanthocephalawereputtogetherinthecladeSyndermata(AHLRICHS1995a,
b;mELONEetal.1998;WALLACEetal.,2006).Otherstudiesindicatedhomology
betweenthejawsofrotifersandgnathostomulids(Ax1963andREISINGER1961).
YetotherresearcherslinkedtheRotifera,Gnathostomulida,Micrognathozoaand
Acanthocephalatogetherinoneclade:theGnathifera(AHLRICHS1995a,b,1997;
HASZPRUNAR1996a;mELONEetal.1998;KRISTENSENandFUNCH2000;SøRENSEN
2000;ZRZAVý2003).
ThephylogeneticpositionofGnathiferaintheMetazoawasstilluncertain
andnewstudiesquestionedthemonophylyofGnathifera(GIRIBETetal.2004;
FUNCHetal.2005).Analysesbasedpartlyorcompletelyonmoleculardataestab-
lishedthattheGnathiferacouldbeapolyphyleticgroup(LITTLEWOODetal.1998)
orparaphyleticwithreferencetoCycliophora,GastrotrichaorMyzostomida,
forexample(ZRZAVýetal.2001;GIRIBET2002).Manyresearchersconsiderthat,
basedonmorphologicalstructureaswellasmolecularstudies,theAcanthocepha-
lashouldbeseenasadvancedrotifers(GAREYetal.1996;AHLRICHS1997;GAREY
etal.1998;mARKWELCH2000;HERLYNetal.2003),andithasalsobeensuggest-
edthattheMicrognathozoa(KRISTENSENandFUNCH2000)areasistergroupto
theMonogononta(DESmET2002).
Studiesofthegenomesequence(18SrRNA)providedmolecularevidence
thattheAcanthocephalaandBdelloideaaresistergroups(GAREYetal.1996).
Broadergeneticstudiesconfirmedtheseresults(GARCIA-VARELAandNADLER
2006;WITEKetal.2008).
Currently,basedonphylogeneticstudies,rotifersareplacedinthephyloge-
neticanimaltreeinthecladePlatyzoatogetherwiththePlatyhelminthes,Gastro-
tricha,Gnathostomulida,MicrognathozoaandAcanthocephala.ThePlatyzoais
oneoftheSpiraliacladesintheMetazoa,Ecdysozoa,Protostomia(HEjNOLetal.
2009;forFONTANETO2014).Detailedconsiderationsonthephylogeneticposition
ofRotiferacanbefoundintheworksofFUSSmAN(2011)andFONTANETO(2014).
18
