Plastid DNA sequences and oospore characters of some European species ofTolypellasectionTolypella(Obtusifolia, Characeae) indicate a new crypticTolypellaspecies from the Mediterranean island Sardinia

Abstract

AbstractIn Europe, the genusTolypella(Characeae) comprises four to eightTolypellaspecies in sectionsRothiaandTolypellathat have been distinguished by vegetative morphology and gametangial characters such as antheridial size and oospore cell wall ornamentation. However, morphological species differentiation is difficult in some cases due to overlapping and variable vegetative features, which in many cases are difficult to observe clearly.To clarify the taxonomic status of the five European species ofTolypellain sectionTolypella, sequence data of the plastid genesatpB,rbcL andpsbC forTolypella glomerata(Desv.) Leonh.,Tolypella hispanicaAllen,Tolypella nidifica(O.F. Müll.) A. Braun,Tolypella normaniana(Nordst.) Nordst. andTolypella salinaCor. were combined with data on oospore morphology, including oospore wall ornamentation.Gene sequence data identified five distinct clusters, but they differed from the morphologically identified five species. ‘T. glomerata’ consisted of some of the samples morphologically identified asT. glomerataand seven samples ofT. normaniana, while the remainingT. glomeratasamples clustered with specimens of unclear affiliation (“Tolypella. sp.”). ‘T. hispanicaI’ consisted of samples from various locations, whereas “T.hispanicaII” consisted of samples ofT. hispanicafrom the Mediterranean island, Sardinia. The remaining cluster consisted of all the specimens that had been determined asT. salinaorT. nidificain addition to two specimens ofT. normaniana. Oospore morphology was most clearly distinguishable forT. glomerata. Oospore characteristics for all other taxa were not as informative but showed some geographical and/or environmentally influenced differences, especially forT. nidificaandT. salina.Our results suggest a significantly different taxonomy ofTolypellasect.Tolypellain which specimens normally identified asT. glomeratamight be two different species,T. glomerataand an unidentified species;T. nidificaandT. salinaare not separate species;T. normanianais a diminutive variant ofT. nidificaorT. salina; andT. hispanicacomprises two different species, one from the Mediterranean island Sardnia.