Browsing by Author "Porley, Ron"
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- Climate-driven vicariance and long-distance dispersal explain the Rand Flora pattern in the liverwort Exormotheca pustulosa (Marchantiophyta)Publication . Rodrigues, Ana S. B.; Martins, Anabela; Garcia, César Augusto; Sérgio, Cecília; Porley, Ron; Fontinha, Susana; González-Mancebo, Juana M.; Gabriel, Rosalina; Phephu, Nonkululo; Van Roy, Jacques; Dirkse, Gerard; Long, David; Stech, Michael; Patiño, Jairo; Sim-Sim, ManuelaThe ‘Rand flora’ is a biogeographical disjunction which refers to plant lineages occurring at the margins of the African continent and neighbouring oceanic archipelagos. Here, we tested whether the phylogeographical pattern of Exormotheca pustulosa Mitt. was the result of vicariance induced by past climatic changes or the outcome of a series of recent long-distance dispersal events. Two chloroplast markers (rps4-trnF region and psbA-trnH spacer) and one nuclear marker (ITS2) were analysed. Phylogenetic and phylogeographical relationships were inferred as well as divergence time estimates and ancestral areas. Exormotheca possibly originated in Eastern Africa during the Late Oligocene/Early Miocene while Exormotheca putulosa diversified during the Late Miocene. Three main E. pustulosa groups were found: the northern Macaronesia/Western Mediterranean, the South Africa/Saint Helena and the Cape Verde groups. The major splits among these groups occurred during the Late Miocene/Pliocene; diversification was recent, dating back to the Pleistocene. Climate-driven vicariance and subsequent long-distance dispersal events may have shaped the current disjunct distribution of E. pustulosa that corresponds to the Rand Flora pattern. Colonization of Macaronesia seems to have occurred twice by two independent lineages. The evolutionary history of E. pustulosa populations of Cape Verde warrants further study.
- Observations on Riccia sorocarpa Bisch. subsp. erythrophora R.M.Schust. ex Konstant. & L.Söderstr. and its occurrence in Portugal and the AzoresPublication . Sérgio, Cecília; Gabriel, Rosalina; Sim-Sim, Manuela; Martins, Anabela; Porley, Ron; Garcia, César AugustoINTRODUCTION: Recent bryological research in Portugal has revealed the occurrence of a littleknown segregate of the Riccia sorocarpa group, representing the first record for mainland Portugal and the Azores of Riccia sorocarpa Bisch. subsp. erythrophora R.M.Schust. ex Konstant. & L.Söderstr. New data are presented on the taxonomy and phytogeography of this globally rare taxon. METHODS: A revision of approximately 200 samples of Riccia sorocarpa s.l. from selected Portuguese herbaria, together with some recent field collections, was carried out, based on the results of light and scanning electron microscopy. KEY RESULTS AND CONCLUSIONS: Our findings confirm that Riccia sorocarpa subsp. erythrophora is a distinct subspecies, and show that morphological differences of the thallus, primarily the violet-red purple bases of the ventral scales, are the most important characters for its delimitation. Scanning electron micrographs of spores of this taxon are presented for the first time. Phytogeographically, our data significantly extend the known distribution of the subspecies.