ibclogo XVI International Botanical Congess


Abstract Number: 2722
Session = 11.4.4


DIVERSIFICATION AND RELATIONSHIPS OF EXTANT HOMOSPOROUS LYCOPODS


Niklas Wikström* & Paul Kenrick*** Dep. of Botany, Stockholm university ** Dep. of Palaeontology, The Nat. Hist. Museum, London


Results from a series of phylogenetic analyses (rbcL, trnL-trnF intron/spacer sequences) of homosporous lycopods (Lycopodiaceae) imply that much extant species diversity in this ancient family originated recently. Biogeographic data in the diverse predominantly epiphytic Huperzia group indicate that most diversification postdates the Mid to Upper Cretaceous. Perhaps as much as 90-95% of all living Huperzia species are included in groups that have originated since the final rifting of S. America and Africa. In the ground-living strobilate groups relationships are less clear, but here there is also evidence of widespread Late Mesozoic and Cenozoic cladogenesis. These patterns are further corroborated by analyses of sequence data using nonparametric rate smoothing to estimate divergence times.


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