American Journal of Botany, Vol 84, 1137, Copyright © 1997 by Botanical Society of America, Inc.

SYSTEMATICS

Systematics of Nothofagus (Nothofagaceae) based on rDNA spacer sequences (ITS): taxonomic congruence with morphology and plastid sequences

PS Manos

Phylogenetic relationships were examined within the southern beech family Nothofagaceae using 22 species representing the four currently recognized subgenera and related outgroups. Nuclear ribosomal DNA sequences encoding the 5.8s rRNA and two flanking internal transcribed spacers (ITS) provided 95 phylogenetically informative nucleotide sites from a single alignment of ~588 bases per species. Parsimony analysis of this variation produced two equally parsimonious trees supporting four monophyletic groups, which correspond to groups designated by pollen type. These topologies were compared to trees from reanalyses of previously reported rbcL sequences and a modified morphological data set. Results from parsimony analysis of the three data sets were highly congruent, with topological differences restricted to the placement of a few terminal taxa. Combined analysis of molecular and morphological data produced six equally parsimonious trees. The consensus of these trees suggests two basal clades within Nothofagus. Within the larger of the two clades, tropical Nothofagus (subgenus Brassospora) of New Guinea and New Caledonia are strongly supported as sister to cool-temperate species of South America (subgenus Nothofagus). Most of the morphological apomorphies of the cupule, fruit, and pollen of Nothofagus are distributed within this larger clade. An area cladogram based on the consensus of combined data supports three trans-Antarctic relationships, two within pollen groups and one between pollen groups. Fossil data support continuous ancestral distributions for all four pollen groups prior to continental drift; therefore, vicariance adequately explains two of these disjunctions. Extinction of trans-Antarctic sister taxa within formerly widespread pollen groups explains the third disjunction; this results in a biogeographic pattern indicative of phylogenetic relationship not vicariance. For the biogeographically informative vicariant clades, area relationships based on total evidence support the recently advanced hypothesis that New Zealand and Australia share a unique common ancestry. Contrary to previous thought, the distribution of extant Nothofagus is informative on the area relationships of the Southern Hemisphere, once precise phylogenetic relationships are placed in the context of fossil data.

This article has been cited by other articles:

				J. G. Puntieri, J. E. Grosfeld, M. Stecconi, C. Brion, and D. Barthelemy Bud and growth-unit structure in seedlings and saplings of Nothofagus alpina (Nothofagaceae) Am. J. Botany, August 1, 2007; 94(8): 1382 - 1390. [Abstract] [Full Text] [PDF]

				C. Torres-Diaz, E. Ruiz, F. Gonzalez, G. Fuentes, and L. A. Cavieres Genetic Diversity in Nothofagus alessandrii (Fagaceae), an Endangered Endemic Tree Species of the Coastal Maulino Forest of Central Chile Ann. Bot., July 1, 2007; 100(1): 75 - 82. [Abstract] [Full Text] [PDF]

				S. Wright, J. Keeling, and L. Gillman The road from Santa Rosalia: A faster tempo of evolution in tropical climates PNAS, May 16, 2006; 103(20): 7718 - 7722. [Abstract] [Full Text] [PDF]

				I. Poole and D. J. Cantrill Cretaceous and Cenozoic vegetation of Antarctica integrating the fossil wood record Geological Society, London, Special Publications, January 1, 2006; 258(1): 63 - 81. [Abstract] [PDF]

				I. V. Bartish, U. Swenson, J. Munzinger, and A. A. Anderberg Phylogenetic relationships among New Caledonian Sapotaceae (Ericales): molecular evidence for generic polyphyly and repeated dispersal Am. J. Botany, April 1, 2005; 92(4): 667 - 673. [Abstract] [Full Text] [PDF]

				M. STECCONI, P. MARCHELLI, J. PUNTIERI, P. PICCA, and L. GALLO Natural Hybridization between a Deciduous (Nothofagus antarctica, Nothofagaceae) and an Evergreen (N. dombeyi) Forest Tree Species: Evidence from Morphological and Isoenzymatic Traits Ann. Bot., December 1, 2004; 94(6): 775 - 786. [Abstract] [Full Text] [PDF]

				D. A. Baum, S. DeWitt Smith, A. Yen, W. S. Alverson, R. Nyffeler, B. A. Whitlock, and R. L. Oldham Phylogenetic relationships of Malvatheca (Bombacoideae and Malvoideae; Malvaceae sensu lato) as inferred from plastid DNA sequences Am. J. Botany, November 1, 2004; 91(11): 1863 - 1871. [Abstract] [Full Text] [PDF]

				J. G. PUNTIERI, D. BARTHELEMY, C. MAZZINI, and C. BRION Periods of Organogenesis in Shoots of Nothofagus dombeyi (Mirb.) Oersted (Nothofagaceae) Ann. Bot., January 1, 2002; 89(1): 115 - 124. [Abstract] [Full Text] [PDF]

				M. A. Jaramillo and P. S. Manos Phylogeny and patterns of floral diversity in the genus Piper (Piperaceae) Am. J. Botany, April 1, 2001; 88(4): 706 - 716. [Abstract] [Full Text]

				G. D. Weiblen Phylogenetic relationships of functionally dioecious FICUS (Moraceae) based on ribosomal DNA sequences and morphology Am. J. Botany, September 1, 2000; 87(9): 1342 - 1357. [Abstract] [Full Text]

				Z.-D. Chen, S. R Manchester, and H.-Y. Sun Phylogeny and evolution of the Betulaceae as inferred from DNA sequences, morphology, and paleobotany Am. J. Botany, August 1, 1999; 86(8): 1168 - 1181. [Abstract] [Full Text] [PDF]