Phylogenetic relationships of conifers inferred from Partial 28S rRNA gene sequences

Abstract

The conifers, which traditionally comprise seven families, are the largest and most diverse group of living gymnosperms. Efforts to systematize this diversity without a cladistic phylogenetic framework have often resulted in the segregation of certain genera and/or families from the conifers. In order to understand better the relationships between the families, we performed cladistic analyses using a new data set obtained from 28S rRNA gene sequences. These analyses strongly support the monophyly of conifers including Taxaceae. Within the conifers, the Pinaceae are the first to diverge, being the sister group of the rest of conifers. A recently discovered Australian genus Wollemia is confirmed to be a natural member of the Araucariaceae. The Taxaceae are nested within the conifer clade, being the most closely related to the Cephalotaxaceae. The Taxodiaceae and Cupressaceae together form a monophyletic group. Sciadopitys should be considered as constituting a separate family. These relationships are consistent with previous cladistic analyses of morphological and molecular (18S rRNA, rbcL) data. Furthermore, the well-supported clade linking the Araucariaceae and Podocarpaceae, which has not been previously reported, suggests that the common ancestor of these families, both having the greatest diversity in the Southern Hemisphere, inhabited Gondwanaland.

Phylogenetic Analysis of Araucariaceae: Integrating Molecules, Morphology, and Fossils

“…The phylogenetic relationships among conifer families obtained in the simultaneous analysis and, in particular, the position of Araucariaceae as sister to Podocarpaceae are in agree- ment with previous phylogenetic hypotheses for the group (Chaw et al 1997;Stefanovic et al 1998;Bowe et al 2000;Magalló n and Sanderson 2002;Quinn et al 2002;Rai et al 2008;Leslie et al 2012) and also with the recently proposed classification of Christenhusz et al (2011), in which Araucariaceae and Podocarpaceae belong to the order Araucariales. Today, most of its diversity is restricted to the Southern Hemisphere.…”

“…In this case, as in all the remaining analyses performed, the searches were ended after consensus stabilization. We rooted the trees in the branch leading to Pinaceae because it has been repeatedly obtained as sister of the remaining extant conifer families (Chaw et al 1997;Stefanovic et al 1998;Bowe et al 2000;Quinn et al 2002). mation is also congruent with the combined analysis in terms of relationships within Araucariaceae ( fig.…”

“…Gilmore and Hill (1997), Kunzmann (2007), and Liu et al (2009) retrieved Wollemia as sister to Agathis, with Araucuaria at the base of this clade. This hypothesis is also supported by an analysis that included representatives of all living conifer families (Stefanovic et al 1998;Leslie et al 2012). On the other hand, Setoguchi et al (1998) obtained Wollemia as the sister group to a clade formed by Agathis and Araucaria.…”

Perspective: The Origin of Flowering Plants and Their Reproductive Biology?a Tale of Two Phylogenies

“…Obviously such studies say nothing directly about relationships of angiosperms to fossil taxa, but they do address the view that angiosperms are related to Gnetales. Only a few molecular analyses have linked angiosperms and Gnetales, and this with low statistical support (Hamby and Zimmer 1992, Stefanovic et al 1998, Rydin et al 2002. Some analyses have placed Gnetales at the base of seed plants (Hamby and Zimmer 1992, Albert et al 1994, Sanderson et al 2000, Rydin et al 2002, but tests using likelihood and other methods suggest that this arrangement is a result of long-branch attraction, particularly affecting third codon positions (Sanderson et al 2000, Magallón and Sanderson 2002, Rydin et al 2002, Burleigh and Mathews 2004.…”

A Dendroctonus bark engraving (Coleoptera: Scolytidae) from a middle Eocene Larix (Coniferales: Pinaceae): early or delayed colonization?

“…The insect responsible for this damage is an unidentifiable bark beetle within the modern genus Dendroctonus Erichson (Scolytidae), whose modern relatives are economically destructive species that occur on North American conifers (Anderson, 1960). Considerable progress relevant to this study has included advances in the systematics and phylogeny of the Pinaceae and its collateral and substituent lineages (Frankis, 1989;Farjon, 1990;Tsumura et al, 1995;Chaw et al, 1997;Xiao-Quan et al, 1997;Stefanovic et al, 1998), as well as an examination of the phylogeny and evolution of host-plant associations of the Scolytidae and the Pinaceae-feeding bark beetle, Dendroctonus, based on molecular systematic analyses (Kelley and Farrell, 1998;Sequeira, Normark, and Farrell, 2000). Given this background, the middle Eocene bark beetle gallery system described in this report provides relevant data for addressing four questions regarding the macroevolutionary history of the Pinaceae and one of their associated herbivore lineages.…”