Pauline Y. Ladiges

New Caledonia–Australian connections: biogeographic patterns and geology

A review is presented of current knowledge of the tectonic rifting of eastern Gondwana in the context of possible land continuity between Australia and New Caledonia and the dating of events. Comment is made on the level of endemicity of the modern-day biota of New Caledonia, with examples of phylogenetic analyses, biogeographic patterns and estimated divergence dates among particular taxa, including birds (kagu-sunbittern clade), Nothofagus and Myrtaceae. The geological history of the region is complex but there is evidence of land persisting into the Cenozoic (Paleocene/Eocene) that possibly allowed old biota to persist. Vicariance explanations of divergences cannot be justifiably dismissed in favour of long-distance, over-water dispersal for such taxa.

A phylogenetic analysis of the Acacieae and Ingeae (Mimosoideae: Fabaceae) based on trnK, matK, psbA-trnH, and trnL/trnF sequence data

Abstract A phylogenetic analysis of exemplars of Acacieae, Ingeae, and some Mimoseae, based on trnK, matK, psbA-trnH, and trnL/trnF sequence data, is presented. The results support other recent studies in showing that neither the Ingeae nor Acacieae is monophyletic. Some subgenera of Acacia, specifically subgenera Acacia and Phyllodineae, are monophyletic, but subg. Acacia is in a basal polychotomy with various members of Mimoseae and a large clade with the other members of Ingeae and Acacieae. Acacia subg. Phyllodineae is sister group to members of the Ingeae. Both the Ingeae and Acacia subg. Aculeiferum are paraphyletic.

Gondwana, vicariance biogeography and the New York School revisited

The many methods of biogeographic analysis proposed in recent years generate artefactual results that impede understanding, discovery and progress. Eliminating geographic paralogy from data reduces or eliminates artefactual interpretation. Recent cladistic studies of extant Nothofagus agree in showing only three informative nodes relevant to intercontinental relationships. In cladistic representations of global distributions, Gondwana is at or near the base of the geographically informative nodes, which force Gondwana to appear as a centre of origin of modern life in general. Centres of origin are artefacts of comparison based on geographically uninformative and paralogous nodes. Postmodern revivals of dispersalism fail to acknowledge, explain, avoid, learn from and improve on the artefactual centres of origin of the 20th century dispersalism, as represented particularly by the New York School: W. D. Matthew (1871–1930), K. P. Schmidt (1890–1957), G. G. Simpson (1902–1984), P. J. Darlington, Jr (1904–1983) and G. S. Myers (1905–1985).

Acacia s.s. and its Relationship Among Tropical Legumes, Tribe Ingeae (Leguminosae: Mimosoideae)

Abstract To search for the sister taxon of Acacia s.s. (tribe Acacieae) and to further knowledge of the phylogeny of the related tribe Ingeae, we have sequenced two regions of nuclear ribosomal DNA (ITS and ETS). Sixty species from tribe Ingeae (26 genera), together with representatives from each of five lineages of tribe Acacieae, have been sampled. Ingeae and Acacia s.s. form a well supported clade, with a monophyletic Acacia s.s. nested within a paraphyletic Ingeae. Based on our sampling, the closest relative of Acacia s.s. is most likely one of the Australian species of the genus Paraserianthes s.l.: Paras. lophantha subsp. lophantha or Paras. toona. Related to Acacia s.s. and Paraserianthes s.l. is a group of Ingeae from Australia and South East Asia: Archidendron p.p., Archidendropsis, Pararchidendron, and Wallaceodendron. This study is a preliminary step in resolving the intergeneric relationships of tribe Ingeae. Genetic relationships within Ingeae appear to conform to morphological groups previously identified as genera and informal alliances; some notable exceptions are discussed.

Molecular phylogeny of Acacia subgenus Phyllodineae (Mimosoideae : Leguminosae) based on DNA sequences of the internal transcribed spacer region

The largest monophyletic group within Acacia is subgenus Phyllodineae, with more than 950 predominately Australian species, the majority characterised by adult foliage consisting of phyllodes. Molecular sequence data from the internal transcribed spacers (ITS) of the nuclear ribosomal DNA repeat were used to investigate the monophyly of seven sections within the subgenus. A nested PCR approach was used to amplify the ITS region. Fifty-one species representative of all sections were sequenced together with one outgroup taxon Lysiloma divaricata (Ingeae). Phylogenetic parsimony analysis suggested that there are two main clades within Phyllodineae but that only one section, Lycopodiifoliae, is apparently monophyletic. In one of the main clades, Lycopodifoliae is related to some taxa in sections Alatae and Pulchellae and some members of section Phyllodineae. In the second main clade, sections Juliflorae, Plurinerves and Botrycephalae cluster with other members of section Phyllodineae. The two sections that are characterised by bipinnate foliage, Botrycephalae and Pulchellae, are nested within phyllodinous clades, indicating that at least two separate reversals to bipinnate leaves have occurred. Botrycephalae is paraphyletic with respect to taxa from section Phyllodineae that have single-nerved phyllodes and racemose inflorescences.

ETS sequences support the monophyly of the eucalypt genus Corymbia (Myrtaceae)

The generic classification of the eucalypts, especially recognition of the genus Corymbia, has been controversial. The phylogeny of Corymbia and related eucalypt groups was investigated using nuclear ETS sequences, and combined ETS and ITS sequences. Both the ETS and combined datasets support the monophyly of Corymbia. Three major eucalypt clades are confirmed: Corymbia + Angophora; Eucalyptus s.s.; and the Eucalyptopsis group. Within Corymbia, relationships are broadly consistent with phylogenies based on morphological and anatomical characters; sections Ochraria, Blakearia, and Politaria are all supported as monophyletic; sect. Rufaria is monophyletic with the inclusion of the monotypic sect. Apteria. Within Eucalyptus s.s., relationships are generally consistent with those shown by previous molecular studies. Within the Eucalyptopsis group, Allosyncarpia is sister to the clade Stockwellia + Eucalyptopsis. Relationships between the major eucalypt clades are equivocal, but combined analysis of ETS and ITS data shows Corymbia + Angophora as sister to Eucalyptus-the rainforest taxa of the Eucalyptopsis group being outside this clade. Patterns of relationship and distribution are consistent with differentiation of major lineages of Corymbia prior to the isolation of taxa (now relictual) in eastern and south-western Australia, arguably before the midMiocene.

Comment on a new classification of the eucalypts.

Brooker’s classification of the eucalypts, which combines Angophora, Corymbiaand Eucalyptus into one genus, is contrary to phylogenetic evidence based on eight different data sets including morphology, RFLPs, and sequence data for various regions of nuclear and chloroplast DNA (5S rDNA spacer region, ITS1, ITS2, trnL intron, trnL-F spacer and psbA-trnH spacer). On this evidence and the principle of recognising monophyletic taxa, we reject his synonymy of these genera.

Microsatellites retain phylogenetic signals across genera in eucalypts (Myrtaceae)

The utility of microsatellites (SSRs) in reconstructing phylogenies is largely confined to studies below the genus level, due to the potential of homoplasy resulting from allele size range constraints and poor SSR transferability among divergent taxa. The eucalypt genus Corymbia has been shown to be monophyletic using morphological characters, however, analyses of intergenic spacer sequences have resulted in contradictory hypotheses- showing the genus as either equivocal or paraphyletic. To assess SSR utility in higher order phylogeny in the family Myrtaceae, phylogenetic relationships of the bloodwood eucalypts Corymbia and related genera were investigated using eight polymorphic SSRs. Repeat size variation using the average square and Neis distance were congruent and showed Corymbia to be a monophyletic group, supporting morphological characters and a recent combination of the internal and external transcribed spacers dataset. SSRs are selectively neutral and provide data at multiple genomic regions, thus may explain why SSRs retained informative phylogenetic signals despite deep divergences. We show that where the problems of size-range constraints, high mutation rates and size homoplasy are addressed, SSRs might resolve problematic phylogenies of taxa that have diverged for as long as three million generations or 30 million years.

Phylogeny, major clades and infrageneric classification of Corymbia (Myrtaceae), based on nuclear ribosomal DNA and morphology

Phylogenetic relationships of sections and species within Corymbia (Myrtaceae), the bloodwood eucalypts, were evaluated by using combined analyses of nuclear rDNA (ETS + ITS) and morphological characters. Combining morphological characters with molecular data provided resolution of relationships within Corymbia. The analyses supported the monophyly of the genus and recognition of the following two major clades, treated here as new subgenera: subgenus Corymbia, including informal sections recognised by Hill and Johnson (1995), namely Rufaria (red bloodwoods), Apteria and Fundoria; and subgenus Blakella, including sections Politaria (spotted gums), Cadagaria, Blakearia (paper-fruited bloodwoods or ghost gums) and Ochraria (yellow bloodwoods). Hill and Johnson’s section Rufaria is monophyletic if Apteria and Fundoria are included. It is evident that, among the red bloodwoods, series are not monophyletic and several morphological characters result from convergent evolution. There was strong morphological and molecular evidence that the three species of red bloodwoods that occur in south-western Western Australia (series Gummiferae: C. calophylla and C. haematoxylon, and series Ficifoliae: C. ficifolia) form a monophyletic group, separate from the eastern C. gummifera (series Gummiferae), which is probably sister to the clade of all other red bloodwoods. Phylogenetic results supported recognition of new taxonomic categories within Corymbia, and these are formalised here.

Molecular phylogeny and biogeography of Melaleuca, Callistemon and related genera (Myrtaceae)

To resolve the relationships of taxa within the Beaufortia suballiance (Myrtaceae), 72 ingroup taxa were analysed by parsimony methods and nrDNA sequence data from the 5S and ITS-1 ribosomal DNA spacer regions. Although basal nodes in the consensus tree (combined data set) are not supported by bootstrap or jackknife values, a number of clades are well supported, showing that Melaleuca is polyphyletic. Monophyletic groups include: endemic species of Melaleuca from New Caledonia (including species of Callistemon recently transferred to Melaleuca); the tropical Melaleuca leucadendra group; Australian species of Callistemon, which relate to species of Melaleuca predominantly from the South-East; and a group of south-western and eastern Australian melaleucas that relate to a clade of three south-western genera, Eremaea, Conothamnus and Phymatocarpus. Calothamnus, Regeliaand Beaufortiamay also relate to this latter group. Lamarchea is possibly related to northern melaleucas. The results have implications for generic revisions of the large genus Melaleuca. Biogeographic subtree analysis, based only on supported nodes of the taxon cladogram, showed New Caledonia, New Guinea, Eastern Queensland and the Northern Desert unresolved at the base of the area cladogram. The position of some of these areas is likely to be artifactual, but New Caledonia is interpreted as in the correct position. At a higher node, the monsoonal northern areas of Australia (Kimberley, Arnhem and Cape York), Atherton, the Pilbara and Western Desert relate to the southern regions, which form a group. The South-West of Australia is related to Eyre and Adelaide (designated area ‘South’) and Tasmania is related to the South-East and MacPherson–Macleay. The vicariance between northern and southern regions in Australia possibly relates to an early major climatic change (from the Early Tertiary). The biogeographic analysis helped illuminate taxon relationships.