Topic
Lomatia
About: Lomatia is a research topic. Over the lifetime, 27 publications have been published within this topic receiving 466 citations.
Papers
TL;DR: A well-corroborated cladograms are produced for the subtribe Embothriinae and its sister-taxon, Lomatia, which have almost identical distributions within eastern Australia and western South America and seem to be consistent with conventional geological theories.
Abstract: The Proteaceae are often said to be a 'relict Gondwanan group' because they are disjunctly distributed over several southern continental blocks. Such distributions are shown by 12 different taxa above species-level in the family, which is thus potentially useful in cladistic studies of Southern Hemisphere biogeography. We have produced well-corroborated cladograms for the subtribe Embothriinae and its sister-taxon, Lomatia. These taxa have almost identical distributions within eastern Australia and western South America. Distributions of most species of Embothriinae are relatively narrow and we have used them to define areas of endemism for analysis. We analysed the biogeographic relationships of these areas under Assumptions 1 and 2 of Nelson and Platnick and Assumption 0 of Zandee and Roos, using R.D.M. Page's program COMPONENT. When analysed separately, Embothriinae and Lomatia share no area-cladograms under any assumption. The similarity between the two suites of area-cladograms, obtained in turn under each assumption, was assessed in terms of the symmetric difference of triplets. Under Assumptions 0 and 2 at least, the similarity between area-cladograms of Lomatia and Ernbothriinae appeared higher than would be expected due to chance. We took this as a fair indication that the two groups share congruent area-patterns, which justified analysing them as a single group. When analysed as a whole, the {Lomatia + Ernbothriinae} clade yielded a single most parsimonious cladogram under the 'items of error' parsimony criterion (Assumption 1) and the same cladogram plus several others under the 'Wagner' parsimony criterion (Assumption 0). The single cladogram on which these analyses agree seems to be consistent with conventional geological theories, assuming a history of vicariance events caused by continental break-up and climatic change.
62 citations
TL;DR: The flora at Berwick Quarry contains species which are consistent with rainforest in the region, however, the flora is also notable for the presence of leaves of Eucalyptus, leaving little doubt that the flora represents a mixture of rainforest and open forest taxa.
Abstract: The Late Oligocene to possibly earliest Early Miocene Benvick Quany macrofossil flora was first described very early in this century by Henry Deane, but has since been largely ignored. Recent work at the quarry has led to major new collections and a reinvestigation of the flora. Seventeen taxa of macrofossils have been recovered, including Agathis, Dacrycarpus, four species of Lauraceae, Gymnostoma, Nothofagus, Eucalyptus, an indeterminate Myrtaceae and Proteaceae, three possible Cunoniaceae, and six unidentified taxa. Fagus maideni Deane is formally transferred to Nothofagus Blume. Nothofagus johnstoni Hill, Fagus luemanni Deane, and Atherosperma berwickense Deane, are considered to be junior synonyms of the species N. maideni (Deane) comb. nov. Only one of the seven fossil species of Eucalyptus established by Deane can be recognised in our material: E kitsoni Deane. His Lomatia species are probably Cunoniaceae. The Berwick Quarry flora contains species which are consistent with rainforest in the region, however, the flora is also notable for the presence of leaves of Eucalyptus, leaving little doubt that the flora at Berwick Quarry represents a mixture of rainforest and open forest taxa. The vegetation was probably a mosaic of open and closed forest, representing some of the earliest evidence for seasonality in Australia during the development of the modem flora. Palynological samples are dominated by Nothofagus subgenus Brassospora and Fuscospora.
55 citations
TL;DR: Lomatia shows evidence of both incomplete lineage sorting and extensive hybridization between co-occurring species and the Hunter River Valley is identified as the most important long-term biogeographic barrier for the genus in southeastern Australia.
Abstract: Premise of the study: The glacial cycles of the Quaternary did not impact Australia in the same way as Europe and North America. Here we investigate the history of population isolation, species differentiation, and hybridization in the southeastern Australian landscape, using fi ve species of Lomatia (Proteaceae). We use a chloroplast DNA phylogeography to assess chloroplast haplotype (chlorotype) sharing among these species and whether species with shared distributions have been affected by shared biogeographic barriers. Methods: We used six chloroplast DNA simple sequence repeats (cpSSR) across fi ve species of Lomatia, sampled across their entire distributional range in southeastern Australia. Resulting size data were combined, presented as a network, and visualized on a map. Biogeographical barriers were tested using AMOVA. To explore hypotheses of chlorotype origin, we converted the network into a cladogram and reconciled with all possible species trees using parsimony-based tree mapping. Key results: Some chlorotypes were shared across multiple species of Lomatia in the study, including between morphologically differentiated species. Chlorotypes were either widespread in distribution or geographically restricted to specifi c regions. Biogeographical structure was identifi ed across the range of Lomatia . The most parsimonious reconciled tree incorporated horizontal transfer of chlorotypes. Conclusions: Lomatia shows evidence of both incomplete lineage sorting and extensive hybridization between co-occurring species. Although the species in the study appear to have responded to a number of biogeographic barriers to varying degrees, our fi ndings identifi ed the Hunter River Valley as the most important long-term biogeographic barrier for the genus in southeastern Australia.
39 citations
TL;DR: Distinct parental habitats and phenotypes are expected to form barriers that contribute to the rapid reversion of hybrid populations to their parental character state, due to limited opportunities for hybrid/intermediate advantage.
36 citations
TL;DR: Cytological evolution and distribution of the Proteaceae have been discussed and a scheme representing possible chromosome number relationships drawn up.
Abstract: Chromosome numbers have been determined for 19 genera and 53 species of Proteaceae in Australia. The chromosomes are small in all genera except Persoonia n = 7, Placospermum n = 7 (Johnson and Briggs 1963) and Bellendena n = 5 (Venkata Rao 1957), which have chromosomes comparable in size with those in the Liliaceae and Ranunculaceae. In other Australian genera chromosome numbers range from n = 14 (Cenarrhenes, Macadamia, Xylornelum, Lambertia, Banksia, Dryandra), n = 13 (Isopogon, Petrophile, Stirlingia, Adenanthos), n = 11 (Conospermum, Telopea, Lomatia, Stenocarpus) to n = 10 (Symphionema, Grevillea, Hakea). There are no genera counted so far in Australia with n = 12, a number common to many South African Proteaceae. Only one example of intrageneric polyploidy in the family is reported, for Persoonia toru A. Cunn. n = 14 by Hair and Beuzenberg (1959), while Venkata Rao (1957) discovered one example of intrageneric difference in number in two species of Orites with n = 14, 15, but in all other members of the family investigated, the chromosome numbers are constant for all species of the one genus, indeed for all the genera in certain tribes, e.g. Banksieae. Cytological evolution and distribution of the family have been discussed and a scheme representing possible chromosome number relationships drawn up.
34 citations
Related Topics (5)
Performance Metrics
| Year | Papers |
|---|---|
| 2021 | 1 |
| 2020 | 1 |
| 2018 | 1 |
| 2015 | 1 |
| 2014 | 1 |
| 2013 | 2 |