Trevor C Wilson

Integrative taxonomy resolves the cryptic and pseudo-cryptic Radula buccinifera complex (Porellales, Jungermanniopsida), including two reinstated and five new species

Abstract Molecular data from three chloroplast markers resolve individuals attributable to Radula buccinifera in six lineages belonging to two subgenera, indicating the species is polyphyletic as currently circumscribed. All lineages are morphologically diagnosable, but one pair exhibits such morphological overlap that they can be considered cryptic. Molecular and morphological data justify the re-instatement of a broadly circumscribed ecologically variable R. strangulata, of R. mittenii, and the description of five new species. Two species Radula mittenii Steph. and R. notabilis sp. nov. are endemic to the Wet Tropics Bioregion of north-east Queensland, suggesting high diversity and high endemism might characterise the bryoflora of this relatively isolated wet-tropical region. Radula demissa sp. nov. is endemic to southern temperate Australasia, and like R. strangulata occurs on both sides of the Tasman Sea. Radula imposita sp. nov. is a twig and leaf epiphyte found in association with waterways in New South Wales and Queensland. Another species, R. pugioniformis sp. nov., has been confused with Radula buccinifera but was not included in the molecular phylogeny. Morphological data suggest it may belong to subg. Odontoradula. Radula buccinifera is endemic to Australia including Western Australia and Tasmania, and to date is known from south of the Clarence River on the north coast of New South Wales. Nested within R. buccinifera is a morphologically distinct plant from Norfolk Island described as R. anisotoma sp. nov. Radula australiana is resolved as monophyletic, sister to a species occurring in east coast Australian rainforests, and nesting among the R. buccinifera lineages with strong support. The molecular phylogeny suggests several long-distance dispersal events may have occurred. These include two east-west dispersal events from New Zealand to Tasmania and south-east Australia in R. strangulata, one east-west dispersal event from Tasmania to Western Australia in R. buccinifera, and at least one west-east dispersal from Australia to New Zealand in R. australiana. Another west-east dispersal event from Australia to Norfolk Island may have led to the budding speciation of R. anisotoma. In contrast, Radula demissa is phylogeographically subdivided into strongly supported clades either side of the Tasman Sea, suggesting long distance dispersal is infrequent in this species.

Molecular phylogeny and systematics of Prostanthera (Lamiaceae)

Abstract. Prostanthera is the largest genus of Lamiaceae in Australia and was last comprehensively revised in 1870. To test the classification, and the homology of the morphological characters on which it is based, we analysed nuclear (ETS) and chloroplast (trnT–F and ndhF–rpl32) sequence data for 71 species of Westringieae (Lamiaceae) in separate and combined datasets by using maximum-parsimony and Bayesian-inference methods. Results supported the monophyly of the Westringieae, but indicated that Prostanthera is paraphyletic with respect to Wrixonia, requiring the latter to be synonymised with the former. Although combinations of datasets provided some degree of infrageneric resolution within Prostanthera sensu lato, none of its sections or series could be recovered unambiguously. Prostanthera section Prostanthera and P. section Klanderia (regarded as entomophilous and ornithophilous, respectively) did not form a sister relationship, and neither could be unequivocally resolved as monophyletic. However, all species of P. section Klanderia nested within P. section Prostanthera raising the possibility that P. section Prostanthera is paraphyletic. Similarly, the phylogeny of Prostanthera based on molecular data could not be reconciled with the morphological definition of the traditionally recognised series. We recommend abandoning Bentham’s series as a means of organising morphological variation within the genus, but acknowledge that it is premature to discard Bentham’s sections. The evolutionary and systematic implications of the lack of congruence between our molecular phylogeny and morphologically defined subgeneric taxa are discussed.

Great Expectations: Correlations between Pollinator Assemblages and Floral Characters in Lamiaceae

Premise of research. Pollination syndromes are used to infer pollinators from floral attributes when field observations of floral visitors are lacking. Such inferences are often found to be incorrect or too generalized. To investigate the relationship between pollinators and observable differences in a genus of Lamiaceae with flowers that appear ornithophilous and entomophilous, we experimentally quantified floral morphology and pollinator assemblages in a phylogenetic perspective. Methodology. Floral morphology was examined using multivariate analysis of geometric morphometrics (corolla shape described by landmarks), linear dimensions, and nonmetric attributes for 17 species of Prostanthera. Pollination effectiveness was determined through censuses of floral visitors and interactions by pollinators with flowers, and multivariate statistics were used to examine correspondence between these data and nonlandmark characters. Ancestral state reconstruction was performed using geometric morphometric data and a phylogenetic tree. Pivotal results. Three floral morphologies were identified in Prostanthera, each of which was associated with a unique pollinator assemblage and corroborated by our detailed field observations. A higher abundance of bees visited flowers with the ancestral (bee) floral type, which had a long corolla, porrect adaxial lobes, and long anther appendages. Visits by birds were more frequent to the derived bird floral type, characterized by red or green flowers with larger nectar volumes, longer and narrower corollas, and a reflexed abaxial lobe. Another derived lineage attracted a higher abundance of generalist flies and beetles (beetle+fly floral type). This lineage had flowers with a shorter corolla tube, reflexed adaxial lobes, and shorter anther appendages. Conclusions. When pollinator frequency was used as a proxy for pollinator effectiveness, the correspondence between the floral types and pollinator assemblages supported traditional concepts of bird and insect pollination syndromes. Intermediates between these floral types also corresponded with phylogenetic position and pollinator assemblage. Linear measurements of floral attributes were just as reliable as landmark data in predicting pollinator assemblages. By combining a molecular phylogeny with the above data, evidence indicated that the bird and beetle+fly floral types diversified from an ancestral bee floral type, demonstrating at least one evolutionary specialization for birds, as well as another shift toward a more generalized pollination syndrome. This combination of techniques presents a potential application with which to investigate the evolution of pollination.