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Species delimitation in recent New Zealand species radiations Heidi M. Meudt Museum of New Zealand Te Papa Tongarewa Wellington, New Zealand http://nzprn.otago.ac.nz/wiki/bin/view/NZPRN/WebHome
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Outline – NZ species delimitation Importance and challenges NZ overview – 20 largest genera Four examples Outlook OurisiaVeronicaPlantagoRanunculus
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Delimiting species boundaries Importance –Species are fundamental units for description –Understanding patterns & processes –Assisting effective management Challenges –Reproductive isolation not complete –Hybridisation & introgression –Polyploidy –Parallel evolution –Conflicts among operational criteria Veronica tetragona
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20 NZ genera with most native spp. 838 total species –from 14 families –43% NZ seed plant flora –26 – 122 species per genus (median = 37, mean = 42) 55% (11) with revisions since NZ Flora (1961) –Full (9), partial (2) –73% (8) with explicit criteria or concepts –Operational criteria Descriptive morphology, geography, cytology, ecology (11) Statistical morphological analyses (5) Others (1-5) (Wilton, unpubl., Landcare Research) (Meudt, unpubl.)
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Criteria (and concepts) in NZ Ranunculus (Fisher 1965) –“The only necessary characteristic of a species is that certain attributes should be discontinuous with those of other species… [R]eliable taxonomic distinctions are first applicable at the point where morphological overlaps cease.” Leptinella (Lloyd 1972) –“A combined biological plus morphological species concept has been used. Groups of populations which are reproductively isolated… have been given the status of taxonomic species if they are also morphologically distinguishable.” Epilobium (Raven & Raven 1976) –Species are “…morphologically and ecologically definable units that occupy large geographical areas… [and are] important genetic entities with definable physiological characteristics…” Veronica (Bayly & Kellow 2006) –Species are “…morphologically recognisable… distinct biological entities or lineages” with the underlying assumption that morphological differences “generally reflect underlying reproductive or evolutionary processes.” Ourisia, Plantago (Meudt et al. 2009, in review) –“Species are separately evolving lineages or metapopulations… This unified [species] concept allows the use of diverse lines of evidence to test species boundaries…” (incl. morphology, AFLPs, cytology, geography, ecology) [e.g., de Quieroz 1998, 2007]
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Criteria (and concepts) in NZ Ranunculus (Fisher 1965) –“The only necessary characteristic of a species is that certain attributes should be discontinuous with those of other species… [R]eliable taxonomic distinctions are first applicable at the point where morphological overlaps cease.” Leptinella (Lloyd 1972) –“A combined biological plus morphological species concept has been used. Groups of populations which are reproductively isolated… have been given the status of taxonomic species if they are also morphologically distinguishable.” Epilobium (Raven & Raven 1976) –Species are “…morphologically and ecologically definable units that occupy large geographical areas… [and are] important genetic entities with definable physiological characteristics…” Veronica (Bayly & Kellow 2006) –Species are “…morphologically recognisable… distinct biological entities or lineages” with the underlying assumption that morphological differences “generally reflect underlying reproductive or evolutionary processes.” Ourisia, Plantago (Meudt et al. 2009, in review) –“Species are separately evolving lineages or metapopulations… This unified [species] concept allows the use of diverse lines of evidence to test species boundaries…” (incl. morphology, AFLPs, cytology, geography, ecology) [e.g., de Quieroz 1998, 2007]
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Criteria (and concepts) in NZ Ranunculus (Fisher 1965) –“The only necessary characteristic of a species is that certain attributes should be discontinuous with those of other species… [R]eliable taxonomic distinctions are first applicable at the point where morphological overlaps cease.” Leptinella (Lloyd 1972) –“A combined biological plus morphological species concept has been used. Groups of populations which are reproductively isolated… have been given the status of taxonomic species if they are also morphologically distinguishable.” Epilobium (Raven & Raven 1976) –Species are “…morphologically and ecologically definable units that occupy large geographical areas… [and are] important genetic entities with definable physiological characteristics…” Veronica (Bayly & Kellow 2006) –Species are “…morphologically recognisable… distinct biological entities or lineages” with the underlying assumption that morphological differences “generally reflect underlying reproductive or evolutionary processes.” Ourisia, Plantago (Meudt et al. 2009, in review) –“Species are separately evolving lineages or metapopulations… This unified [species] concept allows the use of diverse lines of evidence to test species boundaries…” (incl. morphology, AFLPs, cytology, geography, ecology) [e.g., de Quieroz 1998, 2007]
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Ourisia P LANTAGINACEAE Operational criteria Descriptive morphology, geography & ecology AFLPs congruent (Cytology uninformative; 2n = 48) Species limits 13 NZ species, 2 with subspecies Evidence for hybridisation cpDNA geographically structured May explain unresolved backbone of AFLP phylogeny Meudt 2006; Meudt & Simpson 2006, 2007; Meudt et al. 2009, in prog.
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Veronica cushions P LANTAGINACEAE V. thomsonii V. myosotoides V. chionohebe Meudt 2008, Meudt & Bayly 2008; leaf illustrations by Bobbi Angell. V. ciliolata subsp. ciliolata V. pulvinaris V. ciliolata subsp. fiordensis Distance 0.1 AFLP NJ Jaccard (TREECON) tree - 158 indiv Operational criteria Morphology analyses & geography (Cytology uninformative; 2n = 42) (Alpine ecology similar: “snow hebes”) AFLPs congruent or uninformative Species limits 4 cushion species V. ciliolata with 2 subspecies V. chionohebe = morph, ecol, geog distinct from V. thomsonii V. myosotoides ≠ ecol, geog distinct (morph intermediate)
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P. lanigera group 2n=12, 24 P. lanigera P. novae-zelandiae P. raoulli group 2n=48, 96 P. raoulli P. sp. nov. P. picta P. spathulata P. triantha 2n=12 P. aucklandica 2n=? P. obconica 2n=12 P. triandra group 2n=48, 60, 72 P. unibracteata P. triandra MP tree - 77 indiv, 1443 chars – losses favoured 4:1 (Meudt 2011) AFLPs triandra + masoniae unibracteata picta spathulata sp. nov. raoulli NTSYS – SAHN UPGMA clustering - 178 indiv, 56 chars - Gower’s dis. matrix (Meudt in review) morphology obconica triantha aucklandica lanigera + novae-zelandiae Plantago P LANTAGINACEAE
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Plantago P LANTAGINACEAE P. lanigera (2n=12, 24) P. novae-zelandiae (2n=24) P. unibracteata (2n=60) P. unibracteata (2n=72) P. triandra (2n=48) Operational criteria Morphology analyses, cytology (Geography, habitats similar) AFLPs & molecular cytogenetics congruent or uninformative/complex Species limits 4 species in this group No evidence for P. triandra subspp. Chromosome races ≠ ecol, morph, geog distinct in P. lanigera, P. unibracteata P. unibracteata is allopolyploid with complex, multiple origins NTSYS – MDS ordination, 69 indiv, 49 chars - Gower’s dis. matrix (Meudt in review)
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cpDNA JSAnrDNA ITS R. insignis 2n=48 R. nivicola 2n=96 R. verticillatus 2n=48 Ranunculus R ANUNCULACEAE (Carter, Lockhart et al. in prep.)
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(Lehnebach, Lockhart et al. in prep.) 1mm 100μm 1mm Ranunculus R ANUNCULACEAE Operational criteria Morphological data – multivariate analyses Geography – weak correlation of latitude & morphology DNA sequences – congruent or uninformative (0 – 2 mutations per lineage) Species limits 3 species – R. monroi, R. lobulatus, R. insignis Recognition – floral, leaf, stem characters Contact zones – hybridisation & introgression R. monroi R. lobulatus R. insignis Undet. Ranunculus insignis
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Conclusions and outlook NZ species delimitation –Downstream effects in research & conservation –Common concepts & criteria –Data congruence (e.g., Ourisia, Veronica) –Challenges underscore evolutionary processes (e.g., Plantago, Ranunculus) Future developments –More comprehensive treatments (e.g., Myosotis, Aciphylla) –Justification of species limits –Testing limits with new methods –Review & comparative studies
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Acknowledgements NZPRN colleagues Ilse Breitwieser & fellow symposium speakers Richard Carter & Carlos Lehnebach for sharing slides of unpublished Ranunculus data Phil Garnock-Jones for photos http://nzprn.otago.ac.nz/wiki/bin/view/NZPRN/WebHome
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