Integrative taxonomy

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Integrative taxonomy

• Gustav Paulay
• Florida Museum of Natural History
• University of Florida

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Integrative taxonomy

• Use of multiple lines of evidence
• Field - museum - lab
• Ecology - behavior - morphology - genetics -
  geography
• Distinguishing between morphs and species
• Two or more independent characters showing
  distinction between species

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Integrative taxonomy Actinopyga mauritiana -
guamensis
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Integrative taxonomy Actinopyga mauritiana -
guamensis
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Not seeing species where there are

• cukes vs. primates
• different foci for sensory perception
• unequal rates of evolution
• phenotype morphology, behavior, color pattern...
• genotype sequence divergence
• reproductive isolation

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Supposed distribution of Scutellastra flexuosa
and exusta
Powell, 1968
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but what is really going on...
NJ K2P COI
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Seeing species where there arent

• ecophenotypic variation
• ontogenetic variation
• geographic variation
• ecological variation - depth, habitat, etc
• polymorphism
• paralogous loci
• former divergence now united

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Paralogous locimitochondrial genes gone nuclear
in Alpheus
Williams Knowlton 2001 Mol Biol Evol
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Cypraea tigris a species differentiated, then
united
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ESU - reciprocal monophyly

• DNA - gene flow - BSC
• reciprocal monophyly implies lack of recent
  genetic connections
• need several samples of each form to test
• reliability of conclusion depends on depth of
  intra- vs. inter-specific variation
• in sympatry - separate biological species
• in allopatry - separate ESUs, species status
  subjective

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Basinal/subbasinal speciation common
Cypraea punctata complex

• perceived as other dominant mode of speciation by
  past studies
• predominant mode in Cypraeidae, Aspidochirotida,
  Diogenidae, Parribacus

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Where are the species limits?
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Lack of reciprocal monophyly

• morphs rather than species
• distinct species, but
• introgression
• insufficient time for sorting
• deep coalescent
• rapid speciation

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Introgression in Astralium
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Introgression in Bohadschia argus?

• Unusual form only in W Pacific never seen in
  Polynesia, etc.
• Need compare independent markers to test

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Insufficient time for sortingGene trees vs.
species treescoalescence theory
Avise 1999 Phylogeography
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Evolution of reproductive isolation

• Slow
• most gastropod
• deep divergence among allopatric ESUs
• clear reciprocal monophyly
• slow to secondary sympatry / biological species
• Rapid
• echinoids, holothuroids
• shallow divergence among sympatric species
• potential paraphyletic species
• rapid to secondary sympatry / biological species

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Astralium rhodostomum complex

1. Two deeply divergent clades A B sympatric on 8
   island groups
2. 30 ESUs so far
3. Pigmentation separates major and minor clades.

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Persistence of allopatry - Cypraeidae
94 divergences lt 10 Ma retain allopatry (115 of
122)
94 divergences lt 10 Ma retain signal (115 of 122)
Geographic signal
no signal
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Echinometra mathaei complex Rapid secondary
sympatryFacilitated by rapid evolution of
fertilization proteins?
1 Ma
COI
Bindin
Bindin
COI
Landry et al. 2003 Proc Roy Soc
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Cukes like urchins Actinopyga obesa complex
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Stichopus variegatus complex
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Advantages of sequence data

• Directly test genetic connections
• Very large number of characters
• Independent markers - independent sources
• Independent of morphology - so can trace
  evolution of form, etc on gene tree without
  circularity

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Potential problems with sequence data

• depth of coalescent vs. interspecific divergence
• paralogous sequences
• introgression
• selective sweeps
• homogenization through drift