Cryptic and not-so-cryptic species in sea cucumbers

François Michonneau

@FrancoisInvert

University of Florida &Florida Museum of Natural History

Sanciangco et al, 2013 doi:10.1371/journal.pone.0056245.g001

Sanciangco et al, 2013 doi:10.1371/journal.pone.0056245.g001

» Study of diversification

● Clear understanding of species limits● Comprehensive geographic sampling● Accurate estimation of the timing of events

» Study of diversification

● Clear understanding of species limits● Comprehensive geographic sampling● Accurate estimation of the timing of events

but...● Very limited fossil record● Morphology not always useful● Species distributions change through time

» Study of diversification

● Clear understanding of species limits● Comprehensive geographic sampling● Accurate estimation of the timing of events

but...● Multi-locus data● Statistical models

» General approach

● Species delineation● General Mixed Yule Coalescent● Multi-species coalescent (*BEAST)

● Timing of diversification● Time-calibrated phylogeny (BEAST)● Using closure of isthmus of Panama

» H. impatiens (Forsskål, 1775)

» H. impatiens (Forsskål, 1775)

"Of all holothurians, Holothuria impatiens is, I believe, the most perplexing to the systematist for it displays a diversity of color most unusual in a holothurian", Clark 1921

» Sampling

● Geographical sampling:● 220 individuals across range

» Sampling

● Geographical sampling:● 220 individuals across range

● Genetic sampling:● Mitochondrial 2487 bp● Nuclear:

– 1250 bp (protein, anonymous)– 2206 bp (ribosomal)

» Species delineation with GMYC

Time

» Species delineation with GMYC

Time

» Species delineation with GMYC

COI

» Species delineation with *BEAST

● Statistical model● Multi-species coalescent● Estimate demographic

parameters● Model comparison

● Bayes Factors● Path & stepping-stone

sampling● Test number of species

and assignment

» Species delineation with *BEAST

» Species delineation with *BEAST

» Species delineation with *BEAST

» Species delineation with *BEAST

» Species delineation with *BEAST

2 MY 0

» Rates of secondary sympatry● Turbinids

● 100% allopatry between sister ESUs (Meyer et al 2005)

● Cowries● 94% allopatry

between sister ESUs (Meyer & Paulay)

» Conclusions

● At least 12 species● Some can be told apart● Others cannot

● Recent radiation● Rapid secondary sympatry● Mechanisms?

● Better understanding of patterns of diversity

» Funding

● NSF● PEET● DDIG● ADBC (iDigBio)

● University of Florida

Questions?

@FrancoisInvert

francois.michonneau@gmail.com

Photos CC-BY available at:http://francoismichonneau.net/photos/