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Browsing by Author "Toonen, R. J."

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    Ecomorph or endangered coral? DNA and microstructure reveal Hawaiian species complexes: montipora dilatata/ flabellata/turgescens & M. patula/verrilli
    (2010) Forsman, Z. H.; Concepcion, G. T.; Haverkort, R. D.; Shaw, Ross; Maragos, J. E.; Toonen, R. J.
    M. dilatata, M. flabellata, and M. patula and 80 other scleractinian corals were petitioned to be listed under the US Endangered Species Act (ESA), which would have major conservation implications. One of the difficulties with this evaluation is that reproductive boundaries between morphologically defined coral species are often permeable, and morphology can be wildly variable. We examined genetic and morphological variation in Hawaiian Montipora with a suite of molecular markers (mitochondrial: COI, CR, Cyt-B, 16S, ATP6; nuclear: ATPsβ, ITS) and microscopic skeletal measurements. Mitochondrial markers and the ITS region revealed four distinct clades: I) M. patula/M. verrilli, II) M. cf. incrassata, III) M. capitata, IV) M. dilatata/M. flabellata/M. cf. turgescens. These clades are likely to occur outside of Hawai'i according to mitochondrial control region haplotypes from previous studies. The ATPsβ intron data showed a pattern often interpreted as resulting from hybridization and introgression; however, incomplete lineage sorting may be more likely since the multicopy nuclear ITS region was consistent with the mitochondrial data. Furthermore, principal components analysis (PCA) of skeletal microstructure was concordant with the mitochondrial clades, while nominal taxa overlapped. The size and shape of verrucae or papillae contributed most to identifying groups, while colony-level morphology was highly variable. It is not yet clear if these species complexes represent population-level variation or incipient speciation (CA<1MYA), two alternatives that have very different conservation implications. This study highlights the difficulty in understanding the scale of genetic and morphological variation that corresponds to species as opposed to population-level variation, information that is essential for conservation and for understanding coral biodiversity.
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    Is Montipora dilatata an endangered coral species or an ecotype? Genes and skeletal microstructure lump seven Hawaiian species into four groups
    (2010) Forsman, Z. H.; Concepcion, G. T.; Haverkort, R. D.; Shaw, Ross; Maragos, J. E.; Toonen, R. J.
    Montipora dilatata is considered to be one of the rarest corals known. Thought to be endemic to Hawaii, only a few colonies have ever been found despite extensive surveys. Endangered species status would have major conservation implications; however, coral species boundaries are poorly understood. In order to examine genetic and morphological variation in Hawaiian Montipora, a suite of molecular markers (mitochondrial: COI, CR, Cyt-B, 16S, ATP6; nuclear: ATPsβ, ITS), in addition to a suite of measurements on skeletal microstructure, were examined. The ITS region and mitochondrial markers revealed four distinct clades: I) M. patula/M. verilli, II) M. incrassata, III) M. capitata, IV) M. dilatata/M. flabellata/M. turgescens. The nuclear ATPsβ intron tree had several exceptions that are generally interpreted as resulting from recent hybridization between clades or incomplete lineage sorting. Since the multicopy nuclear ITS region was concordant with the mitochondrial data, incomplete lineage sorting of the ATPsβ intron is a more likely explanation. Principal components analysis (PCA) of microstructure measurements agreed with the genetic clades rather than the nominal taxa. These species groups therefore either represent recent or insipient (CA <1MYA) species or morphological variants of the same biological species. These clades are likely to occur outside of Hawaii according to mitochondrial control region haplotypes from previous studies. Common garden experiments were conducted on distinct morphotypes of M. capitata to test the hypothesis that micro-skeletal traits can be phenotypically plastic in this genus. Although the experiment suffered high mortality from parasitic flatworms, verrucae (rice-grain sized bumps) were documented to form on formerly smooth colonies, indicating plasticity. This study contributes towards understanding the relationship between genetic and morphological variation in this taxonomically challenging group, which is essential for effective conservation and the key to understanding the evolution and biodiversity of reef building corals.