World Congress of Malacology Antwerp ... - Unitas Malacologica

distant populations of the same morphotype again indicating that cohesion of morphotypes was
mainly due to selection. The actual distribution of morphotypes and haplotypes as well as the high
genetic diversity also suggested that the area provided refugia during the Pleistocene glaciations.
Molecular phylogeny and morphological evolution of pholadoidean boring bivalves (Bivalvia:
Myoida)
Haga, Takuma 1 ; Kase, Tomoki 2
1. Department of Biological Science, Graduate School of Sciences, The University of Tokyo, 7-3-1
Hongo, Bunkyo-ku, Tokyo 113-0033, Japan,
Email: haga@kahaku.go.jp
2. Department of Geology, National Museum of Nature and Sciences, 3-23-1 Hyakunin-cho,
Shinjuku-ku, Tokyo 169-0073, Japan,
Email: kase@kahaku.go.jp
The superfamily Pholadoidea consists of Pholadidae (piddocks) and Teredinidae (shipworms) with
over 150 modern species living in the deep sea to freshwater rivers. They have unique morphologies
adapted to mechanical boring into various substrata such as sand, mud, rocks and woods. A wellaccepted
hypothesis on the evolutionary pathway in Pholadoidea is that the sand- and mud-borers
were preceded by the wood- and rock-borers.
To test this hypothesis, we reconstructed a phylogeny of Pholadoidea based on sequence data from
four genes (complete 18S rRNA, partial Histone 3, 16S rRNA, and CO1) for 81 species from 26
genera as an ingroup. Phylogenetic trees were constructed using MP and Bayesian method with a
maximum 3,171 bp dataset, and then 60 morphological characters were parsimoniously mapped and
reconstructed on the cladogram to search synapomorphies.
Our result shows that Pholadidae, Xylophagainae, Jouannetiinae and Teredinidae are major clades
supported by strong statistical values, and that the wood- and rock-borers with anterior-boring
mechanism are ancestral while the sand- and mud-borers with ventral-boring mechanism are
derivative within the Pholadoidea, which clearly contradicts the previous hypothesis. Our molecular
study reveals interesting patterns of morphological evolution in the phylogeny of Pholadidae: the
more generalized soft-bottom infaunal mode of life (associated with simplified morphologies and
posterior elongation of valves observed in Pholadidae) among bivalves was derived from more
specialized rock- and wood-boring mode of life. The wood-boring Xylophagainae and Teredinidae,
which harbor associated bacteria for xylotrophy, are phylogenetically distant to each other, suggesting
that the associated bacteria was acquired independently in those groups. The Pholadoidea would have
gained high species diversity by exploiting various kinds of substrata through mechanical boring
rather than chemical boring.
Harmonic radar evidence for wind dispersal and homing capability in the tree snail genus
Achatinella (Pulmonata: Achatinellidae)
Hall, Kevin T. 1 ; Hadfield, Michael G. 2
1. University of Hawaii at Manoa, 2538 McCarthy Mall, EDM 152, Honolulu,
Hawaii, 96822, USA, Email: kthall@hawaii.edu
2. Kewalo Marine Laboratories, 41 Ahui Street, Honolulu, Hawaii, 96813, USA,
Email: hadfield@hawaii.edu
Conservation efforts for the endangered Achatinella tree snails, which are endemic to the island of
Oahu, Hawaii, will likely soon include translocations among the remaining wild and captive-bred
populations. Natural dispersal rates are being determined as part of optimizing this approach and will
be incorporated into models of population connectivity and gene flow. The first of three methods
used for observing dispersal was harmonic radar tracking, which yielded some surprising results in
addition to the intended short-term dispersal rates. Solely utilizing capture-mark-recapture (CMR)
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