World Congress of Malacology Antwerp ... - Unitas Malacologica

passively dispersed into the Mediterranean by currents. C. richardi is known alive from other
Western Mediterranean sites and its status of permanent resident in the basin cannot be excluded.
A molecular phylogeny of heterodont bivalves (Bivalvia: Heterodonta): new analyses of 18S
rRNA and 28S rRNA genes
Taylor, John D.; Williams, Suzanne T.; Glover, Emily A.; Dyal, Patricia
Department of Zoology, The Natural History Museum, London SW7 5BD, UK,
Email: j.taylor@nhm.ac.uk
A new molecular phylogeny is presented for the highly diverse, bivalve subclass Heterodonta. The
study, the most comprehensive for heterodonts to date, used new sequences of 18S rRNA and 28S
rRNA genes for 100 species from 49 family groups with species of Palaeoheterodonta as outgroups.
Results confirm previous analyses that an Carditidae/ Astartidae/ Crassatellidae clade is basal and
sister group to all other heterodonts including Anomalodesmata. Thyasiroidea occupy a near basal
position between the Crassatelloidea and Anomalodesmata. Lucinidae form a well-supported
monophyletic group distinct from Thyasiridae and Ungulinidae. The Solenoidea and Hiatelloidea link
as sister groups distant from the Tellinoidea and Myoidea respectively where they had been
previously associated. The position of the Gastrochaenidae is unstable but does not group with
myoideans. Species of four families of Galeommatoidea form a clade that also includes Sportellidae
of the Cyamioidea. The Cardioidea and Tellinoidea form highly supported, long-branched, individual
clades but group as sister taxa. A major clade including Veneroidea, Mactroidea, Myoidea and other
families is given the unranked name Neoheterodontei. There is no support for a separate order
Myoida. Dreissenidae group within the clade including Myidae, Corbulidae, Pholadidae and
Teredinidae. The Corbiculoidea is confirmed as polyphyletic with the Sphaeridae and Corbiculidae
forming separate clades within the Neoheterodontei. Hemidonacidae are unrelated to the Cardiidae
but nest within the Neoheterodontei. The Gaimardiidae group near to the Ungulinidae and not with
Cyamioidea. Ungulinidae form a well-supported clade within the Neoheterodontei. Monophyly of
Glossoidea, Arcticoidea and Veneroidea is unconfirmed. The fossil record of heterodonts indicates
that the basal clades of Crassatelloidea, Anomalodesmata and Lucinoidea diverged early in the Lower
Palaeozoic. Other groups such as the Hiatelloidea, Solenoidea, Gastrochaenidae probably originated
in the late Palaeozoic, while Cardioidea and Tellinoidea appeared in the Triassic and major groups of
Neoheterodontei radiated in the Late Mesozoic.
Morphology, ecology and species: diversification patterns in an ancient lake species flock of
Tylomelania (Cerithioidea: Pachychilidae) from Lake Mahalona, Sulawesi, Indonesia
Tenner, Silke; Glaubrecht, Matthias; von Rintelen, Thomas
Museum of Natural History, Humboldt University Berlin, Invalidenstrasse 43, 10115 Berlin,
Germany,
Email: silke.tenner@museum.hu-berlin.de
Ancient lakes are ideal model systems for the study of speciation and diversification processes in
general. The five lakes of the ancient Malili system on the Indonesian island Sulawesi harbour 25
species of the viviparous gastropod Tylomelania (Caenogastropoda: Cerithioidea: Pachychilidae),
which show a remarkable degree of inter- and intraspecific morphological differentiation. We here
focus on the seven sympatric species of Tylomelania in comparatively small Lake Mahalona, which
is situated between two major lakes.
Lake Mahalona species were initially delimited using shell and radula characters. All seven taxa have
characteristic shells, embryonic shells and radulae. In addition, all species show a clear substrate
preference, even though some taxa may occur on several substrates, such as rock and wood, or gravel
and mud. The correlation between radula form (i.e. trophic morphology) and substrate is less clear.
Species occurring almost exclusively on one substrate and showing no significant variation in their
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