World Congress of Malacology Antwerp ... - Unitas Malacologica

genetic data. The resulting diversity and phylogeography for both groups of terrestrial mollusc can be
linked to major geological vicariance event in the Miocene and Pliocene. Also, the phylogenetic tree
showed that a number of endemic species on Mount Kinabalu are remnants during the Pleistocene
climate fluctuation.
Occurrence of Retinella (Lyrodiscus) in Quaternary west-european sequences: taxonomical
status and palaeoclimatic implication
Limondin-Lozouet, Nicole
Laboratoire de Géographie Physique, 1 Pl. A. Briand, 92195 Meudon cedex France,
Email: limondin@cnrs-bellevue.fr
Recent studies undertaken at several sites in the Somme and the Seine valleys (Northern France)
together with revision of ancient collections have provided new data on occurrences of the genus
Retinella (Lyrodiscus) within Pleistocene interglacial deposits.
This new material has led to a revision of first the taxonomic status and second the
palaeoenvironmental and climatic significance of the genus in a Quaternary perspective.
Taxonomic reassessment of the species shows that Retinella (Lyrodiscus) skertchlyi Kerney 1976 is a
junior synonym of Retinella (Lyrodiscus) elephantium (Bourguignat, 1869) and that at least two
extinct species of R. (Lyrodiscus) are known in Western Europe during the Quaternary.
Occurrences of Retinella (Lyrodiscus) within interglacial deposits are discussed using records of
different temperate periods at different European locations, mainly British, German and Deutsch
sites. Until now the genus does not appear after the Holsteinian. Within MIS 11 north-west European
tufa deposits the species belongs to a peculiar assemblage representative of humid forest biotopes
developed under fully temperate conditions. However R. (Lyrodiscus) might also appear in silt
sequences, associated with species representative of more open environments which induce a
different palaeoenvironmental significance. Variations of shell morphology, morphostratigraphical
context and malacological assemblages are discussed at a west-european scale.
Reproduction, ecology and evolution of the Indo-Pacific limpet
Scutellastra flexuosa (Quoy & Gaimard, 1834)
Lindberg, David R.
Department of Integrative Biology & Museum of PaleontologyUniversity of California, Berkeley,
CA 94720-3140, USA,
Email: drl@Berkeley.Edu
The patellogastropod Scutellastra flexuosa was studied at Temae islet reef on Moorea, Society
Islands, French Polynesia between 1998 and 2001 to compare and contrast the respective roles of
deep phyletic history with recent adaptations in shaping its current ecological and life history
characteristics. Most of the characters examined are consistent with related specialist species and are
therefore determined by ancestry. These characteristics include habitat restriction, algal gardening,
local distribution, home site fidelity, adult/juvenile differentiation and protandric hermaphroditism.
The only character that appears autapomorphic and a possible adaptation to its proximal setting is its
small body size. Large body size is often associated with species that maintain and defend territories.
However, the variance in size in clades with and without territorial species presents a more complex
picture. The putative size reduction of S. flexuosa has not affected many of the specialized traits
shared within its lineage and it remains a classic territorial taxon albeit in miniature. The phyletic
pattern that emerges here is one of a clade dominated by specialist species that gave rise to generalist
species that in turn gave rise to another group of specialists with identical traits albeit in different
habitats.
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