Abstract
The central Indo-west Pacific biodiversity hotspot is of outstanding biological interest in terms of both taxonomy and ecology. However, the molluscan fauna of the region is poorly known. Here we present death assemblages of the subtidal (1–56 m) waters off Eastern Sumatra, Indonesia. Molluscan shells were sampled from a variety of settings from estuaries to coral reef-related carbonate environments. A total of 5064 shells was counted and 197 species were identified. Four shelly death assemblages which are defined by characteristic taxa are found in specific environments. A deposit-feeding community with low diversity and low abundances was recorded in settings with high amounts of terrigenous mud. Greater abundances and higher diversity were found farther offshore, especially in carbonate sediments in the vicinity of offshore islands where pteriomorphian bivalves are characteristic taxa. Protobranch bivalves, especially a species of Nuculana, appear to be best adapted to the organic-rich but food-limited, muddy substrate of the proximal marine environment influenced by peat-draining rivers. Thus, in addition to dominating deep-sea molluscan assemblages, some protobranch bivalves appear to be specialists in exploiting refractory organic materials of shelf environments.
Acknowledgements
We would like to sincerely thank the crews and participants of the MatahariKu cruises 2012 and 2013, as well as the colleagues of the BMBF-funded Science for the Protection of Indonesian Coastal Ecosystems (SPICE) programme for their support and discussions. We are particularly grateful to Francisca Wit (ZMT Bremen) and Dominik Kneer (AWI Sylt) for providing unpublished salinity and suspended matter concentration data. Mr Susilohadi (MGI Bandung) is acknowledged for kindly providing sampling equipment and Karin Boos (MARUM Bremen) for assisting with ‘R’. Thanks are due to Pierre Lozouet (Muséum National d'Histoire Naturelle, Paris) and John D. Taylor (The National History Museum, London) for sharing their expertise in molluscan taxonomy and ecology. We wish to thank two anonymous reviewers for constructive criticisms and Winston Ponder for editing corrections that greatly improved the manuscript. The research cruise was funded by the German Ministry of Research and Education (BMBF) under grants 03F0642A for the project CISKA within the frame of the German-Indonesian cooperation SPICE III. This study is part of K.W. Master Thesis (Wiemers Citation2013).