Autochthonous aquatic arthropods are only rarely found in the sediments of the Eocene Lake Messel. This has led to the assumption that certain abiotic conditions prevented a stable colonisation of aquatic groups. In recent years, the analysis of small fossil fish coprolites has shown that aquatic life was present in the former Lake Messel. A food web of different taxa of aquatic insect larvae and crustaceans was traced. Very abundant among the remains in the coprolites are larvae and pupae of phantom midges (Diptera: Chaoboridae). This article focuses on the survey of identified remains of immature chaoborids in the coprolites. In addition, it gives an outline of the major role that large populations of phantom midges can play in the pelagic ecosystem of a lake. Chaoborids are important both as prey for planktivorous fish and as predators of the smaller zooplankton. Via comparison with extant meromictic lakes, one can infer that the older phantom midge larvae displayed a vertical diurnal migration behaviour. They probably remained during the day within the anoxic water layers of the monimolimnion of the former Lake Messel to minimise the effect of predation by planktivorous fish. Lakes with large chaoborid populations are known to exist since the Jurassic.

To cite this paper: Wedmann, S. & Richter, G. 2007. The ecological role of immature phantom midges (Diptera: Chaoboridae) in the Eocene Lake Messel, Germany. In: Brothers, D.J. & Mostovski, M.B., eds, Congress Proceedings Fossils X 3, Pretoria, South Africa, 7-11 February 2005. Pietermaritzburg: Natal Museum, pp. 59-70.
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Wedmann, S. & Richter, G. 2007. The ecological role of immature phantom midges (Diptera: Chaoboridae) in the Eocene Lake Messel, Germany. African Invertebrates 48 (1): 59-70.