Processes generating Diversity Patterns in Antarctic Shelf and Deep-Sea Shrimps (Crustacea: Decapoda: Caridea): Genetic and Morphometric Analyses combined with Enviromental Niche Models (ENMs)
Zusammenfassung der Projektergebnisse
In this study, it was planned to analyze the phylogeographic history, population structure, genetic/morphological variability and the distribution of the shallow-water shrimp Chorismus antarcticus and the deep-sea shrimp Nematocarcinus lanceopes in detail for the first time using a variety of different methods: a) mitochondrial and nuclear DNA sequences, b) microsatellites c) morphology/morphometric studies and d) Environmental Niche Models (ENMs). a) We assessed and evaluated the genetic structure of the decapod shrimps Chorismus antarcticus and Nematocarcinus lanceopes from various locations around Antarctica in order to test whether disruptive or unifying ecological and evolutionary forces affect both species’ gene pools. Based on three different gene fragments, we found no significant differentiation among populations or regions. However, we found signatures of a population expansion in the late Pleistocene hinting at an impact of large-scale glaciations in particular on the shallow water shrimp Chorismus antarcticus, supporting a (re)colonization and demographic expansion of this shrimp species in response to climate oscillation. b) Due to the fact that Antarctic shrimps do not represent typical model organisms of molecular and morphological studies, we faced various methodological and practical problems in the isolation of microsatellites, extending invested time and resources. Population genetic analyses are in progress, and a first summary of microsatellite loci for Nematocarcinus lanceopes will be published soon. c) As consequence of their storage and transport, many structures of our shrimps became damaged. Beside this, potential morphometric characters revealed high degrees of plasticity and a large intrapopulation variation and a strong overlapping among the studied populations, limiting the use of this approach for our analyzed specimens drastically. d) Our SDMs complete the so far only fragmented information about the potential distributions of Notocrangon antarcticus, Chorismus antarcticus and Nematocarcinus lanceopes around the Antarctic continent. In addition, modeling projections for the LGM clearly point at a bottleneck event affecting genetic diversity in shallow water shrimp species, according to our molecular data for Chorismus antarcticus, and a northward shift but less affected habitat for the deep-sea shrimp Nematocarcinus lanceopes. The models clearly display the complete width of their environmental niche of the species across the currently realized distribution on a broad scale.
Projektbezogene Publikationen (Auswahl)
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(2010). Bioclimatic Models as predictive GIS tools for the identification of potential refuges and possible migration pathways. In: Habel, J. C., Assmann, T. (eds.): Surviving on a Changing Climate - Phylogeography and Conservation of Relict Species. Springer Press. Pp. 373-384
Rödder, D., Dambach, J.
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(2010). Genetic homogeneity and circum-Antarctic distribution of two benthic shrimp species of the Southern Ocean, Chorismus antarcticus and Nematocarcinus lanceopes. Marine Biology 157, 1783- 1797
Raupach, M.J., Thatje, S., Dambach, J., Rehm, P., Misof, B., Leese, F.
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(2010). Parametric and non-parametric masking of randomness in sequence alignments can be improved and leads to better resolved trees. Frontiers in Zoology 7:10
Kück, P., Meusemann, K., Dambach, J., Thormann, B., von Reumont, B., Wägele, J.W., Misof, B.
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(2010). Roads, highways and trails to Antarctica: case studies of Crustaceans based on molecular markers. TERRA NOSTRA – Schriften der GeoUnion Alfred-Wegener-Stiftung 2010/5, 49-50
Raupach, M.J., Dambach, J., Leese, F.
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(2011). Applications and future challenges in marine species distribution modeling. Aquatic Conservation: Marine and Freshwater Ecosystems 21, 92-100
Dambach, J., Rödder, D.
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(2012). Effects of Late- Cenozoic glaciation on habitat availability in Antarctic benthic decapod crustaceans. PLoS ONE 7(9): e46283
Dambach, J., Thatje, S., Rödder, D., Basher, Z., Raupach, M.J.
