Quantification of intra-specific morphological variability of aquatic biota along environmental gradients can produce biological proxies that can be applied to paleoenvironmental reconstructions. This morphology-derived proxy information can be especially valuable when dealing with low-diversity fossil assemblages, i. e. in situations when paleoenvironmental inference based on species composition of the assemblage is less effective. We analyzed valve size and outline shape of the widespread and highly environmentally tolerant ostracode species Limnocythere inopinata collected in 15 lakes and ponds of Western Mongolia. We quantified shape variability among and within these living populations in relation to water chemistry and physical habitat variables. Our results indicate that: (1) a population's mean valve outline is related to habitat type, (2) surface water temperature, the alkalinity to sulphate ratio, specific conductance and total phosphorus together explain a high portion of the variance in mean valve outline between populations, and (3) a quantitative model inferring the alkalinity to sulphate ratio from mean valve outline has an R2 of 0.88 and RMSEP of 0.17. These results corroborate the hypothesis that high morphological variability in this ostracode species is due to both ecophenotypic variance and high clonal diversity associated with a mixed reproductive strategy (a combination of sexual and parthenogenetically reproducing lineages), and underline the value of morphometric techniques in paleoecology.
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Acknowledgments We thank Y. Khand (Mongolian Academy of Sciences) and S.N. Soninkhishig (National University of Mongolia) for invaluable support during fieldwork and J.E. Almendinger for assembling and processing the water chemistry data. Collection of the study material was supported by the National Science Foundation (NSF) under grants DEB-0316503 to Mark Edlund and James E. Almendinger (Science Museum of Minnesota). Any opinions, findings and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of NSF. The research was funded by a PhD grant of the Institute for the Promotion of Innovation through Science and Technology in Flanders (IWT-Vlaanderen) to the first author. We also thank Mark Brenner, Finn Viehberg and one anonymous referee for helpful comments. This is contribution 10-06 of the Limnological Research Center of the University of Minnesota.
- Clonal ecology
- Ecophenotypic variation
- Morphometric techniques