Genetic diversity of minnows (Phoxinus spp.) in Germany and beyond

• Applicant: Dr. Madlen Stange
• Subject Area: Systematics and Morphology (Zoology) ; Evolution, Anthropology
• Term: since 2025
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 566161397

An estimated 90 % of the world's species are currently undescribed, with a significant proportion being cryptic species. These are genetically different but morphologically barely distinguishable species. Their identification is crucial for understanding life cycles, population dynamics, and their habitats. Cryptic species complicate biodiversity assessments and conservation measures, as the unknown can neither be counted nor protected. While biodiversity hotspots such as the neotropics are the focus of scientific attention, native cryptic species also deserve more attention. As part of the PhoxDiv project, we are focussing on the genetic diversity and distribution of fish called Eurasian minnows (Phoxinus spp.) in Germany and beyond. The genus Phoxinus contains numerous cryptic species that were only brought to light less than a decade ago with the help of single-gene analyses. Four minnow species are now recognized in Germany, one of which is listed as a national responsibility species in the German Red List. Due to their recent recognition as independent species, little is known about their exact distribution ranges and their precise genetic and morphological differentiations. The first objective of this study is to determine the population structure and geographical distribution of all Phoxinus species in Germany. In addition, the second objective is to analyse the distribution range of the national responsibility species P. morella beyond Germany. In the third objective, genomic analyses will be combined with morphological data to identify taxonomically and ecologically relevant morphological features. On this basis, a guide to species differentiation for laypersons will be developed. The methodology includes the collection of samples from new sites, which represent gaps so far, and collection material that represents the genome of P. morella; whole genome sequencing of the studied individuals to increase genetic markers for differentiation analyses; and morphological analyses using traditional and geometric morphometrics. The results will shed light on species boundaries, population structure and the impact of historical biogeographical processes on the distribution of minnows in Germany. The inclusion of morphological data will support taxonomic research and facilitate the development of effective conservation strategies.

• DFG Programme: Research Grants