Slenderneck beetle (Leptodirus hochenwartii Schmidt, 1832 is one of the iconic
subterranean animals. Nevertheless, the taxonomy of the species remains complex and
unresolved. Therefore, using classical and geometric morphometrics, we attempted to
identify morphological differences between six predefined phylogenetic groups of the
species. We conducted the analysis on 170 individuals from the entire species range. All
specimens were photographed under a stereomicroscope. These photographs served as
the basis for linear digital measurements, which were then used for analysis of variance
(ANOVA) and linear discriminant analysis (LDA). Through the latter, based on multiple
measurements we achieved a relatively high rate of correctly identified individuals.
Additionally, differences between groups were tested with geometric morphometry.
From the photographs, we obtained coordinates of the shape of pronotum and right
elytron and performed a Procrustes analysis on them. Using these data, we conducted
principal component analysis (PCA) and calculated the statistical significance of
differences between groups with multivariate analysis of variance (MANOVA).
Differences were detected both in the shape of the pronotum and the shape of the right
elytron with the pronotum shape proving to be much more informative in distinguishing
phylogenetic groups. Our results will serve as a basis for a taxonomic revision of the
genus Leptodirus, because they further confirm that the phylogeographic groups are
independent taxa at the species level.
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