Morphological variation in Echinorhynchus truttae Schrank, 1788 and the E. bothniensis Zdzitowiecki & Valtonen, 1987 species complex from freshwater fishes of northern Europe

Sexual dimorphism in Echinorhynchus truttae revealed by principal component analysis of morphometric and meristic variables for 53 females and 25 males. The first (PC1) and second (PC2) principal components account for 36% and 24% of the variation in the data, respectively. Analysis based on data in Suppl. materials 1, 2

Scatterplot of the loadings for PC1 and PC2. Key: BL, body length; BW, body width; PL, proboscis length; PW, proboscis width; PRL, proboscis receptacle length; PRW, proboscis receptacle width; LL, lemniscus length; LW, lemniscus width; HKL, maximum hook blade length; NROWS, number of longitudinal rows of hooks; HKSROW, maximum number of hooks per longitudinal row.