Geometric morphometrics - a sensitive method to distinguish diatom morphospecies: a case study on the sympatric populations of Reimeria sinuata and Gomphonema tergestinum (Bacillariophyceae) from the River Becva, Czech Republic
Fránková, Markéta; Ková, Aloisie; PoulíNeustupa, Jiří; Pichrtová, Martina; Marvan, Petr
Conventional and geometric morphometric methods were applied on sympatric nature populations of two pennate diatom species Reimeria sinuata and Gomphonema tergestinum. Although both species differ in their autecology and distribution, they occurred at the same sites and exhibited high morphological variation. Typical representatives of Gomphonema tergestinum and Reimeria sinuata were accompanied by transitional types so that traditional identification of all specimens based on expert knowledge was not straightforward. Both investigated taxa overlapped in their cell length and breadth, thus these characteristics were not sufficient for discrimination between their local populations. On the other hand, landmark-based geometric morphometrics provided better discrimination of the species, correlating with their traditional taxonomic delimitation and type material. We used the relative warps analysis of Procrustes aligned data to illustrate structure of empirical morphospace formed by investigated diatoms. Apparent clustering of the objects into two species groups was demonstrated in natural populations, as well as in the dataset including the type material.