Heterolepidoderma sinus, Kolicka, 2015

Kolicka, Małgorzata, 2019, From saline to salty? Heterolepidoderma sinus (Chaetonotida, Chaetonotidae) from subsaline coal mine settling ponds, Zootaxa 4559 (3), pp. 568-572 : 569

The presence of H. sinus

constitutes another issue. Despite the relatively good knowledge on Gastrotricha from Poland, this species has not been reported in fresh water habitats. The pond where H. sinus was recorded during the current study is at a distance of about 550 km from the type locality. It is possible that H. sinus has the ability to produce resting eggs, just as the freshwater representatives of Chaetonotida do. In this framework, the population we found in the pond results from resting eggs arrived by that are resistant to unfavourable environmental conditions passive dispersal e.g. by birds, surface runoff or wind (e.g. Kolicka et al. 2015). Conversely, H. sinus could have inhabited this particular pond, which is separated from neighbouring coal mine settling ponds belonging to the same drainage system. This is quite probable, as submerged macrophytes ( Ruppia maritima ) are present in an adjacent saline pond ( Halabowski et al. 2018). R. maritima is a very tolerant plant for various salinity ranges and is present mainly in marine and brackish, but also in freshwater habitats ( Sowa et al. 2018 and citation therein). It is a species that is commonly present in Puck Bay (Baltic Sea) (e.g. Węsławski et al. 2013), thus small invertebrate eggs such as those of gastrotrichs could easily have been brought to inland saline water together with these submerged macrophyte propagules, where they found favourable conditions for population development.