The first sign of Surirella tientsinensis (Surirellaceae, Bacillariophyceae) spreading in the Carpathian region

Abstract

A characteristic, panduriform, large (ca 80 μm in length) diatom was sporadically detected in the Hungarian rivers in 2021 and 2022. Surirella tientsinensis Skvortzov emend. Liu was regarded as an Asian endemic species practically from its description until the second decade of the 21st century. Here we present the first Hungarian occurrence of the taxon from 2021, which is the second record for Europe, aft er the previously published Ukrainian data. In 2022 Surirella tientsinensis was detected from two other Hungarian river sampling localities. Due to the unmistakable outlook of the species, probably it is a new member of the Hungarian diatom flora, and its parallel occurrences in some localities within a short time, is noteworthy.