Craticula buderi (Bacillariophyceae) in Poland

Craticula buderi (Hustedt) Lange-Bertalot was established by Hustedt in 1954 as Navicula buderi, after which this diatom was transferred to the genus Craticula by Lange-Bertalot (Rumrich et al. 2000). I found several specimens of C. buderi in the Chechło River in southern Poland during diatomological studies of this area. Craticula buderi is known from North America (USA; e.g., Bahls 2009), South America (Colombia; e.g., MontoyaMoreno et al. 2013), Australia (Queensland) and New Zealand (Bostock & Holland 2010), and the Middle East (Israel; Tsarenko et al. 2000). In the Arctic it is known from Ellesmere Island (Michelutti et al. 2013), and in Europe from Great Britain (Hartley et al. 1986), Germany (Hofmann et al. 2013) and Romania (Cărăuş 2012). This diatom is widespread in Central Europe, where it is known from water of high calcium content and moderate to higher electric conductivity, including saline water (Lange-Bertalot 2001; Bąk et al. 2012; Pliński & Witkowski 2013). Previously the species was reported only from two localities in northern and central Poland (Dziengo 2003; Żelazna-Wieczorek 2011; Fig. 1). There is little published data on the distribution of C. buderi in Poland. For the diatom names regarded as synonyms of Craticula buderi (Navicula pseudohalophila Cholnoky 1960, Navicula adsidua R. E. M. Archibald 1971) I found no information on their distribution in Poland. Other Navicula species similar to Craticula buderi [Navicula simplex Krasske, N. halophila (Grunow) Cleve] are known from Poland (Siemińska & Wołowski 2003). Navicula simplex Krasske is known from the Baltic coastal zone (Rumek 1948; Mańkowski & Rumek 1975; Ringer 1985), the Mazurian area (Chudyba 1979), the Vistula River near Warsaw (Wysocka 1952; Tyszka-Mackiewicz 1983) and a fish pond in Mydlniki near Kraków (Siemińska 1947). The last diatom that can be mistaken for Craticula buderi is Navicula halophila [= Craticula halophila (Grunow ex Van Heurck) Mann]. Craticula buderi was regarded as a synonym of Navicula halophila by Krammer and Lange-Bertalot (1986). Now these two species are treated as separate taxa, Craticula buderi and C. halophila, which differ considerably in valve shape and size (Lange-Bertalot 2001). Craticula halophila is well known from saline springs and waters of high to very high electrolyte content. This publication discusses the distribution of Craticula buderi in Poland and provides brief information about its morphological variability in LM and SEM, observed in the samples collected from the Chechło River.