Two aquatic moss species, Calliergon megalophyllum and Drepanocladus sordidus (Amblystegiaceae, Bryophyta), which had been considered extinct in the Czech Republic, were found in the Třeboň Basin, South Bohemia, in 2016–2017. They co-occurred in extensive reed- and sedge-dominated fen pools with humic water on the shore of an old fishpond and the former species was also discovered in a small humic pool in an old shallow sand-pit. The new Czech sites of these rare boreal species represent one of the southernmost known outposts within their entire European range. Previously, the two species were only known from single records in the Czech Republic from the late 19th and early 20th centuries. To confirm our morphological observations, we used phylogenetic analyses of DNA sequence variation in four chloroplast loci (atpB-rbcL, trnL-trnF, rpl16, trnG) and one nuclear region, the internal transcribed spacers of ribosomal DNA (ITS). We found (1) monophyly of all Calliergon megalophyllum specimens tested; (2) based on chloroplast DNA sequences, monophyly among all Drepanocladus sordidus specimens and representatives of Pseudocalliergon turgescens and P. lycopodioides moss species; (3) based on nuclear ITS sequences, monophyly of all original D. sordidus specimens. These results corroborate morphological studies and thus confirm the existence of natural sites for the studied moss species in the Třeboň Basin, South Bohemia, Czech Republic.

中文翻译：

---

欢迎再次来到捷克！鉴于它们在欧洲的分布和栖息地的偏爱，南波希米亚的稀有北部苔藓Calliergon megalophyllum和Drepanocladus sordidus（Amblystegiaceae）。

2016-2017年，在南波西米亚的特里波ň盆地发现了两个水生苔藓物种，即大角羊Calliergon megalophyllum和Drepanocladus sordidus（Amblystegiaceae，苔藓植物）已灭绝。它们是在一个以芦苇和莎草为主导的广泛的芬池中共存的，在一个老鱼塘的岸边有腐殖质水，在一个旧的浅沙坑的一个小腐殖质池中也发现了前一种物种。这些罕见的北方物种的新的捷克遗址代表了整个欧洲范围内最南端的前哨基地之一。以前，这两个物种仅在19世纪末至20世纪初才从捷克共和国的单一记录中得知。为了证实我们的形态学观察，我们对四个叶绿体位点（atpB-rbcL，trnL-trnF，rpl16，trnG）和一个核区域，即核糖体DNA（ITS）的内部转录间隔子。我们发现（1）测试的所有Calliergon megalophyllum标本都是单生的；（2）根据叶绿体DNA序列，在所有Drepanocladus sordidus标本中以及假单胞假单胞菌（Pseudocalliergon turgescens）和苔藓假单胞菌（P. lycopodiodiodes moss）物种的代表中都是单生的；（3）基于所有原始D. sordidus标本的核ITS序列。这些结果证实了形态学研究，因此证实了捷克共和国南波西米亚特里博ň盆地中所研究的苔藓物种的自然地点的存在。在所有Drepanocladus sordidus标本中以及对Pseudocalliergon turgescens和P. lycopodioides moss种的代表中均属单生；（3）基于所有原始D. sordidus标本的核ITS序列。这些结果证实了形态学研究，因此证实了在捷克共和国南波希米亚州特热波ň盆地中所研究的苔藓物种存在自然地点。在所有Drepanocladus sordidus标本中以及对Pseudocalliergon turgescens和P. lycopodioides moss种的代表中均属单生；（3）基于所有原始D. sordidus标本的核ITS序列。这些结果证实了形态学研究，因此证实了捷克共和国南波西米亚特里博ň盆地中所研究的苔藓物种的自然地点的存在。