Lophozia svalbardensis (Lophoziaceae) in continental North America, Greenland and Siberia, its identity, variation, and differentiation

Lophozia excisa var. succulenta (≡ Lophoziopsis excisa var. succulenta) is a synonym of Lophozia svalbardensis. This conclusion is based on morphological investigation and a subsequent molecular-genetic study which revealed an absence of variability amon nucleotide sequences of ITS1-2 nrDNA and trnL-F cpDNA in specimens from Arctic Alaska, west Siberian Arctic and Svalbard. Lophozia svalbardensis is reported for the first time for continental North America, Greenland and Siberia based on revised data on the distribution of Lophozia excisa var. succulenta. An expanded description of Lophozia svalbardensis, its variation, differentiation and photomicrographs of specimens from the Seward and Gydanskiy peninsulas are provided. The variability of pigmentation pattern, cell walls, perianth structure and gemmae is described.

Methods
Representative specimens examined: Norway, Svalbard, Nordaustlandet, Gustav V Land, Murchisonfjorden, south– east slope on north–west coast of Nordvika Bay, 80°03′13″N, 18°48′26″E, 196 m a.s.l., bank of lake, rock field, on covered by bryophytes nonsorted circles among crushed rocks, 17 Aug 2007, Konstantinova N.A. & A.N. Savchenko K135-3-07 (isotype of L. svalbardensis, LE); Denmark, West Greenland, Agpat [Appat Island], R.M. Schuster & K. Damsholt 66-1465 (C, paratype of L. excisa var. succulenta); Russia, West Siberia, Yamal Peninsula, Neromoyakha watershed slope, on bare soil among Solarina crocea, 20 Jul 1990, V. Golubkov (LE); GYDANSKIY PENINSULA, cotton grassdwarf shrub-moss tundra, 71.9082°N, 78.6625°E, on loamy wet soil, 2017, E. I. Troeva G2-4 (LE); USA, Alaska, Seward Peninsula, Southern Killeak Lake, lake shore, ca 66°20′N, 164°08′E, on bare ground, 24 Jul 1992, Potemkin 92-90-04 (LE).

To provide a molecular comparison with DNA data from the type specimen of L. svalbardensis (GenBank accession numbers MW298768 and MW297149) the ITS1-2 nrDNA and trnL-F cpDNA sequences were produced for the two abovecited specimens (Potemkin 92-90-04 from Alaska and Troeva G2-4 from Gydanskiy Peninsula). The procedures of DNA extraction and amplification followed protocols described in Konstantinova et al. (2020). Obtained sequences were assembled and aligned in BioEdit ver. 7.0.1 (Hall 1999). The molecular variability of the tested samples was evaluated as the value of p-distances for both ITS1-2 and trnL-F in Mega ver. 5.1 (Tamura et al. 2011).

Lophozia excisa var. succulenta（≡ Lophoziopsis excisa var. succulenta）为Lophozia svalbardensis的同物异名。该结论基于形态学调查与后续分子遗传学研究——研究显示，采自北极阿拉斯加、西西伯利亚北极区域及斯瓦尔巴群岛的标本，其ITS1-2 nrDNA（核核糖体DNA内转录间隔区1-2）与trnL-F cpDNA（叶绿体DNA trnL-F基因间隔区）的核苷酸序列无任何变异。

基于对Lophozia excisa var. succulenta分布的修订数据，Lophozia svalbardensis首次被报道见于北美大陆、格陵兰与西伯利亚。本研究对Lophozia svalbardensis进行了扩充描述，涵盖其变异特征、分化情况，并附采自苏厄德半岛与格达半岛标本的光学显微照片；同时详细描述了该物种的色素沉着模式、细胞壁、蒴萼结构及芽胞的变异情况。

## 材料与方法

### 供试代表性标本
本次检视的标本包括：
挪威，斯瓦尔巴群岛，东北地岛，古斯塔夫五世地，默奇森峡湾，诺德维卡湾西北岸东南坡，80°03′13″N，18°48′26″E，海拔196米，湖岸岩屑堆，生于碎石间被苔藓植物覆盖的非分选环中，2007年8月17日，Konstantinova N.A. 与 A.N. Savchenko K135-3-07（L. svalbardensis等模式标本，馆藏于LE标本馆）；
丹麦，西格陵兰，阿帕特岛（原标注Agpat），R.M. Schuster 与 K. Damsholt 66-1465（C标本馆馆藏，L. excisa var. succulenta副模式标本）；
俄罗斯，西西伯利亚，亚马尔半岛，涅罗莫亚哈流域坡面，生于Solarina crocea间的裸土中，1990年7月20日，V. Golubkov（LE馆藏）；
格达半岛，棉花草-矮灌丛-苔藓苔原，71.9082°N，78.6625°E，生于湿润壤土中，2017年，E. I. Troeva G2-4（LE馆藏）；
美国，阿拉斯加，苏厄德半岛，南基利亚克湖，湖岸，约66°20′N，164°08′E，生于裸地中，1992年7月24日，Potemkin 92-90-04（LE馆藏）。

为与L. svalbardensis模式标本的DNA数据（GenBank登录号MW298768与MW297149）开展分子比对，研究人员对上述两份标本（阿拉斯加的Potemkin 92-90-04与格达半岛的Troeva G2-4）进行了ITS1-2 nrDNA与trnL-F cpDNA序列扩增。DNA提取与扩增流程遵循Konstantinova等（2020）发表的实验方案。所得序列通过BioEdit v7.0.1（Hall 1999）完成组装与比对，随后采用Mega v5.1（Tamura等2011）计算ITS1-2与trnL-F区域的p距离，以评估供试样本的分子变异度。