ISSN 1346-7565 Acta Phytotax. Geobot. 68 (3): 145–174 (2017) doi:10.18942/apg.201706 Systematic Study of the Yakushimabryum and Related Genera in the Pylaisiadelphaceae (Bryophyta) HIROYUKI AKIYAMA Museum of Nature and Human Activities, Hyogo / Institute of Environmental Sciences, University of Hyogo, Yayoigaoka-6, Sanda, Hyogo 669-1546, Japan. *[email protected] Phylogenetic relationships among the members of the epiphytic genus Yakushimabryum H. Akiyama et al. and related genera (Pylaisiadelphaceae) were studied using cpDNA (rbcL, rps4, and trnL-F) gene se- quences as well as morphological features. Present analyses (1) suggested the presence of three clades in the Pylaisiadelphaceae and Sematophyllaceae (Pylaisiadelphaceae s. str., Sematophyllaceae s. str. + Het- erophyllioideae, and Clastobryum), and (2) confirmed the distinctive generic status of Yakushimabryum from other members of the family. One new genus Orientobryum H. Akiyama and two new species O. ovalifolium H. Akiyama and Y. brevigemmium H. Akiyama were recognized and described. In addition, a close inter-relationship of Pseudotrismegistia undulata (Broth. & Yasuda) H. Akiyama & Tsubota and Heterophyllium amblystegum (Mitt.) J. Yu et al. (= Mastopoma subfiliferum Horik. & Ando) was con- firmed. Four new combinations, O. oligonema (Cardot & P. de la Varde) H. Akiyama (≡ Clastobryum oligonema Cardot & P. de la Varde), Y. subintegrum (P. Tixier) H. Akiyama (≡ Aptychella subintegra P. Tixier), Y. tonkinense (Broth.) H. Akiyama (≡ Clastobryum tonkinense Broth. & Paris), and Pseudotris- megistia amblystega (Mitt.) H. Akiyama (≡ Stereodon amblystegus Mitt.) were proposed. Key words: Clastobryum, Gammiella, Heterophyllioideae, Orientobryum oligonema, Orientobryum ovalifolia, Pseudotrismegistia amblystega, Yakushimabryum brevigemmium, Yakushimabryum subinte- grum, Yakushimabryum tonkinense Recent progress in molecular phylogeny has scarcely inflated, smaller alar cells often arranged shown its strength in revealing relationships and in a scalariform manner (except for Clasto- has given new insights into pleurocarpous bryo- bryum), the frequent presence of filamentous phyte systematics (Tsubota et al. 2000, 2001a, b, pseudoparaphyllia, and by non-collenchymatous 2002, Shaw et al. 2003, Ignatov et al. 2007, exothecial cells. Most of the members are epi- O'Brien 2007, Olsson et al. 2009, Merget & Wolf phytic and form small populations geographical- 2010, Ho et al. 2012, Huttunen et al. 2013, and ly distantly separated from each other. It is one of many others). As for the Hypnales, which in- the reasons why the family includes a number of cludes most species of pleurocarpous mosses, endangered species, for example, Aptychella ro- however, persuasive outcomes have been less busta (Broth.) M. Fleisch., Clastobryum glabres- successful because of little genetic differentiation cens (Z. Iwats.) B. C. Tan, Z. Iwats. & D. H. Nor- among species, genera, and even families. ris, and Gammiella ceylonensis (Broth.) B. C. Tan The Pylaisiadelphaceae are one of the mem- & W. R. Buck, in Japan (Ministry of the Environ- bers of the Hypnales. The family was first estab- ment 2015). Previous phylogenetic analyses based lished by Goffinet & Buck (2004), distinguishing on molecular markers (rps4 and nad5) suggested it from its close relative, Sematophyllaceae, by the non-monophyletic nature of the Pylaisiadel- 146 Acta Phytotax. Geobot. Vol. 68 phaceae (Cox et al. 2000). On the other hand, sev- Taxon sampling for molecular analyses eral genera of the family, such as Aptychella Most of the examined samples for DNA se- (Broth.) Herzog (Akiyama et al. 2015) and Taxi- quence analyses were extracted directly from thelium Spruce ex Mitt. (Câmara 2011), have been plants newly collected by me or in a few cases subjected to detailed molecular phylogenetic from recently (less than five years) collected her- analyses. barium specimens. Field studies, with permission The main objectives of this paper are (1) to ex- to make collections, were carried out at Doi In- amine the relationships among the members pre- thanon National Park in northern Thailand, Bi- viously classified in the Pylaisiadelphaceae and doup-Nui Ba National Park in southern Vietnam, Sematophyllaceae, and (2) to reveal the taxonom- Tam Dao National Park in northern Vietnam, the ic positions of Yakushimabryum longissimum H. Cameron Highlands, Genting Highlands, and Mt. Akiyama, Y. Chang, T. Yamag. & B.C. Tan (Aki- Kinabalu in Malaysia, Dongyan Shan in northern yama 2014, Akiyama et al. 2011) and Gammiella Taiwan, Syuejin and Dasyue Shan in central Tai- tonkinensis (Broth.) B. C. Tan & W. R. Buck (Tan wan, as well as several localities in southwestern & Buck 1989), along with a pendulous morph of Japan. the latter species formerly recognized as G. tou- The phylogenetic analyses were aimed at wii B. C. Tan (Tan 1990) in a broader perspective. determining the taxonomic positions of Yakushimabryum was first established by Akiya- Yakushimabryum longissimum and Gammiella ma et al. (2011). Suzuki et al. (2013) synonymized tonkinensis and their relationship to each other Y. longissimum, the sole species of the genus, un- and to previously described species, such as der Gammiella tonkinensis. Akiyama (2014) and Gammiella touwii B. C. Tan and Aptychella sub- Akiyama et al. (2015) disagreed with that conclu- integrum P. Tixier. Therefore, 14 populations of sion and provided additional evidence from ex- Y. longissimum s. lat. (including two of G. touwii ternal morphology and molecular phylogenic and two of A. subintegra) and 19 of Gammiella data to support the recognition of Yakushimabryum tonkinensis were included in the present study as a genus separate from Gammiella and Apty- (Appendix). In addition, a single specimen col- chella. Therefore, a larger scale analysis with ex- lected in northern Vietnam (as Y. brevigemmium tensive taxon sampling, mainly from the Pylaisi- in Figs. 1 & 2) was also included. Five species adelphaceae and Sematophyllaceae, was planned. from Aptychella were also included based on the In addition, I have recognized that some speci- results of Akiyama et al. (2015). Seven samples mens of Clastobryum species were misidentified of Clastobryum oligonema Cardot & P. de la Var- as Gammiella tonkinensis in the course of exami- de, which has been often confused with G. tonki- nation of a number of herbarium specimens. This nensis and synonymized under Aptychella tenui- is the reason for including Clastobryum oligone- ramea (Mitt) Tixier based on insufficient evi- ma in the analysis. dence (Tixier 1977), were also included in the analyses to determine the actual relationship to G. tonkinensis. Materials and Methods As in the case of Akiyama et al. (2015), I se- lected ingroup terminals from the members of the Sematophyllaceae in a broad sense, that is, Sema- Examination of herbarium specimens tophyllaceae s. str. and Pylaisiadelphaceae (Gof- A number of herbarium specimens, including finet et al. 2009). In addition, I included three types, which were used to fix nomenclatural is- species of Clastobryum Dozy & Molk., i.e., C. sues, were borrowed from the following herbaria; scalare (Müll. Hal.) Tixier (two samples), C. gla- BM, FH, H, HIRO, HYO, KYO, L, NICH, NY, brescens (Z. Iwats.) B. C. Tan, Z. Iwats. & D. H. PC, SING, SINU, and TNS. Norris, and C. spiculiferum (Dixon) B. C. Tan, Z. Iwats. & D. H. Norris in the present analyses. October 2017 AKIYAMA—Systematic Study of Yakushimabryum 147 They were included to better understand the rela- (T92+G+I), and rbcL (T93N+G+I; Tamura & Nei tionship of Clastobryum oligonema to Gammiel- 1993) datasets separately yielded no conflicting la tonkinensis; the latter was once recognized as branches with high bootstrap support or posterior a member of Clastobryum. In addition, Fauriella probabilities and thus combined data sets of all tenuis (Mitt.) Cardot was included since Li et al. three sequences were used for further analyses. (2014) revealed its affinity to the Pylaisiadelpha- There was no ambiguity in the alignment except ceae. As a result, I included a total of 20 genera for hyper variable sites of trnL-F, which were de- that have been recognized as members of the Py- leted and not used in the analyses. Gaps in the laisiadelphaceae and Sematophyllaceae. As for alignment were treated as missing data. the Pylaisiadelphaceae, 12 out of 15 genera previ- I performed Maximum Likelihood (ML) and ously recognized in the family (Goffinet et al. Maximum Parsimony (MP) analyses using 2009) were included in the present analyses. Cli- MEGA 7.0.21 (Kumar et al. 2016) with the option macium dendroides (Hedw.) F. Weber & D. Mohr of partial deletion (PD; site coverage cutoff 95%) (Climaciaceae) and Pleuroziopsis ruthenica for missing data, and Baysian (BI) analyses using (Weinm.) Kindb. ex E. Britton (Pleuroziopsiace- MrBayes ver. 3.2.2 (Ronquist & Huelsenbeck ae) were used as outgroup terminals (Cox et al. 2003). For MP analyses, I used default settings 2000). A total of 83 samples (22 genera and 43 with TBR branch-swapping with 1,000 random species) were used in the present analysis. Vouch- addition replicates. I used T92+G+I model in the er information for the newly registered acces- ML analysis, which were determined as the opti- sions in DDBJ are provided in the Appendix. mal model according to the Akaike's Information Criterion (AIC: Akaike 1973) as implemented in DNA extraction, amplification, and sequencing MEGA 7.0.21. I did non-parametric bootstrap- DNA extraction and amplification followed