Cyathodium tetrasporum (Cyathodiaceae, Marchantiopsida), a new species of liverworts with spores permanently united in tetrads
Abstract
The genus Cyathodium (Marchantiophyta: Cyathodiaceae), a phylogenetically distinct lineage of cave-adapted liverworts, is characterized by a female involucre on the ventral surface of thalli and a distinctive green luminescence of thalli. Globally, 12 species of this genus are currently accepted, with a species diversity center in the Himalayas. During our taxonomic survey of the Chinese bryoflora, we found a remarkable undescribed species that exhibits spores permanently united in tetrads. Molecular evidence of chloroplast markers (psbA-trnH, rbcL and rps4) resolved it as sister to Cyathodium tuberosum Kashyap. Here, this plant is described as Cyathodium tetrasporum sp. nov. Cyathodium becomes the third genus of the class Marchantiopsida with species characterized by spores permanently united in tetrads, after Riccia and Sphaerocarpos. Detailed morphological descriptions, comparative analyses with congeners, SEM images of spores, and a provisional IUCN conservation assessment are provided.
References
Bachman S., Moat J., Hill A.W., de la Torre J. & Scott B. 2011. Supporting Red List threat assessments with GeoCAT: geospatial conservation assessment tool. ZooKeys 150: 117–126. https://doi.org/10.3897/zookeys.150.2109
Cox C.J., Goffinet B., Newton A.E., Shaw A.J. & Hedderson T.A.J. 2000. Phylogenetic relationships among the diplolepideous-alternate mosses (Bryidae) inferred from nuclear and chloroplast DNA sequences. The Bryologist 103: 224–241. https://doi.org/10.1639/0007-2745(2000)103[0224:PRATDA]2.0.CO;2
Dixit A.K. & Kerketta M.A. 2020. Cyathodium denticulatum Udar et Srivastava: A rare liverwort new to Chhattisgarh, Central India. Current Botany 12: 171–174. https://doi.org/10.25081/CB.2020.V11.5882
Duckett J. & Ligrone R. 2006. Cyathodium Kunze (Cyathodiaceae: Marchantiales), a tropical liverwort genus and family new to Europe, in Southern Italy. Journal of Bryology 28: 88–96. https://doi.org/10.1179/174328206X105353
Evans A.W. 1939. The classification of Hepaticae. Botanical Review 5: 49–96.
Forrest L.L. & Crandall-Stotler B.J. 2004. A phylogeny of the simple thalloid liverworts (Jungermanniopsida, Metzgeriidae) as inferred from five chloroplast genes. Monographs in Systematic Botany from the Missouri Botanical Garden 98: 119–140.
Glime J.M. 2007. Bryophyte Ecology. Vol. 1: Physiological Ecology. Michigan Technological University and the International Association of Bryologists, Houghton.
Gradstein S.R., Wilson R., Ilkiu-Borges A.L. & Heinrichs J. 2006. Phylogenetic relationships and neotenic evolution of Metzgeriopsis (Lejeuneaceae) based on chloroplast DNA sequences and morphology. Botanical Journal of the Linnean Society 151: 293–308. https://doi.org/10.1111/j.1095-8339.2006.00531.x
Kalyaanamoorthy S., Minh B.Q., Wong T.K.F., von Haeseler A. & Jermiin L.S. 2017. ModelFinder: fast model selection for accurate phylogenetic estimates. Nature Methods 14: 587–589. https://doi.org/10.1038/nmeth.4285
Katoh K. & Standley D.M. 2013. MAFFT multiple sequence alignment software version 7: improvements in performance and usability. Molecular Biology and Evolution 30: 772–780. https://doi.org/10.1093/molbev/mst010
IUCN 2012. The IUCN Red List Categories and Criteria, Version 3.1. Second edition. IUCN Red List Unit, Cambridge. Available from https://www.iucnredlist.org [accessed 15 Mar. 2025].
Miller M.A., Pfeiffer W. & Schwartz T. 2010. Creating the CIPRES Science Gateway for Inference of Large Phylogenetic Trees. 2010 Gateway Computing Environments Workshop (GCE), 14 Nov. 2010. New Orleans: 1–8. https://doi.org/10.1109/GCE.2010.5676129
Minh B.Q., Schmidt H.A., Chernomor O., Schrempf D., Woodhams M.D., von Haeseler A. & Lanfear R. 2020. IQ-TREE 2: New models and efficient methods for phylogenetic inference in the genomic era. Molecular Biology and Evolution 37: 1530–1534. https://doi.org/10.1093/molbev/msaa015
Paton J.A. 1999. The Liverwort Flora of the British Isles. Harley Books, Colchester.
Ronquist F., Teslenko M., van der Mark P., Ayres D.L., Darling A., Höhna S., Larget B., Liu L., Suchard M.A. & Huelsenbeck J.P. 2012. MrBAYES 3.2: efficient Bayesian phylogenetic inference and model selection across a large model space. Systematic Biology 61: 539–542. https://doi.org/10.1093/sysbio/sys029
Salazar Allen N. 2001. Cyathodium bischlerianum, sp. nov. (Marchantiales) a new species from the Neotropics. The Bryologist 104 (1): 141–145. https://doi.org/10.1639/0007-2745(2001)104[0141:CBSNMA]2.0.CO;2
Salazar Allen N. 2005. Cyathodium. In: Bischler-Causse H., Gradstein S.R., Jovet Ast S., Long D.G. & Salazar Allen N. (eds) Marchantiidae. Flora Neotropica Monographs 97: 1–267.
Salazar Allen N. & Korpelainen H. 2006. Notes on neotropical Cyathodium. Cryptogamie, Bryologie 27 (1): 86–95.
Schiffner V. 1900. Die Hepaticae der Flora Von Buitenzorg I. Band. E. J. Brill, Leiden.
Schuster R.M. 1984. Evolution, phylogeny and classification of the Hepaticae. In: Schuster R.M. (ed.)New Manual of Bryology. Vol. 2: 982–1070. Hattori Botanical Laboratory, Nichinan.
Schuster R.M. 1992a. The Hepaticae and Anthocerotae of North America. V. Columbia University Press, New York.
Schuster R.M. 1992b. The Hepaticae and Anthocerotae of North America. VI. Columbia University Press, New York.
Shen C., Xu H., Huang W.Z., Zhao Q. & Zhu R.L. 2024. Is RNA editing truly absent in the complex thalloid liverworts (Marchantiopsida)? Evidence of extensive RNA editing from Cyathodium cavernarum. New Phytologist 242: 2817–2831. https://doi.org/10.1111/nph.19750
Smith G.M. 1955. Cryptogamic Botany. Vol. 2. Second edition. McGraw Hill, New York.
Söderström L., Hagborg A., von Konrat M., Bartholomew-Began S., Bell D., Briscoe L., Brown E., Cargill D.C., Cooper E.D., Costa D.P., Crandall-Stotler B.J., Dauphin G., Engel J.J., Feldberg K., Glenny D., Gradstein S.R., He X., Ilkiu-Borges A.L., Heinrichs J., Hentschel J., Katagiri T., Konstantinova N.A., Larrain J., Long D.G., Nebel M., Pócs T., Puche F., Reiner-Drehwald E., Renner M.A.M., Sass-Gyarmati A., Schäfer-Verwimp A., Segarra Moragues J.G., Stotler R.E., Sukkharak P., Thiers B.M., Uribe J., Váňa J., Villareal J.C., Wigginton M., Zhang L. & Zhu R.L. 2016. World checklist of hornworts and liverworts. PhytoKeys 59: 1–828. https://doi.org/10.3897/phytokeys.59.6261
Srivastava S.C. & Dixit R. 1996. The genus Cyathodium Kunze. Journal of the Hattori Botanical Laboratory 80: 149–215.
Sundberg S. 2013. Spore rain in relation to regional sources and beyond. Ecography 36: 364–373. https://doi.org/10.1111/j.1600-0587.2012.07664.x
Tamura K., Stecher G., Peterson D., Filipski A. & Kumar S. 2013. MEGA6: Molecular evolutionary genetics analysis Version 6.0. Molecular Biology and Evolution 30 (12): 2725–2729. https://doi.org/10.1093/molbev/mst197
Udar R. 1964. Palynology of Bryophytes. In: Nair P.K.K. (ed.) Advances in Palynology: 79–100. National Botanical Gardens, Lucknow.
Udar R. & Singh D.K. 1978. Cyathodium indicum Udar et Singh, sp. nov. from western Himalayas India. Journal of Bryology 10 (2): 139–142.
Villarreal A.J.C., Crandall-Stotler B.J., Hart M.L., Long D.G. & Forrest L.L. 2016. Divergence times and the evolution of morphological complexity in an early land plant lineage (Marchantiopsida) with a slow molecular rate. New Phytologist 209: 1734–1746. https://doi.org/10.1111/nph.13716
Wang L.S., Jia Y., Zhang X.C. & Qin H.N. 2018. Species Catalogue of China. Vol. 1: Plants: A Synoptic Checklist (I). Science Press, Beijing. [In Chinese.]
Wilson R., Gradstein S., Heinrichs J., Groth H., Ilkiu–Borges A. & Hartmann F. 2004. Phylogeny of Lejeuneaceae: a cladistic analysis of chloroplast gene rbcL sequences and morphology with preliminary comments on the mitochondrial nad4-2 spacer region. Monographs in Systematic Botany from the Missouri Botanical Garden 98: 189–202.
Wu Y.H. & Gao C. 2006. Notes on Chinese Cyathodium Kunze. Bulletin of Botanical Research 26 (5): 522–526. [In Chinese.]
Xiang Y.L. & Zhu R.L. 2019. Sphaerocarpales (Marchantiophyta) new to China, with special references to a new species of Sphaerocarpos from Hengduan Mountains. The Bryologist 122 (4): 586–596. https://doi.org/10.1639/0007-2745-122.4.586
Xiang Y.L. & Zhu R.L. 2023. Morphological and molecular evidence for a new species, Mannia gradsteinii sp. nov. (Aytoniaceae) from southwestern China. Cryptogamie, Bryologie 44: 237–245. https://doi.org/10.5252/cryptogamiebryologie2023v44a12
Xiang Y.L. & Zhu R.L. 2025. Phylogenetic position of Cyathodium indicum (Cyathodiaceae, Marchantiophyta), a rare Indian liverwort newly found in China. Journal of Bryology 47 (2): 118–126. https://doi.org/10.1080/03736687.2025.2493477
Xiang Y.L., Jin X.J., Shen C., Cheng X.F., Shu L. & Zhu R.L. 2022. New insights into the phylogeny of the complex thalloid liverworts (Marchantiopsida) based on chloroplast genomes. Cladistics 38 (6): 649–662. https://doi.org/10.1111/cla.12513
Zanten B.O. van & Gradstein S.R. 1988. Experimental dispersal geography of Neotropical liverworts. Beihefte zur Nova Hedwigia 90: 41–94.
Zhang D., Gao F., Jakovlić I., Zou H., Zhang J., Li W.X. & Wang G.T. 2020. PhyloSuite: An integrated and scalable desktop platform for streamlined molecular sequence data management and evolutionary phylogenetics studies. Molecular Ecology Resources 20 (1): 348–355. https://doi.org/10.1111/1755-0998.13096.
Zheng T.X., Inoue Y., Luo L., He Q., Wang P. & Jia Y. 2025. A northernmost distribution record of Cyathodium (Cyathodiaceae), with validation of subg. Metacyathodium. Taiwania 70 (2): 371–376. https://doi.org/10.6165/tai.2025.70.371
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