Aneura mirabilis

Aneura mirabilis is a parasitic species of liverworts in the family Aneuraceae.[2] It was first described in 1933, as Cryptothallus mirabilis.[3] Plants of this species are white as a result of lacking chlorophyll, and their plastids do not differentiate into chloroplasts.[4]

Aneura mirabilis
Scientific classification Edit this classification
Kingdom: Plantae
Division: Marchantiophyta
Class: Jungermanniopsida
Order: Metzgeriales
Family: Aneuraceae
Genus: Aneura
Species:
A. mirabilis
Binomial name
Aneura mirabilis
(Malmb.) Wickett et Goffinet[1]
Synonyms[1]
  • Cryptothallus mirabilis Malmb.

Description

Aneura mirabilis is a subterranean myco-heterotroph that obtains its nutrients from the abundant fungi growing among its tissues rather than from photosynthesis. The infecting fungus is a basidiomycete, a species of Tulasnella, which is also the case in fungi associated with other species of Aneura,[5] as well as the related genus Riccardia. However, this is not the case for other members of the Metzgeriales that have been studied.[3] Plants are white, lacking chlorophyll, and their plastids do not differentiate into chloroplasts.[4] They are small, seldom growing more than 3 cm (1.2 in) long.[6]

The species is dioicous, with individual plants producing either antheridia or archegonia, but never both. The female plants (with archegonia) are typically ten times the size of the male plants.[3] The development of reproductive structures is not controlled by photoperiod, but does require a temperature of at least 21 °C (70 °F) following a period of sufficiently low temperature.[7]

Taxonomy

Aneura mirabilis was first reported by M. Denis in 1919, who considered it simply as a form of A. pinguis lacking chlorophyll.[5] In 1933, S. Malmborg placed it in a separate genus, Cryptothallus. Apart from lacking chlorophyll, it is very similar to species in the genus Aneura, and the validity of recognizing Cryptothallus as a separate genus was questioned by Karen Renzaglia in 1982, who suggested it may be considered "merely as an achlorophyllous species of Aneura."[8] A molecular phylogenetic study in 2008 placed the species firmly within Aneura, and it was transferred to that genus.[5] This decision was confirmed by a larger molecular phylogenetic study in 2010.[9]

It is suggested that the ancestor of Aneura mirabilis, like the related A. pinguis, had a mutualistic mycorrhizal association with Tulasnella, which was also able to form mycorrhizal connections with neighbouring trees. This evolved into a relationship where A. mirabilis gave up photosynthesis and obtained all its nutrients from the fungus, which in turn obtained them from the associated trees. Other evolutionary lineages of myco-heterotrophic plants have been shown to have evolved from photosynthetic, mycorrhizal ancestors.[5]

Initially, A. mirabilis was the only species of bryophyte known with the same combination of characteristics,[10] but in 1977 and 1979, a second species was collected in Costa Rica, and described in 1996 as Cryptothallus hirsutus (now Aneura crumii[1]).[11] As of 2008, it had not been observed again.[5]

Distribution and habitat

Plants have been found in locations across northern Europe, and once in Greenland.[3] They grow in bogs and are typically found underneath peat moss or other dense moss growth near birch trees.[6]

References
  1. Söderström, Lars; Hagborg, Anders; von Konrat, Matt; Bartholomew-Began, Sharon; Bell, David; Briscoe, Laura; Brown, Elizabeth; Cargill, D. Christine; da Costa, Denise Pinheiro; Crandall-Stotler, Barbara J.; Cooper, Endymion; Dauphin, Gregorio; Engel, John; Feldberg, Kathrin; Glenny, David; Gradstein, S. Robbert; He, Xiaolan; Hentschel, Joern; Ilkiu-Borges, Anna Luiza; Katagiri, Tomoyuki; Konstantinova, Nadezhda A.; Larraín, Juan; Long, David; Nebel, Martin; Pócs, Tamás; Puche, Felisa; Reiner-Drehwald, Elena; Renner, Matt; Sass-Gyarmati, Andrea; Schäfer-Verwimp, Alfons; Segarra-Moragues, José; Stotler, Raymond E.; Sukkharak, Phiangphak; Thiers, Barbara; Uribe, Jaime; Váňa, Jiří; Wigginton, Martin; Zhang, Li & Zhu, Rui-Liang (2016). "World checklist of hornworts and liverworts". PhytoKeys (59): 1–828. doi:10.3897/phytokeys.59.6261. ISSN 1314-2003. PMC 4758082. PMID 26929706.
  2. Wickett, N. J.; Zhang, Y.; Hansen, S. K.; Roper, J. M.; Kuehl, J. V.; Plock, S. A.; Wolf, P. G.; Depamphilis, C. W.; Boore, J. L.; Goffinet, B. (2008). "Functional gene losses occur with minimal size reduction in the plastid genome of the parasitic liverwort Aneura mirabilis". Molecular Biology and Evolution. 25 (2): 393–401. doi:10.1093/molbev/msm267. PMID 18056074.
  3. Schuster, Rudolf M. (1992). The Hepaticae and Anthocerotae of North America. Vol. V. Chicago: Field Museum of Natural History. pp. 574–579. ISBN 0-914868-20-9.
  4. Sigee, D. C. (1969). "The fine structure of plastids in the apical region of the gametophyte of Cryptothallus mirabilis Malmb". Transactions of the British Bryological Society. 5 (4): 820–822. doi:10.1179/006813869804146745.
  5. Wickett, N. J. & Goffinet, B. (2008). "Origin and relationships of the myco-heterotrophic liverwort Cryptothallus mirabilis Malmb. (Metzgeriales, Marchantiophyta)". Botanical Journal of the Linnean Society. 156 (1): 1–12. doi:10.1111/j.1095-8339.2007.00743.x.
  6. Hill, David Jackson (1969). "The absence of chlorophyll in the spores of Cryptothallus mirabilis Malmb". Transactions of the British Bryological Society. 5 (4): 818–819. doi:10.1179/006813869804146781.
  7. Chopra, R. N. & Kumra, P. K. (1988). Biology of Bryophytes. New York: John Wiley & Sons. pp. 93–96. ISBN 0-470-21359-0.
  8. Renzaglia, Karen S. (1982). A comparative developmental investigation of the gametophyte generation in the Metzgeriales (Hepatophyta). Bryophytorum Bibliotheca. Vol. 24. Vaduz: J. Cramer.
  9. Preussing, M.; Olsson, S.; Schäfer-Verwimp, A.; Wickett, N.J.; Wicke, S.; Quandt, D. & Nebel, M. (2010). "New insights in the evolution of the liverwort family Aneuraceae (Metzgeriales, Marchantiophyta), with emphasis on the genus Lobatiriccardia". Taxon. 59 (5): 1424–1440. doi:10.1002/tax.595009. Retrieved 2021-08-19.
  10. Schofield, W. B. (1985). Introduction to Bryology. New York: Macmillan. pp. 184, 192. ISBN 0-02-949660-8.
  11. Crum, Howard & Bruce, James (1996). "A new species of Cryptothallus from Costa Rica". The Bryologist. 99 (4): 433–438. doi:10.2307/3244107. JSTOR 3244107.
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