Schneider, Craig W.

Wynne, Michael J.

English

Trinity College

Trinity College Trinity College Digital Repository Faculty Scholarship 1-2021 Proposal of Medeiothamnion thouarsii (Montagne) comb. nov. (Wrangeliaceae, Rhodophyta) Michael J. Wynne University of Michigan - Ann Arbor Craig W. Schneider Trinity College, craig.schneider.1@trincoll.edu Follow this and additional works at: https://digitalrepository.trincoll.edu/facpub  Part of the Biology Commons                                       No. 176 (22 January 2021) ISSN 2009-8987  Page 1 of 5 Copyright: © 2021 The authors. Open access article distributed under Creative Commons Attribution License CC BY-NC.  	Proposal of Medeiothamnion thouarsii (Montagne) comb. nov. (Wrangeliaceae, Rhodophyta)  Michael J. Wynne, University of Michigan Herbarium, Ann Arbor, Michigan 48108, USA (correspondence: mwynne@umich.edu)  Craig W. Schneider, Department of Biology, Trinity College, Hartford, Connecticut 06106, USA  We here discuss the taxonomic history and conspecificity of two species of Wrangeliaceae known from New Zealand and the temperate coast of Pacific South America. Callithamnion thouarsii Montagne was described by Montagne (1837: 351) on the basis of a collection from Valparaiso, Chile made by Abel Aubert du Petit-Thouars (1793–1864), whom he honoured with the epithet. Later, Montagne (1839: 9) referred to his own species but this time with a query, and he also depicted it (Montagne 1847, pl. 7, fig. 5). Kützing (1861, p. 27, pl. 85, fig. II) later illustrated it. De Toni (1903: 1413) transferred the species to Antithamnion with a query, and G. Feldmann (1950: 311, fig. 13) later referred it to Sphondylothamnion, as S. thouarsii (Montagne) G.Feldmann. Dixon (1963: 222) was of the view that as there was considerable resemblance between the distichous forms of European S. multifidum (Hudson) Nägeli and the Chilean taxon, the retention of specific status for it was by no means certain, and to date no one has merged the two species (e.g., Maggs & Hommersand 1993, Guiry & Guiry 2021). Little is known of Callithamnion thouarsii other than Montagne’s original Chilean material, and G. Feldmann (1950: 311, fig. 13) identified specimens distributed—as Antithamnion plumula (J.Ellis) Thuret—by Victor Lindauer in his Algae Nova-Zelandicae Exsiccatae Fasc. IX, No. 223 [Aug. 1946] as Callithamnion thouarsii and proposed its transfer to Sphondylothamnion. Fig. 1 is an example of Lindauer’s exsiccata No. 223 from F.   Medeiothamnion lyallii (Harvey) E.M.Gordon was proposed by Gordon (1972: 59) for specimens from South I., Stewart/Rakiura I., and Ruapuke I. of New Zealand. She noted that G. Feldmann (1950) had identified the Lindauer No. 223 specimen from Valparaiso as Callithamnion thouarsii. When Gordon (1972: 63) later examined Lindauer’s specimen in PC, she concluded it was more similar to M. lyallii than to Sphondylothamnion multifidum, particularly in the position of the tetrasporangia, which tend to be grouped at the distal ends of the whorl-branchlet cells. Adams (1994: 241) noted that “this extremely variable plant has been known locally [in New Zealand] by several names including Antithamnion flaccidum, A. plumula and Sphondylothamnion thouarsii. Its relationship with southern South American species, particularly Antithamnion flaccidum (J.D.Hooker & Harvey) De Toni, requires investigation.” Adams felt that due to its abundance in the Foveaux Strait area (between Stewart Island and the South Island) particularly in “inlets and anchorages frequented by early sealers, whalers and traders,” that it may have been introduced to New Zealand, presumably from South America. Nelson (2013: 232), however, referred to Medeiothamnion lyallii as a New Zealand endemic. Brauner (1979: 342) examined the type of Callithamnion thouarsii in PC noting that it was “… probably a Medeiothamnion”. In the same work, he moved Callithamnion flaccidum J.D.Hooker & Harvey, a species from the Atlantic coast of southern South America, to Medeiothamnion, subsuming the generitype, M. santacrucense Pujals (Pujals 1970), under M. flaccidum (J.D.Hooker & Harvey) Brauner. In her comprehensive key to the species of Medeiothamnion, Gordon (1972) clearly distinguished the New Zealand species, M. lyallii, and the Argentinian M. santacrucense on the basis that the hypogynous cell of carpogonial branches had adaxial involucral branchlets, the number of whorl-branchlets on axial cells and whether they produced rhizoidal cortication on the axes. Therefore, as M. lyallii and C. thouarsii clearly represent a single taxon, the South American species on the east coast currently known as M. santacrucense is a distinct species.                                        No. 176 (22 January 2021) ISSN 2009-8987  Page 2 of 5 Copyright: © 2021 The authors. Open access article distributed under Creative Commons Attribution License CC BY-NC.  	In spite of multiple studies, no one has formally synonymized Medeiothamnion lyallii and Sphondylothamnion thouarsii, despite it having been assumed as such since the treatment of the two species by Gordon (1972: 49), where she stated that S. thouarsii “… is now recognized as Medeiothamnion lyallii comb. nov.”. As Callithamnion thouarsii is the earliest available name, the following new combination is proposed:  Medeiothamnion thouarsii (Montagne) M.J.Wynne & C.W.Schneider, comb. nov. Basionym: Callithamnion thouarsii Montagne, Annales des Sciences Naturelles, Botanique, Seconde série 8: 351, 1837. Holotype: PC 0047016 (Fig. 2). Type locality: Valparaiso [Chile] Etiquette on the label: Ceramium (Callithamnion) Thouarsii Montag. n. sp. Capt. Du Petit Thouars 1835, Valparaiso. Homotypic synonyms: Antithamnion thouarsii (Montagne) De Toni 1903: 1403. Sphondylothamnion thouarsii (Montagne) G.Feldmann 1950: 311. Heterotypic synonyms: Wrangelia lyallii Harvey 1855: 236.  Type locality: Rakiura Island, Foveaux Strait, New Zealand; leg. David Lyall, January 1851, s.n. Type in BM. Medeiothamnion lyallii (Harvey) E.M.Gordon 1972: 59. Note: Montagne (1837: 351) referred only to a collection by Du Petit Thouars from Valparaiso represented by a single specimen at PC. As there are no syntypes or isotypes, this specimen is automatically the holotype.  The recognition of Medeiothamnion thouarsii as a species occurring both in New Zealand and the Pacific coast of South America adds to the many species with such wide-ranging distributions in the Southern Hemisphere (Levring 1960, Santelices 1980, Hoffmann & Santelices 1997).   Adams, N.M. (1994). Seaweeds of New Zealand. An Illustrated Guide. pp. [1]–360, 116 pls. Christchurch: Canterbury University Press. Brauner, J.F. (1979). Developmental morphology and taxonomy of Medeiothamnion flaccidum (Hooker & Harvey) comb. nov. (Ceramiaceae, Rhodophyta) from South America. Phycologia 18: 338–346. De Toni, G.B. (1903). Sylloge algarum omnium hucusque cognitarum. Vol. IV. Florideae. Sectio III. pp. [i], frontispiece, [iii-v], 775, 775 bis, 776, 777 bis, 777–1521 + 1523–1525. Patavii [Padua]: Sumptibus auctoris. Dixon, P.S. (1963). Sphondylothamnion multifidum (Huds.) Näg. in western Europe. British Phycological Bulletin 2: 219–223, 2 figs.   Feldmann, G. (1950). Sur quelques Céramiacées de Nouvelle-Zelande. Bulletin du Muséum National d'Histoire Naturelle, Série 2, 22: 131–141, 307–314, 13 figs. Gordon, E.M. (1972). Comparative morphology and taxonomy of the Wrangelieae, Sphondylothamnieae and Spermothamnieae (Ceramiaceae, Rhodophyta). Australian Journal of Botany, Supplement 4: 1–180, 63 figs, 3 tables. Guiry, M.D. & Guiry, G.M. (2021). AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. http://www.algaebase.org; searched on 15 Jan. 2021. Harvey, W.H. (1855). Algae. In: The Botany of the Antarctic Voyage of H.M. Discovery Ships ‘Erebus’ and ‘Terror’, in the years 1839-1843, under the command of Captain Sir James Clark Ross.... II. Flora Novae-Zelandiae. Part II. Flowerless plants. (Hooker, J.D. Ed.), pp. 211–266, pls. 107-121. London: Reeve. Hoffmann, A. & Santelices, B. (1997). Flora marina de Chile central. Marine flora of central Chile. Santiago, Chile: Ediciones Universidad Catolica de Chile. 434 pp.                                       No. 176 (22 January 2021) ISSN 2009-8987  Page 3 of 5 Copyright: © 2021 The authors. Open access article distributed under Creative Commons Attribution License CC BY-NC.  	Kützing, F.T. (1861). Tabulae phycologicae: oder. Abbildungen der Tange, Vol. XI. pp. [i–iii], 1–32, 100 pls. Nordhausen: Gedruckt auf kosten des Verfassers (in commission bei W. Köhne). Levring, T. (1960). Contributions to the marine algal flora of Chile. Acta Universitatis Lundensis 56(10): 1-85. Maggs, C.A. & M.H. Hommersand (1993). Seaweeds of the British Isles. Vol. 1 Rhodophyta. Part 3A Ceramiales. pp. [i] –xiii, [1] –444, 1 map. The Natural History Museum. London: HMSO Publications.  Montagne, C. (1837). Centurie de plantes cellulaires exotiques nouvelles. Annales des Sciences Naturelles, Botanique, Seconde série 8: 345–370. Montagne, J.P.F.C. (1839, 1847). Cryptogamie. In: A.D. d’Orbigny, Voyage dans l‘Amérique Méridionale (le Brésil, la republique...) exécuté pendant les années 1826, 1827, 1828, 1829, 1830, 1831, 1832 et 1833. Vol. 7. Botanique. Part I. Sertum patagonicum., pp. 3–39. Vol. 8 [Atlas]: pls. 1-7 [1847]. Paris, chez P. Bertrand; Strasbourg: V. Levrault.  Nelson, W.A. (2013). New Zealand seaweeds. An illustrated guide. pp. [1]–328. Wellington: Te Papa Press. Pujals, C. (1970). Medeiothamnion nuevo género de Ceramiaceae. Revista del Museo Argentino de Ciencias Naturales "Bernardino Rivadavia" e Instituto Nacional de Investigacion de las Ciencias Naturales (Botanica) 3(10): 287–299. Ramírez, M.E. & Santelices, B. (1991). Catálogo de las algas marinas bentónicas de la costa temperada del Pacífico de Sudamérica. Monografías Biológicas 5: 1–437.  Santelices, B. (1980). Phytogeographic characterization of the temperate coast of South Americas. Phycologia 19(1): 1–12, 8 figs, 1 table.                                         No. 176 (22 January 2021) ISSN 2009-8987  Page 4 of 5 Copyright: © 2021 The authors. Open access article distributed under Creative Commons Attribution License CC BY-NC.  	  Fig. 1. Victor M. Lindauer’s Algae Nova-Zelandicae Exsiccatae No. 223 (incorrectly identified as Antithamnion plumula (J.Ellis) Thuret) = Medeiothamnion thouarsii). Cryptogamic Herbarium specimen 1210701 in F (Field Museum, Chicago).                                       No. 176 (22 January 2021) ISSN 2009-8987  Page 5 of 5 Copyright: © 2021 The authors. Open access article distributed under Creative Commons Attribution License CC BY-NC.  	  Fig. 2. Holotype of Callithamnion thouarsii Montagne. PC 0047016.  

Proposal of Medeiothamnion thouarsii (Montagne) comb. nov. (Wrangeliaceae, Rhodophyta)

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Proposal of Medeiothamnion thouarsii (Montagne) comb. nov. (Wrangeliaceae, Rhodophyta)

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