The status of the name Alysium holtingii C. Agardh, a red alga described from Brazil, and a depiction of the type specimen

BIOLOGICAL SCIENCES

The status of the name Alysium holtingii C. Agardh, a red alga described from Brazil, and a depiction of the type specimen

Michael J. Wynne

Department of Ecology and Evolutionary Biology and Herbarium, University of Michigan, Ann Arbor, Michigan 48109, U.S.A.

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ABSTRACT

The type specimen of the red alga Alysium holtingii C. Agardh, described from Brazil, is located in the Lund Herbarium, and it is depicted for the first time in a publication. It is taxonomically identical to Dichotomaria obtusata (J. Ellis and Solander) Lamarck and thus can be treated as a later taxonomic synonym. Alysium is regarded as congeneric with Dichotomaria.

Key words:Alysium, Brazil, Dichotomaria obtusata, red algae, taxonomy, type specimen.

RESUMO

O espécime tipo da alga vermelha Alysium holtingii C. Agardh, descrito para o Brasil, está localizado no Herbário Lund, e é aqui apresentado. Ele é taxonomicamente idêntico a Dichotomaria obtusata (J. Ellis e Solander) Lamarck e portanto deve ser tratado como um sinônimo taxonômico posterior. Alysium é considerado como congenérico com Dichotomaria.

Palavras-chave:Alysium, Brasil, Dichotomaria obtusata, algas vermelhas, taxonomia, espécime tipo.

INTRODUCTION AND BACKGROUND

In recent years the red algal genus Galaxaura Lamouroux (1812) has been shown to be heterogeneous. Tricleocarpa was proposed by Huisman and Borowitzka (1990) as a segregate genus from Galaxaura, and Dichotomaria Lamarck (1816), long regarded as congeneric with Galaxaura, has been reinstated (Huisman et al.2004). In the ongoing revision of the family Galaxauraceae (Wang et al. 2005), the status of the ill-known genus Alysium deserves attention. Alysium was established by C. Agardh (1823), with the single species A. holtingii C. Agardh ("Ulva holtingii Mert. msc.") from the coast of Brazil, the specimen having been sent by Mertens to Agardh. Although the genus had only a brief description, the single species was provided with a more detailed account. C. Agardh (1824) repeated the name in his 'Systema algarum'. Sprengel (1827) recognized the genus, referring to two species, the original species A. holtingii and a new species, A. perrini Sprengel from the West Indies. But because the legitimate and available name Galaxaura oblongata (J. Ellis and Solander) J.V. Lamouroux was cited after A. perrini, it is an illegitimate name. Léman (1828) referred to Alysium holtingii as a plant from Brazil distinguished by its membranous, hollow, inflated frond, provided with constrictions, giving it an articulated aspect as well as by its reticulate, pentagonal covering.

In their account of Alysium holtingii (as " Hoeltingii"), Martius et al. (1833) said it was discovered by "Hoelting" on the ocean shore near Sebastianópolis. It is not clear how they were able to provide this more precise information about the type locality.

Sebastianópolis is an earlier name for Rio de Janeiro, or officially "São Sebastião do Rio de Janeiro". Martens' (1870) summary of records of Brazilian algae included Galaxaura obtusata with Alysium holtingii listed as a synonym, and he referred to the record of A. holtingii from "Rio" by Martius et al. (1833).

Decaisne (1842) recognized Galaxaura and placed both Alysium C. Agardh and Dichotomaria Lamarck(1816) in its synonymy. Decaisne (1842) treated Alysium holtingii (as "Hottingii") as conspecific with Galaxaura obtusata (J. Ellis and Solander) Lamouroux (1816).

Kützing (1843) altered Agardh's orthography of the name to Halysium, a name that was already occupied by a genus of hyphomycetous fungi (Corda 1837). Kützing assigned the genus to the family Lemaneaceae ['Familia XXXVII. Lemanieae'] and recognized a total of ten species. The first of these was H. holtingii, with "Alysium holtingii Ag." cited, and significantly "Corallina obtusata Ellis and Solander Tab. 22, Fig. 2" was listed as a taxonomic synonym. Kützing also indicated "Westindien: Mertens! (Herb. berol.)", revealing that he had seen Mertens' authentic material then in the Berlin Herbarium. The other species that were placed in Halysium were: H. oblongatum (J. Ellis and Solander) Kützing, H. cylindricum (J. Ellis and Solander) Kützing, H. rugosum (J. Ellis and Solander) Kützing, H. marginatum (J. Ellis and Solander) Kützing, H. fruticulosum (J. Ellis and Solander) Kützing, H. lapidescens (J. Ellis and Solander) Kützing, H. induratum (J. Ellis and Solander) Kützing, H. lichenoides (J. Ellis and Solander) Kützing, and the new species H. canaliculatum Kützing, that was described from the coast of Brazil. All of these species occurred in the tropical western Atlantic (West Indies, the Bahamas, Jamaica, Brazil, or "Antillenmeer"). Halysium rugosum was the only one of these species depicted by Kützing (1843, Pl. 43, Fig. 1).

Kützing (1849, 1858) subsequently followed Decaisne (1842) in treating these species as belonging to the genus Galaxaura. His list included the species Galaxaura canaliculata (Kützing) Kützing (1849). Decaisne's (1842) inclusion of Alysium in Galaxaura has also been followed by Schmitz and Hauptfleisch (1897),De Toni (1897), and Kylin (1956). J.G. Agardh (1876) treated his father's genus Alysium as a new subgenus of Galaxaura, and he assigned the following three species to this subgenus: G. obtusata, G. umbellata (Esper) J.V. Lamouroux, and G. decaisnei J. Agardh. Two varieties, a and b, were recognized within Galaxaura obtusata: a Opuntioides included Corallina obtusata J. Ellis and Solander and thus would be the nominate variety; b oblongata included Corallina oblongata J. Ellis and Solander (1786) as well as Alysium holtingii C. Agardh. At present, Corallina oblongata is placed in Tricleocarpa,where it is treated as conspecific with T. fragilis (Linnaeus) Huisman et Townsend (1993). Therefore, if J. Agardh's (1876) treatment of A. holtingii in the synonymy of G. obtusata (J. Ellis and Solander) Lamouroux [var.] oblongata (J. Ellis and Solander) J.G. Agardh is correct, then the generic name Alysium would predate Tricleocarpa Huisman and Borowitzka (1990). On the other hand, if Alysium holtingii is a taxonomic synonym of Corallina obtusata, which is now Dichotomaria obtusata (J. Ellis and Solander) Lamarck, then Alysium can be relegated to synonymy with Dichotomaria.

The detailed floristic accounts by Taylor (1960) and Oliveira (1977) made no specific mention of Alysium holtingii C. Agardh, nor did the historical accounts by Taylor (1931) and Joly (1952) refer to C. Agardh's Alysium holtingii. The fact that the type specimen of A. holtingii has never been depicted in the literature motivated me to locate it and also to determine whether its taxonomic assignment lies with Tricleocarpa fragilis or Dichotomaria obtusata.

OBSERVATIONS

The type specimen of Alysium holtingii (Fig. 1) was located in the Agardh Herbarium (as No. 32432) inLund, Sweden, and received on loan. Label information (Fig. 2a) includes the following words near the specimen: "Ulva holtingii M. ab oris Brasil. Holting 1819" and "Cm. 1821" [meaning that it was communicated/sent from Mertens to Agardh in 1821]. Also near the species name is "n.òp.", which is interpreted as "n.sp.". In the bottom left corner of the sheet (Fig. 2b) are the words: "Alysium holtingii Ag." and "Ulva holtingii Mert." The specimen has a bushy, spreading aspect with an overall height of 5 cm. It is made up of distinctly segmented axes (Fig. 3), with branching from 5 to 8 orders. Thebranching pattern is dichotomous or sub-dichotomous. The axes appear to be cylindrical rather than flattened but have collapsed due to their hollow nature. Individual segments are 1-2.5 mm in width and 3-5 (-6) mm in length. The specimen appears chalky and bleached, but the distal tips are relatively dark, reflecting the non-calcified condition of these growing regions. The surface of the segments is glabrous. The joints appear to be uncalcified.

A small fragment was excised and treated with dilute HCl to decalcify. Then sections were gently made with a single-edged razor blade. The outer layer of cortical cells were mostly adherent upon decalcification and presented a continuous aspect of polygonal cells (5-, 6-, and 7-sided) in surface view, the cells measuring 20-28 µm across. Older surface cells were more rounded in outline and ranged from 30-50 µm. There were 2 or 3 layers of cortical cells. In the interior of the thallus were very loosely-organized branching medullary filaments, 10-22 µm in width and of indeterminate length.

The moniliform habit and the collapsed nature of the thallus upon drying conform to the accounts given for Dichotomaria obtusata by various workers, such as Papenfuss et al. (1982), Huisman and Borowitzka (1990), Littler and Littler (2000) (all as Galaxaura obtusata) and Chou (1945, as the taxonomic synonym G. robusta). Huisman and Kurihara (2006) characterized Dichotomaria obtusata as having thalli that are terete throughout and segmented. According to Abbott (1999), the terete axes in this species are "often collapsed", in agreement with the condition in the specimen of Alysium holtingii. In Tricleocarpa, the outer cortical cells become disengaged upon decalcification (Huisman and Borowitzka 1990, Abbott 1999), and the cortical cells become smaller toward the surface (Huisman and Kurihara 2006). These observations allow us to conclude that Alysium holtingii is taxonomically identical to Dichotomaria obtusata and thus can be placed in its synonymy. This confirms the ideas of Decaisne (1842), Kützing (1843), Martens (1870), De Toni (1897), and Kjellman (1900) but not of J. Agardh (1976), who treated the species as identical with Galaxaura oblongata (now Tricleocarpa fragilis). Similarly, Alysium C. Agardh is to be listed as a heterotypic synonym of Dichotomaria.

The illegitimate name Alysium perrini Sprengel (1827), for which the available name Galaxaura oblongata was cited, can be listed in the synonymy of Tricleocarpa fragilis (Linnaeus) Huisman and R.A. Townsend. Huisman and Townsend (1993) demonstrated that Eschara fragilis Linnaeus (1758) is an older taxonomic synonym for Corallina oblongata J. Ellis and Solander (1786).

The Brazil-based Galaxaura canaliculata (Kützing) Kützing is treated in the synonymy of Dichotomaria marginata (J. Ellis and Solander) Lamarck (Lamarck 1816, De Toni 1897, Silva et al. 1996).

ACKNOWLEDGMENTS

I am grateful to Mr. Patrik Frödén of the Botanical Museum in Lund for arranging the loan of Alysium holtingii and for providing me with scanned images that were used in this study. I thank Dra. Margareth Sales of the Universidade Federal Rural de Pernambuco for translating the Abstract into Portuguese.

Manuscript received on July 21, 2007; accepted for publication on December 18, 2007; presented by ALEXANDER W.A. KELLNER

• ABBOTT IA. 1999. Marine red algae of the Hawaiian Islands. Honolulu, Hawai'i: Bishop Museum Press, xv + 477 p.
• AGARDH CA. 1822-1823. Species algarum... Vol. 1, part 2 Lundae [Lund], p. [i-viii] + 169398 (1822), 399531 (1823).
• AGARDH CA. 1824. Systema algarum. Lundae [Lund]. xxxviii + 312 p.
• AGARDH JG. 1876. Species genera et ordines algarum. 3(1). Lipsiae [Leipzig], vii + 724 p.
• CHOU RC-Y. 1945. Pacific species of Galaxaura I. Asexual types. Pap Mich Acad Sci Arts Lett 30: 3555, 10 pls.
• CORDA AKJ. 1837. Icones fungorum hucusque cognitorum. Tomus I. Abbildungen der Pilze und Schwarmme. Pragæ: JG Calve, [vi] + 32 p., 7 pls.
• DECAISNE J. 1842. Mémoire sur les corallines ou Polypiers calcifères. Ann Sci Nat Bot sér 2(18): 96128.
• DE TONI GB. 1897. Sylloge algarum omnium hucusque cognitarum. Vol. IV.Florideae. Sectio I. Patavii[Padova], lxi + 388 p.
• ELLIS J AND SOLANDER D. 1786. The natural history of many curious and uncommon zoophytes collected from various parts of the globe. London: Benjamin White and Son, xii + 208 p., 63 pls.
• HUISMAN JM AND BOROWITZA MA. 1990. A revision of the Australian species of Galaxaura (Rhodophyta, Galaxauraceae), with a description of Tricleocarpa gen. nov. Phycologia 29: 150172.
• HUISMAN JM AND KURIHARA A. 2006. Dichotomaria In: HUISMAN JR, Algae of Australia Nemaliales. Canberra: Australian Biological Resources Study, p. 1621.
• HUISMAN JM AND TOWNSEND RA. 1993. An examination of Linnaean and pre-Linnaean taxa referable to Galaxaura and Tricleocarpa (Galaxauraceae, Rhodophyta). Bot J Linn Soc 113: 95101.
• HUISMAN JM, HARPER JT AND SAUNDERS GW. 2004. Phylogenetic study of the Nemaliales (Rhodophyta) based on large-subunit ribosomal DNA sequences supports segregation of the Scinaiaceae fam. nov. and resurrection of Dichotomaria Lamarck. Phycol Res 52: 224234.
• JOLY AB.1952. An approach to the bibliography of Brazilian algae. Bol Inst Oeanogr Univ São Paulo 3: 101113.
• KJELLMAN FR. 1900. Om floridé-slägtet Galaxaura dess organorgrafi och systematic. Kongl Svenska Vetenskaps Handl 33(1): 1109, 20 pls.
• KÜTZING FT. 1843. Phycologia generalis. xxxii + 459 p., 80 pls. Brockhaus: Leipzig.
• KÜTZING T. 1849. Species algarum. vi + 922 p. Lipsiae [Leipzig]: Brockhaus.
• KÜTZING FT. 1858. Tabulaephycologicae. Vol. 8. ii+48p., 100 pls. Nordhausen.
• KYLIN H. 1956. Die Gattungen der Rhodophyceen. Lund: Gleerups, xv + 673 p.
• LAMARCK JB. 1816. Histoire naturelle des animaux sans vertèbres. Vol. 2. Paris: Déterville, 568 p.
• LAMOUROUX JVF. 1812. Sur la classification des Polypiers coralligènes non entièrement pierreux. Nouv Bull Sci Soc Philom Paris 3: 181188.
• LAMOUROUX JVF. 1816. Histoire des polypiers coralligènes flexibles, vulgairement nommés zoophytes. Caen. lxxxiv + 560 p., 19 pls.
• LÉMAN DS. 1828. Ulva In: LEVRAULT FG (Ed), Dictionnaire des Sciences Naturelles vol. 56 (TUA-VAZ). Strasbourg and Paris: Le Normant, p. 240248.
• LINNAEUS C. 1758. Caroli Linnaei... Systema Naturae per regna tri naturae, secundum classes, ordines, geners, species... Tomus I Pars II. Editio duodecimam reformata. Holmiae [Stockhom]: Laurentii Salvii.
• LITTLER DS AND LITTLER MM. 2000. Caribbean reef plants. An identification guide to the reef plants of the Caribbean, Bahamas, Flora and Gulf of Mexico. Washington DC: OffShore Graphics, Inc, 542 p.
• MARTENS G DE. 1870. Conspectus algarum Brasiliae hactenus detectarum. Vidensk. Meddel Naturhist Foren, Kjobenhavn 1869, ser 3(1): 297314.
• MARTIUS CFP VON, ESCHWEILER FG AND NEES VON ESENBECK CGD. 1833. Flora brasiliensis seu enumeratio plantarum in Brasilia... J.G. Cottae, Stuttgart and Tubingen. Vol 1(1): Algae, lichens, hepaticae, p. [i]-iv, [1]-390.
• OLIVEIRA FEC DE. 1977. Algas marinhas bentônicas do Brasil. Tese de Doutorado. Univ São Paulo, Inst Biocienc, São Paulo, SP, Brasil, 407 p.
• PAPENFUSS GF, MSHIGENI KE AND CHIANG Y-M. 1982. Revision of the red algal genus Galaxaura with special reference to the species occurring in the western Indian Ocean. Bot Mar 25: 401444.
• SCHMITZ F AND HAUPTLEISCH P. 1897. Chaetangiaceae. In: ENGLER A AND PRANTL K (Eds), Die natürlichen Pflanzenfamilien... Engelmann: Leipzig, p. 335339.
• SILVA PC, BASSON PW AND MOE RL. 1996. Catalogue of the benthic marine algae of the Indian Ocean. Univ Calif Publ Bot 79. xiv + 1, 259 p.
• SPRENGEL K. 1827. Caroli Linnaei... Systema vegetabilium, editio decima sexta, Vol. IV, Pars I, Classis 24. [iv] + 592 p. Gottinga [Gottingen]
• TAYLOR WR. 1931. A synopsis of the marine algae of Brazil. Rev Algol 5: 279313.
• TAYLOR WR. 1960. Marine algae of the eastern tropical and subtropical coasts of the Americas. Ann Arbor: Univ Michigan Press, ix + [1] + 870 p.
• WANG W-L, LIY S.-L AND LIN S.-M. 2005. Systematics of the calcified genera of the Galaxauraceae (Nemaliales, Rhodophyta) with an emphasis on Taiwan species. J Phycol 41: 685703.

Publication Dates

• Publication in this collection
  14 May 2008
• Date of issue
  June 2008

History

• Accepted
  18 Dec 2007
• Received
  21 July 2007