Bull. Natl. Mus. Nat. Sci., Ser. B, 40(4), pp. 133–138, November 22, 2014

Morphology of Aneurianna ogasawaraensis sp. nov.
(Rhodomelaceae, Rhodophyta), A New Marine Deep
Sublittoral Red Alga from the Ogasawara Islands, Japan
Taiju Kitayama
Department of Botany, National Museum of Nature and Science,
Amakubo 4–1–1, Tsukuba, Ibaraki 305–0005, Japan
E-mail: kitayama@kahaku.go.jp(Received 14 August 2014; accepted 24 September 2014)

Abstract A new red alga, Aneurianna ogasawaraensis sp. nov. (Rhodomelaceae, Ceramiales,
Rhodophyta) was collected from the deep sublittoral water (73–97 m in depth) off Hahajima Island
and Chichi-jima Island, Ogasawara Islands, Japan. This genus was established by Phillips (in2006) separating from Lenormandia (including Lenormandiopsis) mainly because of the presenceof endogenous branching and elliptic blade-surface pattern (“elliptical areolation”). This new species from Ogasawara Islands belongs to Aneurianna in having “elliptical areolation” and is distinguishable from the other known species of the genus in having occasionally branching stipes,
elliptical blades rounded at the base, dentate margins, and conspicuous midribs.
Key words : Aneurianna ogasawaraensis, morphology, Ogasawara Islands, red algae, Rhodophyta.

Introduction
The red marine algal genus Aneurianna Phillips is a member of the tribe Amansieae (Rhodomelaceae, Ceramiales, Rhodophyta), in which
only Aneurianna and Lenormandia Sonder have
foliar blades. According to the original description of the genus (Phillips, 2006), Aneurianna
differs from Lenormandia in having endogenous
branching and elliptic surface pattern with various irregularly ordered ellipses on the blade (socalled “elliptical areolation”) and incurved orinﬂexed apices, in contrast to absence of endogenous branching, rhombic surface pattern withregularly arranged rhombi (“rhombic areolation”)
and ﬂat apices of Lenormandia. Aneurianna
includes three species: Aneurianna lorentzii(Weber-van Bosse) L.E.Phillips (type species), A.
nozawae (R.E.Norris) L.E.Phillips and A. dentata
L.E.Phillips. In particular, the Phillipsʼ new species, A. dentata, is unique and different from theother two speices in having elliptical blades withdentate margins.
Though A. lorentzii has a broad distribution to
the Indo-Paciﬁc Ocean including India, Japan,
Philippines, Indonesia, East Timor, Northern
Australia and New South Wales, distributions of
A. nozawae and A. dentata are restricted to small
areas of South Africa and Western Australia
respectively (Guiry and Guiry, 2014). In Japan
only A. lorentzii was recorded from several
islands belonging to Satsunan Islands,
Kagoshima Prefecture, Southern Japan: “Aneuria
lorenzii”, by Okamura (1929) and Nozawa(1965); “Lenormandiopsis lorenzii”, by Yoshida(1998); “Aneuianna lorenzii”, by Yoshida andYoshinaga (2010). In Japan, since Okamura(1929), the speciﬁc epithet has been spelled as“lorenzii”, though “lorentzii” is correct because in
the original description Weber-van Bosse (1911:31) spelled “Aneuria Lorentzi n. sp.” as a dedica-

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Taiju Kitayama

tion to the Dutch explorer, Dr. Hendrikus A.
Lorentz, who collected the type specimens of thespecies in Thursday Island, Torres Strait, Northern Australia in 18 June 1907.
Since 2010, as part of a review of geographical change in the Japanese marine benthic algalﬂora, the author has investigated deep sublittoral
algal habitats around the Ogasawara Islands (＝Bonin Islands), where notably rare brownalgae,
Discosporangium
mesarthrocarpum(Meneghini) Hauck (Kitayama, 2012) and Zosterocarpus ogasawaraensis Kitayama (Kitayama, 2013) have also been collected so far. During the investigations in the Ogasawara Islands, a
red algal material referable to Aneurianna, which
was unable to be identiﬁed with any known species, was collected twice. In this study, to conﬁrm the identity of a deep sublittoral red algal
species collected from off the coasts of both
Hahajima Island and Chichijima Island, in the
Ogasawara Islands, the author make anatomical
observations on the alga using a microscope.
Materials and Methods
The red algal material referable to the genus
Aneurianna was collected from the deep sublittoral zone (73–97 m in depth) off Hahajima Island
and Chichijima Island in the Ogasawara Islands
by dredge using the research vessel, the Koyo (87tonnage), operated by the Ogasawara Fisheries
Center, Tokyo Metropolitan in 2010 and 2013.
For preservation, the material was dried on
sheets of paper or ﬁxed in 10% Formalin-seawa-

ter. Anatomical observations were made on thematerial using a microscope. Voucher specimens
were deposited in the algal herbarium of the
National Museum of Nature and Science (TNS).
In this paper I basically follow the terminology
used by Phillips (2006).
Results
Order Ceramiales Oltmanns, 1904
Family Rhodomelaceae Areschoug, 1847
Tribe Amansieae Schmitz, 1889
Aneurianna ogasawaraensis Kitayama, sp. nov.
[Figs. 1–11]
Description: Thalli with erect thalli, up to
10 cm in height, stipitate, attached to solid substratum by a discoid holdfast, pink to red incolour. Stipes short, terete, occasionallybranched. Blades ﬂattened, orbicular to elliptical,
dorsiventral, up to 3.5 cm in width, rounded at
the base, with single midribs; apices loosely
incurved; margines dentate with triangularspines; surface pattern irregular elliptic. Medullae composed of irregularly ordered cells under asingle-layered cortex; a central-axial cell with
ﬁve pericentral cells and a few pseudopericentral
cells present. Reproductive organs unknown.
Holotype: TNS-AL 188560 (Fig. 1) deposited
in TNS (National Museum of Nature and Science, Tsukuba, Japan).
Type locality: Off Hahajima Island, Ogasawara Islands, Japan (26°44′08–15″N, 142°06′00–

Figs. 1–11. Aneurianna ogasawaraensis Kitayama. 1. Holotype. Thallus from Hahajima Island, Ogasawara
Islands, Japan (a dried specimen, TNS-AL 188560). 2. Isotypes including a ramiﬁed thallus (arrowhead) from
Hahajima Island, Ogasawara Islands, Japan (a dried specimen, TNS-AL 188561). 3. A thallus having abranched stipe from Chichijima Island, Ogasawara Islands, Japan (a dried specimen, TNS-AL 188564). 4.
Transverse section of midrib in the lower portion of blade. 5. Margin of the blade of the lower thallus showing
marginal dentations. This is an enlargement of the square frame in Fig. 2. 6. Detail of marginal dentations
showing a triangular spine and a divided spine. 7. Apical portion of blade with loosely incurved apex. 8.
Transverse section of upper portion of blade showing a central-axial cell (star). 9. Surface view of blade showing “elliptical areolation,” cell pattern with irregularly ordered various elliptical pattern visible through a layerof small cortical cells. 10. Transverse section of basal portion of blade showing a central-axial cell (star). Thiscross-section is slightly “V”-shaped in outline. 11. Transverse section of middle portion of blade showing acentral-axial cell (star), ﬁve pericentral cells (p) and three pseudopericentral cells (?).

Aneurianna ogasawaraensis sp. nov.

21″E; 73–81 m in depth).
Specimens examined: Off Hahajima Island,Ogasawara Islands, Japan (26°44′08–15″N,142°06′00–21″E; 73–81 m in depth), 5 July 2010,135leg. T. Kitayama (TNS-AL 188561–188563); Off
Chichijima Island, Ogasawara Islands, Japan(27°05′27″–04′68″N, 142°08′50″–08′37″E; 90–
97 m in depth), 16 July 2013, leg. T. Kitayama

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Taiju Kitayama(TNS-AL 188564).
Etymology: The species epithet ʻogasawaraensisʼ is from the Japanese name of theIslands (＝Bonin Islands).
Japanese name: Sujiari-gusa.
Habitat: Growing on rocky substrata.
Vegetative morphology: Thalli are erect, up to
9.8 cm in height, stipitate, epilithic, attached tostones (Figs. 1, 2). Holdfasts are discoid. Stipes
are short, cylindrical, occasionally branched (Fig.
2: arrowhead, Fig. 3). Blades are ﬂattened, orbicular (when young) to elliptical, up to 3.5 cm inwidth, rounded at the base, dark pink to red incolour (Figs. 1–3). Each blade has a midrib fromthe lower portion to the middle portion. Midribs
are conspicuous, single on each blade, formed bythickening of meddulae in the central portion of
the fronds (Fig. 4). Veins or microscopic lines areabsent. Margins of the blades are dentate (Fig. 5).
The marginal dentations are determinate, composed of many spines arranged at regular intervals. Spines are triangular, occasionally divided(Fig. 6). Apical portions of the blades are cavedin the center and the apices are incurved loosely(Fig. 7). The blades are composed of red singlelayered cortices with small cells and colorless
medullae with irregular-sized cell layers (Fig. 8).
The surface pattern is “elliptical areolation”. Various irregularly ordered ellipses are visible
through a layer of small cortical cells (Fig. 9).
The blades are dorsiventral and slightly “V”shaped in transverse view in the lowermost portions (Fig. 10). Medullae possess a central-axial
cell (star), ﬁve pericentral cells (p) and a few
pseudopericentral cells (?) (Fig. 11).
Reproductive morphology: Unknown.
The speciﬁc characters distinguishing Aneurianna ogasawaraensis from other members of thegenus are shown in Table 1. A. ogasawaraensis
agrees well with A. dentata, except for shape ofbasal portion of blades, presence of midribs, andramiﬁcation of stipes.
Discussion
The new red alga from the Ogasawara Islands,
Aneurianna ogasawaraensis, possess most of themain characteristics of the genus Aneurianna
deﬁned by Phillips (2006): broadly foliar blades;

Table 1. Comparisons of habit and morphology among Aneurianna ogasawaraensis and the other species of thegenus in the world

Height of thalli
BladesWhole shape
Width
ApicesBase
Margins
Midribs
Endgenous
branching
StipesDepth of habitat
Distribution

A. ogasawaraensis(Present study)

A. dentata(Phillips, 2006)

A. lorentzii(Phillips, 2006; Webervan Bosse, 1911)

A. nozawae(Phillips, 2006; Norris,
1987a, b)

up to 10 cm

up to 30 cm

up to 30 cm

up to 38 cm

orbicular to ellipticalup to 3.5 cm
incurved
round
dentatedistinct (macroscopic)
absentovate to ellipticalup to 8 cm
incurved
acute*
dentateabsentabsentirregular—
ﬂat or inﬂexed
round*
entire or lobed
faint (microscopic)
present

various
up to 12 cm
incurved
acute*
crenateabsent (or short)present

occasionally branched
73–97 mNorth Paciﬁc(Ogasawara Isls.)

unbranched
2–12 mIndian Ocean(S. Australia)

occasionally branchedsometimes branched
1–50 m45–60 mIndo-Paciﬁc
Indian Ocean (Natal)(S. India, Japan, Philippines, Indonesia, East
Timor, N. Australia,
New South Wales)* Judging from Figs. 4, 6, 7, 19, 21, 31–33 in Phillips (2006).

Aneurianna ogasawaraensis sp. nov.

discoid to hapteral holdfast, central axes encircled
by ﬁve pericentral cells and 1–4 pseudopericentral
cells; apices incurved or inﬂexed or ﬂat; two interdigitating layers derived from dorsal lateral pericentral cells; cortex single-layered; blade surfaces
marked by irregularly ordered elliptical pattern(“elliptic areolation”). In microscopic morphology,
the present species is basically not so different
from all other species of Aneurianna. However,Phillips (2006) mentioned another two essential
generic features: endogenous branching and lacking of midribs. The present species has no endogenous branching and possesses conspicuous midribs.
Endogenous branching observed in the tribe
Amansieae is inner ramiﬁcation of central axes
running under the cortical layers in the blade. On
the basis of the presence of endogenous branching in her new species, “Aneuria lorentzii,”
Weber-van Bosse (1911) raised J. Agardh(1982)ʼs subgenus “Aneuria” to a new genus separating from Lenormandia, though J. Agardhʼs“Aneuria” included only Lenormandia latifolia
Harvey et Greville in Harvey (1847). Papenfuss(1967) established Lenormandiopsis as a subsutitution for “Aneuria” because it was a later homonym of the liverwort genus Aneura Dumortier.
Aneurianna deﬁned by Phillips, who synonymized Lenormandiopsis Papenfuss with Lenormandia Sonder, is almost equivalent to “Aneuria”(J.Agardh) Weber-van Bosse (Phillips, 2006, p.
214). Lenormandia latifolia has no endogenous
branching, and thus endogenous branching isregarded as the most essential generic character
for Aneurianna. However, Aneurianna ogasawaraensis and A. dentata have no endogenous
branching in their blades. Both species keep ﬁne
elliptical blades without dividing all through thegrowth, while A. lorentzii and A. nozawae formed
irregular or various blades with many lobes andbranches. It suggests that absence of endogenous
branching maintains a simple elliptical outline of137

blades in A. ogasawaraensis and A. dentata.
Midribs are macroscopic structures of thickening medulla and distinguishable from microscopic veins, which are composed of several ﬁlaments of central axes. Aneurianna ogasawaraensis
differs from the other three species of the genus
in having a clear macroscopic midrib on eachblade. In fact, A. lorentzii has also faint midribs
or midlines (Phillips, 2006, p. 222), though thestructures are microscopic and may be axial ﬁlaments inside the blade tissue. On the other hand,
midribs in A. ogasawaraensis are macroscopic
structures formed by thickening of central areasof the blade, which is caused by cell divisions of
medullary layers in the central portion of blades.
In addition, according to Norris (1987b, p. 88),
A. nozawae has “a short midrib sometimes evident adjacent to stipe” on the blade, but there isno detail of the structures.
Although the signiﬁcance of absence ofendogenous branching and presence of midribs
in the present species is still unknown, the four
species of Aneurianna at the present state are
uniﬁed only on basis of the “surface areolation ofirregularly sized ellipses” as Phillips (2002)
made a key to this taxon (as Lenormandiopsis
pro parte). “Areolation” means blade–surface pattern when viewed under a microscope: “rhombic
areolation” is used for the generic features ofLenormandia, which has surface pattern withorderly lined rhombi on the blades. In particular,
for separating the two genera, Aneurianna andLenormandia, “areolation” seems to be usefulrather than absence/presence of endogenous
branching and midribs.
To clarify the relationship among the Aneurianna ogasawaraensis and other species of thegenus Aneurianna and to redeﬁne its generic circumscription, observations of reproductive
organs and molecular analyses on the new materials from Ogasawara Islands are required.

Key to the species of Aneurianna
1a. Blades irregularly shaped; margins of blades entire, lobed or crenate; lacking spines; endogenous
branching present . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

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Taiju Kitayama

1b. Blades elliptical; margins of blades dentate, bearing triangular spines; endogenous branchingabsent . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
2a. Margins of blades entire, lobed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A. lorentzii
2b. Margins of blades crenate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A. nozawae
3a. Blades acute at the base, lacking midribs; branching of stipes absent . . . . . . . . . . . . . . . . . A. dentata
3b. Blades round at the base, with midribs; branching of stipes present . . . . . . . . . . A. ogasawaraensis

Acknowledgments
I am grateful to Mr. Yuji Aoki, director of the
Ogasawara Fisheries Center, Tokyo Metropolitan, and the crew of the research vessel, Koyo,
for providing me the facilities to process the
specimens. I thank Drs. Hiroshi Namikawa,
Hironori Komatsu, Toshihiko Fujita, and Kazunori Hasegawa, Department of Zoology, National
Museum of Nature and Science, for their kind
help in the ﬁeld study in the island. I also thankDr. Masahiro Suzuki, Department of Biological
Sciences, Graduate School of Science, University of Tokyo, for his helpful comments for thisstudy, and Mr. Alex Barnes, North Carolina,
U.S.A., for correcting the English of the manuscript. This study was undertaken as a part of thesurveys of the ﬂora of Izu and Ogasawara Archipelagoes, Japan during 2006–2010, entitled“Study on Environmental Changes in the Sagami
Sea and Adjacent Area with Time Serial Comparison of Fauna and Flora.” A part of this study was
supported by Grants-in-Aid for ScientiﬁcResearch (no. 25440225) from the Ministry of
Education, Culture, Sports, Science and Technology, Japan.
References
Agardh, J. G. 1892. Anatecta Algologica. Asta Universitets lundensis 28: 1–182.
Guiry, M. D. and Guiry, G. M. 2014. AlgaeBase. Worldwide electronic publication, National University of
Ireland, Galway. http://www.algaebase.org; searchedon 8 August 2014.
Harvey, W. H. 1847. Nereis Australis. 64 pp., 26 pls.
Reeve Brothers, London.

Kitayama, T. 2012. First record of Discosporangium mesarthrocarpum (Meneghini) Hauck (Phaeophyceae,
Ochrophyta) from the Ogasawara Islands, Japan. Bulletin of the National Museum of Nature and Science,
Series B 38: 147–152.
Kitayama, T. 2013. Morphology of Zosterocarpus ogasawaraensis sp. nov. (Phaeophyceae, Ochrophyta), a new
marine deep-water brown alga from the Ogasawara
Islands, Japan. Bulletin of the National Museum of
Nature and Science, Series B 39: 159–164.
Norris, R. E. 1987a. Lenormandiopsis (Rhodomelaceae),
newly recorded from Africa, with a description of L.
nozawae sp. nov. and comparison with other species.
Japanese Journal of Phycology 35: 81–90.
Norris, R. E. 1987b. Structure and reproduction in Lenormandiopsis nozawae (Rhodomelaceae, Rhodophyta).
Cryptogamie, Algologie 8: 211–221.
Nozawa, R. E. 1965. On the female organ of “Sujinashigusa”, Aneuria lorenzii Weber van Bosse from Japan.
Bulletin of the Japanese Society of Phycology 8: 76–80(in Japanese).
Okamura, K. 1929. Icones of Japanese Algae 6: 4–5, pl.
253.
Papenfuss, G. F. 1967. Notes on algal nomenclature–V.
Various Chlorophyceae and Rhodophyceae. Phykos 5:
95–105.
Phillips, L. E. 2002. Taxonomy and molecular phylogenyof the red algal genus Lenormandia (Rhodomelaceae,
Ceramiales). Journal of Phycology 38: 184–208.
Phillips, L. E. 2006. A re-assessment of the species previously included in Lenormandiopsis including thedescription of Aneurianna gen. nov. (Rhodomelaceae,
Ceramiales). Cryptogamie, Algologie 27: 213–232.
Weber-van Bosse, A. 1911. Notice sur quelques genres
nouveaux dʼalgues de lʼArchipel Malaisien. Annales duJardin Botanique de Buitenzorg 24: 25–33.
Yoshida, T. 1998. Marine Algae of Japan [Shin Nihon
Kaiso-shi; Nihon-san Kaiso-rui Soran]. 25＋1222 pp.
Uchida Rokakuho, Tokyo (in Japanese).
Yoshida, T. and Yoshinaga, K. 2010. Checklist of marine
algae of Japan (revised in 2010). Japanese Journal of
Phycology 58: 69–122 (in Japanese).