Botanical Studies (2010) 51: 237-248.
SYSTEMATICS
Comparison of Ceriops pseudodecanda sp. nov. (Rhizophoraceae), a new mangrove species in Australasia, with related species
Chiou-Rong SHEUE1,2 *, Ho-Yih LIU3, Chi-Chu TSAI4, and Yuen-Po YANG3'5
1Department of Biological Resources, National Chiayi University, 300 Syuefu Rd., Chiayi 600, Taiwan
2 Department of Life ^Sciences, National Chung Hsing University, 250, Kuo Kuang Rd., Taichung 402, Taiwan
3Department of Biological Sciences, National Sun Yat-sen University, 70 Lien-hai Rd., Kaohsiung 804, Taiwan
4Kaohsiung District Agricultural Improvement Station, 2-6 Dehe Rd., Changihih Township, Pingtung County 908, Taiwan
5Department of Bioresources, Dayeh University, 168 University Rd., Dacun, Changhua 515, Taiwan
(Received August 28, 2008; Accepted September 24, 2009)
ABSTRACT. The notion that the widespread mangrove genus Ceriops consists of three species, C. austra-lis (White) Bailment, Smith & Stoddart, C. decandra (Griff.) Ding Hou and C. tagal (Perr.) C. B. Rob., is still widely accepted. However, our recent studies have shown that the previously recognized species Ceriops decandra can be separated into three species, C. decandra, C. zippeliana Blume and Ceriops pseudodecandra sp. nov. Sheue, Liu, Tsai & Yang based on morphological and molecular evidence. The last entity is newly described in this treatment, which has been misapplied with the name C. decandra for several decades in Aus­tralia, Papua New Guinea and Seram, New Guinea (Irian Jaya) of Indonesia. Morphologically, the new species is more similar to C. decandra and C. zippeliana than to C. australis and C. tagal. Furthermore, molecular phylogenetic analysis also supports the notion that C. pseudodecandra is distinctly a new species. Here, the botanical descriptions with an illustration and the distribution ranges of the related species are provided. A key to differentiate species of Ceriops and a comparison with an emphasis on these three morphologically similar species are given as well.
Keywords: Australia; Ceriops decandra; Ceriops pseudodecandra; Ceriops zippeliana; Indonesia; Mangroves; Papua New Guinea.
INTRODUCTION
Mangroves are the characteristic intertidal plant formations found along the sheltered tropical and subtropical coastlines. The mangrove flora consists of around 36 genera in 26 families (Saenger, 2002). Among the members, the pan-tropical family Rhizophoraceae, which comprises 16 genera and about 120 species of evergreen trees and shrubs (Hou, 1958), is the richest mangrove family with four exclusively mangrove genera. However, a detailed morphological and anatomical study of the mangrove Rhizophoraceae showed that two species belonged to Kandelia and Ceriops, separately, and should be added or described (Sheue, 2003). The species Kandelia obovata Sheue, Liu and Yong was later reported as a new species from East Asia (Sheue et al., 2003) and received a strong support by the study using microsatellite markers (Giang et al., 2006).
The last revision of the genus Ceriops was put forward by Hou (1958), with two species recognized: C. tagal
*Corresponding author: E-mail: crsheue@nchu.edu.tw; Tel: +886-5-22857395.
(Perr.) C. B. Rob. and C. decandra (Griff.) Ding Hou. Ceriops tagal is a common and familiar constituent of mangroves with a wide distribution range, from East Africa throughout Malaysia to Micronesia, Melanesia and northern Australia (Hou, 1958; Duke, 2006). Ceriops decandra is thought to range from India through Thailand, Vietnam and the Malay Peninsula, Java, Borneo, Philippines to New Guinea (Hou, 1958; Tomlinson, 1986; Field, 1995; Naskar and Mandal, 1999; Duke, 2006).
Ceriops australis (White) Ballment, Smith & Stoddart (1988) was added as the third member of the genus which was originally recognized as a variety of C. tagal by White (1926). The evidence for its elevation to species level was based on isozyme characters as well as the morphological feature of hypocotyl (Ballment et al., 1988). A recent evaluation concerning the taxonomic status of the species based on morphological and molecular evidence (Sheue et al., 2009a) supports this treatment.
As previously mentioned, another uncertain species was noticed in the genus Ceriops Arn. (Sheue, 2003). This uncertain species of Ceriops has been reverted to its original name C. zippeliana from its current applied name
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C. decandra (Sheue et al., 2009b). Ceriops zippeliana is morphologically and genetically discernible from C. decandra which occurs from India, Burma and the west coast of Thailand; and C. zippeliana should be the correct name for the populations in southeastern Asia to which the name C. decandra is misapplied (Sheue et al., 2009b). Moreover, a further analysis on the populations of the current 'C. decandra" in New Guinea and Australia reveals that they are morphologically different from C. zippelianan and C. decandra. This raises the question about the taxonomic status of the populations and attracts our interest to clarify their species identity.
After a detailed study using herbarium specimens, fresh materials, and visits to the habitats in Australia and Indonesia over four years, the authors have come to the conclusion that the so-called 'C. decandra, of Australia, New Guinea and Seram actually is yet an undescribed species based on morphological characters, palynological evidence and molecular evidence obtained in this study. Here, the botanical descriptions and the distribution ranges of this new species and related species are presented. A key to distinguish the five taxa of Ceriops is provided and the interspecific morphological differences are discussed, with an emphasis on the three morphologically similar species of C. decandra, C. pseudodecandra and C. zippeliana.
MATERIALS AND METHODS
Morphological and pollen characteristics
Fresh samples and herbarium materials were examined and photographed. Three to ten branches with flowers and viviparous seedlings were collected from each of five individuals of C. pseudodecandra along the riverbank of Blackmore River at Darwin of Northern Territory, Cairns of Queensland (October, 2005) and Cardwell of Queensland in Australia (May, 2007). In addition, a field survey for distribution range of Ceriops was especially carried out in Ambon, Seram, Sulawesi, Bali and Lombok of Indonesia (July- August, 2009). Voucher specimens were deposited in the Herbarium of National Chiayi University (CHIA). The specimens examined were from herbaria BM, BO, CAL, DNA, GH, HAST, IBSC, K, L, MO, PPI, SING, SINU and TAI (Holmgren and Holmgren, 1998).
Pollen grains were smeared on the surface of a microscope slide and examined with an Olympus BH-2 Light Microscope first to measure the size (N=30). Also, pollen grains were air dried and scattered on the surface of the stub covered with double-side tape and coated with gold directly. These samples were examined and photographed with a Hitach S-2400 Scanning Electron Microscope.
Molecular evidence
Materials. Samples of Ceriops decandra, C. zippeliana and C. pse udodecandra were collected at different localities of India, Singapore and Australia. Both C.
tagal and C. australis were included as outgroups for comparison (Table 1). Three to five leaves were taken from each individual and stored with silica gel in zip-lock plastic bags until DNA isolation. Voucher specimens were deposited at the Herbarium of National Chiayi University (CHIA).
DNA extraction, PCR amplification and electrophoresis, DNA recovery and sequencing. The detailed procedures of DNA extraction, conditions of PCR and sequencing for this study were similar to those described in the previous report (Sheue et al., 2009a) and the universal primers for amplifying the trnL intron of chloroplast DNA were the same as described by Taberlet et al. (1991).
Data analyses. DNA sequence alignment was conducted using the program ClustalW multiple alignment in BioEdit (Hall, 1999). Genetic relationships were then determined using the program MEGA version 4 (Tamura et al., 2007). The genetic distance matrix was calculated by the two-parameter method of Kimura (1980) and then used to construct the phylogenetic trees using the Neighbor joining (NJ) method (Saitou and Nei, 1987). Maximum parsimony (MP) analyses (Fitch, 1971) were done using code modified from the Close-Neighbor-Interchange (CNI) algorithm (Rzhetsky and Nei, 1992) in MEGA version 4 (Tamura et al., 2007). Bootstrapping (1000 replicates) was carried out to estimate the support for both NJ and MP topologies (Felsenstein, 1985; Hillis and Bull, 1993). The strict consensus parsimonious tree was then constructed using the program MEGA version 4 (Tamura et al., 2007).
TAXONOMIC TREATMENT
Ceriops pseudodecandra Sheue, Liu, Tsai, and Yang, sp. nov.―TYPE: Australia: Darwin Harbour: on banks of tidal Blackmore River (12°3'54.4" S, 130°57'56.9" E), C.-R. Sheue M234, 26th October 2005 (holotype: DNA;
isotypes: BM, BO, DNA, GH, HAST, K, L, MO and SING). Figures 1-3 and Table 2
Ceriops decandra auct. non (Griff.) Ding Hou: Hou, Flora Malesiana, ser. 1, vol. 5: 471, 1958. pro part.
Folia pseudodecandra vel obovato-elliptica, 6-12 cm longa, 2.5-5 cm lata, venis lateralibus primariis 8-12, petiolis 1.2-3.5 cm longis. Pedunculis brevissimis. Petala 5, multi-fida, lobis apice 12-18 laciniatis, cilia in dimidio inferiore.
Small trees up to 6 m tall; bark grayish brown with horizontal fissures of main stem, flaky and flanged buttresses at base. Leaves oblong to elliptic-obovate, 6-12(-13) cm x 2.5-5(-6) cm, apex obtuse, rounded to emarginate, base attenuate, lateral veins 8-12 pairs; petiole 1.2-3.5 cm long. Stipules 2-3 cm long at extension stage before dropping, with 8-12 layered, 80-100 colleters inside at adaxial base. Inflorescence compact bifurcate cyme­like, usually borne at the upper nodes of a branch, axillary, (2-)3-20 flowered. Bracteole 2-lobed, disc-like, sessile, 2 mm long, apex rounded with small fissures. Calyx lobes 5, erect while flowering and fruiting, ovate, acute, 3 mm
SHEUE et al. ― Ceriops pseudodecandra sp. nov., a new mangrove species
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Table 1. A list of molecular study for the 20 specimens of Ceriops decandra (Griff.) Ding Hou, C. pseudodecandra Sheue, Liu, Tsai and Yang, C. zippeliana Blume and two outgroup species of this genus, and their different geographical distributions and accession numbers.
No.
Taxon
Locations
Accession no.
Rh-26
C.
decandra
Pichavarum, India (IN)
EF118952
Rh-28
C.
decandra
West Sundarbans, India (IN)
EF118953
Rh-29
C.
decandra
West Sundarbans, India (IN)
EF118954
Rh-30
C.
decandra
West Sundarbans, India (IN)
EF118955
Rh-34
C.
decandra
West Sundarbans, India (IN)
EF118956
Rh-35
C.
decandra
West Sundarbans, India (IN)
EF118957
Rh-36
C.
decandra
West Sundarbans, India (IN)
EF118958
Rh-14
C.
zippeliana
Pasir Ris Nature Park, Singapore (SING)
EF118977
Rh-43
C.
zippeliana
Pasir Ris Nature Park, Singapore (SING)
EF118973
Rh-44
C.
zippeliana
Pasir Ris Nature Park, Singapore (SING)
EF118974
Rh-45
C.
zippeliana
Pasir Ris Nature Park, Singapore (SING)
EF118975
Rh-46
C.
zippeliana
Pasir Ris Nature Park, Singapore (SING)
EF118976
Rh-56
C.
zippeliana
Pasir Ris Nature Park, Singapore (SING)
EF118982
Rh-57
C.
zippeliana
Pasir Ris Nature Park, Singapore (SING)
EF118983
Rh-74
C.
pseudodecandra
Cairns, Australia (AU)
EF118959
Rh-84
C.
pseudodecandra
Cairns, Australia (AU)
EF118963
Rh-75
C.
pseudodecandra
Darwin, Australia (AU)
EF118960
Rh-76
C.
pseudodecandra
Darwin, Australia (AU)
EF118961
Rh-77
C.
pseudodecandra
Darwin, Australia (AU)
EF118962
Rh-13
C.
australis
Moreton Bay, Australia (AU)
EF118948
Rh-31
C.
tagal
West Sundarbans, India (IN)
EF118987
x 1.5 mm, calyx tube c. 2 mm in height. Petals 5, white, turning brownish, linear-rectangular, 2-2.5 mm x 1.5 mm (including terminal cilia), apex fingers-like, fringed with 12-18 sinuate cilia, 0.5 mm long, base broad, upper half margins glabrous, lower half margins hairy (< 0.1 mm),. Stamens 10, almost equal in length; filament 1.3 mm long; anther 0.9 mm long, ovoid, dorsifixed, with one short connective protrusion. Ovary inferior, 3-locular, 2 ovules in each locule, style 1.5 mm long, stigma 1, very shortly trifid. Persistent calyx tube hemi-globular, 4-5 mm in height, 6-9 mm in width, persistent lobes 5, 2.5-3.0 mm x 1.0 mm, slightly obliquely erect or ascending. Fruit ovoid-conical, 1.0-1.3 cm x 0.5-0.8 cm (calyx tube not included). Hypocotyl clavate, 10-16 cm x 0.5-0.8 cm, sharply ridged and sulcate, with an elongated acuminate apex (root tip), erect to pendant; epicotyl 10-13 mm long.
Distribution. Australia: northern coastal areas of Northern Territory and northern and eastern Queensland; Indonesia: Provinsi Papua, Provinsi Irian Jayat Barat (Irian Jaya), the Daru Islands and Seram (east, Hoti and Bula); Papua New Guinea: entire coastal mangrove areas (Figure 4).
Specimens examined. AUSTRALIA. Northern
Territory: Brennan 4563 (DNA), Craven 4611, 4613, 6430
(DNA), Dunlop 8644 (DNA), van Kerkhof 50 (DNA), Mckean 1026, 1027 (DNA), Rankin 1721 (DNA), Risler and Kerrigan 1 86 (DNA), Risler and Mangion 346 (DNA), Russel-Smith and Lucas 5801 (DNA), Sheue M232-M235 (CHIA), Smith D3126 (DNA), Wells s. n. [1975], [1978], [1979] (DNA), Wells 26 (DNA), Wightman388, 476, 535, 542, 1480, 2104, 2471, 2289, 7328 (DNA). Queensland: Macnae s. n. [1962] (GH, L), Neldner 3733 (DNA), Sheue M241, M315-M317 (CHIA), Smith 3998, 11593, 11617, 12443 (GH, L). PAPUA NEW GUINEA. Boroi (Prov. Madang, Dist. Bogia): Iserentant 9052, 9423 (BM); Central District: Darbyshire 777 (BO, GH), Wiakabu et al. LAE70426 (BO); East Papua: Pullen 8155 (GH, MO); Gulf District: Kerema Bay: Schodde 4204 (K). INDONESIA. ARU ISLANDS: Turner and Mamesah 22 (BO, GH, K); Irian Jaya: Fanani and Wiharja 405 (BO), Johns 9648 (BO), Salverda 150 (BO), Utteridge 37 van Royen 4921 (BO, GH); Moluccas: Seram (east): Buwalda 5981 (BO), Mirmanto and Rukandi ERI46 (BO), Komassi 927 (BO), Sheue M481-482 (CHIA); Western Division: Daru Island: Foreman et al. LAE60490 (GH), Brass 6213 (BM), 6214 (K), Pringgo 42 (BO), Streimann and Lelean NGF18467 (GH), Simaga 786 (GH), Versteegh BW4928 (GH); West of Hisiu: Leach 3803 (GH); Yapen Island: Aet andIdjan 682 (GH, K, L), 971 (BO, K).
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Figure 1. Illustration of Ceriops pseudodecandra Sheue, Liu, Tsai, and Yang. A, A shoot with flowers, fruit and hypocotyl; B, Seedlings with a prominent epicotyl up to 1.3 cm and elongated oblong young leaves; C, Fruit with a persistent hemi-globular calyx tube, erect calyx lobes, and a clavate hypocotyl with an acuminate sharp apex; D, Stipule; E, Half part of the adaxial base of stipule with colleters; F, A dense bifurcate cyme-like inflorescence; G, Lateral view of a flower; H, Top view of a flower; I-J, Lateral views of flowers, part of calyx lobes and petals removed; K, Lateral view of petals from a flower; L, Sepals of adaxial (left) and abaxial (right) sides; M, Petals of adaxial (right) and abaxial (left) sides; N, Stamens; O, Style; P, Cross section of ovary. (Material from Holotype: DNA, C.-R. Sheue M234, 26th October 2005, collected from banks of tidal Blackmore River of Darwin Harbour, Australia)
SHEUE et al. ― Ceriops pseudodecandra sp. nov., a new mangrove species
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Ceriops decandra (Griff.) Ding Hou, Flora Males. 1, 5: 471. 1958. pro part. & descr. emend. & excl. syn. C. zippeliana Blume (Table 2) (Holotype, CAL: Ejusdem Icones, vol. 8, t. 116 ！)
Bruguiera decandra Griff. (1836) 10.
Ceriops roxburgiana Arn. (1838) 364. pro part.
Rhizophora decandra Roxb. (1814) 36. nomen.
Shrub or small tree, 2-5 m tall; bark light-gray, peeling off into thin flakes, stilt roots developed at base. Leaves oval to obovate, 4-9 cm x 2.5-6 cm, apex obtuse, rounded to emarginate, base obtuse to cuneate, lateral veins 8-10 (-11) pairs; petiole 1.2-1.8 cm long. Stipules 1.2-2.4
Figure 2. Habitat and morphological characters of Ceriops pseudodecandra Sheue, Liu, Tsai, and Yang. A-B, Plants in the mangroves of Darwin, Northern Territory of Australia; C-E, Plants in the mangroves of Cairns, Queensland of Australia. A, An individual tree with patch-like detached bark and buttress near trunk base; B, Stems with horizontal fissures (narrow arrow) on bark and reddish brown wood (broad arrow). Note a fruit with a lifted hypocotyl (H); C, Two young seedlings with typically oblong leaves; D, Dense bifurcate cyme-like inflorescences, each with 6-10 flowers; E, Fruit (brown color) and the elongated hypocotyls toward different directions (arrows).
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in each locule, style 2.5-3 mm long, stigma 1, very shortly trifid. Persistent calyx tube hemi-globular, 5-9 mm in height, persistent lobes 5, 4 x 1.6-2.0 mm, ascending. Fruit ovoid, 0.6-1.0 cm x 0.5-0.6 cm. Hypocotyl clavate, 8-13 x 0.5-0.7 cm, ridged and sulcate, width approximately the same, slightly tappering towards a blunt apex (root tip), erect to pendant; epicotyl 2-3 mm long.
Notes. The type of this species (Ejusdem Icones, vol. 8, t. 116) and the drawing of Roxburgh,s collection 1140 in Kew Library were examined. Basically, the latter was a copy from the former but omitting the dissected flower with pistil and a stamen. See Sheue et al. (2009b) for the illustration and specimens examined.
Distribution. India, Bangladesh through Burma to southeastern Thailand (Satun) (Figure 4).
Ceriops zippeliana Blume, Mus. Bot. 1: 143. 1849.
Ceriops decandra auct. non (Griff.) Ding Hou (1958) 471. pro part.
Main diagnostic characters were listed in Table 2. See Sheue et al. (2009b) for detailed description, illustration and specimens examined.
Distribution. The southwestern coast of southern Malay Peninsula through Singapore, Bintan Island, the east coast of the Malay Peninsula to the Gulf of Thailand to Vietnam, the Philippines, Borneo, Sulawesi (Celebes), Moluccas (Seram), Lesser Sunda Islands and Java (Figure
4).
Key to species of Ceriops of Rhizophoraceae
1a. Petal apex with 3(-5) clavate appendages; inflorescence axis relatively long and slender (10-30 mm x 2 mm), bending downwards.
2a. Hypocotyl terete (without ridges) usually less than 10 cm long at maturity; base of calyx lobe in flowering 12-15 mm in width; stipule usually shorter than 1.2 cm long at extension stage ........ C. australis
2b. Hypocotyl angular (with ridges) 9- 25 cm long at maturity; base of calyx lobe in flowering 18-25 mm in width; stipule usually longer than 1.2 cm long at extension stage ............................................ C. tagal
1b. Petal apex fringed with 1 2-25 sinuate cilia; inflorescence axis relatively short and stout (3-10 mm x 3-4 mm), erect.
3a. Inflorescence simple and head-like with 3-5 flowers; petals hairless along margins; persistent calyx tube short (2-3 mm) and disc-like ............... C. zippeliana
3b. Inflorescence dense bifurcate cyme-like with 6-20 flowers; petal hairy at least along lower margins; persistent calyx tube long (4-9 mm) and hemi-globular (dome-like).
4a. Entire margins of petals with dense and long hairs (0.5 mm); style 2.5- 2.8 mm long, epicotyl 2-3 mm long; length ratio of fruit to calyx tube 1~1.5 at maturity ............................ C. decandra
Figure 3. Floral characters of Ceriops pseudodecandra Sheue, Liu, Tsai, and Yang. Abbreviations: A: anther; B: secondary bract; Bl: bracteole; CL: calyx lobe; F: filament; P: petal; St: style. A-B, Floral lateral views, two calyx lobes and petals removed in B; C, Petals of adaxial (left) and abaxial (right) sides. Note the lower half margins with loose and short hairs (< 0.1 mm) (between the two white arrows) and a longitudinal ridge of the abaxial side (black arrow); D, Stamen; E-F, Polar view (E) and equatorial view (F) of pollen grains, exine smooth with sparsely distributed punctae. Scale bars: 1.5 mm in A-B; 1 mm in C-D; 5 |im in E-F.
cm long, with 7-8 layered colleters inside adaxial base. Inflorescence compact bifurcate cyme-like, axillary, generally 16 buds, (4-)6-1 0(-12) matured. Bracteole 2-lobed, disc-like, sessile, 1 -2 mm in length, apex rounded, with 0-3 colleters inside. Calyx lobes 5, erect while in flowering and in fruiting, ovate, acute, 4 mm x 2 mm. Petals 5, white, turning brownish, linear-rectangular, 4 mm x 1.8-2.0 mm (including terminal cilia), apex fingers-like, fringed with 20-25 sinuate cilia, 0.8-1.25 mm long, margins entire with long and dense hairs (0.5 mm), base broad, folded longitudinally with a distinctive ridge. Stamens 10, equal in size; filament 1.6-2.0 mm long; anther 1-1.2 mm long, ovoid, dorsifixed, with one long connective protrusion. Ovary inferior, 3-locular, 2 ovules
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Table 2. The comparison of morphological characters among Ceriops decandra (Griff.) Ding Hou, C. pseudodecandra Sheue, Liu,
Tsai and Yang and C. zippeliana Blume.
Characters
Ceriops decandra
Ceriops pseudodecandra
Ceriops zippeliana
Stipule
1.2-2.4 cm before dropping, with
2.0-3.0 cm before dropping, with 80-100 2.5-3.6 cm before dropping, with
50-70 colletors at adaxial base
colletors at adaxial base (8-12 layered)
154-190 colletors at adaxial base
(7-8 layered)
(18-20 layered)
Leaf
Oval to obovate, 4.0-9.0 cm x
Oblong to elliptic-obovate,
Obovate-elliptic, 5.5-11.0 cm x 3.0-7.5
2.5-6.0 cm, lateral veins 8-10(-11),
6.0-12.0(-13.0) cm x 2.5-5.0(-6.0) cm,
cm, lateral veins (9-)11-12(-13),
petiole 1.2-1.8 cm in length
lateral veins 8-12, petiole 1.2-3.5 cm
petiole 1.5-2.6 cm in length
in length
Inflore-
16 buds, (4-)6-10(-12) matured,
(2-)3-20 flowered, dense bifurcate
3-5(-7) flowered, simple head-like,
scence
dense bifurcate cyme-like, with
cyme-like, with primary and additional
with primary bract only
primary and additional bracts
bracts
Bracteole
1-2 mm in length
2 mm in length
2.6 mm in length
Calyx
5 lobed, 4.0 mm x 2.0 mm
5 lobed, 3.0 mm x 1.5 mm
5 lobed, 2.0-3.0 mm x 2 mm
Corolla
5, 4.0 mm x 1.8-2.0 mm (including
5, 2.0-2.5 mm x1.5 mm (including
5, 3.0-3.5 mm x1.8 mm (including
terminal cilia), entire margins
terminal cilia), upper half margins
terminal cilia), margins hairless, apex
with dense and long hairs (0.5
glabrous, lower half margins with
finger-like fringed with sinuate 13-17
mm), apex finger-like fringed with
loose and short hairs (< 0.1 mm), apex
cilia, 0.5-0.8 mm long
20-25 sinuate cilia, 0.8-1.25 mm
finger-like fringed with 12-18 sinuate
long
cilia, 0.5-0.6 mm long
Stamens
10, filament 1.6-2.0 mm long,
10, filament 1.3 mm long, anther 0.9
10, filament 1.0 mm long, anther 1.0
anther 1.0-1.2 mm long, with one
mm long, with one short connective
mm long, with one short connective
long connective protrusion
protrusion
protrusion
Style
Style 2.5-2.8 mm long
Style 1.4-1.5 mm long
Style 2.0-2.2 mm long
Pollen
L = 21.0 士 1.49 jam in equator view,
L = 19.7 士 1.2 jam in equator view,
L = 15.43 ±1.16 jam in equator view,
exine scabrate with punctae
exine smooth with sparsely distributed
exine irregularly regulo-reticulate
punctae
Fruit
Calyx hemi-globular (dome-like),
Calyx tube hemi-globular, 4-5 mm high,
Calyx tube shallow disc-like, 2-3 mm
5-9 mm high, persistent lobes
persistent lobes 5, 2.5-3.0 mm x 1.0
high, persistent lobes 5, 2-2.5 x 1-1.5
5, 4.0 x1.6-2.0 mm; fruit ovoid,
mm; fruit ovoid-conical, 1.0-1.3 cm x
mm; fruit ovoid-conical, 1.2-1.5 cm
0.6-1.0 cm x 0.5-0.6 cm, no
0.5-0.8 cm, no special decoration
x 1.0 cm, with netted decoration
special decoration
Hypocotyl
8-13 cm x 0.5-0.7 cm, gradually
10-16 cm x 0.5-0.8 cm, gradually
9-17 cm x 0.7-0.8 cm, gradually
thickening with a blunt apex (root
thickening with an acuminate sharp
thickening with a acute sharp apex
tip)
apex
Epicotyl
2-3 mm long
10-13 mm long
2-3 mm long
4b. Lower half margins of petals with loose and short hairs (0.1 mm); style 1.4-1.5 mm long, epicotyl 10-12 mm long; length ratio of fruit to calyx tube 2~3 at maturity .....................C. pseudodecandra
Molecular evidence
Sequence alignment and characteristics. PCR products from all samples studied were directly sequenced. The accession numbers of those plastid DNA sequences from the seven accessions of C. decandra, seven accessions of C. zippeliana, and five accessions of C. pseudodecandra plus two outgroups are shown in Table 1. Those sequences were aligned and resulted in 662 characters, from which 17 and 13 were variable and informative parsimony sites, respectively. The aligned data matrix and tree files are available from the author (tsaicc@mail.kdais.gov.tw). The
genetic distance estimated from the 2-parameter method of Kimura (1980) is 0.0034 between C. decandra and C. pseudodecandra and 0.0051 between C. zippeliana and C. pseudodecandra. Two stable transversions are found within this DNA region between C. pseudodecandra and C. decandra/C. zippeliana (data not shown).
Phylogeny reconstruction. The phylogenetic tree for the intron of trnL used characters that are equally weighted. Based on the MP method, the analysis yields 300 equally parsimonious trees with a length of 18 steps, a consistency index (CI) of 1.0, and a retention index (RI) of 1.0. The strict consensus tree is shown in Figure 5. More than 50% of the bootstrap values are shown below/above the supported branches for MP tree. The NJ tree and the MP strict consensus tree constructed from plastid DNA data are highly congruent (Figure 5, MP tree presented only).
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Figure 4. The distribution ranges of Ceriops decandra (Griff.) Ding Hou (solid circle), C. pseudodecandra Sheue, Liu, Tsai, and Yang (open circle) and C. zippeliana Blume (double circle). The question mark refers to the doubtful locality in area of Ambon and western Seram where no population of C. zippeliana has been found currently.
Based on the MP tree, accessions of C. pseudodecandra form a clade supported by a 82% bootstrap value and are separated from either accessions of C. decandra or accessions of C. zippeliana. Therefore, the molecular data also support the distinctness of accessions of C. pseudodecandra.
Ceriops pseudodecandra often appears as a small tree less than 5 m in height, with grayish brown bark, flaky and flanged buttresses at base (Figure 2A) with horizontal fissures of main stem (Figure 2B). However, a sheet of specimen Simaga 786 (GH) recorded it a tree 12 m in height at Daru of Papua New Guinea. Compared to the brown stem and flaky base of C. pseudodecandra, C. australis and C. tagal usually have a gray-white to orange-brown stems with protruded and rounded lenticels.
The leaf shape of the new species is mostly oblong to elliptic-obovate with 8-12 pairs of lateral veins (Table 2), and interestingly the populations from New Guinea have especially typically oblong leaves up to 13 cm in length. The elongated oblong leaves of the young seedlings in shade environment could easily be observed from the habitat (Figure 2C). The features of somewhat oblong leaves and distinctly acuminate leaf bases of the
Figure 5. The strict consensus parsimonious tree of seven accessions of Ceriops decandra (Griff.) Ding Hou, five accessions of C. pseudodecandra Sheue, Liu, Tsai, and Yang, seven accessions of C. zippeliana Blume and plus two outgroups derived from the trnL intron sequence. Bootstrap values > 50% are shown on each branch.
SHEUE et al. ― Ceriops pseudodecandra sp. nov., a new mangrove species 245
new species are helpful to discern it from other species of Ceriops. Wightman (2006) accurately described C. decandra (i.e. C. pseudodecandra) in Northern Territory of Australia as having elliptic-oblong leaves. In addition, Tomlinson (1986) noticed the larger and darker leaves of C. decandra (i.e. C. pseudodecandra) in Queensland and assumed that it might be a result of habitat differences. The sun leaves of C. pseudodecandra with slightly reflex margins are often orientated straight up in the air to avoid strong sunlight (Figure 2D-E). This phenomenon of sun leaves is also quite common for C. australis and C. tagal in Australia and they have even more strongly reflexed margins (Sheue, per. observ.).
The feature of inflorescence has an important diagnostic value for differentiating the two groups of Ceriops, namely C. australis and C. tagal, and C. decandra, C. pseudodecandra and C. zippeliana. The former group has relatively long and slender peduncles and the latter group has short and stout ones. Moreover, the inflorescence of C. zippeliana is simple head-like (Sheue et al., 2009b); however, those of C. decandra and C. pseudodecandra are dense bifurcate cyme-like (Table 2). This difference can be observed from the series of bracts below each bracteole of a flower and has been noted by Sheue (2003). Ceriops zippeliana only has a primary bract (Sheue et al., 2009b) while C. decandra (Sheue et al., 2009b) and C. pseudodecandra have additional secondary bracts or even more multi-ranked bracts of an inflorescence with more flowers.
Features of petal morphology also correlated with the inflorescence features used to divide the genus into two groups, petals of C. australis and C. tagal with 3 (-5 of C. australis) clavate appendages (Sheue et al., 2009a); petals of C. decandra (Sheue et al., 2009b), C. pseudodecandra and C. zippeliana (Sheue et al., 2009b) with finger-like fringes containing 12-25 sinuate cilia (Table 2; Figure 3A-C). Furthermore, the most conspicuous difference of the petal for the latter three taxa is the feature of petal margins. The margins of the petals of C. zippeliana are hairless (Sheue et al., 2009b) whereas those of C. decandra are densely covered with long hairs c. 0.5 mm in length (Sheue et al., 2009b) and only the margins of the lower half petals of C. pseudodecandra are covered with loose and short hairs less than 0.1 mm (Figure 3C).
The difference of the floral parts and pollen grains of these three species of Ceriops is distinctive (Table 2). Ceriops decandra has relatively larger flower size (4 mm long calyx lobes) and floral parts (including sepal, petal, stamen and style) than those of C. pseudodecandra and C. zippeliana (2-3 mm long of calyx lobes). All the species of Ceriops have tri-colporate pollens (Das and Ghose, 1990; Sheue, 2003). In terms of the size of pollen grains, those of C. decandra are the largest (21 [im in length) and those of C. zippeliana are the smallest (15.4 [im in length). The pollen grains of the new species (19.7 [m in length) are slightly smaller than those of C. decandra. The most evident pollen character served for differentiating these
taxa is the micro-surface features. The pollen grains of new species have smooth with sparsely distributed punctae exine (Figure 3D-E) while those of C. decandra have scabrate with punctae exine (Das and Ghose, 1990; Sheue et al., 2009b) and those of C. zippeliana have irregularly regulo-reticulate exine (Sheue et al., 2009b).
The ovoid fruit of Ceriops has persistent calyx tubes and calyx lobes and their detailed morphology is useful for interspecific differentiation (Table 2). The new species (Figure 1 C) and C. decandra (Sheue et al. , 2009b) have hemi-globular (dome-like) calyx tubes, 5- 9 mm in height while C. zippeliana (Sheue et al., 2009b) has shallow disc-like calyx tubes about 2-3 mm in height. However, the fruit of the new species is more similar to C. zippeliana appears as ovoid-canical. This feature leads to a higher ratio of fruit length to calyx tube length of C. pseudodecandra (2-3) than that of C. decandra (1-1.5). The hypocotyl of the viviparous seedling of C. decandra is gradually thickened with a blunt apex (root tip) and that of C. zippeliana is also gradually thickened but with a sharp apex (Sheue et al., 2009b). The hypocotyl of the new species slightly resembles that of C. zippeliana, but has a more distinctly elongated acuminate sharp apex (Figure 1C). In addition, an easily recognizable feature of the seedling is the length of the epicotyls. The epicotyls of the new species are prominent and much longer (usually 10-13 mm in length) than those of the other species of Ceriops (2-3 mm in length) (Figure 1B). It is noteworthy that the length of epicotyl of the new species is constant and could serve as a good character to differentiate C. pseudodecandra from other taxa of this genus although this feature has not been mentioned before.
The major flowering peak of C. pseudodecandra is during September to November, and fruiting occurs from October to February in both the Northern Territory (Wightman, 2006) and northern Queensland (Duke, 2006) of Australia. Based on the observation of herbarium specimens and a field trip (Sheue, personal observation), the populations of New Guinea (including Papua New Guinea and Indonesia) seem to flower earlier, from July to October, and some may start from January to June. It is quite common to have the mature viviparous seedlings with cotyledon collars on the same tree while flowering. It is highly possible that the fruit and propagule maturation takes about 1 2 months in C. pseudodecandra, as for C. australis in the Darwin area of northern Australia
(Coupland et al., 2005).
Based on our current field survey and examination of herbarium specimens, the distribution range of C. pseudodecandra includes Seram, the Daru Islands, Irian Jaya of Indonesia, Papua New Guinea and Northern Territory and Queensland of northern Australia (Figure 4). The southern boundary in Queensland is down to Hinchinbrook Channel in the east of Queensland (Duke, 2006; Sheue, personal obser.). In Australia, it occurs scattered through tidal forest, but more commonly toward landward margins of tidal waterways (Wightman, 2006).
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Generally, this new species does not form a monotypic stands, but prefers mixed forests (Duke, 2006), occurring with Ceriops, Bruguiera, Xylocarpus and Rhizophora (Sheue, personal obser.).
It is interesting to examine the distributional relationship of C. pseudodecandra and C. zippeliana in South Asia. According to herbarium specimen information, C. zippeliana ranges from West Malaysia through Singapore, eastern Malay Peninsula, to the Philippines, Borneo and most of Indonesia, but not including Irian Jaya (Sheue et al., 2009b). Although two herbarium specimens of C. zippeliana had been collected from Maluku area in 19th century, there is no such population found in Seram and Ambon (the major islands of Maluku) according to the current field trip in 2009 by the first author and the surveys of Indonesian scientists (Suhardjono, personal communication). However, the new species, C. pseudodecandra was found by the first author in eastern Seram (Hoti, Bula) which was accordant with the early historical collection. Due to the misapplication of the name C. decandra for these two species prevailing in these areas over several decades, a detailed survey for the distributional ranges of these two taxa around New Guinea and its surrounding islands is still necessary.
Besides the previous morphological and palynological evidence, the molecular evidence of the trnL intron of plastid DNA supports the taxonomic status of C. pseudodecandra as a new taxon as well. In this study, the genetic distance is 0.0034 between C. decandra and C. pseudodecandra and 0.0051 between C. zippeliana and C. pseudodecandra. Based on the MP tree, accessions of C. pseudodecandra form a clade supported by a 82% bootstrap value and are separated from either accessions of C. decandra or accessions of C. zippeliana (Figure 5). Using the inter-simple sequence repeat (ISSR), Tan et al. (2005) attempted to understand the population genetic s truc tu re o f th e p re vio us l y re c og nized C . de c a n dra populations (including three taxa), in the Malay Peninsula and North Australia. At the species level, high genetic variation (P=72%, HE=0.253, and 7=0.379) and high estimate of Gst (up to 0.882) were detected and the populations were grouped into different major geographic regions from a UPGMA dendrogram (Tan et al., 2005). After the attentive taxonomic studies on Ceriops, the UPGMA dendrogram reported by Tan et al. (2005) could be harmonized with the geographic range of the three taxa of Ceriops reported in this study (Figure 4).
Over all, the new species exhibits a high morphological similarity to C. decandra and C. zippeliana, and shows several intermediate features between these two taxa. The occurrence of this new species appears to restrict in Australasia geographic region of Indo West Pacific, according to world distribution of mangroves (Duke, 1 992). A further intensive survey of this taxon in this region still needed. In addition, as Juncosa and Tomlinson's (1988) suggested 'If we can devote at least as much time to observation as we are doing speculation
about phylogenies, then our understanding is likely to improve', a comprehensive observation for the mangrove species with their distributional ranges may be still needed.
Acknowledgements. The authors thank two anonymous reviewers for valuable suggestions, M. S. B. Ku for improving manuscript; D. Foster, C. Mangion, K. Metcalfe, P. Saenger and G. Wightman (Australia) for helping to collect materials; S. H. Yen for copying the references in London; C. K. Liao for the line drawing of the specimen; S. H. Chen for describing features of pollen grains and the following herbaria for permission to study and/or loans of specimens, BO, BM, CAL, DNA, GH, HAST, IBSC, K, L, MO, PPI, SING, SINU and TAI. This
study was supported by the National Science Council
(NSC95-2621-B-020-004-MY2) of the Republic of
China and part of the fund of National Chiayi University
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擬印度細蕊紅樹（紅樹科）一產自大洋洲的新種紅樹林
植物及其相近種的比較
許秋容1,2 劉和義3,4 蔡奇助4 楊遠波3,5
1國立嘉義大學生物資源學系
2國立中興大學生命科學系
3國立中山大學生物科學系
4行政院農業委員會高雄區農業改良場
5大葉大學生物資源學系
分布廣泛的細蕊紅樹屬{Ceriops)包含三種紅樹林植物：澳洲細蕊紅樹（C. australis)、印度細蕊紅
樹（C. decandra)與細蕊紅樹(C. tagal)之看法至今仍廣爲接受。然而，近年的硏究發現原來所認知的C.
decandra實則包含三個分類群'C. decandra 、齊氏細蕊紅樹(C. zippeliana)和一新種一擬印度細蕊紅樹
(C. pseudodecandra)。本文即報導此一產於澳洲、巴布亞新幾內亞及印尼的新種紅樹林植物，數十年來
本物種一直被錯誤地認定爲C. decandra 。本新種較接近於C. decandra與C. zippeliana '且表現出若干
介於此兩者之間之形態特性；除此，分子生物學的證據亦支持C. pseudodecandra成爲一新種的地位。
本文提供了新種植物與其相近種的描述、繪圖和分布、本屬植物的檢索表及此三種相近物種間的詳盡比
較與討論。
關鍵詞：澳洲；印度細蕊紅樹；擬印度細蕊紅樹；齊氏細蕊紅樹；印尼；紅樹林；巴布亞新幾內亞。