Four Species of Halimeda viz. H. incrassata, H. opuntia. H simulans and H taenicola

collected from Lakshadweep islands are described in detail

Kaliaperumal, N

Kalimuthu, S

Rajendran, M

Sundararajan, M

CMFRI Digital Repository

... -, Seaweed Re!. Utiln., 21 fl&2) ,' 161 -169 , 1999 Studies on species of Halimeda from Lakshadweep M. SUNDARARAJAN', M. RAJENDRAN ', N. KALlAPERUMAL ' AND S. KALIMlJfHU • I Department of Botany, Arignar Anna Govt. Arts College, Namakkol, India , Govl. Higher Secondary School, Yethapur, Salem Districl, India J. • Regional Centre of Central Marine Fisheries Research Inslilule, Marine Fisheries - 623 520, India ABSTRACT Four Species 'Of Halimeda viz. H. incrassala, H. opun/ja. H simularu and H taen;cdla collected from Lakshadweep islands are described in detail . Introduction Calcareous algae are an integral part of the coral reef ecosystem and ' they contribute to a great extent to the building up of tbe coral rocks. These algae belong to various taxonomic groups. Halimeda is one of the most common calcareous marine algae in tropical waters. Krishnamurthy and Joshi (1970) listed 6 species of Halimeda from Indian coast. They are Halimeda discoidea Decaisne, H. gracilis Harvey ex J. Agardb, H. macrolobo Decaisne, H. opunlio (Linnaeus) Lamouroux, H. popyracea Zanardini and H. tuna (Ellis & So lander) Lamouroux. Krishnamurthy and Jayagopal (1995) reported H. gracilis, H. macrolob~, H. opuntio and H. luna from the Galaxea reef at Krusadai Island. Sundararajan el. al. ( 1996) described H. dislorla (Yamada) Hillis collected from Pamban area, in addition to H. discoidea Decaisne , H. macroloba Decaisne and H. luna (Ellis & So lander) Lamouroux. In a report on the survey of marine algal resources of Laksbadweep. Subbaramaiah el. al. (1979) reported the occurrence of Halimeda gracilis from the lagoons of Agathi, Amen;, Kadamath, Chedat Kiltan, Androth, Kalpeni and Minicoy islands. Kaliaperumal el. 01. (1989) bave reported the occurrence of H. gracilis from all islands of Lakshadweep and H. incrassala at Kalpeni Island, H. macroloba at KaJpeni and Androth islands and H. opunlia f opunlia (typica) at Kalpeni and Kavaratti islands. In the present study, some Halimeda species collected from Lakshadweep were examined in detail and 4 species, H. incrassla (Ellis) Lamouroux, H. opuntia (Linnaeus) Lamouroux, H. simulans Howe and H. /(Jenicola WR Taylor (Plate I) are described . Of these, only H. opunlia (Linnaeus) Lamouroux has been recorded previously from India. Materials and Methods Specimens of Halimeda were collected from the Lakshadweep islands during the period January to March 1987 by CENTRAL  MARINE FISHERIES RESEARCH INSTITUTE, COCIN.M Sundararajan, M Rajendran, N. Kaliaperumal and S. KalimUlhu 162 N. Kaliaperumal and S. Kalimuthu. The materials were washed tborougbly in seawater and preserved in 5% fonnalin. The external morphology of each species was studied. For studying tbe internal anatomy, segments of tbe tballus were decalcified by soaking tbem in Perenyi's fluid (Sundararajan et. al., 1996). After complete decalcification, segments were separated, repeatedly washed in !Tesh water and then placed in a drop of 10% glycerine in the middle of a slide. The material was carefully teased out so as to expose the coenocytic filaments. Few semipennanent slides were prepared !Tom the lower mature region and nodal regions. Microscopic observations were made on dimensions of the medullary filaments, their mode of branching, the extent of cortex, number of layers of utricles and number of peripheral utricles borne upon an inner utricle. The behaviour of the medullary filaments at the node was also studied. The filaments of the node exhibit different types of fusion among themselves. Camera-Iucida drawings of these structures were made. The identifi-cation of the species was made using the monograph on Halimeda by Hillis (l959). Halimeda incrassata (Ellis) Lanrouroux The specimens collected from Kalpeni island were examined. The plants grow to about 20 cm in height, branching mostly trIchotomously, dichotomy being noticed occassionally. When the branching is dichotomous, the three branches originate respectively from the three lobes of a lower segment. One of the important characters to be observed is the complanate nature of branching i.e. the branches occur in a single plane. The segments in the upper half of the thallus are moderately calcified. The segments in the lower region of the thallus are cylindrical and about 5 mm in beight. Majority of the other segments are broadly fusifonn viz. broader in the middle with either and being narrower, .thereby presenting a somewhat monilifonn appea-rance. The margin of the segment is invariably trilobed, occasionally undulate. The length of the segment varies from 3-4 mm, the breadth !Tom 1.5-6 mm. The thickness of the segments is upto I mm. Anatomically, there is a central medulla surrounded by a cortex. The medulla comprises vertically running coenocytic filaments, 93.5 to 131 !lm in diameter. These filaments branch mostly trichotomously. From the medullary filaments many cortical filaments arise laterally which ~onstitute the cortex. The cortical filaments are made up of 3 to 4 layers ofutricles. The innennost utricle is not inflated but elongated, measuring 374 !lm in height. The secondary utricle bears on its apex 2 peripheral utricles. In surface view tbe peripheral utricles present an angular apperance with a diameter ranging !Tom 37 to 56 !lm (Fig. I). At the nodal region all the medullary filaments are adherent in the middle . The above description largely confonns to that by Hillis (1959). Halimeda opuntia (Linnaeus) Lamouroux The specimens examined were collected from Androth island. The plant grows to a height of 30 cm. It branches sparsely, dichoiomously and trichotomously. The segments are smaller and highly variable. Some are cylindrical, some cuneate and some renifonn. Some are ribbed. The length of the segment ranges !Tom 3-5 mm and the breadth 2-6 mm. The margin of the segment is entire or predominantly trilobed, The thickness of the segment is nearly I mm. Some of the segments are oriented slightly in different directions so that they look distorted. The vertical medullary filaments are mostly trichotomously branched with a diameter of 18.7 -37.4 !lm. Lateral cortical < . ~ CENTRAL  MARINE FISHERIES RESEARCH INSTITUTE, COCHIN.Studies on species of Halimeda from Lalcshadweep filaments arise from the medullary filaments. In the cortical filaments there are 3 to 4 layers of utricles. The secondary utricle is elongated (131 !lm) and bears 3 to 6 peripheral utricles at its tip which are rounded in surface view measuring 28 - 37.4 !lm in diameter (Fig. 2). After decalcification, the peripheral utricles remain separated. At the nodal region the medullary filaments fuse in pairs to a longer distance, thereby showing an extended fusion. The description given above is in agreement with that of Hillis (1959). Halimeda simulans Howe The specimens examined were collected from Androth island. The plant grows to about 10 em in height attached to substrarum by means of a holdfast which is slightly flattened. The thallus is moderately calcified but the density of calcification is comparatively higher in the lower segments. The predominant mode of branching is trichotomous. Though the plant exhibits fairly dense branching, the branches are complanate in a single plane. The segments, small or big, do not show much variability in shape unlike in other species. In the specimen, the lowermost few segments are narrowly cylindrical and about 2 mm long. Other segments are reniform or subcuneate. They measure 1-3 mm in length and 2-5 mm in breadth. The margin is entire or trilobed, some segments are ribbed. As far as the anatomy is concerned, the thallus has a central medulla surrounded by a cortex. The medulla is composed of vertically running medullary filaments . The medullary filaments are largely trichotomously branched. They measure 56-112 11m in diameter. From these medullary filaments arise lateral cortical filaments. The innermost urticle is elongated (336 11m) and does not show any structural variation. The innennost utricle bears about 163 3 secondary utricles (93.5 !lm in height) bearing two peripheral utricles. The peripheral utricles present an angu lar appearance in surface view with a .diameter ranging from 56.1 to 74.8 !lm (Fig. 3). At the nodal region all the medullary filaments remain united communicating with each other through pores. The description ofthis species is in agreement with that of Hillis (1959). Halimeda taenicola W. R. Taylor The specimens collected from Androth island were examined. The plants grow erect to a height of7 cm attached to stones by means of a hold fast which is irregularly cylindrical and about I em in height. In the upper half, the plant branches densely, sometimes about five branches arising from a single middle segment. Further branching is mostly dichotomous, trichotomy being occasional. While the lower segments are heavily calcified. the intensity of calcification decreases towards the upper segments. The lower 2 or 3 segments are cylindrical or subcuneate, while the other segments are trapezoidal. The uppermost I or 2 segments are comparatively much smaller and cylindrical or cuneate in appearance . The length of the segments vary from 4 mm to 10 mm and the breadth from 2 mm to 10 rom. Anatomically there is a cenrral medulla composed of vertically running medullary filaments from which arise lateral cortical filaments. Medullary filaments branch both dichotomously and trichotomously. The diameter of the medullary filament ranges from 37.4 11m to 112.2Ilm. Cortical filaments are made of 2 to 3 layers of utricles. The innermost utricles is much larger measuring 280.5 I'm in length atfd 149.6 11m in breadth. The secondary utricle bears 2 to 4 peripheral utricles . After decalcification peripheral utricles remain adherent without any separation. They are angular in surface view (Fig. 4). CENTRAL  MARINE FISHERIES RESEARCH INSTITUTE, COCHIN.M. Sundararajan, M. Rajendran, N. Kaliaperumal and S. Kalimuthu 164 o ( c B 200~ t Fig. 1. Halimeda incrassala A. Union of all the medullary filaments in the nodal region: B - C. Cortical filament with peripheral utides; D. Surface vjew 0/ the peripheral ulrides. ... CENTRAL  MARINE FISHERIES RESEARCH INSTITUTE, COCHIN., . . ) Studies on species of Halimeda from Lalrshadweep /65 l Fig. 2. Halimeda opuntia A. Medullary filaments showing 'Exlended fusion': B - C. .Wedullary filament showing a lateral filament with peripheral utric/es; D, Surface \'Iew of peripheral ulricles. CENTRAL  MARINE FISHERIES RESEARCH INSTITUTE, COCHIN.M. Sundararajan, M. Rajendran, N. Kaliaperumal and S. Kalimuthu 166 200l-lm Fig. 3. Halimeda simulans A Union of all the medullary - ments In the nodal region; B. Cortical filament ending WIth perlpheral utricle: C. Surface view of peripheral' ttlrjcles ·of l • CENTRAL  MARINE FISHERIES RESEARCH INSTITUTE, COCHIN._ __ I Stum#!., nn ,meci#!., nfHalimeda frnm l.ohhDdween 167 . ~ 200f-tm Fig. 4. HaJimeda taenicola A. Medullary filaments showing 'Extendedfosion'; B, Medullaryjilamenl showing a lateral filament with peripheral ulricies; C. Surface view of peripheral utricies, CENTRAL  MARINE FISHERIES RESEARCH INSTITUTE, COCHIN..tt. SlIndararajan, ol/. Rajendran, .v. Kaliaperllmal and S. Kalimlllllll 168 J 1 .~ Plate I f A) Haltmeda opuntia (8) /I taenicola (C) H simulans (D) H incrassata CENTRAL  MARINE FISHERIES RESEARCH INSTITUTE, COCHIN.• .' .. I I Studies on species a/Halimeda/rom LaksiUJdweep The diameter ranges from 37 !lm to 56 !lm. At the nodal region, three filaments fuse together for a long distance before branching. Thus they exhibit an extended type of fusion. Aclmowiedgement The authors are thankful to Prof. V. Krishnamurthy, Director, Krishnamurthy Institute of Algology, Chennai for confirming the identification and for valuable suggestions. Literature cited Hillis, L. W. 1959. A review of the genus Halimeda (Order Siphonales). Pub I. Inst. Mar. Sci. Univ., Texas. 169 Kaliaperumal, N., P. Kaladbaran and S. Kalimuthu 1989. Seaweed and seagrass resources. CMFRI Bull., 43 : 167· 175. Krishnamurthy, V. and H. V. Joshi 1970. A check list of Indian marine algae . CSMCRI, Bhavanagar, 36 pp. Krishnamurthy, V. and K. Jayagopal 1995. Calcareous algae of the Galaxea Reef, Krusad.ai Island, Tamilandu. Seaweed Res. Utiln., 17 ( 1& 2) 117·121. Subbaramaiah, K. , K. Rarnarao and M.R.P.Nair 1979. Report on the survey of marine algal resources ofLakshadweep for 1977· 79. CSMCRI, Bhavnagar 39 pp. Sundararajan,M., C.Selvaraju and V. Krishna· murthy 1996. On some species of Halimeda Lamouroux from Indian waters. Seaweed Res. Utiln., 18 (I & 2) : 21 ·32 . CENTRAL  MARINE FISHERIES RESEARCH INSTITUTE, COCHIN.

Studies on species of Halimeda from Lakshadweep

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Studies on species of Halimeda from Lakshadweep

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