NEW RECORDS OF PHYTOPLANKTON FOR BANGLADESH . 9 . SOME RARE AND A NEW SPECIES

Ten taxa belonging to Chlorophyceae, Cyanophyceae, Bacillariophyceae and Euglenophyceae, and one with an uncertain taxonomic position have been described in this paper. Of these, 10 taxa have been found to be globally rare and new records for Bangladesh, whereas Strombomonas islamii Khondker sp. nov. has been described as new to science. Introduction Islam (1969, 1972) studied some rare planktonic green algae in the Bangladesh territory. Recently, under the domain of a research project ‘Epidemiology and Ecology of Vibrio cholerae in Bangladesh’ an extensive collection programme of phytoplankton was performed in two southern coastal districts, namely Pirojpur and Barisal of Bangladesh between 2004 and 2007. In this programme, 13 domestic ponds and a river channel belonging to Mathbaria upazila of Pirojpur district and Bakerganj upazila of Barisal district were explored and the outcome was a collection of 1,008 samples. While working on these plankton samples, the present authors noticed the occurrence of a number of interesting species which were rather difficult to identify. After an extensive literature search, some taxa were proved to be globally rare and one was designated as new to science. Other relatively common taxa worked out from the same collections, but proved to be new reports for Bangladesh, have been published in a series of papers (Khondker et al., 2006, 2007 a, b, c, d, 2008 a, b, c, d). The present paper records the systematic accounts of 10 rare taxa which are new records for Bangladesh and one new species of phytoplankton. Materials and Methods Net and Lugol's solution-sedimented samples of phytoplankton were used for the present study. Details of the methodology, frequency of sampling and description of the sampling stations could be found in Khondker et al. (2006). 1 Corresponding author. E-mail: mkhondker@yahoo.com 2 International Centre for Diarrhoeal Disease Research, Bangladesh, Dhaka, Bangladesh. 3 Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA. 4 Centre of Marine Biotechnology, University of Maryland Biotechnology Institute, Baltimore, Maryland, USA. 5 University of Maryland Institute for Advanced Computer Studies, College Park, Maryland, USA.


Introduction
studied some rare planktonic green algae in the Bangladesh territory.Recently, under the domain of a research project 'Epidemiology and Ecology of Vibrio cholerae in Bangladesh' an extensive collection programme of phytoplankton was performed in two southern coastal districts, namely Pirojpur and Barisal of Bangladesh between 2004 and 2007.In this programme, 13 domestic ponds and a river channel belonging to Mathbaria upazila of Pirojpur district and Bakerganj upazila of Barisal district were explored and the outcome was a collection of 1,008 samples.
While working on these plankton samples, the present authors noticed the occurrence of a number of interesting species which were rather difficult to identify.After an extensive literature search, some taxa were proved to be globally rare and one was designated as new to science.Other relatively common taxa worked out from the same collections, but proved to be new reports for Bangladesh, have been published in a series of papers (Khondker et al., 2006(Khondker et al., , 2007(Khondker et al., a, b, c, d, 2008 a, b, c, d) a, b, c, d).The present paper records the systematic accounts of 10 rare taxa which are new records for Bangladesh and one new species of phytoplankton.

Materials and Methods
Net and Lugol's solution-sedimented samples of phytoplankton were used for the present study.Details of the methodology, frequency of sampling and description of the sampling stations could be found in Khondker et al. (2006).

Taxonomic enumeration
Systematic accounts of 10 rare taxa of phytoplankton have been provided with photomicrographs.One new species under the genus Strombomonas Delf.has also been described.Ten taxa belong to four algal classes, namely Chlorophyceae, Cyanophyceae, Bacillariophyceae and Euglenophyceae.Taxonomic position of one taxon is uncertain.In the description, the taxa are arranged after Smith (1950).
Note: The species was reported from Australia and found to grow on the carapace of Copepods (Huber-Pestalozzi, 1955).In the present study the species grew attached to the lorica of Trachelomonas sp.Huber-Pestalozzi (1955), however, did not produce any figure of the species.The present taxon fits well with the measurements and description as provided by Huber-Pestalozzi (1955), and therefore, it has been tentatively placed under C. ovale.Mathbaria , Station No. 6, 19.07.2004, 16.08.2004. 4. Lepocinclis sphagnophila Lemm.(Fig. 9) (Prescott, 1982, 406, 89: 11-13) Cells ovoid to fusiform, posterior end gradually narrowed to a short pointed caudus, anterior suddenly narrowed to blunt apex, at the centre of which flagellum appears.Lorica spindle-shaped, yellow brown.Anterior end dumbbell-head-like, posterior cylindrical with a terminal appendix.Cell content concentrated in the head region.Anterior end slightly narrowed to a blunt end, from which a long flagellum appears.Lorica 27-74 µm long, 13-20 µm broad at the head region.Caudus 14 µm long, mouth part 3.3 µm broad.Flagellum 60 µm long.
Type locality: The sample was collected from a typical road side village pond named 'Bakerganj Helipad Government Pond' in Bakerganj, Barisal, Bangladesh, Z max = 2.4 m, A = 371 m 2 .The water of the pond is used for bathing, washing and for other domestic uses by the villagers.The bank of the pond is covered with bushes and trees.
Note: The species forms large, often irregular, clathrate colonies with homogeneous mucilage when grown in benthic condition.Under planktonic condition it does not develop clathrate colonies rather microscopic and small colonies (Desikachary, 1959).The present material was collected from a bloom in a pond.Bakerganj, Station No. 1, 27.11.2006.ICDDR,B for kindly supporting this research.Latin diagnosis of the new species done by Prof. Syed Hadiuzzaman, Department of Botany, University of Dhaka is also gratefully acknowledged.