Abstract
The diatom genus Fallacia includes species having a conopeum which is a perforated thin sheath of silica lying along the apical axis on the external valve face and a hyaline lateral area in the internal valve face. In surveying the benthic diatoms of Basra, a new small brackish water species, Fallacia fawensis was found associated with fine-grained substrata on the western bank of Shatt Al–Arab River, Southern Iraq. This epipelic species is described based on light and scanning electron microscopy and characterized by having a porous conopeum covering the area between raphe sterna and mantle, narrow elongated marginal striae, and a structure similar to lateral hyaline areas in the valve internal side. The terminal raphe endings on the external valve face, below valve apex, the raphe sternum inner margins come close to each other, blocking raphe canal but leaving a lacuna-like thin groove for connection with the deflected upper part of the open raphe canal. These features separated this species from allied taxa of the genus and also from closely related genera, Pseudofallacia and Germaniella. Notes on the ecology and distribution of the new species as well as the associated diatom taxa are provided.
References
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Garcia, M. (2003) Observations on the diatom genus Fallacia (Bacillariophyta) from southern Brazilian sandy beaches. Nova Hedwigia 77: 309–330. https://doi.org/10.1127/0029-5035/2003/0077-0309
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Hinton, G.C.F. & Maulood, B.K. (1980) Some diatoms from brackish water habitats in southern Iraq. Nova Hedwigia 31: 475–486.
Kützing, F.T. (1849) Species Algarum. F.A. Brockhaus, Leipzig 1 (6): 1–922.
Liu, Y., Kociolek, J.P., Fan, Y. & Wang, Q. (2012) Pseudofallacia gen. nov., a new freshwater diatom (Bacillariophyceae) genus based on Navicula occulta Krasske. Phycologia 51: 620–626. https://doi.org/10.2216/11-098.1
Li, Y., Suzuki, H., Nagumo, T. & Tanaka, J. (2014) Auxosporulation, morphology of vegetative cells and perizonium of Fallacia tenera (Hust.) D.G.Mann (Bacillariophyceae). Phytotaxa 164: 239–254. https://doi.org/10.11646/phytotaxa.164.4.3
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Li, Y., Suzuki, H., Nagumo, T., Tanaka, J., Sun, Z. & Xu, K. (2019) Three new species of Fallacia from intertidal sediments in Japan. Diatom Research 3: 75–83. https://doi.org/10.1080/0269249X.2019.1606855
Maulood, B.K., Hinton, G.C.F., Whitton, B.A. & Al-Saady, H.A. (1981) On the algal ecology of the lowland Iraqi marshes. Hydrobiologia 80: 267–276. https://doi.org/10.1007/BF00018367
Metzeltin, D., Lange-Bertalot, H. & García-Rodriguez, F. (2005) Diatoms of Uruguay Compared with other taxa from South America and elsewhere. Iconographia Diatomologica 15: 1–736.
Mohamed, A.R.M. & Abood, A.N. (2017) Ecological health assessment of the Shatt Al-Arab River. IOSR Journal of Agriculture and Veterinary Science 10: 1–8.
Procopiak, L.K. & Fernandes, L.F. (2003) Valve morphology of the benthic diatom Fallacia marnieri (Manguin) Witkowski (Sellaphoraceae-Bacillatiophyta). Brazilian Journal of Biology 63: 113–119. https://doi.org/10.1590/S1519-69842003000100015
Ross, R., Cox, E.J., Karayeva, N.I., Mann, D.G., Paddock, T.B.B., Simonsen, R. & Sims, P.A. (1979) An amended terminology for the siliceous components of the diatom cell. Nova Hedwigia 64: 513–533.
Round, F.E., Crawford, R.M. & Mann, D.G. (1990) The diatoms, Biology and Morphology of the Genera. Cambridge University Press, Cambridge.
Sabbe, K., Vyverman, W. & Muylaert, K. (1999) New and little-known Fallacia species (Bacillariophyta) from brackish and marine intertidal sandy sediments in Northwest Europe and North America. Phycologia 38: 8–22. https://doi.org/10.2216/i0031-8884-38-1-8.1
Smith, W. (1856) A synopsis of the British Diatomaceae; with remarks on their structure, functions and distribution; and instructions for collecting and preserving specimens. Vol. 2. A-E. John van Voorst., London, pp. 1–107.
Stancheva, R. & Manoylov, K.M. (2018) Fallacia californica sp. nov. (Bacillariophyta), a new freshwater diatom species from streams in California, USA. Phytotaxa 345: 104–118. https://doi.org/10.11646/phytotaxa.345.2.2
Werum, M. & Lange-Bertalot, H. (2004) Diatoms in springs from Central Europe and elsewhere under the influence of hydrologeology and anthropogenic impacts. Iconographia Diatomologica 13: 3–417.
Witkowski, A. (1991) Fallacia cassubiae sp. nov., a new brackish-water diatom from the Puck Bay (Southern Baltic Sea), Poland. Diatom Research 6: 401–409. https://doi.org/10.1080/0269249X.1991.9705184
Witkowski, A. (1993) Fallacia florinae (Moeller) comb. nov. a marine, epipsammic diatom. Diatom Research 8: 215–219. https://doi.org/10.1080/0269249X.1993.9705254
Witkowski, A., Lange-Bertalot, H. & Metzeltin, D. (2000) Diatom Flora of Marine Coasts I. In: Lange-Bertalot, H. (Ed.) Iconographia Diatomologica. Vol. 7. Annotated Diatom Micrographs. Diversity-Taxonomy-Identification. Koeltz Scientific Books, Königstein, Germany, pp. 1–925.
Al-Handal, A.Y. (2009) Littoral diatoms from the Shatt Al-Arab estuary, North West Arabian Gulf. Cryptogamie Algologie 30: 153–183.
Al-Handal, A.Y. & Al-Shaheen, M.A. (2019) Diatoms in the wetlands of Southern Iraq. Bibliotheca Diatomologica 67: 1–241.
Al-Yamani, F.Y. & Saburova, M.A. (2011) Illustrated guide on the benthic diatoms of Kuwait´s marine environment. Institute for Scientific Research, Lucky Press, Kuwait, 352 pp.
Bory de Saint-Vincent, J.B.G.M. (1822) Bacillariées. Dictionnaire Classique d’Histoire naturelle 2: 127–129.
Garcia, M. (2003) Observations on the diatom genus Fallacia (Bacillariophyta) from southern Brazilian sandy beaches. Nova Hedwigia 77: 309–330. https://doi.org/10.1127/0029-5035/2003/0077-0309
Genkal, S.I. & Yarushina, M.I. (2017) The species of the genus Fallacia A.J. Stickle & D.G. Mann (Bacillariophyta) in Russia: morphology, taxonomy, ecology and distribution. International Journal on Algae 19: 99–110. https://doi.org/10.1615/InterJAlgae.v19.i2.10
Guiry, M.D. & Guiry, G.M. (2020) AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. [https://www.algaebase.org]
Hantizsch, C.A. (1860) Neue Bacillarien: Nitzschia vivax var. elongata, Cymatopleura nobilis. Hedwigia 2: 1–40.
Hinton, G.C.F. & Maulood, B.K. (1980) Some diatoms from brackish water habitats in southern Iraq. Nova Hedwigia 31: 475–486.
Kützing, F.T. (1849) Species Algarum. F.A. Brockhaus, Leipzig 1 (6): 1–922.
Liu, Y., Kociolek, J.P., Fan, Y. & Wang, Q. (2012) Pseudofallacia gen. nov., a new freshwater diatom (Bacillariophyceae) genus based on Navicula occulta Krasske. Phycologia 51: 620–626. https://doi.org/10.2216/11-098.1
Li, Y., Suzuki, H., Nagumo, T. & Tanaka, J. (2014) Auxosporulation, morphology of vegetative cells and perizonium of Fallacia tenera (Hust.) D.G.Mann (Bacillariophyceae). Phytotaxa 164: 239–254. https://doi.org/10.11646/phytotaxa.164.4.3
Li, Y., Suzuki, H., Nagumo, T., Tanaka, J., Sun, Z. & Xu, K. (2015) Fallacia decussata, sp. nov. : a new marine benthic diatom (Bacillariophyceae) from Northeast Asia. Phytotaxa 224: 258–266. https://doi.org/10.11646/phytotaxa.224.3.4
Li, Y., Suzuki, H., Nagumo, T., Tanaka, J., Sun, Z. & Xu, K. (2019) Three new species of Fallacia from intertidal sediments in Japan. Diatom Research 3: 75–83. https://doi.org/10.1080/0269249X.2019.1606855
Maulood, B.K., Hinton, G.C.F., Whitton, B.A. & Al-Saady, H.A. (1981) On the algal ecology of the lowland Iraqi marshes. Hydrobiologia 80: 267–276. https://doi.org/10.1007/BF00018367
Metzeltin, D., Lange-Bertalot, H. & García-Rodriguez, F. (2005) Diatoms of Uruguay Compared with other taxa from South America and elsewhere. Iconographia Diatomologica 15: 1–736.
Mohamed, A.R.M. & Abood, A.N. (2017) Ecological health assessment of the Shatt Al-Arab River. IOSR Journal of Agriculture and Veterinary Science 10: 1–8.
Procopiak, L.K. & Fernandes, L.F. (2003) Valve morphology of the benthic diatom Fallacia marnieri (Manguin) Witkowski (Sellaphoraceae-Bacillatiophyta). Brazilian Journal of Biology 63: 113–119. https://doi.org/10.1590/S1519-69842003000100015
Ross, R., Cox, E.J., Karayeva, N.I., Mann, D.G., Paddock, T.B.B., Simonsen, R. & Sims, P.A. (1979) An amended terminology for the siliceous components of the diatom cell. Nova Hedwigia 64: 513–533.
Round, F.E., Crawford, R.M. & Mann, D.G. (1990) The diatoms, Biology and Morphology of the Genera. Cambridge University Press, Cambridge.
Sabbe, K., Vyverman, W. & Muylaert, K. (1999) New and little-known Fallacia species (Bacillariophyta) from brackish and marine intertidal sandy sediments in Northwest Europe and North America. Phycologia 38: 8–22. https://doi.org/10.2216/i0031-8884-38-1-8.1
Smith, W. (1856) A synopsis of the British Diatomaceae; with remarks on their structure, functions and distribution; and instructions for collecting and preserving specimens. Vol. 2. A-E. John van Voorst., London, pp. 1–107.
Stancheva, R. & Manoylov, K.M. (2018) Fallacia californica sp. nov. (Bacillariophyta), a new freshwater diatom species from streams in California, USA. Phytotaxa 345: 104–118. https://doi.org/10.11646/phytotaxa.345.2.2
Werum, M. & Lange-Bertalot, H. (2004) Diatoms in springs from Central Europe and elsewhere under the influence of hydrologeology and anthropogenic impacts. Iconographia Diatomologica 13: 3–417.
Witkowski, A. (1991) Fallacia cassubiae sp. nov., a new brackish-water diatom from the Puck Bay (Southern Baltic Sea), Poland. Diatom Research 6: 401–409. https://doi.org/10.1080/0269249X.1991.9705184
Witkowski, A. (1993) Fallacia florinae (Moeller) comb. nov. a marine, epipsammic diatom. Diatom Research 8: 215–219. https://doi.org/10.1080/0269249X.1993.9705254
Witkowski, A., Lange-Bertalot, H. & Metzeltin, D. (2000) Diatom Flora of Marine Coasts I. In: Lange-Bertalot, H. (Ed.) Iconographia Diatomologica. Vol. 7. Annotated Diatom Micrographs. Diversity-Taxonomy-Identification. Koeltz Scientific Books, Königstein, Germany, pp. 1–925.