Notas científicas

 

Thompsodinium intermedium (Dinophyceae), a freshwater planktonic species in Mexico

 

Thompsodinium intermedium (Dinophyceae), una especie planctónica de agua dulce en México

 

José A. Aké-Castillo*

 

Instituto de Ciencias Marinas y Pesquerías, Universidad Veracruzana. Calle Hidalgo 617, Col. Río Jamapa, 94290 Boca del Río, Veracruz, México. * aake@uv.mx

 

Recibido: 22 agosto 2013
Aceptado: 27 enero 2014

 

Abstract

Morphological description of Thompsodinium intermedium found in a karstic sinkhole Dzityá, in Yucatán is provided. This is the only locality in Mexico where the species has been recorded. Taxonomic circumscription of the species has changed considerably since its original description. An emended diagnosis for the species is provided, as well as for the genus. Worldwide distribution of Thompsodinium intermedium is provided.

Key words: dinoflagellate, emended diagnosis, karstic sinkhole, thecae.

 

Resumen

Se proporciona la descripción morfológica de Thompsodinium intermedium encontrado en el cenote Dzityá en Yucatán, único registro en México. La circunscripción de la especie ha cambiado considerablemente desde su descripción original, por lo que se propone una diagnosis enmendada para la especie y para el género. Se muestra la distribución mundial de Thompsodinium intermedium.

Palabras clave: dinoflagelado, enmienda, cenote, teca.

 

Cenote Dzityá (or Chen-Ha) is a small karstic sinkhole (10.89 x 7.40 m, 4.60 m mean depth) located close to Mérida City, Yucatán Mexico (21.06° N, 89.69° W). In 2 samples of phytoplankton collected in April and May 1999 from this sinkhole, the occurrence of a dinoflagellate was observed. This microalga was studied by light (Leica dmil) and electron microscopes (SEM-JEOL-5600). The morphology indicates that the species belongs to the genus Thompsodinium Bourrelly. Description of the species follows:

Thompsodinium intermedium (Thompson) Bourrely 1970: the cells are 20-32 µm in width and 22-33 µm in length with a ratio width/height of 0.7-0.95, so the cells are ovate or spherical. The cells are dorsoventrally slightly compressed. Many small chloroplasts and a small eyespot are present. Tabulation is Po, x, 4', 3a, 6'', 6c, 4s, 5''', 2'''' (Figs. 1, 2). The second intercalary plate and the third apical plate can be in "remotum" or "contactum" position. The sulcal posterior plate is large extending to the antapex looking like a plate of hypotheca. The third and fourth postcigular plates are large and the antapical plates are dissimilar in size and shape.

Diagnostic characters of the species have changed in the interpretation of the type of hypothecal and sulcal plates (Table 1). Nowadays, the intercalary plate at hypotheca described by Thompson (1950) is known to be a large posterior sulcal plate (Sp) (Carty 1989). Since the original description is not correct anymore, an emended diagnosis of the species (and therefore the monotypic genus) is necessary to attain an adequate taxonomic circumscription of the species:

Thompsodinium Bourrelly emend. Aké-Castillo, herein.

Cells with tabulation Po, 4', 3a, 6'', 6c, 4s, 5''', 2''''. Arrangement of the 2a and 3' plates in remotum, contactum or conjuction position.

Type species: Thompsodinium intermedium (Thompson) Bourrely emend. Aké-Castillo, herein.

Thompsodinium intermedium (Thompson) Bourrelly emend. Aké-Castillo, herein.

Basyonym: Peridinium intermedium Thompson 1950 Lloydia 13:277-299 p. 298 figs 80-88 (non Peridinium intermedium Playfair 1919).

Synonyms (taxonomic): Peridinium pseudointermedium Couté and Iltis 1984, Thompsodinium pseudointermedium (Couté and Iltis) Krakhmalny 2011.

Ovate to spherical cells with 20-42 µm wide and 22-47 µm in length. Tabulation Po, x, 4', 3a, 6'', 6c, 4s, 5''', 2'''' with a distinctive large posterior sulcal plate.

Lectotype: Figs. 80-88 in Thompson 1950 (designated by Bourrelly 1970).

Type locality: Chanute, Kansas, USA.

Distribution: freshwater environments in USA, Mexico, Belize, Brazil, Ivory Coast and Ukranie (Fig. 3).

The occurrence of this dinoflagellate in Mexico is known until now only from cenote Dzityá since 1988. It is the dominant species (Sánchez-Molina et al., 1994) and causes blooms with cell densities between 254 860 and 550 370 cells/l (Pacheco, 1988).

I thank Víctor Ontiveros who sampled cenote Dzityá; Nery Segovia, from Biblioteca-Ciencias Biológicas y Agropecuarias, UADY; Angela Pacheco from Biblioteca Central, UNAM and Arlette Fuentes from INECOL facilitated acquisition of literature. A. F. Krakhmalny kindly sent basic papers. Tiburcio Láez assisted at the Scanning Electron Microscope Unit, INECOL, A. C.

 

Literature cited

Bourrelly, P. 1970. Les algues d'eau douce: initiation á la sistematique. 3. Les algues vertes. Boubée N. Paris. 572 p.         [ Links ]

Carty, S. 1989. Thompsodinium and two Species of Peridiniopsis (Dinophyceae): taxonomic notes based on scanning electron micrographs. Transactions of the American Microscopical Society 108:64-73.         [ Links ]

Carty, S. 1993. Contribution to the dinoflagellate flora of Ohio. Ohio Journal of Science 93:140-146.         [ Links ]

Carty, S. and D. Wujek. 2003. A new species of Peridinium and new records of dinoflagellates and silica-scaled chrysophytes from Belize. Caribbean Journal of Science 39:136-139.         [ Links ]

Cardoso, L. S. and L. C. Torgan. 2007. Dinoflagelados em diversos habitats e hidroperíodos na zona costeira do sul do Brasil. Acta Botanica Brasilica 21:411-419.         [ Links ]

Coute, A. and A. Iltis. 1984. Mise au point sur la flore peridiniale Algae, Pyrrhophyta d'eau douce de Cote d'Ivoire. Revue d'Hydrobiologie Tropicale 171:53-64.         [ Links ]

Johansen, J. R., R. L. Lowe, S. Carty, K. Fučiková, C. E. Olsen, M. H. Fitzpatrick, J. A. Ress and P. C. Furey. 2007. New algal species records for Great Smoky Mountains National Park, with an annotated checklist of all reported algal taxa for the park. Southeastern Naturalist, Special issue 1:99-134.         [ Links ]

Krakhmalny, A. F. 2011. New record of Thompsodinium intermedium (R. H. Thomps.) Bourr. (Dinophyta) in Ukraine. International Journal of Algae 13:117-123.         [ Links ]

Ngô, H. M. and L. A. Pfiester. 1990. Freshwater dinoflagellates from North Deming Pond, Minnesota, USA. Transactions of the American Microscopical Society 109:380-398.         [ Links ]

Pacheco, H. G. 1988. Florecimiento masivo de un dinoflagelado en el cenote Dzityá (Chen-Ha), Yucatán. Tesis, Escuela de Química, Universidad Autónoma de Yucatán. Mérida. 57 p.         [ Links ]

Popovský, J. 1970. Some thecate dinoflagellates from Cuba. Archiv für Protistenkunde 112:252-258.         [ Links ]

Popovský, J. and L. Pfiester. 1990. Dinophyceae (Dinoflagellida). Band 6. Reprinted 2008 Süßwasserflora von Mitteleuropa. Spektrum Akademischer, Heidelberg. 272 p.         [ Links ]

Sánchez-Molina, I., C. Zetina-Moguel, R. Medina-González and L. Pérez-Aranda. 1994. Phytoplankton composition in cenote Dzitya, Yucatán, Mexico. Abstracts of presentations, North American Lake Management Society, Florida. Lake Reservoir Management 9:111.         [ Links ]

Thompson, R. H. 1950. A new genus and new records of freshwater Pyrrhophyta in the Desmokontae and Dinophyceae. Lloyd 13:277-299.         [ Links ]