Licmophora debilis
Family: Licmophoraceae
Licmophora debilis image
Licmophora debilis  

Species Description: Valves of this species are spathulate with a maximum width at about 1/3 the length from the apex (Fig. 1, SEM of entire valve). The antapex is somewhat attenuated and terminated in a radiate series of areolae (Fig. 2, SEM of antapex). There is a rimportula at the antapical end, perpendicular to the narrow sternum (Fig. 2). In girdle view, (not seen) the cells are, as with other Licmophora species, narrowly wedge-shaped (as in Licmophora flabellata Fig. 1), and presumably grow in stalked colonies. The size variation is 12-17 X 3-5µm (Honeywill 1998) or 50-70 X 2.5-7µm (Hustedt 1930-66). The valve in Fig. 1 is 19.3 X 3.7µm. There are 32 striae in 10µm. It is rare in the IRL; this is the only entire valve seen, near the Fort Pierce Inlet. It is widely distributed on the European coast, and has been listed from the U.S. East coast, Biscayne Bay, and Gulf of Mexico.

Honeywill C. 1998. A study of British Licmophora species and a discussion of its morphological features. Diat Res 13: 221-271.

Hustedt F. 1930-1966. Die Kieselalgen Deutschlands, Österreich und der Schweiz. In: Dr. L. Rabenhorst’s Kryptogamen-Flora von Deutschlands, Österreich und der Schweiz 7(1): 1-920, 7(2): 1-845, 7(3): 1-816. J Cramer Verlag, Weinheim.

Annulus: A hyaline ring of slightly thickened silicon on a valve surface.

Areolae: A regularly repeated perforation through the cell wall.

Auxospore: A special cell that restores cell size; normally a result of sexual reproduction.

Auxospore Envelope: A hyaline envelope that surrounds the auxospore cell.

Auxosporulation: The process of auxospore formation.

Capitate: Head-shaped.

Fascia: A plain, unthickened transverse strip.

Foramina: Opening on one side of a complex areola.

Homothallic: Possessing both male and female capability in a single morphologically and physiologically identical cell.

Hyaline Line: An unperforated siliceous strip between two striae.

Interstriae: An unperforated siliceous strip between two striae.

Morphogenesis: A developmental sequence that causes an organism to develop its shape.

Mucilage: Glycoproteins and/or exopolysaccharides excreted by some diatoms.

Ocellus: A group of small pores surrounded by a thickened hyaline rim and raised from the surface of the valve.

Oogamous: Sexual reproduction in which the sperm is small and motile, and the egg is larger and nonmotile.

Oogonia: Female gametangia.

Otaria: Membranous costae that occur opposite each other on a valve, especially the genus Rhizosolenia.

Pili: Long siliceous hairs on a diatom valve.

Poroid: Simple unchambered hole through a diatom valve.

Pseudoseptum: A siliceous projection to the cell interior at the edge of the valve.

Rimoportula: A tubelike opening through the cell wall with an internal flattened tube or lip-like slit; also called labiate process.

Rimoportula Tube: The external portion of a rimoportula.

Rostrate: The blunt tapered end of a valve, shaped like a beak.

Spermatogonangia: In sexual reproduction, the cell that produces sperm cells.

Spinules: Little spines.

Uniseriate: Arranged in a single series of cells.

Vegetative Cells: Cells that are a result of asexual division.

Licmophora debilis image
Licmophora debilis