Kinneret Algae Atlas

Phylum: Dinoflagellata
Class: Dinophyceae
Order: Peridiniales
Habitat: plankton, littoral
Organization: flagellated single cells
Color: golden-brown to greyish
Cell shape: ovoid or prolate spheroid
Cell diameter (D): 17 - 24 µm, median: 21 µm (N=160)
Cell length (L): 20 – 27.5 µm, median: 23 µm (N=160)
Cell biovolume: 3050 - 8200 µm³, median: 5450 µm³.
Biovolume equation: V, µm³ = (4/3)π L (D/2)² (prolate sphaeroid)

Morphological features

Cells are pentangular (having 5 sides) and flattened dorsi-ventrally (Plates 1, 2, 3). The epitheca is conical and apiculate; the hypotheca is excavated at the antapex (its bottom side, Plates 2,3), both theca are equal in size. The wide, deep cingulum encircles the cell, the sulcus is broad, deep and reaches the antapex. It produces a marked concavity in the antapical profile. Chloroplasts are present. The protoplasm may have a dark granular appearance, such that it is grayish in color. Numerous highly refractive granules may or may not be present in the cell periphery (Plates 1, 2).

Plate 1. Glochidinium penardiforme, light microscopy. The large dinoflagellate nucleus is evident, filling most of the hypotheca. Photo: Alla Alster.

Plate 2. Glochidinium penardiforme, SEM photo by Barbara Hickel.

Plate 3. Glechodinium penardiforme. Hand drawings from Popovsky and Pfeister 1991.

Ecology

Glechodinium penardiforme is another relatively rare species in Lake Kinneret. It occurred quite regularly between 1983 and 1997, then disappeared from the plankton for 10 years to re-appear in 2008 (Fig. 1). Its mean water column abundance never exceeded 20 cells mL⁻¹. Little is known about this species.

Additional figures

Figure 1. Time series of Glechodinium penardiforme abundance (cells mL⁻¹), Lake Kinneret, 1970-2020. Prior to 1983 the species wasn’t counted.

Cite this record as: Tamar Zohary, Alla Alster. 7 May 2026. Electronic publication. Israel Oceanographic & Limnological Research. https://kinneret-algae-atlas.org/ Searched on —.