Glochidinium penardiforme – 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 (having 5 sides) and flattened dorsi-ventrally (Plates 1, 2, 3). The is conical and ; the is excavated at the (its bottom side, Plates 2,3), both are equal in size. The wide, deep encircles the cell, the is broad, deep and reaches the antapex. It produces a marked concavity in the 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. Glochidinium penardiforme. Hand drawings from Popovsky and Pfeister 1991.

Ecology

Glochidinium 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 Glochidinium penardiforme abundance (cells mL^-1), Lake Kinneret, 1970-2020. Prior to 1983 the species wasn’t counted.

Cite this record as: Dr. Tamar Zohary, Dr. Alla Alster. 16 June 2026. Electronic publication. Israel Oceanographic & Limnological Research. https://kinneret-algae-atlas.org/ Searched on —.