Lingulodinium polyedrum (Stein) Dodge, 1989
Species Overview:
Lingulodinium polyedrum is an armoured, marine, bioluminescent dinoflagellate species. This warm-water species is a red tide former that has been associated with fish and shellfish mortality events.
Taxonomic Description:
Cells of Lingulodinium polyedrum are angular, roughly pentagonal and polyhedral-shaped (Fig. 1). Cells range in size from 40-54 µm in length and 37-53 µm in transdiameter width. No apical horn or antapical spines present (Fig. 1). Thecal plates are thick, well defined, and coarsely areolate. Distinct ridges are present along the plate sutures (Figs. 1,2). Numerous large trichocyst pores are present within areolae (Fig. 3) (Kofoid, 1911, Dodge, 1985, Dodge, 1989, Lewis and Burton, 1988, Fukuyo et al., 1990, Steidinger and Tangen, 1996).
Thecal Plate Description:
The plate formula for L. polyedrum is: Po, 3', 3a, 6'', 6c, 7s, 6''', 2''''. The epitheca bears shoulders, nearly straight sides, and an off-center apex which is flattened or slightly pointed (Figs. 1,4). The apical pore plate (Po) contains a raised inner elliptical ridge (Fig. 2). The first apical plate (1') is long and narrow, comes in direct contact with the Po, and bears a ventral pore on its right side (Figs. 1,2,4). The deeply excavated cingulum is nearly equatorial, and displaced one to two times its width. It is descending with narrow ribbed lists (Figs. 1,2,4). The deep sulcus invades the epitheca slightly and widens posteriorly. The hypotheca has straight sides and a truncated antapex (Figs. 1,2,4) (Kofoid, 1911, Dodge, 1985, Dodge, 1989, Lewis and Burton, 1988, Fukuyo et al., 1990, Steidinger and Tangen, 1996).
Morphology and Structure:
L. polyedrum is a photosynthetic species with dark orange-brown chloroplasts. The unusual carotenoid, peridinin, is present in the chloroplasts. Also present is a pusule, a C-shaped nucleus, and scintillons (light-emitting organelles) (Kofoid, 1911, Schmitter, 1971, Jeffrey et al., 1975).
Reproduction:
L. polyedrum reproduces asexually by binary fission. Sexual reproduction is also part of the life cycle for this species forming colorless spherical spiny cysts.