Marine Species Identification Portal : Prorocentrum reticulatum

Prorocentrum reticulatum Faust, 1997

Species Overview:

Prorocentrum reticulatum is an armoured, marine, benthic dinoflagellate species. This species is associated with coral rubble in tropical coastal regions of the Caribbean Sea.

Taxonomic Description:

P. reticulatum is a bivalvate species often observed in valve view. Cells are oval (Fig. 1)and range in size from 55-60 µm long to 40-45 µm wide. The thecal surface is reticulated consisting of a network of ridges with alternating shallow depressions (Figs. 1-3). The depressions are variable in size and shape, each with a narrow, kidney-shaped pore (Figs. 2,3). This unusual reticulate pattern is unique to this species and is a useful diagnostic feature. The intercalary band is smooth and void of striations (Figs. 1,2) (Faust, 1997).

The periflagellar area is a deep V-shaped triangle located apically on the right valve (Figs. 1,2). The periflagellar pores, flagellar and auxiliary pores, are unequal in size and are each surrounded by a narrow periflagellar collar (Fig. 2). The architecture of the periflagellar area of this species is distinct: there are three small accessory pores adjacent to the flagellar pore, as well as three small accessory pores adjacent to the auxiliary pore (Fig. 2). The left anterior margin exhibits a thickened, curved and flattened apical collar that borders the periflagellar area (Fig. 2) (Faust, 1997).

Morphology and Structure:

Prorocentrum reticulatum is a photosynthetic species containing golden chloroplasts and a posteriorly located nucleus (Faust, 1997).

Reproduction:

Prorocentrum reticulatum reproduces asexually by binary fission.

Species Comparison:

The reticulae of P. reticulatum adds to the growing list of valve ornamentations in the genus Prorocentrum: areolae (e.g. P. hoffmannianum (Faust, 1990b); poroids (e.g. P. maculosum (Faust, 1993b); radially arranged trichocyst pores (e.g. P. mexicanum (Faust, 1990b), and shallow surface depressions (e.g. P. micans (Steidinger and Tangen, 1996).

A smooth intercalary band is characteristic of other benthic Prorocentrum species: P. norrisianum (Faust, 1997), P. lima (Faust, 1991), P. hoffmannianum (Faust, 1990b), P. foraminosum (Faust, 1993b), P. arenarium, P. sabulosum and P. sculptile (Faust, 1994), and P. belizeanum (Faust, 1993a).

The architecture of the periflagellar area of P. reticulatum is distinct from P. maculosum (Faust, 1993b), P. playfairi (Croome and Tyler, 1987) and P. lima (Faust, 1991); the latter three species have eight platelets, whereas in P. reticulatum the architecture appears more complex (Faust, 1997). P. reticulatum (Faust, 1997), P. sabulosum (Faust, 1994), P. belizeanum (Faust, 1993a) and P. hoffmannianum (Faust, 1990b) share a distinct feature in the periflagellar area: three small accessory pores adjacent to a periflagellar pore (Faust, 1997).
Other Prorocentrum species exhibit a periflagellar collar surrounding a periflagellar pore: P. maculosum (Faust, 1993b); P. hoffmannianum (Faust, 1990b); P. sabulosum (Faust, 1994); P. belizeanum (Faust, 1993a); and P. lima (Faust, 1991).

The anterior region of the left valve in both P. sabulosum and P. reticulatum exhibits a curved and flattened apical collar that borders the periflagellar area (Faust, 1997).

Ecology:

P. reticulatum is a benthic species. Cells are motile or attach to coral rubble (Faust, 1997).

Toxicity:

The toxicity of this species is unknown.

Habitat and Locality:

Populations of P. reticulatum are associated with coral rubble in tropical coastal regions of the Caribbean Sea (Faust, 1997).

Images

P.reticulatum2.TIF (Fig. 2. SEM. Periflagellar area: a narrow V-shaped depression on right valve. Narrow periflagellar collar wraps around flagellar and auxiliary pores (arrowheads). Longitudinal flagellum present (arrow). Left anterior margin with a thickened, curved and flattened apical collar that borders periflagellar area. A=auxiliary pore; F=flagellar pore.)
P.reticulatum3.TIF (Fig. 3. SEM. Reticulae: a network of ridges with round to oval depressions. Within surface depressions are narrow kidney-shaped openings (arrows). Bacteria on cell surface (arrowheads).)

Prorocentrum reticulatum