Prorocentrum foraminosum Faust, 1993b
Species Overview:
Prorocentrum foraminosum is an armoured, marine, benthic dinoflagellate species. This species is associated with floating detritus and sediment in tropical embayments of the Caribbean Sea.
Taxonomic Description:
Prorocentrum foraminosum is a bivalvate species often observed in valve view. Cells are 46-66 µm long and 31-42 µm wide with a distinct V-shaped periflagellar region on the right valve (Fig. 1). Cells are oblong to ovate, with relatively thick thecal valves. Thecal valves are convex (Figs. 5-7), and are covered with scattered valve pores (270-350 pores per valve) (Figs. 1-8). Pores are round, evenly sized, and situated in shallow depressions unevenly distributed on the valve surface (Figs. 3,4). Marginal pores are absent. Valve centers are devoid of pores. The intercalary band is smooth (Figs. 1,2,4-7); in young cells it is flattened (Fig. 7), but in mature cells it is wider and more rounded (Fig. 5) (Faust, 1993b).
The periflagellar area is a small, narrow triangular V-shaped depression found apically on the right valve (Figs. 5,6). It is made up of eight apical platelets and two periflagellar pores: a large oblong flagellar pore (F) and a smaller auxiliary pore (A). The anterior end of the left valve is slightly tapered and truncate (Fig. 2) (Faust, 1993b).
Morphology and Structure:
Cells of P. foraminosum are photosynthetic with golden-colored chloroplasts, starch bodies, a centrally located pyrenoid, and a small nucleus situated posteriorly (Faust, 1993b).
Reproduction:
Prorocentrum foraminosum reproduces asexually via binary fission in a thin-walled division cyst, or sexually producing a colorless cyst (Fig. 11) (Faust, 1990a).
Species Comparison:
The periflagellar region of P. foraminosum has one flagellar pore and one auxiliary pore with no ornamentation (Faust, 1993b). A similar arrangement is also present in P. arenarium (Faust, 1994), P. faustiae (Morton, 1998), P. norrisianum (Faust, 1997) and P. ruetzlerianum (Faust, 1990b).
P. foraminosum can be mistaken for P. lima; however, the former species can be distinguished by its oblong to oval cell shape, large cell size, and different sized flagellar and auxiliary pores (Faust, 1993b).
Remarks:
Recently, sand-dwelling Prorocentrum species were incorrectly identified in light and scanning photographs: as P. lima, a benthic species [Larsen and Moestrup, 1989, fig. 2j (P. foraminosum), fig. 2k (P. mexicanum)]; and as P. marinum, a tropical epiphytic species [Faust, 1990a (P. foraminosum)].