Back
Phelodinium pumilum
Phelodinium pumilum Liengjarern et al., 1980
Holotype: Liengjarern et al., 1980, pl.54, fig.2
Locus typicus: Whitecliff Bay, lsle of Wight, England
Stratum typicum: Late Eocene
Original diagnosis: Liengjarern et al., 1980, p.487
Phelodinium of small size, ambitus bilaterally asymmetrical with reduced antapical horns. right antapical broadly rounded, may be absent. Apical horn small, cylindrical with prominent distal pore. Pericingulum relatively wide, marked by folds. Sulcus distinct.
Original description: Liengjarern et al., 1980, p.487
The amhitus varies from subcircular to distinctly peridinioid: the bilateral asymmetry of the cyst is nearly always evident. The dorso-ventral compression is strong. The pericoels, if observable, are restricted to the cavities beneath the horns. The cylindrical apical horn is distinctive, its truncated distal tip bears a prominent pore bordered by a thickening of the periphragm. The left antapical horn is always developed and is sharply pointed distally. The right antapical horn is often absent but commonly it is represented by a broad lobe.
The periphragm is very thin and transparent and is often folded. The cingulum is only very slightly helicoid, wide in relation to the over-all size or the cyst; anterior and posterior cingular sutures are indicated by low smooth ridges formed by folding of the periphragm. The perisulcus is distinct.
The archeopyle is of a type and shape seen in species of Phelodinium. Peri- and endoperculum are indistinguishable. The operculum may remain attached along its posterior suture.
Dimensions. Holotype. pericyst length 64 µm, breadth 54 µm, apical horn 6 µm, left antapical horn 5 µm, right antapical horn 8 µm.
Range. Pericyst length 50(55)62 µm, breadth 41(46.5)54 µm, apical horn 3.5(4.5)6.4 µm, left antapical horn 2.7(4.5)6.5 µm, right antapical horn 0(1)3 µm. Specimens measured 11
Affinities:
Liengjarern et al., 1980, p.487: The small size, rounded ambitus, bilateral asymmetry, and distinctive apical horn distinguish this species from all known Phelodinium species. Allocation to Phelodinium is based on the archeopyle shape and relative size, the absence of well-defined pericoels and the very strong dorso-ventral compression.
Holotype: Liengjarern et al., 1980, pl.54, fig.2
Locus typicus: Whitecliff Bay, lsle of Wight, England
Stratum typicum: Late Eocene
Original diagnosis: Liengjarern et al., 1980, p.487
Phelodinium of small size, ambitus bilaterally asymmetrical with reduced antapical horns. right antapical broadly rounded, may be absent. Apical horn small, cylindrical with prominent distal pore. Pericingulum relatively wide, marked by folds. Sulcus distinct.
Original description: Liengjarern et al., 1980, p.487
The amhitus varies from subcircular to distinctly peridinioid: the bilateral asymmetry of the cyst is nearly always evident. The dorso-ventral compression is strong. The pericoels, if observable, are restricted to the cavities beneath the horns. The cylindrical apical horn is distinctive, its truncated distal tip bears a prominent pore bordered by a thickening of the periphragm. The left antapical horn is always developed and is sharply pointed distally. The right antapical horn is often absent but commonly it is represented by a broad lobe.
The periphragm is very thin and transparent and is often folded. The cingulum is only very slightly helicoid, wide in relation to the over-all size or the cyst; anterior and posterior cingular sutures are indicated by low smooth ridges formed by folding of the periphragm. The perisulcus is distinct.
The archeopyle is of a type and shape seen in species of Phelodinium. Peri- and endoperculum are indistinguishable. The operculum may remain attached along its posterior suture.
Dimensions. Holotype. pericyst length 64 µm, breadth 54 µm, apical horn 6 µm, left antapical horn 5 µm, right antapical horn 8 µm.
Range. Pericyst length 50(55)62 µm, breadth 41(46.5)54 µm, apical horn 3.5(4.5)6.4 µm, left antapical horn 2.7(4.5)6.5 µm, right antapical horn 0(1)3 µm. Specimens measured 11
Affinities:
Liengjarern et al., 1980, p.487: The small size, rounded ambitus, bilateral asymmetry, and distinctive apical horn distinguish this species from all known Phelodinium species. Allocation to Phelodinium is based on the archeopyle shape and relative size, the absence of well-defined pericoels and the very strong dorso-ventral compression.