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Spiniferites coniconcavus
Spiniferites coniconcavus De Schepper et al., 2004, p.628, figs.5.1–20.
Holotype: De Schepper et al., figs.5.1–6.
Age: late early–early late Pliocene.
Original description (de Schepper et al., 2004):
Spiniferites Coniconcavus new species Figure 5.1–5.20
Spiniferites sp. 1 LOUWYE, HEAD, AND DE SCHEPPER, in press, fig. 7r– 7t.
Diagnosis - Broadly ovoidal spiniferate cysts, bearing gonal processes only. Process stems hollow, broad and conical with concave sides near base, distally becoming cylindrical and narrower; closed distally with short and blunt, usually trifurcate endings. Tabulation expressed by low sutural crests and precingular archeopyle (30). Operculum free.
Description - Spiniferate cysts with broadly ovoidal central body. Cyst wall thin ( <0.3 µm) with shagreenate to faintly scabrate wall surface (best seen using interference contrast optics). Processes gonal, sometimes absent from junctions of cingular plate sutures. Processes broad, hollow, and conical with concave sides near base, distally becoming cylindrical and narrower, with closed, short, and blunt, usually trifurcate endings. Secondary bifurcation absent. Length of conical lower part of process approximately equals length of cylindrical upper part. Flange occurs between bases of two or three antapical processes. Process bases can also be adjoined by flange in apical and cingular area. Tabulation expressed by low sutural crests, sometimes appearing only as dark lines on central body wall. Archeopyle formed by loss of precingular plate 30. Operculum free.
Etymology - Latin, conus and concavus, describing the principal processes, whose bases are cone-shaped with concave sides.
Type - Holotype, sample VB 3.12, slide p2, England Finder reference M27/0. Basal Shelly Unit, Lillo Formation, Verrebroek Dock; upper Lower or lower Upper Pliocene. Figure 5.1–5.6. Royal Belgian Institute of Natural Sciences, Brussels, registration number IRScN b4253.
Measurements - Holotype: endoblast length, 40 µm; endoblast equatorial diameter, 36 µm; maximum process length, 11 µm; maximum width of process base, 14 µm. Range: endoblast length, 38(39.9)40 µm; endoblast equatorial diameter, 34(35.0)36 µm; process length, 7(9.8)12.5 µm; width of process base, 4.0(6.8)9.0 µm; width of process top, 1.0(1.7)2.0 µm. Seven specimens measured.
Occurrence - Basal Shelly Unit and Oorderen Sands Member of the Lillo Formation in the Verrebroek Dock (upper Lower and/ or lower Upper Pliocene).
Discussion - Of the following species, none have the broad conical process bases that characterize Spiniferites coniconcavus. Spiniferites hyperacanthus (Deflandre and Cookson, 1955) Cookson and Eisenack, 1974 and Spiniferites mirabilis (Rossignol, 1964) Sarjeant, 1970 differ additionally in being slightly larger (Spiniferites mirabilis endoblast length, 44–58 µm, Reid, 1974; and Spiniferites hyperacanthus central body diameter, 53–62 µm, Rochon et al., 1999; compared with Spiniferites coniconcavus, endoblast length, 38–40 µm, this study), in having intergonal as well as gonal processes, and in having longer trifurcations on the process tips. Spiniferites membranaceus (Rossignol, 1964) Sarjeant, 1970 has longer trifurcations on the process tips and a sutural crest joining the antapical processes along their complete length. Spiniferites falcipedius Warny and Wrenn, 1997 differs in its larger size (central body length 51–74 µm) and broader process terminations. Spiniferites belerius Reid, 1974 differs in having an apical boss and irregularly shaped processes. The cyst of Gonyaulax baltica Ellegaard, Lewis, and Harding, 2002 has trifurcate process terminations that bifurcate distally, in contrast to the blunt and reduced process terminations on Spiniferites coniconcavus.
Holotype: De Schepper et al., figs.5.1–6.
Age: late early–early late Pliocene.
Original description (de Schepper et al., 2004):
Spiniferites Coniconcavus new species Figure 5.1–5.20
Spiniferites sp. 1 LOUWYE, HEAD, AND DE SCHEPPER, in press, fig. 7r– 7t.
Diagnosis - Broadly ovoidal spiniferate cysts, bearing gonal processes only. Process stems hollow, broad and conical with concave sides near base, distally becoming cylindrical and narrower; closed distally with short and blunt, usually trifurcate endings. Tabulation expressed by low sutural crests and precingular archeopyle (30). Operculum free.
Description - Spiniferate cysts with broadly ovoidal central body. Cyst wall thin ( <0.3 µm) with shagreenate to faintly scabrate wall surface (best seen using interference contrast optics). Processes gonal, sometimes absent from junctions of cingular plate sutures. Processes broad, hollow, and conical with concave sides near base, distally becoming cylindrical and narrower, with closed, short, and blunt, usually trifurcate endings. Secondary bifurcation absent. Length of conical lower part of process approximately equals length of cylindrical upper part. Flange occurs between bases of two or three antapical processes. Process bases can also be adjoined by flange in apical and cingular area. Tabulation expressed by low sutural crests, sometimes appearing only as dark lines on central body wall. Archeopyle formed by loss of precingular plate 30. Operculum free.
Etymology - Latin, conus and concavus, describing the principal processes, whose bases are cone-shaped with concave sides.
Type - Holotype, sample VB 3.12, slide p2, England Finder reference M27/0. Basal Shelly Unit, Lillo Formation, Verrebroek Dock; upper Lower or lower Upper Pliocene. Figure 5.1–5.6. Royal Belgian Institute of Natural Sciences, Brussels, registration number IRScN b4253.
Measurements - Holotype: endoblast length, 40 µm; endoblast equatorial diameter, 36 µm; maximum process length, 11 µm; maximum width of process base, 14 µm. Range: endoblast length, 38(39.9)40 µm; endoblast equatorial diameter, 34(35.0)36 µm; process length, 7(9.8)12.5 µm; width of process base, 4.0(6.8)9.0 µm; width of process top, 1.0(1.7)2.0 µm. Seven specimens measured.
Occurrence - Basal Shelly Unit and Oorderen Sands Member of the Lillo Formation in the Verrebroek Dock (upper Lower and/ or lower Upper Pliocene).
Discussion - Of the following species, none have the broad conical process bases that characterize Spiniferites coniconcavus. Spiniferites hyperacanthus (Deflandre and Cookson, 1955) Cookson and Eisenack, 1974 and Spiniferites mirabilis (Rossignol, 1964) Sarjeant, 1970 differ additionally in being slightly larger (Spiniferites mirabilis endoblast length, 44–58 µm, Reid, 1974; and Spiniferites hyperacanthus central body diameter, 53–62 µm, Rochon et al., 1999; compared with Spiniferites coniconcavus, endoblast length, 38–40 µm, this study), in having intergonal as well as gonal processes, and in having longer trifurcations on the process tips. Spiniferites membranaceus (Rossignol, 1964) Sarjeant, 1970 has longer trifurcations on the process tips and a sutural crest joining the antapical processes along their complete length. Spiniferites falcipedius Warny and Wrenn, 1997 differs in its larger size (central body length 51–74 µm) and broader process terminations. Spiniferites belerius Reid, 1974 differs in having an apical boss and irregularly shaped processes. The cyst of Gonyaulax baltica Ellegaard, Lewis, and Harding, 2002 has trifurcate process terminations that bifurcate distally, in contrast to the blunt and reduced process terminations on Spiniferites coniconcavus.