Back
Nematosphaeropsis labyrinthus
Nematosphaeropsis labyrinthea (Ostenfeld, 1903) Reid, 1974
Originally Pterosperma, subsequently Pterococcus, thirdly Coccopterum, fourthly (and now) Nematosphaeropsis.
Taxonomic junior synonym: Nematosphaeropsis balcombiana, according to Reid (1974, p.592) — however, Wrenn (1988, p.139) retained Nematosphaeropsis balcombiana.
Motile equivalent: Gonyaulax spinifera complex, according to Dodge (1989, p.289).
Wrenn (1988, p.136) retained this species in Pterococcus and did not consider it to be a dinoflagellate; however, Dale in Head and Wrenn (1992, p.12) and Fensome et al. (1993b, p.93) retained this species in Nematosphaeropsis.
Wrenn in Head and Wrenn (1992, p.14) recommended that this name be restricted to the holotype, but see discussion in Rochon et al. (1999, p.30). Rochon et al. (1999, p.30) implied that this species may be the taxonomic senior synonym of Nematosphaeropsis lemniscata.
Holotype: Ostenfeld, 1903, fig,12
Locus typicus: The Faroes
Stratum typicum: Recent
Original description: Ostenfeld, 1903, p.578: Pterosperma labyrinthus
Cell spherical, lamellae (wing-lists) form few and large meshes, vvith undulating sides; lamellae consisting of two closely- Iying layers, which ultimately separate; in the optical section the two layers are seen as two lines which are parallel in the main part, but diverg at an obtuse angle in the upper; seen from the surface the meshes are broad and with a circular dot where three meshes meet.
Reid, 1974, p. 593: Nematosphaeopsis labyrinthea
Description: The test is ovoid and slightly elongate in equatorial view. The surface and processes are smooth. Slender, tall gonal processes with trifurcate and secondarily bifurcate tips arise from the outer layer of a thin two layered wall. The bifurcate tips are usually connected to adjacent processes by parallel trabeculae. These trabeculae replicate the sutures joining the processes at their bases. The test may show an apical node. The girdle and sulcus were not clearly seen because of the overlying trabeculae. Tabulation appears to be the same as that for Spiniferites wity a precingular 3"" archeopyle.
Dimensions: Test 42x40 to 31x31 Ám. Maximum process height 23 Ám.
Wrenn, 1988, considers Nematosphaeropsis labyrinthea (Ostenfeld, 1903) sensu Reid, 1974 [not Pterococcus labyrinthus (Ostenfeld (1903) Lohmann 1904] conspecific with Nematosphaeropsis lemniscata. See also remarks under Nematosphaeropsis lemniscata.
Originally Pterosperma, subsequently Pterococcus, thirdly Coccopterum, fourthly (and now) Nematosphaeropsis.
Taxonomic junior synonym: Nematosphaeropsis balcombiana, according to Reid (1974, p.592) — however, Wrenn (1988, p.139) retained Nematosphaeropsis balcombiana.
Motile equivalent: Gonyaulax spinifera complex, according to Dodge (1989, p.289).
Wrenn (1988, p.136) retained this species in Pterococcus and did not consider it to be a dinoflagellate; however, Dale in Head and Wrenn (1992, p.12) and Fensome et al. (1993b, p.93) retained this species in Nematosphaeropsis.
Wrenn in Head and Wrenn (1992, p.14) recommended that this name be restricted to the holotype, but see discussion in Rochon et al. (1999, p.30). Rochon et al. (1999, p.30) implied that this species may be the taxonomic senior synonym of Nematosphaeropsis lemniscata.
Holotype: Ostenfeld, 1903, fig,12
Locus typicus: The Faroes
Stratum typicum: Recent
Original description: Ostenfeld, 1903, p.578: Pterosperma labyrinthus
Cell spherical, lamellae (wing-lists) form few and large meshes, vvith undulating sides; lamellae consisting of two closely- Iying layers, which ultimately separate; in the optical section the two layers are seen as two lines which are parallel in the main part, but diverg at an obtuse angle in the upper; seen from the surface the meshes are broad and with a circular dot where three meshes meet.
Reid, 1974, p. 593: Nematosphaeopsis labyrinthea
Description: The test is ovoid and slightly elongate in equatorial view. The surface and processes are smooth. Slender, tall gonal processes with trifurcate and secondarily bifurcate tips arise from the outer layer of a thin two layered wall. The bifurcate tips are usually connected to adjacent processes by parallel trabeculae. These trabeculae replicate the sutures joining the processes at their bases. The test may show an apical node. The girdle and sulcus were not clearly seen because of the overlying trabeculae. Tabulation appears to be the same as that for Spiniferites wity a precingular 3"" archeopyle.
Dimensions: Test 42x40 to 31x31 Ám. Maximum process height 23 Ám.
Wrenn, 1988, considers Nematosphaeropsis labyrinthea (Ostenfeld, 1903) sensu Reid, 1974 [not Pterococcus labyrinthus (Ostenfeld (1903) Lohmann 1904] conspecific with Nematosphaeropsis lemniscata. See also remarks under Nematosphaeropsis lemniscata.