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Echinidinium zonneveldiae
Echinidinium zonneveldiae Head, 2003a, p.172, pl.1, figs.1-12.
Holotype: Head, 2003a, pl.1, figs.1-4.
Age: late Pleistocene.
(Head, 2003)
Derivation of name. Named for Karin A. F. Zonneveld in recognition of her work on the genus Echinidinium.
Diagnosis. A species with light- to medium-brown spheroidal central body; and a thin, smooth to ornamented wall bearing solid processes that taper to fine points. Processes are less strongly coloured than the central body, and are circular in transverse cross-section for most of their length, but at least some become irregularly rectangular at base; shafts are smooth. The archeopyle is theropylic, forming a long straight split.
Holotype. Specimen FD 640 (Pl. 1, figs 1–4). Sample: Mom 2a, 200–205 cm; slide 2. England Finder reference U24/4.
Material. Upper Pleistocene (Eemian) of the southern Baltic sites at Mommark, Ristinge Klint and Licze.
Locality and horizon. Holotype: Mommark, Denmark, depth 920.5 cm.
Description. The central body is spheroidal and light to medium brown in colour. The central body wall is less than 0.3 µm thick, with no visible stratification between processes. The outer surface of the wall is smooth, sometimes with sparsely scattered granules or spinules; the inner surface is smooth, faintly granulate or faintly granulorugulate but occasionally more strongly ornamented. Processes are somewhat irregularly distributed over the entire surface of the cyst, but no clear tabulation pattern is apparent. Processes are solid, have smooth shafts, taper to fine points; and are less strongly coloured than central body. Process bases are circular to irregularly rectangular in cross-section, with some irregularly rectangular bases occurring on each cyst. Above their base, processes are always circular in cross-section. Maximum process width varies from c. 1.3 to 3.0 µm; wider processes are always expanded at base. Thicker and thinner processes occur on the same specimen. Processes are mostly of about the same length, but occasional slender processes as short as 2 µm may occur on some specimens (e.g. the holotype). A single process usually arises from each base; but on rare specimens some bases may give rise to as many as three processes (e.g. Pl. 1, figs 5–8). The archeopyle is theropylic, presumably cingular, resulting in a long and nearly straight split that may extend at least half way around the cyst; no accessory sutures were seen.
Dimensions. Holotype: central body 47.5 45.0 µm, process length 2.0 6.5 µm, process width at base 0.5–1.8 µm. Range based on 31 specimens from Licze, Poland: central body maximum diameter 32.5(42.50)50.0 µm, standard deviation 3.72; maximum process length 6.0(7.73)10.0 µm, standard deviation 1.05. Range based on 31 specimens from Mommark, Denmark: central body maximum diameter 35.5(42.52)51.0 µm, standard deviation 4.25; maximum process length 5.0(6.85)10.0 µm, standard deviation 0.97. Specimens have mostly compressed preservation. See also Figure 2.
Remarks. This species differs from all others of the genus, with the exception of ‘Echinidinium transparantum’ below, in the presence of solid tapering processes that arise from irregularly rectangular process bases. The variable ornament seen on the inner surface of the central body wall is often not evenly distributed (e.g. both smooth and faintly granulate areas on the holotype) and may be partly controlled by preservation.
Holotype: Head, 2003a, pl.1, figs.1-4.
Age: late Pleistocene.
(Head, 2003)
Derivation of name. Named for Karin A. F. Zonneveld in recognition of her work on the genus Echinidinium.
Diagnosis. A species with light- to medium-brown spheroidal central body; and a thin, smooth to ornamented wall bearing solid processes that taper to fine points. Processes are less strongly coloured than the central body, and are circular in transverse cross-section for most of their length, but at least some become irregularly rectangular at base; shafts are smooth. The archeopyle is theropylic, forming a long straight split.
Holotype. Specimen FD 640 (Pl. 1, figs 1–4). Sample: Mom 2a, 200–205 cm; slide 2. England Finder reference U24/4.
Material. Upper Pleistocene (Eemian) of the southern Baltic sites at Mommark, Ristinge Klint and Licze.
Locality and horizon. Holotype: Mommark, Denmark, depth 920.5 cm.
Description. The central body is spheroidal and light to medium brown in colour. The central body wall is less than 0.3 µm thick, with no visible stratification between processes. The outer surface of the wall is smooth, sometimes with sparsely scattered granules or spinules; the inner surface is smooth, faintly granulate or faintly granulorugulate but occasionally more strongly ornamented. Processes are somewhat irregularly distributed over the entire surface of the cyst, but no clear tabulation pattern is apparent. Processes are solid, have smooth shafts, taper to fine points; and are less strongly coloured than central body. Process bases are circular to irregularly rectangular in cross-section, with some irregularly rectangular bases occurring on each cyst. Above their base, processes are always circular in cross-section. Maximum process width varies from c. 1.3 to 3.0 µm; wider processes are always expanded at base. Thicker and thinner processes occur on the same specimen. Processes are mostly of about the same length, but occasional slender processes as short as 2 µm may occur on some specimens (e.g. the holotype). A single process usually arises from each base; but on rare specimens some bases may give rise to as many as three processes (e.g. Pl. 1, figs 5–8). The archeopyle is theropylic, presumably cingular, resulting in a long and nearly straight split that may extend at least half way around the cyst; no accessory sutures were seen.
Dimensions. Holotype: central body 47.5 45.0 µm, process length 2.0 6.5 µm, process width at base 0.5–1.8 µm. Range based on 31 specimens from Licze, Poland: central body maximum diameter 32.5(42.50)50.0 µm, standard deviation 3.72; maximum process length 6.0(7.73)10.0 µm, standard deviation 1.05. Range based on 31 specimens from Mommark, Denmark: central body maximum diameter 35.5(42.52)51.0 µm, standard deviation 4.25; maximum process length 5.0(6.85)10.0 µm, standard deviation 0.97. Specimens have mostly compressed preservation. See also Figure 2.
Remarks. This species differs from all others of the genus, with the exception of ‘Echinidinium transparantum’ below, in the presence of solid tapering processes that arise from irregularly rectangular process bases. The variable ornament seen on the inner surface of the central body wall is often not evenly distributed (e.g. both smooth and faintly granulate areas on the holotype) and may be partly controlled by preservation.