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Achomosphaera cracenospinosa
From Fensome et al., 2019:
Achomosphaera? cracenospinosa, (Davey and Williams, 1966b, p.87, pl.3, fig.3) Sarjeant, 1981, p.123.
Holotype: Davey and Williams, 1966b, pl.3, fig.3; Bujak et al., 1980, pl.7, fig.9.
NOW Cordosphaeridium?.
Originally Cordosphaeridium, subsequently (and now) Cordosphaeridium?, thirdly Achomosphaera?.
Questionable assignment: Sarjeant (1981, p.123).
Age: Early Eocene.
Locus typicus: London Clay, Enborne, England
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Original description as Cordosphaeridium cracenospinosum: [Davey and Williams, 1966, p. 87]:
Diagnosis:
Sub-spherical to polygonal central body with wall composed of endophragm and periphragm, up to 1.5 µm in thickness. Endophragm very thin. Archaeopyle apical haplotabular; processes slender, buccinate, erect, or curved, solid or with fine central tubule or hollow, the last two types open distally. Distal margins foliate, bifurcate or digitate. Processes one per plate area.
Description:
The large central body of C. cracenospinosum sp. nov. has a finely reticulate surface. In overall outline this species appears to be sub-spherical, but closer examination shows that often it tends to be polygonal.
The processes are generally single, rarely branched, and in length often exceed half the diameter of the central body. The periphragm often forms a ridge on the surface of the central body where a process arises. Occasionally very fine, shorter processes are present. Many of the processes are solid, others having a narrow central cavity throughout their length or being hollow tubiform. Distally there is considerable variation, digitate endings being the commonest.
Dimensions:
Holotype: diameter of central body 122 by 125 µm, length of processes up to 66 µm.
Range: diameter of central body 75-125 µm, length of processes 17-76 µm.
Affinities:
C. cracenospinosum differs from C. gracilis by its thinner wall, which is only very faintly fibrous, the shape of the central body and the occasional presence of smaller, very fine, processes. It is unusual in having solid and hollow processes, the former however predominate. Process endings comparable to those in Baltisphaeridium pectiniforme Gerlach (1961) from the Oligocene of Germany, are occasionally encountered.
Achomosphaera? cracenospinosa, (Davey and Williams, 1966b, p.87, pl.3, fig.3) Sarjeant, 1981, p.123.
Holotype: Davey and Williams, 1966b, pl.3, fig.3; Bujak et al., 1980, pl.7, fig.9.
NOW Cordosphaeridium?.
Originally Cordosphaeridium, subsequently (and now) Cordosphaeridium?, thirdly Achomosphaera?.
Questionable assignment: Sarjeant (1981, p.123).
Age: Early Eocene.
Locus typicus: London Clay, Enborne, England
---------------------------------------------------------------------------------------------------
Original description as Cordosphaeridium cracenospinosum: [Davey and Williams, 1966, p. 87]:
Diagnosis:
Sub-spherical to polygonal central body with wall composed of endophragm and periphragm, up to 1.5 µm in thickness. Endophragm very thin. Archaeopyle apical haplotabular; processes slender, buccinate, erect, or curved, solid or with fine central tubule or hollow, the last two types open distally. Distal margins foliate, bifurcate or digitate. Processes one per plate area.
Description:
The large central body of C. cracenospinosum sp. nov. has a finely reticulate surface. In overall outline this species appears to be sub-spherical, but closer examination shows that often it tends to be polygonal.
The processes are generally single, rarely branched, and in length often exceed half the diameter of the central body. The periphragm often forms a ridge on the surface of the central body where a process arises. Occasionally very fine, shorter processes are present. Many of the processes are solid, others having a narrow central cavity throughout their length or being hollow tubiform. Distally there is considerable variation, digitate endings being the commonest.
Dimensions:
Holotype: diameter of central body 122 by 125 µm, length of processes up to 66 µm.
Range: diameter of central body 75-125 µm, length of processes 17-76 µm.
Affinities:
C. cracenospinosum differs from C. gracilis by its thinner wall, which is only very faintly fibrous, the shape of the central body and the occasional presence of smaller, very fine, processes. It is unusual in having solid and hollow processes, the former however predominate. Process endings comparable to those in Baltisphaeridium pectiniforme Gerlach (1961) from the Oligocene of Germany, are occasionally encountered.