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Hystrichosphaeridium readei
Hystrichosphaeridium readei Davey and Williams, 1966
Now Kleithriasphaeridium. Originally Hystrichosphaeridium, subsequently (and now) Kleithriasphaeridium.
Holotype: Davey and Williams, 1966, pl.6, fig.3
Locus typicus: Fetcham Mill, England
Stratum typicum: Cenomanian
Original diagnosis: Davey and Williams, 1966, p. 64
Spherical to subspherical central body composed of smooth endophragm and periphragm. Processes, composed of the latter, slightly fibrous, cylindrical and open. Larger processes with two thickenings of periphragm extending along their length over surface of central body and joining up with similar thickenings from neighbouring processes. Processes varying in width and expanding distally, terminating in fairly complicated aculeate or secate margin. Apical archaeopyle usually present.
Dimensions: holotype: diameter of central body 41 by 45 µm, length of processes 23-29 µm, number of processes 24. Range: diameter of central body 31-54 µm, length of processes 20-35 µm.
Original description: Davey and Williams, 1966, p. 64
The most characteristic feature of this species is the presence of thickenings or ribs in the periphragm. These ribs are close together near the distal end of the process and gradually diverge proximally, before separating completely on the surface of the central body, each rib passing to a different neighbouring process. Thus triangular and polygonal networks are seen on the surface of the central body.
The sulcal processes are usually noticeably finer than the others and are very occasionally joined by septa, as seen in the holotype. The septa are probably modified ribs. An apical archaeopyle is usually present. The number of processes in the specimens observed varied between 23 and 27. The reflected tabulation is difficult to determine but it is probably comparable to H. tllbiferum i.e. 4", 6", 6C, 5""", 1p, 1"""" and xs.
Now Kleithriasphaeridium. Originally Hystrichosphaeridium, subsequently (and now) Kleithriasphaeridium.
Holotype: Davey and Williams, 1966, pl.6, fig.3
Locus typicus: Fetcham Mill, England
Stratum typicum: Cenomanian
Original diagnosis: Davey and Williams, 1966, p. 64
Spherical to subspherical central body composed of smooth endophragm and periphragm. Processes, composed of the latter, slightly fibrous, cylindrical and open. Larger processes with two thickenings of periphragm extending along their length over surface of central body and joining up with similar thickenings from neighbouring processes. Processes varying in width and expanding distally, terminating in fairly complicated aculeate or secate margin. Apical archaeopyle usually present.
Dimensions: holotype: diameter of central body 41 by 45 µm, length of processes 23-29 µm, number of processes 24. Range: diameter of central body 31-54 µm, length of processes 20-35 µm.
Original description: Davey and Williams, 1966, p. 64
The most characteristic feature of this species is the presence of thickenings or ribs in the periphragm. These ribs are close together near the distal end of the process and gradually diverge proximally, before separating completely on the surface of the central body, each rib passing to a different neighbouring process. Thus triangular and polygonal networks are seen on the surface of the central body.
The sulcal processes are usually noticeably finer than the others and are very occasionally joined by septa, as seen in the holotype. The septa are probably modified ribs. An apical archaeopyle is usually present. The number of processes in the specimens observed varied between 23 and 27. The reflected tabulation is difficult to determine but it is probably comparable to H. tllbiferum i.e. 4", 6", 6C, 5""", 1p, 1"""" and xs.