Pterospermopsis spinosa Clarke and Verdier, 1967

NOW Whitecliffia. Originally Pterospermopsis (Acritarch), subsequently Pterospermella (Acritarch), thirdly Thalassiphora?, fourthly (and now) Whitecliffia.
Taxonomic junior synonym Hexagonifera perforata (name not validly published), according to Slimani (2001a, p.194).

Holotype: Clarke and Verdier, 1967, pl.17, fig.1
Locus typicus: Isle of Whight, England
Stratum typicum: Senonian

Original diagnosis: Clarke and Verdir, 1967, p.78
A species of Pterospermopsis with a small rounded main body and an outer membrane bearing both perforations and spines (echinae). No opening has been observed.

Original description: Clarke and Verdier, 1967, p.78
The inner body is in contact with the outer membrane only at the apex and antapex giving an equatorial expansion. The main body is smooth. The outer membrane, however, is uniformly sculptured with small perforations. A positive sculpture is also present in the form of spines and short processes with expanded tops again covering the whole of the outer membrane but unlike the perforations they are well separated. No pylome or archaeopyle has so far been seen.

Measurements:HolotypeRange
Overall diameter 93 µm 85-100 µm
Inner body diameter 38 µm 35- 50 µm
Length of spines 5-12 µm 3- 18 µm

Affinities:
Clarke and Verdier, 1967, p.78: P. spinosa differs from all previously described species in the presence of spines on the outer membrane.