Back
Kleithriasphaeridium truncatum
Kleithriasphaeridium truncatum (Benson, 1976) Stover and Evitt, 1978
Originally Diversispina, subsequently (and now) Kleithriasphaeridium.
Taxonomic junior synonym: Cordosphaeridium digitatum (name not validly published), according to Slimani (2001a, p.193).
Schiøler et al. (1997, p.83) considered this to be the possible taxonomic senior synonym of Achilleodinium bianii.
Holotype: Benson, 1976, pl.2, figs.6-9
Locus typicus: Round Bay, Maryland, U.S.A.
Stratum typicum: Late Maastrichtian-Early Paleocene
Original diagnosis: Benson, 1976, p.184: Diversispina truncata
As for genus with the following additions: Cyst main body subspheroidal, cyst wall about 1 Ám in thickness, the processes arising from the thin periphragm. Periphragm exhibits microreticulate sculpture. Apical plate equivalents distinguished by four small processes of varying distal termination. Antapical process is larger than others with complex termination.
Dimensions: Holotype: Cyst main body length 58 Ám; width 54 Ám; process length 33-35 Ám; width 5-12 Ám.
-----------------------------------------------------------------------------------------------------------------------------------------------
Discussion: Schioler et al. 1997, p. 83
The two species Kleithriasphaeridium truncatum (Benson, 1976) Stover & Evitt, 1978 and Achilleodinium bianii Hultberg, 1985 appear to be very similar, judged from the original descriptions and the figured holotypes. In our opinion it is not possible to distinguish the two species on the basis of the description and illustrations of A. bianii given by Hultberg (1985); the two species may in fact be identical. However, as we have not studied the holotypes we hesitate to synonymise the two taxa formally. Herein, we attribute all relevant specimens from the ENCI Quarry to K. truncatum.
Occurrence: Rare below the Castor Horizon, absent above.
-----------------------------------------------------------------------------------------------------------------------------------------------
Originally Diversispina, subsequently (and now) Kleithriasphaeridium.
Taxonomic junior synonym: Cordosphaeridium digitatum (name not validly published), according to Slimani (2001a, p.193).
Schiøler et al. (1997, p.83) considered this to be the possible taxonomic senior synonym of Achilleodinium bianii.
Holotype: Benson, 1976, pl.2, figs.6-9
Locus typicus: Round Bay, Maryland, U.S.A.
Stratum typicum: Late Maastrichtian-Early Paleocene
Original diagnosis: Benson, 1976, p.184: Diversispina truncata
As for genus with the following additions: Cyst main body subspheroidal, cyst wall about 1 Ám in thickness, the processes arising from the thin periphragm. Periphragm exhibits microreticulate sculpture. Apical plate equivalents distinguished by four small processes of varying distal termination. Antapical process is larger than others with complex termination.
Dimensions: Holotype: Cyst main body length 58 Ám; width 54 Ám; process length 33-35 Ám; width 5-12 Ám.
-----------------------------------------------------------------------------------------------------------------------------------------------
Discussion: Schioler et al. 1997, p. 83
The two species Kleithriasphaeridium truncatum (Benson, 1976) Stover & Evitt, 1978 and Achilleodinium bianii Hultberg, 1985 appear to be very similar, judged from the original descriptions and the figured holotypes. In our opinion it is not possible to distinguish the two species on the basis of the description and illustrations of A. bianii given by Hultberg (1985); the two species may in fact be identical. However, as we have not studied the holotypes we hesitate to synonymise the two taxa formally. Herein, we attribute all relevant specimens from the ENCI Quarry to K. truncatum.
Occurrence: Rare below the Castor Horizon, absent above.
-----------------------------------------------------------------------------------------------------------------------------------------------