Back
Conosphaeridium lifum
Conosphaeridium lifum, Slimani et al., 2012, p.341–342, fig.3A–L.
Holotype: Slimani et al., 2012, fig.3A–C,E.
Type locality and bed: Ouled Haddou section, north of Taza, northern Morocco; marl 10 cm below the K/T boundary, uppermost Maastrichtian.
Stratigraphic occurrence: Samples OH 0–14, planktic foraminiferal Abathomphalus mayaroensis Zone (upper Maastrichtian) and Guembelitria cretacea Zone (lower Danian), Ouled Haddou section; molluscan Exogyra costata and Exogyra cancellata zones (uppermost Maastrichtian; Benson 1976).
Age: late Maastrichtian–early Danian.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original description: [Slimani et al., 2012]:
Diagnosis:
A species of Conosphaeridium characterized by a fibrous central body wall and non-striate processes. Processes conical, smooth, hollow at their base, closed distally and commonly solid and dark at their tip.
Description:
Proximate to proximochorate gonyaulacoid dinoflagellate cyst with an ovoid ambitus.
The wall consists of a closely appressed endophragm and periphragm. The endophragm is smooth with a maximum thickness of 1 μm. The periphragm is fibrous to microreticulate and has a maximum thickness of 0.5 μm.
The conical and smooth processes are hollow at their base but distally closed. The distal part of each process is commonly solid and dark (Fig. 3F, G).
The tabulation pattern is gonyaulacoid and is reflected by the intratabular processes (one process per plate) and the archeopyle. The reflected tabulation is 4′, 6′′, 6c, 5–6′′ ′, 1p, 1′′′′. A fibrous ridge up to 2 μm high connects the cingular processes proximally, but this feature is not always present (Fig. 3C, F, I).
The archeopyle is precingular (type P) and is formed by the release of precingular plate 3′′ (Fig. 3F, J). The operculum is free.
Dimensions:
Holotype: central body length, 70 μm; central body width, 58 μm; maximum process length, 5 μm. Range: central body length, 60(65)70 μm; central body width, 50(55)60 μm; average length of process, 5–10 μm (10 specimens measured).
Affinities/Remarks:
Conosphaeridium lifum sp. nov. is conspecific with Conosphaeridium cf. C. striatoconus of Benson (1976, p. 198, pl. 1, figs 4, 5) based on the fibrous to microreticulate surface. Benson (1976) erroneously described the archeopyle of a poorly preserved Conosphaeridium cf. C. striatoconus as apical. The new species differs from Conosphaeridium striatoconum (Deflandre & Cookson, 1955) Cookson & Eisenack, 1969 Cookson, I. C. and Eisenack, A. 1969. Some microplankton from two bores at Balcatta, Western Australia. Journal of the Royal Society of Western Australia, 52: 3–8. and Conosphaeridium abbreviatum Wilson, 1984 by its characteristic fibrous wall surface and smooth processes.
Holotype: Slimani et al., 2012, fig.3A–C,E.
Type locality and bed: Ouled Haddou section, north of Taza, northern Morocco; marl 10 cm below the K/T boundary, uppermost Maastrichtian.
Stratigraphic occurrence: Samples OH 0–14, planktic foraminiferal Abathomphalus mayaroensis Zone (upper Maastrichtian) and Guembelitria cretacea Zone (lower Danian), Ouled Haddou section; molluscan Exogyra costata and Exogyra cancellata zones (uppermost Maastrichtian; Benson 1976).
Age: late Maastrichtian–early Danian.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original description: [Slimani et al., 2012]:
Diagnosis:
A species of Conosphaeridium characterized by a fibrous central body wall and non-striate processes. Processes conical, smooth, hollow at their base, closed distally and commonly solid and dark at their tip.
Description:
Proximate to proximochorate gonyaulacoid dinoflagellate cyst with an ovoid ambitus.
The wall consists of a closely appressed endophragm and periphragm. The endophragm is smooth with a maximum thickness of 1 μm. The periphragm is fibrous to microreticulate and has a maximum thickness of 0.5 μm.
The conical and smooth processes are hollow at their base but distally closed. The distal part of each process is commonly solid and dark (Fig. 3F, G).
The tabulation pattern is gonyaulacoid and is reflected by the intratabular processes (one process per plate) and the archeopyle. The reflected tabulation is 4′, 6′′, 6c, 5–6′′ ′, 1p, 1′′′′. A fibrous ridge up to 2 μm high connects the cingular processes proximally, but this feature is not always present (Fig. 3C, F, I).
The archeopyle is precingular (type P) and is formed by the release of precingular plate 3′′ (Fig. 3F, J). The operculum is free.
Dimensions:
Holotype: central body length, 70 μm; central body width, 58 μm; maximum process length, 5 μm. Range: central body length, 60(65)70 μm; central body width, 50(55)60 μm; average length of process, 5–10 μm (10 specimens measured).
Affinities/Remarks:
Conosphaeridium lifum sp. nov. is conspecific with Conosphaeridium cf. C. striatoconus of Benson (1976, p. 198, pl. 1, figs 4, 5) based on the fibrous to microreticulate surface. Benson (1976) erroneously described the archeopyle of a poorly preserved Conosphaeridium cf. C. striatoconus as apical. The new species differs from Conosphaeridium striatoconum (Deflandre & Cookson, 1955) Cookson & Eisenack, 1969 Cookson, I. C. and Eisenack, A. 1969. Some microplankton from two bores at Balcatta, Western Australia. Journal of the Royal Society of Western Australia, 52: 3–8. and Conosphaeridium abbreviatum Wilson, 1984 by its characteristic fibrous wall surface and smooth processes.