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Lopsidinium
From Williams et al., 2017:
[Lopsidinium, Dolby, 2014, p. 173.
Type species: Lopsidinium subrisum, Dolby, 2014 (pl.1, fig.2)]
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Original description: [Dolby, 2014]:
Diagnosis:
Elongate, ellipsoidal, chorate and acavate cysts bearing hollow, cylindrical or tapering processes, distally flared, restricted to the apex, antapex and longitudinal, ventral (sulcal) or ventral and dorsal series. The left and right lateral surfaces are devoid of processes. There is no indication of a cingulum or of tabulation except for the archaeopyle sutures and sulcal notch. The archaeopyle is apical.
Affinities:
The genus resembles Bourkidinium (Morgan 1975) Nøhr-Hansen 1993, but the processes in that genus are restricted to the polar areas. Two specimens identified as B. granulatum by Nøhr-Hansen 1993 (plate 3, figures 4 and 5) from the Middle Albian of northeast Greenland have single ventral/sulcal processes and may possibly be a species of Lopsidinium gen. nov. The processes in Tanyosphaeridium Davey & Williams 1966 are intratabular with a latitudinal arrangement.
[Lopsidinium, Dolby, 2014, p. 173.
Type species: Lopsidinium subrisum, Dolby, 2014 (pl.1, fig.2)]
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Original description: [Dolby, 2014]:
Diagnosis:
Elongate, ellipsoidal, chorate and acavate cysts bearing hollow, cylindrical or tapering processes, distally flared, restricted to the apex, antapex and longitudinal, ventral (sulcal) or ventral and dorsal series. The left and right lateral surfaces are devoid of processes. There is no indication of a cingulum or of tabulation except for the archaeopyle sutures and sulcal notch. The archaeopyle is apical.
Affinities:
The genus resembles Bourkidinium (Morgan 1975) Nøhr-Hansen 1993, but the processes in that genus are restricted to the polar areas. Two specimens identified as B. granulatum by Nøhr-Hansen 1993 (plate 3, figures 4 and 5) from the Middle Albian of northeast Greenland have single ventral/sulcal processes and may possibly be a species of Lopsidinium gen. nov. The processes in Tanyosphaeridium Davey & Williams 1966 are intratabular with a latitudinal arrangement.