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Magallanesium
From Williams et al., 2017:
[Magallanesium, Quattrocchio and Sarjeant, 2003, p. 138, 140.
Type species: Deflandrea macmurdoensis, Wilson, 1967a (figs.11-13)]
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Original description: [Quattrocchio and Sarjeant, 2003]:
Diagnosis:
Cornucavate peridinioid cysts of asymmetrically rhomboidal to somewhat rounded ambitus. Episome larger than hyposome, lacking “shoulders”. Apical horn well developed, of variable size and shape; hyposome with well-developed left antapical horn, but with right antapical horn always short and sometimes feebly developed. The periphragma may be laevigate to granulose; it bears a general cover of spines, sometimes aligned or concentrated into penitabular groups, sometimes without apparent arrangement.
Cingulum shallow, concave, bordered by raised ridges that may be spinose; sulcus only feebly marked, as an area devoid of spines.
Archaeopyle formed by anterior intercalary plate 2a, which is hexa- and isodeltaform. Operculum adnate posteriorly or lost.
Discussion: (On 32 specimens of M. macmurdoense, Quattrocchio and Sarjeant, 1996).
This genus is differentiated from Spinidinium and Volkheimeridium by the form of the archaeopyle and additionally from Volkheimeridium by the lack of raised ridges or crests along sutures (though, in some species, lines of spines may indicate the position of plate boundaries). Plate 2a is proportionately larger in this genus than in either Spinidinium or Volkheimeridium, while the archaeopyle sutures on either side of plate 4’’ are less consistently developed or not at all. The proportions and the general cover of spines distinguish this genus from all others yet reported from late Cretaceous-Tertiary sediments.
[Magallanesium, Quattrocchio and Sarjeant, 2003, p. 138, 140.
Type species: Deflandrea macmurdoensis, Wilson, 1967a (figs.11-13)]
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original description: [Quattrocchio and Sarjeant, 2003]:
Diagnosis:
Cornucavate peridinioid cysts of asymmetrically rhomboidal to somewhat rounded ambitus. Episome larger than hyposome, lacking “shoulders”. Apical horn well developed, of variable size and shape; hyposome with well-developed left antapical horn, but with right antapical horn always short and sometimes feebly developed. The periphragma may be laevigate to granulose; it bears a general cover of spines, sometimes aligned or concentrated into penitabular groups, sometimes without apparent arrangement.
Cingulum shallow, concave, bordered by raised ridges that may be spinose; sulcus only feebly marked, as an area devoid of spines.
Archaeopyle formed by anterior intercalary plate 2a, which is hexa- and isodeltaform. Operculum adnate posteriorly or lost.
Discussion: (On 32 specimens of M. macmurdoense, Quattrocchio and Sarjeant, 1996).
This genus is differentiated from Spinidinium and Volkheimeridium by the form of the archaeopyle and additionally from Volkheimeridium by the lack of raised ridges or crests along sutures (though, in some species, lines of spines may indicate the position of plate boundaries). Plate 2a is proportionately larger in this genus than in either Spinidinium or Volkheimeridium, while the archaeopyle sutures on either side of plate 4’’ are less consistently developed or not at all. The proportions and the general cover of spines distinguish this genus from all others yet reported from late Cretaceous-Tertiary sediments.