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Bradleyella adela
Bradleyella adela, (Fenton et al., 1980), Wollam, 1983
Originally Dichadogonyaulax, subsequently Ctenidodinium, thirdly (and now) Bradleyella.
Holotype: Fenton et aI., 1980, pl.14, fig.3; text-figs.3A-B
Locus typicus: Hook Norton, Oxfordshire, England
Stratum typicum: Late Bajocian
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Original description as Dichadogonyaulax adela: [Fenton et al., 1980, p. 155-156]:
Diagnosis:
Small proximate cyst, spheroidal to ovoidal outline, dorso-ventrally flattened. Lacking polar and median horns. Epicyst slightly smaller than hypocyst. Paracingulum relatively broad, strongly laevorotatory. Parasutures absent or indistinct, defined by simple lines, low rounded ridges, or rarely by alignment of low granules. Parasutures preferentially developed on epicyst.
Paratabulation formula 4", 6", 6c, 6""", 1"""".
Archaeopyle epicystal, schism occurring along the anterior margin of the paracingulum.
Description:
The cyst possesses a ?double-layered wall, up to 1 µm thick. The epicyst is slightly smaller than the hypocyst, the latter appearing to be more rigid in construction than the epicyst which is prone to break up along the parasutures. Four apical paraplates occur, paraplate 1" occupying an anterior prolongation of the parasulcus. Paraplates 2"-4" are polygonal, with paraplate 4" being slightly reduced in area. Six roughly trapezoidal precingular paraplates occur, with paraplate 3" being reduced in area. Paraplate 6" is reduced to an elongate shape adjacent to the anterior parasulcal area. The paracingulum is relatively broad (3-5 µm), strongly laevorotatory and offset by about twice its width. It is subdivided into six paraplates, with paraplate lc the smallest. The undivided parasulcus is long and extends almost the whole length of the ventral surface. An expansion in width of the anterior area creates the impression of an intercalary paraplate, but no confirmative evidence could be found. The width is approximately constant on the hypocyst. Six postcingular paraplates are identified, with paraplate 1""" being severely reduced becoming narrow and elongate. The remainder are approximately trapezoidal in outline. The antapex is made up of a single small, subquadrate paraplate. The surface of the cyst varies from faint to coarsely scabrate, with the occasional development of low (< 1 µm) isolated granules. The granules, when present, are often aligned in rough approximation to the parasutures. The latter are normally indistinct and may be completely absent from the hypocyst. The parasutures are best developed as very low rounded ridges (< 1 µm) or lines along which the epicyst may break up. In all the specimens observed the epicyst remained attached to the hypocyst on the ventral surface after archaeopyle development.
Dimensions:
Cyst width 26(30)37 µm (18 specimens measured), length-30(35)48 µm; holotype width-37 µm, length-48 µm.
Affinities:
D. adelos differs from all other species of Dichadogonyaulax by its small size, paratabulation, and parasutural ornament. The paratabulation is very indistinct, only being fully resolved on the holotype. Its absence on the hypocyst gives D. adelos a superficial resemblance to the genus Mancodinium Morgenroth, 1970. However, the latter differs in possessing a more complex epicystal paratabulation and a non-tabulate hypocyst.
Originally Dichadogonyaulax, subsequently Ctenidodinium, thirdly (and now) Bradleyella.
Holotype: Fenton et aI., 1980, pl.14, fig.3; text-figs.3A-B
Locus typicus: Hook Norton, Oxfordshire, England
Stratum typicum: Late Bajocian
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original description as Dichadogonyaulax adela: [Fenton et al., 1980, p. 155-156]:
Diagnosis:
Small proximate cyst, spheroidal to ovoidal outline, dorso-ventrally flattened. Lacking polar and median horns. Epicyst slightly smaller than hypocyst. Paracingulum relatively broad, strongly laevorotatory. Parasutures absent or indistinct, defined by simple lines, low rounded ridges, or rarely by alignment of low granules. Parasutures preferentially developed on epicyst.
Paratabulation formula 4", 6", 6c, 6""", 1"""".
Archaeopyle epicystal, schism occurring along the anterior margin of the paracingulum.
Description:
The cyst possesses a ?double-layered wall, up to 1 µm thick. The epicyst is slightly smaller than the hypocyst, the latter appearing to be more rigid in construction than the epicyst which is prone to break up along the parasutures. Four apical paraplates occur, paraplate 1" occupying an anterior prolongation of the parasulcus. Paraplates 2"-4" are polygonal, with paraplate 4" being slightly reduced in area. Six roughly trapezoidal precingular paraplates occur, with paraplate 3" being reduced in area. Paraplate 6" is reduced to an elongate shape adjacent to the anterior parasulcal area. The paracingulum is relatively broad (3-5 µm), strongly laevorotatory and offset by about twice its width. It is subdivided into six paraplates, with paraplate lc the smallest. The undivided parasulcus is long and extends almost the whole length of the ventral surface. An expansion in width of the anterior area creates the impression of an intercalary paraplate, but no confirmative evidence could be found. The width is approximately constant on the hypocyst. Six postcingular paraplates are identified, with paraplate 1""" being severely reduced becoming narrow and elongate. The remainder are approximately trapezoidal in outline. The antapex is made up of a single small, subquadrate paraplate. The surface of the cyst varies from faint to coarsely scabrate, with the occasional development of low (< 1 µm) isolated granules. The granules, when present, are often aligned in rough approximation to the parasutures. The latter are normally indistinct and may be completely absent from the hypocyst. The parasutures are best developed as very low rounded ridges (< 1 µm) or lines along which the epicyst may break up. In all the specimens observed the epicyst remained attached to the hypocyst on the ventral surface after archaeopyle development.
Dimensions:
Cyst width 26(30)37 µm (18 specimens measured), length-30(35)48 µm; holotype width-37 µm, length-48 µm.
Affinities:
D. adelos differs from all other species of Dichadogonyaulax by its small size, paratabulation, and parasutural ornament. The paratabulation is very indistinct, only being fully resolved on the holotype. Its absence on the hypocyst gives D. adelos a superficial resemblance to the genus Mancodinium Morgenroth, 1970. However, the latter differs in possessing a more complex epicystal paratabulation and a non-tabulate hypocyst.