Back
Palaeohystrichophora elongata
Palaeohystrichophora elongata sp. nov., Vieira and Mahdi, 2021
Holotype: Plate 4, figure 1, Vieira and Mahdi, 2021
Type locality: Møre Basin (Norway)
Stratigraphic extent: Late Cretaceous, early Campanian
Original description: Vieira and Mahdi, 2021:
Diagnosis:
Peridiniacean, bicavate dinoflagellate cyst exhibiting one distinct elongated apical horn and one elongated antapical horn. Endocyst and pericyst are elongated in
overall shape, and often the length of the cyst is greater than the breadth. The periphragm is thin and transparent, bearing numerous randomly distributed, very faint, hair-
like processes.
Description:
Proximate peridiniacean, bicavate dinoflagellate cyst of small to intermediate size. Central body dorso-ventrally compressed.
Wall: two layered, comprising a smooth and relatively thick (up to 2 µm) endophragm and smooth, thin and hyaline periphragm, bearing short, hairlike processes, sporadically distributed particularly on the apical and antapical regions. The endophragm is closely adpressed to the periphragm except in the apical and antapical areas,
where pericoel is present.
Endocyst: lenticular and rarely protrudes into the pericyst.
The distinct apical and antapical horns are long (approximately 15 µm).
Archaeopyle: usually indiscernible, if present it is precingular.
Cingulum: may be indicated by faint ridges or folds on the periphragm.
Dimensions:
Pericyst length 61 (74) 94 µm, width 29 (33) 38 µm, endocyst length 29 (34) 39 µm, width 29 (33) 38 µm
20 specimens measured
Affinities/Comparison:
Palaeohystrichophora infusorioides bears the closest resemblance to the present new species, however, comparing the average length of the cyst in 20 P. infusorioides specimens [42 (52) 59 µm], it is clear that this taxon is over 20 µm shorter than the average length of P. elongata [61 (74) 94 µm]. Also, P. infusorioides differs from
this new species by having a peridinoid (two antapical horns) rather than fusiform shape. Palaeohystrichophora granulata differs in having granules and only sporadic hairlike processes on the periphragm.
Holotype: Plate 4, figure 1, Vieira and Mahdi, 2021
Type locality: Møre Basin (Norway)
Stratigraphic extent: Late Cretaceous, early Campanian
Original description: Vieira and Mahdi, 2021:
Diagnosis:
Peridiniacean, bicavate dinoflagellate cyst exhibiting one distinct elongated apical horn and one elongated antapical horn. Endocyst and pericyst are elongated in
overall shape, and often the length of the cyst is greater than the breadth. The periphragm is thin and transparent, bearing numerous randomly distributed, very faint, hair-
like processes.
Description:
Proximate peridiniacean, bicavate dinoflagellate cyst of small to intermediate size. Central body dorso-ventrally compressed.
Wall: two layered, comprising a smooth and relatively thick (up to 2 µm) endophragm and smooth, thin and hyaline periphragm, bearing short, hairlike processes, sporadically distributed particularly on the apical and antapical regions. The endophragm is closely adpressed to the periphragm except in the apical and antapical areas,
where pericoel is present.
Endocyst: lenticular and rarely protrudes into the pericyst.
The distinct apical and antapical horns are long (approximately 15 µm).
Archaeopyle: usually indiscernible, if present it is precingular.
Cingulum: may be indicated by faint ridges or folds on the periphragm.
Dimensions:
Pericyst length 61 (74) 94 µm, width 29 (33) 38 µm, endocyst length 29 (34) 39 µm, width 29 (33) 38 µm
20 specimens measured
Affinities/Comparison:
Palaeohystrichophora infusorioides bears the closest resemblance to the present new species, however, comparing the average length of the cyst in 20 P. infusorioides specimens [42 (52) 59 µm], it is clear that this taxon is over 20 µm shorter than the average length of P. elongata [61 (74) 94 µm]. Also, P. infusorioides differs from
this new species by having a peridinoid (two antapical horns) rather than fusiform shape. Palaeohystrichophora granulata differs in having granules and only sporadic hairlike processes on the periphragm.