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Spiniferites fentonii ssp. pumilus
Derivation of name. The species epithet fentonii was originally designated in honour of our colleague, palynologist Dr. James Fenton. The subspecies name pumilus is derived from the Latin word for ‘dwarf’, ‘short’, or ‘little’, referring to the characteristically reduced process length of this taxon.
Holotype. Plate 7, figure 1; from a cuttings sample 2211m from well 16/1-35S. Cyst size with processes 74um, central body 64um, length of processes 10um.
Type locality. Norwegian North Sea Quad 16, Lista Formation.
Diagnosis. Cyst with a sub-spherical central body. Processes are relatively simple, measuring approximately 1/5 to 1/4 of the central body diameter in length. Distal process terminations are predominantly capitate or briefly bifurcate, with minimal evidence of secondary furcation. The distal portions of the processes are slender and often appear solid, while any membranous structures are generally confined to the proximal halves and linking septa.
Description. Intermediate-sized, chorate dinoflagellate cyst exhibiting strong dorso-ventral compression. The archeopyle is precingular, formed by the loss of plate 300, with the operculum typically free. The central body is sub-spherical in shape. The cyst wall is composed of two layers: a thick, smooth to finely granulate endophragm (<2lm thick), and a thinner, smooth periphragm (<1lm thick). Processes are simple and robust, measuring approximately 1/5 to 1/4 of the central body diameter in length. Their distal ends are primarily capitate or briefly bifurcate, with limited development of secondary furcation. Distal segments of the processes are relatively narrow and solid in appearance, while membranous extensions, when present, are mostly restricted to the proximal portions and the linking septa.
Dimensions. Cyst with processes 70 (74) 80um, central body 56 (60) 68um, length of processes 6 (8) 10um. Number of specimens measured =15.
Comparison. Spiniferites fentonii subsp. fentonii is characterized by longer, more membranous processes typically ranging from approximately one-third to one- half of the central body diameter in length. These processes are generally more complex, often trifurcate distally and terminating in minute bifurcations, frequently with bifid tips (Vieira and Mahdi 2019). In contrast, this subspecies displays processes that are shorter and less elaborate, typically terminating in capitate or briefly bifurcate tips, with limited or no evidence of secondary furcation. Based on these morphological features, S. fentonii subsp. pumilus subsp. nov. can be interpreted as a transitional form between Spiniferites truncatus and S. fentonii subsp. fentonii.
Holotype. Plate 7, figure 1; from a cuttings sample 2211m from well 16/1-35S. Cyst size with processes 74um, central body 64um, length of processes 10um.
Type locality. Norwegian North Sea Quad 16, Lista Formation.
Diagnosis. Cyst with a sub-spherical central body. Processes are relatively simple, measuring approximately 1/5 to 1/4 of the central body diameter in length. Distal process terminations are predominantly capitate or briefly bifurcate, with minimal evidence of secondary furcation. The distal portions of the processes are slender and often appear solid, while any membranous structures are generally confined to the proximal halves and linking septa.
Description. Intermediate-sized, chorate dinoflagellate cyst exhibiting strong dorso-ventral compression. The archeopyle is precingular, formed by the loss of plate 300, with the operculum typically free. The central body is sub-spherical in shape. The cyst wall is composed of two layers: a thick, smooth to finely granulate endophragm (<2lm thick), and a thinner, smooth periphragm (<1lm thick). Processes are simple and robust, measuring approximately 1/5 to 1/4 of the central body diameter in length. Their distal ends are primarily capitate or briefly bifurcate, with limited development of secondary furcation. Distal segments of the processes are relatively narrow and solid in appearance, while membranous extensions, when present, are mostly restricted to the proximal portions and the linking septa.
Dimensions. Cyst with processes 70 (74) 80um, central body 56 (60) 68um, length of processes 6 (8) 10um. Number of specimens measured =15.
Comparison. Spiniferites fentonii subsp. fentonii is characterized by longer, more membranous processes typically ranging from approximately one-third to one- half of the central body diameter in length. These processes are generally more complex, often trifurcate distally and terminating in minute bifurcations, frequently with bifid tips (Vieira and Mahdi 2019). In contrast, this subspecies displays processes that are shorter and less elaborate, typically terminating in capitate or briefly bifurcate tips, with limited or no evidence of secondary furcation. Based on these morphological features, S. fentonii subsp. pumilus subsp. nov. can be interpreted as a transitional form between Spiniferites truncatus and S. fentonii subsp. fentonii.