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Pentadinium dababiyaense
Pentadinium dababiyaense sp. nov.; Soliman, A. & Slimani, H. 2019
Holotype: Sample DBD-24, slide A, England Finder (EF) coordinates J27-2 (Fig. 3DeJ), Soliman, A. & Slimani, H. 2019
Original description: Soliman, A. & Slimani, H. 2019: Pentadinium dababiyaense sp. nov.:
Diagnosis:
A small species of Pentadinium characterized by suturocavate crests that are densely microperforated in a lace-like manner. A conspicuous cavate horn/boss is present at the apex. A gonyaulacoid tabulation is reflected by the suturocavate crests and the precingular archeopyle type P. The operculum is free.
Description:
A small subcircular to oval suturocavate organic-walled dinocyst with two wall layers: an endophragm which is thin to moderately thick (~2 mm), psilate to scabrate, occasionally finely reticulate and a periphragm which is generally thinner than the endophragm, hyaline and closely appressed to the endophragm at the central areas of the plates (Fig. 5M). The endophragm and periphragm are separated along the plate margins to form cavate sutural crests (~10 mm high) that are densely microperforated in a lace-like manner. The perforations are absent where the endophragm and periphragm are appressed. The periphragm is occasionally supported by slender columellae rising from the endophragm. The plate boundaries may be reflected by periphragm thickening at the top of the cavate sutural crests (Fig. 5L). The new species has a cavate apical horn/boss, resulting from the union of the sutural pericoels at the junction of the four apical plates (Fig. 5F, K). The cingulum is suturocavate to wholly cavate. Archeopyle: precingular, formed by the release of the third precingular plate (3'') and the operculum is free.
Tabulation: gonyaulacoid with the formula 3e40, 600, 6c, 6000, 1p, 10000 is indicated by cavate sutural crests and the archeopyle.
Dimension:
Range for 15 specimens measured: overall length 47(55)64 µm; overall width 39(49)59 µm; central body length 34(40)45 µm; central body width 31(36)45 µm
Holotype: overall length 60 µm; overall width 55 µm; central body length 42 µm; central body width 38 µm
Paratype: overall length 55 µm; overall width 45 µm; central body length 40 µm; central body width 35 µm
Affinities:
P. dababiyaense sp. nov. can be distinguished from all species of P. by its lace-like microperforate cavate sutural crests, its suturocavate to wholly cavate cingulum and the presence of a cavate apical horn. Although P. favatum and P. alabamense also might show a separation of endophragm and
periphragm at the plate margins, this is not a consistent feature as in P. dababiyaense. P. favatum has a moderately thick, spongy or honeycomb textured endophragm and a delicately meshed periphragm.
P. dababiyaense sp. nov. resembles P. alabamense but differs in its periphragm perforation style resembling lace, its much lower crests and in the presence of a distinctive cavate apical horn/boss.
P. galileoi, P. polypodum and P. spinulum differ from P. dababiyaense sp. nov. in possessing processes.
Other taxa such as P. circumsutum, P. corium, P. goniferum, P. granulatum, P. imaginatum, P. membranaceum, P. sabulum and P. taeniagerum can all be distinguished from the new species by having a granulate to vermiculate endocyst surface ornamentation and in lacking perforations of the periphragm.
P. lophophorum differs from the new species in having verrucate ornamentation at the centre of the plates. P. darmirae differs from the new species in having a large untabulated ventral area, resulting from the absence of sulcal plates and adjacent precingular and postcingular plates.
Holotype: Sample DBD-24, slide A, England Finder (EF) coordinates J27-2 (Fig. 3DeJ), Soliman, A. & Slimani, H. 2019
Original description: Soliman, A. & Slimani, H. 2019: Pentadinium dababiyaense sp. nov.:
Diagnosis:
A small species of Pentadinium characterized by suturocavate crests that are densely microperforated in a lace-like manner. A conspicuous cavate horn/boss is present at the apex. A gonyaulacoid tabulation is reflected by the suturocavate crests and the precingular archeopyle type P. The operculum is free.
Description:
A small subcircular to oval suturocavate organic-walled dinocyst with two wall layers: an endophragm which is thin to moderately thick (~2 mm), psilate to scabrate, occasionally finely reticulate and a periphragm which is generally thinner than the endophragm, hyaline and closely appressed to the endophragm at the central areas of the plates (Fig. 5M). The endophragm and periphragm are separated along the plate margins to form cavate sutural crests (~10 mm high) that are densely microperforated in a lace-like manner. The perforations are absent where the endophragm and periphragm are appressed. The periphragm is occasionally supported by slender columellae rising from the endophragm. The plate boundaries may be reflected by periphragm thickening at the top of the cavate sutural crests (Fig. 5L). The new species has a cavate apical horn/boss, resulting from the union of the sutural pericoels at the junction of the four apical plates (Fig. 5F, K). The cingulum is suturocavate to wholly cavate. Archeopyle: precingular, formed by the release of the third precingular plate (3'') and the operculum is free.
Tabulation: gonyaulacoid with the formula 3e40, 600, 6c, 6000, 1p, 10000 is indicated by cavate sutural crests and the archeopyle.
Dimension:
Range for 15 specimens measured: overall length 47(55)64 µm; overall width 39(49)59 µm; central body length 34(40)45 µm; central body width 31(36)45 µm
Holotype: overall length 60 µm; overall width 55 µm; central body length 42 µm; central body width 38 µm
Paratype: overall length 55 µm; overall width 45 µm; central body length 40 µm; central body width 35 µm
Affinities:
P. dababiyaense sp. nov. can be distinguished from all species of P. by its lace-like microperforate cavate sutural crests, its suturocavate to wholly cavate cingulum and the presence of a cavate apical horn. Although P. favatum and P. alabamense also might show a separation of endophragm and
periphragm at the plate margins, this is not a consistent feature as in P. dababiyaense. P. favatum has a moderately thick, spongy or honeycomb textured endophragm and a delicately meshed periphragm.
P. dababiyaense sp. nov. resembles P. alabamense but differs in its periphragm perforation style resembling lace, its much lower crests and in the presence of a distinctive cavate apical horn/boss.
P. galileoi, P. polypodum and P. spinulum differ from P. dababiyaense sp. nov. in possessing processes.
Other taxa such as P. circumsutum, P. corium, P. goniferum, P. granulatum, P. imaginatum, P. membranaceum, P. sabulum and P. taeniagerum can all be distinguished from the new species by having a granulate to vermiculate endocyst surface ornamentation and in lacking perforations of the periphragm.
P. lophophorum differs from the new species in having verrucate ornamentation at the centre of the plates. P. darmirae differs from the new species in having a large untabulated ventral area, resulting from the absence of sulcal plates and adjacent precingular and postcingular plates.