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Lejeunecysta longistriata
Lejeunecysta longistriata sp. nov., Uddandam et al. 2020
Holotype: Plate II; 1-3,
Type locality: western Bay of Bengal, Holocene seabed sediments (0-1 cm)
Original description: Uddandam et al. 2020:
Diagnosis:
An Intermediate, proximate, sub pentagonal cyst with dorso-ventral compression. Epicyst slightly shorter than hypocyst, conical with concave to straight sides in dorso-
ventral view with two small acuminate antapical horns and one apical horn. Cyst autophragm is brownish-pigmented consists discontinuous longitudinal striations which are 10–30 μm in length. Paracingulum is not distinctly defined. Parasulcus deep, restricted to hypocyst; the flagellar scar marked by two prominent invaginations. Paratabulation absent except for archeopyle. Archeopyle large simple intercalary, formed by the loss of paraplate 2a.
Description:
A relatively elongate subpentagonal species with brown pigmentation. Cyst dorsoventrally compressed with small, short, sharply distally pointed, conical apical and antapical horns. The three polar horns exhibit acuminate tips with a prominent distal thickening. The epicyst and hypocyst flanks are straight to weakly convex.
Hypocyst: slightly larger than the epicyst.
Lateral horns or protrusions are absent. The antapical concavity is small and the paired antapical horns are located close together at the midline.
Autophragm: of moderate thickness and bears prominent, smooth, discontinuous non-tabular longitudinal striations 10-30 μm in length.
Paratabulation: expressed only in the form of archeopyle.
Archeopyle: large anterior intercalary type 2a, mid-dorsal in position with narrow anterior margin and broad mid-dorsal margin. The posterior margin of the archaeopyle may bear serrated margin. Hexagonal in shape occupying much of the dorsal side of the epicyst (latidelta form).
Operculum: open.
The cingulum is not reflected; however, there is a marked mid-ventral sulcal depression.
Dimensions:
overall length: 106–110 μm, overall width: 98–106 μm, length epicyst and hypocyst: 40-45 and 48-55 μm respectively
8 specimens measured
Affinities/Comparison:
Lejeunecysta longistriata sp. nov. differs from Lejeunecysta oliva (Reid, 1977) Turon and Londeix, 1988 in lacking cingular ridges, and from Lejeunecysta sabrina (Reid,
1977) Bujak, 1984 in being striate and having a convex epicyst. It also differs from Selenopemphix selenoides Benedek, 1972 in not having an echinate cingulum. This new species differs from cysts of Protoperidinium latissimum (Kofoid, 1907) Balech 1974 in having a six-sided, rather than a five-sided, anterior intercalary archaeopyle. It differs from L. paratenella in not having a prominent cingulum and apical granules. It differs from L. epidoma in having an apical thickening and not a prominent dome shape. It differs from L. psuchra in having a pointed apical and antapical horns with ornamentation on the autophragm. L. longistriata differs from Quinquecuspis concreta in possessing in elongated sub pentagonal ambitus and in having a sulcul groove which is not deeply sunken.
Holotype: Plate II; 1-3,
Type locality: western Bay of Bengal, Holocene seabed sediments (0-1 cm)
Original description: Uddandam et al. 2020:
Diagnosis:
An Intermediate, proximate, sub pentagonal cyst with dorso-ventral compression. Epicyst slightly shorter than hypocyst, conical with concave to straight sides in dorso-
ventral view with two small acuminate antapical horns and one apical horn. Cyst autophragm is brownish-pigmented consists discontinuous longitudinal striations which are 10–30 μm in length. Paracingulum is not distinctly defined. Parasulcus deep, restricted to hypocyst; the flagellar scar marked by two prominent invaginations. Paratabulation absent except for archeopyle. Archeopyle large simple intercalary, formed by the loss of paraplate 2a.
Description:
A relatively elongate subpentagonal species with brown pigmentation. Cyst dorsoventrally compressed with small, short, sharply distally pointed, conical apical and antapical horns. The three polar horns exhibit acuminate tips with a prominent distal thickening. The epicyst and hypocyst flanks are straight to weakly convex.
Hypocyst: slightly larger than the epicyst.
Lateral horns or protrusions are absent. The antapical concavity is small and the paired antapical horns are located close together at the midline.
Autophragm: of moderate thickness and bears prominent, smooth, discontinuous non-tabular longitudinal striations 10-30 μm in length.
Paratabulation: expressed only in the form of archeopyle.
Archeopyle: large anterior intercalary type 2a, mid-dorsal in position with narrow anterior margin and broad mid-dorsal margin. The posterior margin of the archaeopyle may bear serrated margin. Hexagonal in shape occupying much of the dorsal side of the epicyst (latidelta form).
Operculum: open.
The cingulum is not reflected; however, there is a marked mid-ventral sulcal depression.
Dimensions:
overall length: 106–110 μm, overall width: 98–106 μm, length epicyst and hypocyst: 40-45 and 48-55 μm respectively
8 specimens measured
Affinities/Comparison:
Lejeunecysta longistriata sp. nov. differs from Lejeunecysta oliva (Reid, 1977) Turon and Londeix, 1988 in lacking cingular ridges, and from Lejeunecysta sabrina (Reid,
1977) Bujak, 1984 in being striate and having a convex epicyst. It also differs from Selenopemphix selenoides Benedek, 1972 in not having an echinate cingulum. This new species differs from cysts of Protoperidinium latissimum (Kofoid, 1907) Balech 1974 in having a six-sided, rather than a five-sided, anterior intercalary archaeopyle. It differs from L. paratenella in not having a prominent cingulum and apical granules. It differs from L. epidoma in having an apical thickening and not a prominent dome shape. It differs from L. psuchra in having a pointed apical and antapical horns with ornamentation on the autophragm. L. longistriata differs from Quinquecuspis concreta in possessing in elongated sub pentagonal ambitus and in having a sulcul groove which is not deeply sunken.