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Bellatudinium hokkaidoanum
Bellatudinium hokkaidoanum, Kurita and Matsuoka, 1994
NOW Laciniadinium. Originally Bellatudinium subsequently (and now) Laciniadinium.
Holotype: Kurita and Matsuoka 1994: Plate 1, 1
Paratypes: Kurita and Matsuoka 1994: Plate I, 2-7.
Type locality: Futamata-sawa tributary, Haboro Town, Hokkaido
Type horizon: Lower part of the Sankebetsu Formation, Late Eocene.
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Original description: [Kurita and Matsuoka, 1994, p. 146-147]:
Diagnosis:
Proximate cyst, peridinioid, rounded pentagonal or ovoidal, with a broad and short apical horn and with or without two small antapical horns, bosses or lobes.
Autophragm thin, easily deformed and folded, transparent generally smooth or laevigate without surface ornamentation, rarely finely granulate. Paracingulum indicated by two equatorial, parallel ridges deriving from low folds of the phragma. Parasulcus indicated by shallow indentation, widens toward antapex.
Archeopyle not discernible.
Paratabulation not indicated other than as paracingulum and parasulcus.
Description:
The species varies extremely in cyst outline from ellipsoidal, ovoidal to roundly pentagonal. The height of the epicyst is more or less equal to that of the hypocyst. The apical horn is usually present and very wide and short, but sometimes lacking.
The antapical horns are also variable; some specimens bear two small bosses with a very short projection which are sometimes unequally developed, and these features are lacking in other specimens.
The autophragm is smooth, slightly laevigate or rarely finely granulate, and easily folded. Occasionally small grana are sparsely present around apical and antapical horns. There are sometimes faint traces of parasutures, but not sufficient for determining the paratabulation.
The paracingulum is almost equatorial, wide and clear, and indicated by indentation of the autophragm or by two parallel folds which margins are smooth and never dentate. The displacement of the paracingulum is not clear.
The parasulcus widens toward the antapex and is indicated by a shallow indentation.
The archeopyle is not discernible; however, a questionable archeopyle was observed in a single specimen (Plate I, 6, 7). It appears to be isodeltaform type I with the posteriorly adnate operculum and with accessory sutures along paraplate boundaries 3"/4" and 4"/5".
Dimensions (in µm):
Holotype; cyst length 40, width 36: range; length 35 44 (average 39), width 31-41 (average 37), nine specimens measured.
Affinities/Remarks:
Bellatudinium hokkaidoanum Kurita and Matsuoka, sp. nov. differs from B. conspicuum Yu et al., 1981 in having an epicyst which is equal in size as the hypocyst, not definitely tapered toward the apex, and in being smaller. The new species differs from B. fusum Yu et al. 1981 in lacking a prominent apical horn.
NOW Laciniadinium. Originally Bellatudinium subsequently (and now) Laciniadinium.
Holotype: Kurita and Matsuoka 1994: Plate 1, 1
Paratypes: Kurita and Matsuoka 1994: Plate I, 2-7.
Type locality: Futamata-sawa tributary, Haboro Town, Hokkaido
Type horizon: Lower part of the Sankebetsu Formation, Late Eocene.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original description: [Kurita and Matsuoka, 1994, p. 146-147]:
Diagnosis:
Proximate cyst, peridinioid, rounded pentagonal or ovoidal, with a broad and short apical horn and with or without two small antapical horns, bosses or lobes.
Autophragm thin, easily deformed and folded, transparent generally smooth or laevigate without surface ornamentation, rarely finely granulate. Paracingulum indicated by two equatorial, parallel ridges deriving from low folds of the phragma. Parasulcus indicated by shallow indentation, widens toward antapex.
Archeopyle not discernible.
Paratabulation not indicated other than as paracingulum and parasulcus.
Description:
The species varies extremely in cyst outline from ellipsoidal, ovoidal to roundly pentagonal. The height of the epicyst is more or less equal to that of the hypocyst. The apical horn is usually present and very wide and short, but sometimes lacking.
The antapical horns are also variable; some specimens bear two small bosses with a very short projection which are sometimes unequally developed, and these features are lacking in other specimens.
The autophragm is smooth, slightly laevigate or rarely finely granulate, and easily folded. Occasionally small grana are sparsely present around apical and antapical horns. There are sometimes faint traces of parasutures, but not sufficient for determining the paratabulation.
The paracingulum is almost equatorial, wide and clear, and indicated by indentation of the autophragm or by two parallel folds which margins are smooth and never dentate. The displacement of the paracingulum is not clear.
The parasulcus widens toward the antapex and is indicated by a shallow indentation.
The archeopyle is not discernible; however, a questionable archeopyle was observed in a single specimen (Plate I, 6, 7). It appears to be isodeltaform type I with the posteriorly adnate operculum and with accessory sutures along paraplate boundaries 3"/4" and 4"/5".
Dimensions (in µm):
Holotype; cyst length 40, width 36: range; length 35 44 (average 39), width 31-41 (average 37), nine specimens measured.
Affinities/Remarks:
Bellatudinium hokkaidoanum Kurita and Matsuoka, sp. nov. differs from B. conspicuum Yu et al., 1981 in having an epicyst which is equal in size as the hypocyst, not definitely tapered toward the apex, and in being smaller. The new species differs from B. fusum Yu et al. 1981 in lacking a prominent apical horn.