Back
Biorbifera
From Williams et al., 2017:
[Biorbifera, Habib, 1972, p. 377-378; Emendation: Below, 1987b, p. 63-64; Riding and Helby, 2001g, p.195,197
Type species: Biorbifera, johnewingii, Habib, 1972 (pl.10, fig.3)]
Locus typicus: DSDP Hole 105, Leg 11, W N Atlantic
Stratum typicum: Early Cretaceous
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original description: [Habib 1972]:
Description:
Relatively small untabulated proximate cyst with indented relatively wide cingulum. Both epitract and hypotract essentially semi-circular in outline. Polar areas always broadly rounded and, with the indented cingulum, tend to give the cyst a dumb-bell or peanut shape. Hypotract larger than epitract. The operculum dehises immediately anterior to the cingulum (epitractal archaeopyle, AP); in the majority of specimens the operculum remains partially attached. Periphragm covered with numerous broadly tapering sharp spines; only very few appear blunt at the tip; spines number from 150 to 250 at the outline; their distribution is less dense in the larger specimens (for example, holotype) and more dense in the smaller.
Range in maximum size of twenty measured specimens is 24 to 38 µm.
Affinities:
This species resembles Tenua pilosa (Ehrenberg) but is clearly distinguished in the archeopyle formation.
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Emended description:
Below, 1987: (Translation: Bureau of Translation, Secretary of State Canada, 1988, Part II, p. 177-178):
Description:
Arrangement of vesicles/plates on the dinoflagellate amphiesma PR, 4', 1a, 5'', 6c, 5''', 1'''', ns; Growth of plates peridinoidal;
Cyst habit proximate, proximochorate, acavate, oblong ovaloidal, epicyst semispheroidal; hypocyst twice as long with equatorial cingulum, cingulum very broad, ribbon-shaped, not very deep, planispiral, posterior portion of hypocyst semispheroidal to semiellipsoidal; size small; wall composed of pedium and very fine luxuriate setules, usually aggregated on limbi, and coarse, acuminate spines measuring less than 1/10 of the cingular diameter of the cyst and covering the surface densely and evenly or in intraareate groups separated by limbi;
areation formula NR PR, NR', NRa, NR''/X'', Xc, NR'''/5''', NR''''/1'''', Xs; Epicyst generally non-areate, only seldom individual precingular intraareate groups separated by limbi; 5 postcingulars all posteriorly, linear IV-nE1''' (VL), IV-nE ''' (LDL), IV-nE3''' (D), IV-nE 4''' (RDR), IV-nE 5''' (VR) and 1 polar VI 1''''; sulcus level, non-partite; archaeopyle epicystal, PR+1'+2'+3'+4'+1a+1''+2''+3''+4''+5''; operculum foederate, adnate, general opercular formula (PR+1'+2'+3'+4'+1a+1''+2''+3''+4''+5'')(a).
Affinities:
The areation is clearly discernible only on the hypocyst of certain specimens, as 5''', 1'''' and it is identical with the pattern known from Valvaeodinium. The subdivision of the epicyst and cingulum is deduced by comparison with Valvaeodinium. Usually the epicystal operculum flaps up only slightly and remains connected ventrally to the hypocyst. The infrequent specimens with isolated opercular calottes, as artefacts, are not considered. The operculum was probably detached mechanically, since in such cases area as does not project clearly from the edge of the archaeopyle, as usually happens with an epicystal archaeopyle (see, e.g. Mancodinium).
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Notes:
G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.
Biorbifera johnewingii Habib, 1972, emend. Below, 1987b. According to Below (1987b, p.63), the cyst is proximate, proximochorate, acavate, elongate, ovaloidal, with the epicyst being semispherical, and the hypocyst being twice the length of the epicyst. The cingulum is more or less planar. The numerous processes are about one-tenth the diameter of the cyst Tabulation, according to Below (1987) is pr, 4', 1a, 5" on epicyst. Size: 24-38 µm.
[Biorbifera, Habib, 1972, p. 377-378; Emendation: Below, 1987b, p. 63-64; Riding and Helby, 2001g, p.195,197
Type species: Biorbifera, johnewingii, Habib, 1972 (pl.10, fig.3)]
Locus typicus: DSDP Hole 105, Leg 11, W N Atlantic
Stratum typicum: Early Cretaceous
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original description: [Habib 1972]:
Description:
Relatively small untabulated proximate cyst with indented relatively wide cingulum. Both epitract and hypotract essentially semi-circular in outline. Polar areas always broadly rounded and, with the indented cingulum, tend to give the cyst a dumb-bell or peanut shape. Hypotract larger than epitract. The operculum dehises immediately anterior to the cingulum (epitractal archaeopyle, AP); in the majority of specimens the operculum remains partially attached. Periphragm covered with numerous broadly tapering sharp spines; only very few appear blunt at the tip; spines number from 150 to 250 at the outline; their distribution is less dense in the larger specimens (for example, holotype) and more dense in the smaller.
Range in maximum size of twenty measured specimens is 24 to 38 µm.
Affinities:
This species resembles Tenua pilosa (Ehrenberg) but is clearly distinguished in the archeopyle formation.
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Emended description:
Below, 1987: (Translation: Bureau of Translation, Secretary of State Canada, 1988, Part II, p. 177-178):
Description:
Arrangement of vesicles/plates on the dinoflagellate amphiesma PR, 4', 1a, 5'', 6c, 5''', 1'''', ns; Growth of plates peridinoidal;
Cyst habit proximate, proximochorate, acavate, oblong ovaloidal, epicyst semispheroidal; hypocyst twice as long with equatorial cingulum, cingulum very broad, ribbon-shaped, not very deep, planispiral, posterior portion of hypocyst semispheroidal to semiellipsoidal; size small; wall composed of pedium and very fine luxuriate setules, usually aggregated on limbi, and coarse, acuminate spines measuring less than 1/10 of the cingular diameter of the cyst and covering the surface densely and evenly or in intraareate groups separated by limbi;
areation formula NR PR, NR', NRa, NR''/X'', Xc, NR'''/5''', NR''''/1'''', Xs; Epicyst generally non-areate, only seldom individual precingular intraareate groups separated by limbi; 5 postcingulars all posteriorly, linear IV-nE1''' (VL), IV-nE ''' (LDL), IV-nE3''' (D), IV-nE 4''' (RDR), IV-nE 5''' (VR) and 1 polar VI 1''''; sulcus level, non-partite; archaeopyle epicystal, PR+1'+2'+3'+4'+1a+1''+2''+3''+4''+5''; operculum foederate, adnate, general opercular formula (PR+1'+2'+3'+4'+1a+1''+2''+3''+4''+5'')(a).
Affinities:
The areation is clearly discernible only on the hypocyst of certain specimens, as 5''', 1'''' and it is identical with the pattern known from Valvaeodinium. The subdivision of the epicyst and cingulum is deduced by comparison with Valvaeodinium. Usually the epicystal operculum flaps up only slightly and remains connected ventrally to the hypocyst. The infrequent specimens with isolated opercular calottes, as artefacts, are not considered. The operculum was probably detached mechanically, since in such cases area as does not project clearly from the edge of the archaeopyle, as usually happens with an epicystal archaeopyle (see, e.g. Mancodinium).
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Notes:
G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.
Biorbifera johnewingii Habib, 1972, emend. Below, 1987b. According to Below (1987b, p.63), the cyst is proximate, proximochorate, acavate, elongate, ovaloidal, with the epicyst being semispherical, and the hypocyst being twice the length of the epicyst. The cingulum is more or less planar. The numerous processes are about one-tenth the diameter of the cyst Tabulation, according to Below (1987) is pr, 4', 1a, 5" on epicyst. Size: 24-38 µm.