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Amphorula dodekovae
Amphorula dodekovae, Zotto et al. 1987; Emendation Monteil, 1990
Holotype: Zotto et al., 1987, pl.2, fig.1
Locus typicus:
Stratum typicum: Kimmeridgian
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Original description: [Zotto et al., 1987, p. 203]: (Translation: LPP)
Proximochorate-septate cysts with subcircular outline in dorso-ventral compression. Cyst wall consists of two appressed layers; pericoels absent. Cyst wall thin, and characterized by evenly distributed fine perforations.
Tabulation is expressed by high flaring septa which may be arcuate semicircular, or closed circular or subcircular, or polygonal in outline; septa are striated, especially near the base, and may be irregularly alveolate.
Cingulum expressed by transversely elongated short ridges, each of which has a short slender process with bifurcate tips at each of its ends. Sulcus is more-or-less straight.
Tabulation formula is gonyaulacacean, Xpr, X", Xa, 6"", 6c, 6""", lp, 1"""" plus 4s. In the precingular series, the processes vary in form in different specimens; however, the sixth precingular plate (6"") is always almost rectangular, with the lateral sides subparallel to the sulcus. In the postcingular series, plate 1""" is the smallest and is represented by an arcuate septum; plates 3""" and 4""" are relatively large and quadrate; plate 6""" is small and attenuated trapezoidal, and plates 2""" and 5""" are of variable form. Postcingular plate 4""" is offset to the right of precingular plate 3"". The posterior intercalary plate (1p) is a high and slender arcuate septal process. The antapical plate (1"""") is represented by a relatively high septal process with a circular outline. The sulcus is constructed of a triangular anterior sulcal plate, two small projections of circular outline, and a posteriorly rounded, heel-shaped, posterior sulcal plate. A thin elliptical ridge joins the anterior sulcal plate (as) with the two short circular projections, but does not contact the posterior sulcal plate (ps).
Archeopyle apical. Operculum free. The number of opercular pieces is not known.
Dimensions:
Size of cysts ranges 50 to 60 µm high, 50 to 65 µm wide.
Brenner, 1988, p.38
Remark: Wall consists of a three-layered cystwall: 1. thin inner membrane, 2. spongious "main" cystwall, 3. thin outer membrane. Outer membrane just intratabular, missing at the parasutures. Sometimes slender connetions between neighbouring paraplates may be developed. Initially the whole cyst may have been covered by this membrane, therefore the cyst may be interpreted as "suturocavate". Paratabulation is gonyaulacoid, dorsal tabulation is Polygonifera-type.
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Supplemental description:
Monteil, 1990, p. 604:
Description:
Proximochorate septate (kledochorate) cyst with subspherical body. Three-layered acavate cyst; periphragm and endophragm appressed except where septa are formed. A discontinuous, ragged and filamentous ectophragm is visible between the paraplates, where it is detached from the periphragm and stretches between the distal end of septa (Fig. 2).
No parasutural features.
Septa high, flaring, penitabular polygonal Adcingular septa closed. polygonal, angular Septa striated, entire. sometimes irregularly alveolate
Archeopyle apical. type (4A), with angular margin: parasulcal notch marked, operculum free.
Paratabulation indicated by archeopyle and septa. gonyaulacacean, inferred formula: ?1-2 pr. ?4", 0a, 6"", 6c, 6""", 1p, 1"""", 5s Septum of the sixth precinqular paraplate (6"") subrectangular with lateral sides subparallel to parasulcus.
Paracingulum indicated by six rectilinear septa. each with one slender distally bifurcate process. at both extremities
Five parasulcal paraplates obviously indicated by five septa: (as) triangular closed (ps) heel-shaped closed and (ras). (rs). (Is) arcuate. The anterior margin of the Is septum touches the triangular 1""" septum The ventral organization is of the L-type.
Emended description:
Five parasulcal paraplates indicated by five septa: as septum triangular closed, ps septum heel shaped closed, ras and rs septa represented by two small circular projections, Is septum arcuate in the left posterior side of the elliptical ring. The anterior margin of the Is septum touches the triangular 1""" septum. The ventral organization is of L-type.
Dimensions:
length of overall cyst: 67 µm, width of overall cyst: 69 µm, length of the septa: 10µm.
Note:
The description given below is mainly based on Bennner, 1988 (P 31. 32. 38 and pl. 17. fig 6) as well as on new information about paratabulation given here
Affinities:
A dodekovae sensu Benner, 1988 differs from A. dodekovae s s in having a discontinuous ectophragm visible between the paraplates at the distal end of septa.
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Dimensions as indicated by Zotto et al. (1987): (1) based on text, p 203, (2) based on legend of pl.2, fig.1:
Dimensions: Holotype Range (1)(2)
length of cyst: 50µm - 60µm 50-60µm
width of cyst: 63µm - 72.5µm 50-65µm
Holotype: Zotto et al., 1987, pl.2, fig.1
Locus typicus:
Stratum typicum: Kimmeridgian
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Original description: [Zotto et al., 1987, p. 203]: (Translation: LPP)
Proximochorate-septate cysts with subcircular outline in dorso-ventral compression. Cyst wall consists of two appressed layers; pericoels absent. Cyst wall thin, and characterized by evenly distributed fine perforations.
Tabulation is expressed by high flaring septa which may be arcuate semicircular, or closed circular or subcircular, or polygonal in outline; septa are striated, especially near the base, and may be irregularly alveolate.
Cingulum expressed by transversely elongated short ridges, each of which has a short slender process with bifurcate tips at each of its ends. Sulcus is more-or-less straight.
Tabulation formula is gonyaulacacean, Xpr, X", Xa, 6"", 6c, 6""", lp, 1"""" plus 4s. In the precingular series, the processes vary in form in different specimens; however, the sixth precingular plate (6"") is always almost rectangular, with the lateral sides subparallel to the sulcus. In the postcingular series, plate 1""" is the smallest and is represented by an arcuate septum; plates 3""" and 4""" are relatively large and quadrate; plate 6""" is small and attenuated trapezoidal, and plates 2""" and 5""" are of variable form. Postcingular plate 4""" is offset to the right of precingular plate 3"". The posterior intercalary plate (1p) is a high and slender arcuate septal process. The antapical plate (1"""") is represented by a relatively high septal process with a circular outline. The sulcus is constructed of a triangular anterior sulcal plate, two small projections of circular outline, and a posteriorly rounded, heel-shaped, posterior sulcal plate. A thin elliptical ridge joins the anterior sulcal plate (as) with the two short circular projections, but does not contact the posterior sulcal plate (ps).
Archeopyle apical. Operculum free. The number of opercular pieces is not known.
Dimensions:
Size of cysts ranges 50 to 60 µm high, 50 to 65 µm wide.
Brenner, 1988, p.38
Remark: Wall consists of a three-layered cystwall: 1. thin inner membrane, 2. spongious "main" cystwall, 3. thin outer membrane. Outer membrane just intratabular, missing at the parasutures. Sometimes slender connetions between neighbouring paraplates may be developed. Initially the whole cyst may have been covered by this membrane, therefore the cyst may be interpreted as "suturocavate". Paratabulation is gonyaulacoid, dorsal tabulation is Polygonifera-type.
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Supplemental description:
Monteil, 1990, p. 604:
Description:
Proximochorate septate (kledochorate) cyst with subspherical body. Three-layered acavate cyst; periphragm and endophragm appressed except where septa are formed. A discontinuous, ragged and filamentous ectophragm is visible between the paraplates, where it is detached from the periphragm and stretches between the distal end of septa (Fig. 2).
No parasutural features.
Septa high, flaring, penitabular polygonal Adcingular septa closed. polygonal, angular Septa striated, entire. sometimes irregularly alveolate
Archeopyle apical. type (4A), with angular margin: parasulcal notch marked, operculum free.
Paratabulation indicated by archeopyle and septa. gonyaulacacean, inferred formula: ?1-2 pr. ?4", 0a, 6"", 6c, 6""", 1p, 1"""", 5s Septum of the sixth precinqular paraplate (6"") subrectangular with lateral sides subparallel to parasulcus.
Paracingulum indicated by six rectilinear septa. each with one slender distally bifurcate process. at both extremities
Five parasulcal paraplates obviously indicated by five septa: (as) triangular closed (ps) heel-shaped closed and (ras). (rs). (Is) arcuate. The anterior margin of the Is septum touches the triangular 1""" septum The ventral organization is of the L-type.
Emended description:
Five parasulcal paraplates indicated by five septa: as septum triangular closed, ps septum heel shaped closed, ras and rs septa represented by two small circular projections, Is septum arcuate in the left posterior side of the elliptical ring. The anterior margin of the Is septum touches the triangular 1""" septum. The ventral organization is of L-type.
Dimensions:
length of overall cyst: 67 µm, width of overall cyst: 69 µm, length of the septa: 10µm.
Note:
The description given below is mainly based on Bennner, 1988 (P 31. 32. 38 and pl. 17. fig 6) as well as on new information about paratabulation given here
Affinities:
A dodekovae sensu Benner, 1988 differs from A. dodekovae s s in having a discontinuous ectophragm visible between the paraplates at the distal end of septa.
------------------------------------------------------
Dimensions as indicated by Zotto et al. (1987): (1) based on text, p 203, (2) based on legend of pl.2, fig.1:
Dimensions: Holotype Range (1)(2)
length of cyst: 50µm - 60µm 50-60µm
width of cyst: 63µm - 72.5µm 50-65µm