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Graptodinium omnireticulatum
Graptodinium omnireticulatum Clowes, 2013, p.321–322, pl.1, figs.10–12.
Holotype: Clowes, 2013, pl.1, figs.10–12.
Age: Lutetian–Priabonian.
Original description: Clowes, 2013:
Graptodinium omnireticulatum sp. nov. Plate 1, figures 10–12
Synonym: Microdinium Cookson & Eisenack n. sp.; Edwards 1977, p. 128, pl. 6, fig. 2(?).
Holotype. Specimen L16341/SM4948, Plate 1, figures 10–12; sample I43/f093, Burnside Formation, Puketeraki core 45.90–45.85 m (Wilson & McMillan 1996, p. 15, 54–58; note that core measurements cited therein commence from the base of the core), Dunedin, New Zealand, grid ref. I43/2655 0313; Upper Bortonian– Kaiatan Stage (Bartonian–Priabonian). Overall length = 35 µm (including operculum), breadth = 37.5 µm at widest point (posterior suture of cingulum), height of sutural septa = 2.5 µm at antapex.
Derivation of name. From the Latin omnis, meaning the whole, and reticulum, meaning a mesh or net, with reference to the virtually complete reticulum which comprises the intratabular ornament.
Description. Cysts small, proximate, subspherical to slightly prolate, lacking horns; the epicyst somewhat or, more usually, considerably smaller than the hypocyst. Cyst walls apparently single-layered. Archaeopyle apical, type (tA); operculum free or, more commonly, attached. Processes lacking; ornament comprising low, solid sutural and intratabular septa. Sutural septa approximately 2 to 3 µm high, particularly distinct in equatorial view, forming a fairly well-defined cladopyxiacean tabulation, ?4’, ?0a, 6’’, 6c, 5 to 6’’’, 1p, 1’’’’. The dorsal postcingular series is particularly prominent. Accessory septa form an irregular intratabular reticulum, typically continuous with the sutural septa but more open and sometimes lacking immediately adjacent to sutures (Plate 1, figure 10). The floors of the muri appear smooth. Cingulum and sulcus clearly expressed by the sutural septa; cingulum broad (5 mm) and typically subdivided, though not always clearly.
Dimensions. Overall length = 29 (35) 45 µm (nine measurements); breadth at widest point = 26 (32) 37 µm (two measurements).
Comparison. Graptodinium omnireticulatum sp. nov. is distinguished from Graptodinium inconditum sp. nov. by its more fully developed reticulum; see above.
Distribution. Other than a possible occurrence from the Alabama Coastal Plain recorded by Edwards (1977), Graptodinium omnireticulatum sp. nov. has not been previously reported. The principal material herein is from the Puketeraki core, with other occurrences of slightly more questionable material from the Cape Foulwind and Hampden Beach sections, as listed in Table 2.
Remarks. In this study, Graptodinium omnireticulatum sp. nov. was encountered far less commonly than Graptodinium inconditum sp. nov. It appears to have a more restricted stratigraphical range in New Zealand, i.e. Bortonian–Kaiatan, or possibly Runangan (Late Lutetian–Priabonian), as opposed to ?Porangan–Whaingaroan (Middle Lutetian–Rupelian or Chattian).
Holotype: Clowes, 2013, pl.1, figs.10–12.
Age: Lutetian–Priabonian.
Original description: Clowes, 2013:
Graptodinium omnireticulatum sp. nov. Plate 1, figures 10–12
Synonym: Microdinium Cookson & Eisenack n. sp.; Edwards 1977, p. 128, pl. 6, fig. 2(?).
Holotype. Specimen L16341/SM4948, Plate 1, figures 10–12; sample I43/f093, Burnside Formation, Puketeraki core 45.90–45.85 m (Wilson & McMillan 1996, p. 15, 54–58; note that core measurements cited therein commence from the base of the core), Dunedin, New Zealand, grid ref. I43/2655 0313; Upper Bortonian– Kaiatan Stage (Bartonian–Priabonian). Overall length = 35 µm (including operculum), breadth = 37.5 µm at widest point (posterior suture of cingulum), height of sutural septa = 2.5 µm at antapex.
Derivation of name. From the Latin omnis, meaning the whole, and reticulum, meaning a mesh or net, with reference to the virtually complete reticulum which comprises the intratabular ornament.
Description. Cysts small, proximate, subspherical to slightly prolate, lacking horns; the epicyst somewhat or, more usually, considerably smaller than the hypocyst. Cyst walls apparently single-layered. Archaeopyle apical, type (tA); operculum free or, more commonly, attached. Processes lacking; ornament comprising low, solid sutural and intratabular septa. Sutural septa approximately 2 to 3 µm high, particularly distinct in equatorial view, forming a fairly well-defined cladopyxiacean tabulation, ?4’, ?0a, 6’’, 6c, 5 to 6’’’, 1p, 1’’’’. The dorsal postcingular series is particularly prominent. Accessory septa form an irregular intratabular reticulum, typically continuous with the sutural septa but more open and sometimes lacking immediately adjacent to sutures (Plate 1, figure 10). The floors of the muri appear smooth. Cingulum and sulcus clearly expressed by the sutural septa; cingulum broad (5 mm) and typically subdivided, though not always clearly.
Dimensions. Overall length = 29 (35) 45 µm (nine measurements); breadth at widest point = 26 (32) 37 µm (two measurements).
Comparison. Graptodinium omnireticulatum sp. nov. is distinguished from Graptodinium inconditum sp. nov. by its more fully developed reticulum; see above.
Distribution. Other than a possible occurrence from the Alabama Coastal Plain recorded by Edwards (1977), Graptodinium omnireticulatum sp. nov. has not been previously reported. The principal material herein is from the Puketeraki core, with other occurrences of slightly more questionable material from the Cape Foulwind and Hampden Beach sections, as listed in Table 2.
Remarks. In this study, Graptodinium omnireticulatum sp. nov. was encountered far less commonly than Graptodinium inconditum sp. nov. It appears to have a more restricted stratigraphical range in New Zealand, i.e. Bortonian–Kaiatan, or possibly Runangan (Late Lutetian–Priabonian), as opposed to ?Porangan–Whaingaroan (Middle Lutetian–Rupelian or Chattian).