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Batiacasphaera elongata
Holotype: Plate II, figs. 9-10.
Diagnosis: A thick-walled, ellipsoidal Batiacasphaera densely covered in low relief grana, verrucae or rugulae. Tabulation gonyaulacacean, archeopyle apical, Type (tA), operculum free.
Etymology: ‘elongata’ in reference to the elongate ellipsoidal body.
Material: Palynological strew sample; 2663 m, Elm-1
Age: Kimmeridgian (D. swanense Zone; Fig. 5) Lithostratigraphic occurrence: The uppermost Frigate Fm and Iris Marl.
Description: An intermediate-sized, ellipsoidal, acavate dinoflagellate cyst, with a rounded antapex and rarely with a short, protruding apical horn. Cyst commonly elongate (Length:Width, 8:5; Plate II, 1–3), rarely ellipsoidal to circular (7:6; Plate II, 6–8). Autophragm 1–2 μm thick, densely covered in coarse, low relief grana and verrucae, which may coalesce to form inconsistent rugulae. Tabulation partially indicated by archeopyle and short accessory sutures, and position of weakly expressed sulcal notch. Tabulation inferred as standard gonyaulacacean; formula:?pr,?4′, 6″,?6c,?6″’,?1p,?1″”,?s (Fig. 6). Archeopyle apical, Type (tA), operculum typically free.
Dimensions: (16 specimens measured) Length with operculum: 65 (72) 82 Length without operculum: 55 (61) 74 Width: 34 (45) 51
Comparison and remarks: The merging of coarser elements to form rugulae, as exhibited by Batiacasphaera elongata (Plate II, 6–8, 12, 13), supports an attribution to Batiacasphaera following the emendation of the genus by Wood et al. (2016).
Batiacasphaera elongata differs from Batiacasphaera subtilis Stover and Helby, 1987a, in having coarser sculptural elements and lacking the apical and antapical thinning of the wall. The densely granulate/verrucate ornamentation of Batiacasphaera elongata distinguishes it from other ovoid/elongate members of the genus, including Batiacasphaera rugulata Schiøler and Wilson, 1998, Batiacasphaera kekerengensis Schiøler and Wilson, 1998, Batiacasphaera reticulata Davey, 1969 and Batiacasphaera retirugosa Xu Jinli et al., 1997 ex He Chengquan et al., 2009.
Batiacasphaera elongata is superficially comparable to Aprobolocysta? varigranosa Duxbury, 1977, but differs in having a more homogenous ornamentation and a less pronounced sulcal notch. Carnarvonodinium granulatum Jiang et al., 1992 is both elongate and granulate, but is much narrower and has finer grana. Of the genus Sentusidinium Sarjeant and Stover, 1978, Batiacasphaera elongata is most similar to Sentusidinium granulosum (Cookson and Eisenack, 1974)Wood et al., 2016, but differs in being significantly larger with coarser grana.
Diagnosis: A thick-walled, ellipsoidal Batiacasphaera densely covered in low relief grana, verrucae or rugulae. Tabulation gonyaulacacean, archeopyle apical, Type (tA), operculum free.
Etymology: ‘elongata’ in reference to the elongate ellipsoidal body.
Material: Palynological strew sample; 2663 m, Elm-1
Age: Kimmeridgian (D. swanense Zone; Fig. 5) Lithostratigraphic occurrence: The uppermost Frigate Fm and Iris Marl.
Description: An intermediate-sized, ellipsoidal, acavate dinoflagellate cyst, with a rounded antapex and rarely with a short, protruding apical horn. Cyst commonly elongate (Length:Width, 8:5; Plate II, 1–3), rarely ellipsoidal to circular (7:6; Plate II, 6–8). Autophragm 1–2 μm thick, densely covered in coarse, low relief grana and verrucae, which may coalesce to form inconsistent rugulae. Tabulation partially indicated by archeopyle and short accessory sutures, and position of weakly expressed sulcal notch. Tabulation inferred as standard gonyaulacacean; formula:?pr,?4′, 6″,?6c,?6″’,?1p,?1″”,?s (Fig. 6). Archeopyle apical, Type (tA), operculum typically free.
Dimensions: (16 specimens measured) Length with operculum: 65 (72) 82 Length without operculum: 55 (61) 74 Width: 34 (45) 51
Comparison and remarks: The merging of coarser elements to form rugulae, as exhibited by Batiacasphaera elongata (Plate II, 6–8, 12, 13), supports an attribution to Batiacasphaera following the emendation of the genus by Wood et al. (2016).
Batiacasphaera elongata differs from Batiacasphaera subtilis Stover and Helby, 1987a, in having coarser sculptural elements and lacking the apical and antapical thinning of the wall. The densely granulate/verrucate ornamentation of Batiacasphaera elongata distinguishes it from other ovoid/elongate members of the genus, including Batiacasphaera rugulata Schiøler and Wilson, 1998, Batiacasphaera kekerengensis Schiøler and Wilson, 1998, Batiacasphaera reticulata Davey, 1969 and Batiacasphaera retirugosa Xu Jinli et al., 1997 ex He Chengquan et al., 2009.
Batiacasphaera elongata is superficially comparable to Aprobolocysta? varigranosa Duxbury, 1977, but differs in having a more homogenous ornamentation and a less pronounced sulcal notch. Carnarvonodinium granulatum Jiang et al., 1992 is both elongate and granulate, but is much narrower and has finer grana. Of the genus Sentusidinium Sarjeant and Stover, 1978, Batiacasphaera elongata is most similar to Sentusidinium granulosum (Cookson and Eisenack, 1974)Wood et al., 2016, but differs in being significantly larger with coarser grana.