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Pontiadinium obesum
Pontiadinium obesum Suto-Szentai, 1982
Now Impagidinium?. Originally Pontiadinium, subsequently (and now) Impagidinium?.
Questionable assignment: Lentin and Williams (1989, p.196).
Holotype: Suto-Szentai, 1982, pl.4, figs.2[a-c]; text-fig.5
Age: Pannonian
Holotype. Sütő-Szentai (1982, p. 229, pl. IV, figs 1–2). Borehole Tengelic-2, depth 636.80–635.50 m, microscope coordinates (Zeiss) 8.2/104. Housed in the holotype collection at the Local History and Natural History Collection of Komló (Komló, Hungary). Holotype slide desiccated; therefore, the specimen is effectively lost (see Supplementary material 6).
Neotype. Plate 2, figures 6–7, England Finder coordinate N49, core PAET 34P, depth 672.5–672.69 m, slide 4, embedded in glycerine jelly. Housed in the Palaeontological Collection of the Hungarian Natural History Museum (Budapest).
Original description. Sütő-Szentai (1982, p. 218) reported that ‘longitudinal and meridional axes of the plankton body are sub-equal in length’ (translated from Hungarian). She considered that the apical and antapical peaks emerge from the ‘plankton’ body, with the apical peak (meaning protrusion) somewhat more developed than the antapical one. Wall 1.5 µm thick, finely granulate and punctate. Archeopyle: 3″, trapezoidal. Tabulation: 4′, 6″, 6c, 6″′, 1p, 1″′′.
Comment. The taxonomic model of Sütő-Szentai (1982) inappropriately interprets proximate and chorate dinoflagellate cysts as life-form stages of the same taxon. In her interpretation, the proximate cysts in Lake Pannon sediments represent the thecate motile (‘plankton’) stage because of a resemblance to thecate cells of Gonyaulax digitalis and a misunderstanding of the cyst–theca relationship (e.g. as reported in Wall and Dale Citation1968).
Emended description. Proximate dinoflagellate cyst with biconical and rounded rhomboidal shape (, figures 3–4, 6–8). Epi- and hypocyst are of similar size, the apical and antapical horns are short and usually of equal length, or the apical protuberance is slightly longer. A gonyaulacacean standard S-type tabulation pattern is indicated by very low sutural septa less than 1.5 µm in height (, figures 3–4, 6–8). The shape of the precingular plate 6″ is triangular and its tip has direct contact with the apical plate 4′ (Plate 2 , figures 4, 6–7). The precingular archeopyle is pentagonal and is formed by the loss of the 3″ plate. The cyst wall surface has a scabrate-granulate surface and is ∼0.8–1.5 µm thick.
Dimensions. The maximum length of the cyst body including the polar protuberances is 64 (80) 94 µm and the maximum equatorial width is 55 (63) 68 µm. The apical protuberance length is 4 (7) 10 µm; the antapical protuberance length range is 4 (5) 10 µm. The holotype measurements are length: 76 µm, equatorial width 69 µm. The neotype specimen is 104 µm in legth with equatorial width of 79 µm, the apical horn is 16 µm, and the antapical is 4 µm in length. Ten specimens were measured from the materials at Našice, from the PAET 34P materials and from Gușterița (Transylvanian Basin, Baranyi et al. 2021).
Comments and comparisions. Based on the material from core PAET 34P, the species description of Pontiadinium obesum is emended here, and a neotype is designated from core PAET 34P, depth 672.5–672.69 m (Plate 2, figures 6–7). The holotype itself could not be retrieved because of the desiccated mounting medium (glycerine jelly) that left the holotype and all of the syntypes unrecogniseable (Supplementary material 6). The holotype is considered to be effectively lost (Gravendyck et al. 2021). Sütő-Szentai (1982) incorrectly described a theca morphology and failed to report details of the plate sutures and structure that are critical to the understanding of variation among Pontiadinium species. Pontiadinium obesum differs from the other Pontiadinium species by its low height-to-width ratio. For the population of PAET 34P the length-to-equatorial width ratio (L:W) is 1.2–1.4. Sutural ridges are low and are sometimes absent or faintly developed and represented by rows of granules. Pontiadinium obesum differs from Pontiadinium pecsvaradensis by the simple low sutural septa, and the cyst wall surface of Pontiadinium obesum is predominantly granulate, while that of Pontiadinium is scabrate-granulate to verrucate. We did not observe specimens with a punctate cyst wall surface as reported by Sütő -Szentai (1982). The apical horn, small antapical protuberance, and low height-to-width ratio of Komewuia? sp. A in Soliman and Riding (2017, pl. V, figs 5–7) are comparable to those of Pontiadinium obesum. It is noted that the caption for Soliman and Riding’s pl. V, figs 5–7 erroneously refers to Komewuia? sp. B. However, the taxonomic descriptions and drawings (Soliman and Riding 2017, p. 20, fig. 8) clearly state that the specimens with a prominent apical horn as seen on pl. V, figs 5–7 are assigned to Komewuia? sp. A compared to Komewuia? sp. B without an apical horn illustrated on pl. V, figs 1–4. Faintly developed granules and thickenings on Komewuia? sp. A of Soliman and Riding (2017, p. 10, pl. V, figs 5–7) might indicate sutural septa. Lentin and Williams (1989) questionably re-assigned ‘Pontiadinium obesum’ Sütő-Szentai 1982 to Impagidinium? obesum although the antapical protuberance is not a characteristic of Impagidinium as described by Stover and Evitt (1978); thus we retain the species in Pontiadinium.
Now Impagidinium?. Originally Pontiadinium, subsequently (and now) Impagidinium?.
Questionable assignment: Lentin and Williams (1989, p.196).
Holotype: Suto-Szentai, 1982, pl.4, figs.2[a-c]; text-fig.5
Age: Pannonian
Holotype. Sütő-Szentai (1982, p. 229, pl. IV, figs 1–2). Borehole Tengelic-2, depth 636.80–635.50 m, microscope coordinates (Zeiss) 8.2/104. Housed in the holotype collection at the Local History and Natural History Collection of Komló (Komló, Hungary). Holotype slide desiccated; therefore, the specimen is effectively lost (see Supplementary material 6).
Neotype. Plate 2, figures 6–7, England Finder coordinate N49, core PAET 34P, depth 672.5–672.69 m, slide 4, embedded in glycerine jelly. Housed in the Palaeontological Collection of the Hungarian Natural History Museum (Budapest).
Original description. Sütő-Szentai (1982, p. 218) reported that ‘longitudinal and meridional axes of the plankton body are sub-equal in length’ (translated from Hungarian). She considered that the apical and antapical peaks emerge from the ‘plankton’ body, with the apical peak (meaning protrusion) somewhat more developed than the antapical one. Wall 1.5 µm thick, finely granulate and punctate. Archeopyle: 3″, trapezoidal. Tabulation: 4′, 6″, 6c, 6″′, 1p, 1″′′.
Comment. The taxonomic model of Sütő-Szentai (1982) inappropriately interprets proximate and chorate dinoflagellate cysts as life-form stages of the same taxon. In her interpretation, the proximate cysts in Lake Pannon sediments represent the thecate motile (‘plankton’) stage because of a resemblance to thecate cells of Gonyaulax digitalis and a misunderstanding of the cyst–theca relationship (e.g. as reported in Wall and Dale Citation1968).
Emended description. Proximate dinoflagellate cyst with biconical and rounded rhomboidal shape (, figures 3–4, 6–8). Epi- and hypocyst are of similar size, the apical and antapical horns are short and usually of equal length, or the apical protuberance is slightly longer. A gonyaulacacean standard S-type tabulation pattern is indicated by very low sutural septa less than 1.5 µm in height (, figures 3–4, 6–8). The shape of the precingular plate 6″ is triangular and its tip has direct contact with the apical plate 4′ (Plate 2 , figures 4, 6–7). The precingular archeopyle is pentagonal and is formed by the loss of the 3″ plate. The cyst wall surface has a scabrate-granulate surface and is ∼0.8–1.5 µm thick.
Dimensions. The maximum length of the cyst body including the polar protuberances is 64 (80) 94 µm and the maximum equatorial width is 55 (63) 68 µm. The apical protuberance length is 4 (7) 10 µm; the antapical protuberance length range is 4 (5) 10 µm. The holotype measurements are length: 76 µm, equatorial width 69 µm. The neotype specimen is 104 µm in legth with equatorial width of 79 µm, the apical horn is 16 µm, and the antapical is 4 µm in length. Ten specimens were measured from the materials at Našice, from the PAET 34P materials and from Gușterița (Transylvanian Basin, Baranyi et al. 2021).
Comments and comparisions. Based on the material from core PAET 34P, the species description of Pontiadinium obesum is emended here, and a neotype is designated from core PAET 34P, depth 672.5–672.69 m (Plate 2, figures 6–7). The holotype itself could not be retrieved because of the desiccated mounting medium (glycerine jelly) that left the holotype and all of the syntypes unrecogniseable (Supplementary material 6). The holotype is considered to be effectively lost (Gravendyck et al. 2021). Sütő-Szentai (1982) incorrectly described a theca morphology and failed to report details of the plate sutures and structure that are critical to the understanding of variation among Pontiadinium species. Pontiadinium obesum differs from the other Pontiadinium species by its low height-to-width ratio. For the population of PAET 34P the length-to-equatorial width ratio (L:W) is 1.2–1.4. Sutural ridges are low and are sometimes absent or faintly developed and represented by rows of granules. Pontiadinium obesum differs from Pontiadinium pecsvaradensis by the simple low sutural septa, and the cyst wall surface of Pontiadinium obesum is predominantly granulate, while that of Pontiadinium is scabrate-granulate to verrucate. We did not observe specimens with a punctate cyst wall surface as reported by Sütő -Szentai (1982). The apical horn, small antapical protuberance, and low height-to-width ratio of Komewuia? sp. A in Soliman and Riding (2017, pl. V, figs 5–7) are comparable to those of Pontiadinium obesum. It is noted that the caption for Soliman and Riding’s pl. V, figs 5–7 erroneously refers to Komewuia? sp. B. However, the taxonomic descriptions and drawings (Soliman and Riding 2017, p. 20, fig. 8) clearly state that the specimens with a prominent apical horn as seen on pl. V, figs 5–7 are assigned to Komewuia? sp. A compared to Komewuia? sp. B without an apical horn illustrated on pl. V, figs 1–4. Faintly developed granules and thickenings on Komewuia? sp. A of Soliman and Riding (2017, p. 10, pl. V, figs 5–7) might indicate sutural septa. Lentin and Williams (1989) questionably re-assigned ‘Pontiadinium obesum’ Sütő-Szentai 1982 to Impagidinium? obesum although the antapical protuberance is not a characteristic of Impagidinium as described by Stover and Evitt (1978); thus we retain the species in Pontiadinium.