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Elytrocysta elongata
Elytrocysta elongata Slimani and Louwye, 2013, p.18, pl.4, figs.1–10.
Holotype: Slimani and Louwye, 2013, pl.4, figs.1–4.
Age: early late Maastrichtian.
Original description (Slimani and Louwye, 2013):
Elytrocysta elongata sp. nov. (Plate IV, 1–10)
1967 ?Membranosphaera sp.; Drugg, p. 30, pl. 5, fig. 11.
1995 Chlamydophorella? aff. wallala Cookson and Eisenack,
1960; Slimani, unpublished Ph.D. Thesis, p. 129.
2011 Elytrocysta sp. A; Slimani et al., fig. 8 m.
Holotype: Sample Meer 1020 m, slide 2, EF coordinates L31/3. Specimen dimensions: total length 30 μm, total width 18 μm (Plate IV, 1–4).
Paratype: Sample Meer 888 m, slide 2, EF coordinates S58/1. Specimen dimensions: total length 32 μm, total width 17 μm (Plate IV, 6–8).
Type locality: Meer, Antwerp province, northern Belgium, well no. 007E0205 of the Geological Survey of Belgium.
Stratigraphic horizon: Lower part of the Upper Campanian, Meer borehole 895 m depth.
Repository: Botanical collection of the National Herbarium (RAB), Scientific Institute, Mohammed V-Agdal University, Rabat, Morocco.
Etymology: From the Latin verb elongare meaning elongate, with reference to the elongate shape of this species.
Diagnosis: A species of Elytrocysta characterized by its small size, an elongate cylindrical shape, and short and regularly distributed processes. The tabulation is generally indicated by an apical archaeopyle (type tA).
Description: The small, holocavate dinocyst has an elongate cylindrical ambitus. The length of the cyst is twice the width. The cyst wall consists of an autophragm and an ectophram that are narrowly but uniformly separated (1–2 µm width). The autophragm is smooth with a maximum thickness of 1 µm. The ectophram is smooth, hyaline and thin with a maximum thickness of 0.5 µm. The autophragm bears numerous, short, solid and non-tabular processes that are isolated and equidistantly spaced. The processes support the ectophragm in a uniform manner. The tabulation is indicated by the archaeopyle only and occasionally by a vague alignment of projections and/or by an ectophragmal depression in the cingular area. The archaeopyle is apical and of type (tA). The observed margin of the archaeopyle is hexagonal. The operculum is distinctly attached ventrally.
Discussion: Elytrocysta elongata sp. nov. is characterized by its cylindrical shape. It is conspecific with Chlamydophorella? aff. wallala of Slimani (1995), Elytrocysta sp. A of Slimani et al. (2011) and probably with Membranosphaera sp. of Drugg (1967). It differs from all the other Elytrocysta species by its smaller size and its elongate cylindrical shape. Elytrocysta druggii Stover and Evitt, 1978 resembles the new species by the type, height and distribution of processes, and the small size, but is dissimilar by its circular to subcircular shape. Drugg (1967, p. 30) had also shown the same differences between his ?Membranosphaera sp. – considered herein as a probable synonym of the new species – and his Membranosphaera maastrichtica. The presence of an archaeopyle in the latter species is the principal feature (among others) that has allowed Stover and Evitt (1978, p. 44) to transfer this species from the Acritarcha to the Division Dinoflagellata. The latter authors consequently renamed the species as E. druggii. According to Stover and Evitt (1978, p. 44) who erected the genus Elytrocysta, this genus differs from the genus Chlamydophorella Cookson and Eisenack, 1958 in having solid rather than tubular processes. Therefore, we attribute the new species to the genus Elytrocysta since it has clearly solid processes. Elytrocysta elongata sp. nov. resembles Chlamydophorella wallala Cookson and Eisenack, 1960 in its shape, but differs distinctly by its solid rather than tubular processes. Chlamydophorella wallala is furthermore twice as large as E. elongata. The stratigraphical range of E. elongata and of its synonyms Chlamydophorella? aff. wallala of Slimani (1995), Elytrocysta sp. A of Slimani et al. (2011) and Membranosphaera sp. of Drugg (1967), is limited to the Campanian to Danian interval, while C. wallala is only known from older Middle and Upper Jurassic strata. Also, the continuous and common occurrence, the wide geographical repartition (USA, NW Europe) and the preservation indicate that E. elongata is autochthonous and not reworked.
Dimensions of measured specimens: Total length 25(30)35 μm, total width 16(18)20 μm, process length 1–2 μm. 14 specimens measured.
Stratigraphic range: Upper part of the Upper Campanian–Danian of Turnhout, northern Belgium (Slimani, 1995); middle part of the Upper Campanian–Uppermost Maastrichtian of Meer, northern Belgium (Slimani et al., 2011); questionable Danian of the Escarpado Canyon, California, USA (Drugg, 1967).
Holotype: Slimani and Louwye, 2013, pl.4, figs.1–4.
Age: early late Maastrichtian.
Original description (Slimani and Louwye, 2013):
Elytrocysta elongata sp. nov. (Plate IV, 1–10)
1967 ?Membranosphaera sp.; Drugg, p. 30, pl. 5, fig. 11.
1995 Chlamydophorella? aff. wallala Cookson and Eisenack,
1960; Slimani, unpublished Ph.D. Thesis, p. 129.
2011 Elytrocysta sp. A; Slimani et al., fig. 8 m.
Holotype: Sample Meer 1020 m, slide 2, EF coordinates L31/3. Specimen dimensions: total length 30 μm, total width 18 μm (Plate IV, 1–4).
Paratype: Sample Meer 888 m, slide 2, EF coordinates S58/1. Specimen dimensions: total length 32 μm, total width 17 μm (Plate IV, 6–8).
Type locality: Meer, Antwerp province, northern Belgium, well no. 007E0205 of the Geological Survey of Belgium.
Stratigraphic horizon: Lower part of the Upper Campanian, Meer borehole 895 m depth.
Repository: Botanical collection of the National Herbarium (RAB), Scientific Institute, Mohammed V-Agdal University, Rabat, Morocco.
Etymology: From the Latin verb elongare meaning elongate, with reference to the elongate shape of this species.
Diagnosis: A species of Elytrocysta characterized by its small size, an elongate cylindrical shape, and short and regularly distributed processes. The tabulation is generally indicated by an apical archaeopyle (type tA).
Description: The small, holocavate dinocyst has an elongate cylindrical ambitus. The length of the cyst is twice the width. The cyst wall consists of an autophragm and an ectophram that are narrowly but uniformly separated (1–2 µm width). The autophragm is smooth with a maximum thickness of 1 µm. The ectophram is smooth, hyaline and thin with a maximum thickness of 0.5 µm. The autophragm bears numerous, short, solid and non-tabular processes that are isolated and equidistantly spaced. The processes support the ectophragm in a uniform manner. The tabulation is indicated by the archaeopyle only and occasionally by a vague alignment of projections and/or by an ectophragmal depression in the cingular area. The archaeopyle is apical and of type (tA). The observed margin of the archaeopyle is hexagonal. The operculum is distinctly attached ventrally.
Discussion: Elytrocysta elongata sp. nov. is characterized by its cylindrical shape. It is conspecific with Chlamydophorella? aff. wallala of Slimani (1995), Elytrocysta sp. A of Slimani et al. (2011) and probably with Membranosphaera sp. of Drugg (1967). It differs from all the other Elytrocysta species by its smaller size and its elongate cylindrical shape. Elytrocysta druggii Stover and Evitt, 1978 resembles the new species by the type, height and distribution of processes, and the small size, but is dissimilar by its circular to subcircular shape. Drugg (1967, p. 30) had also shown the same differences between his ?Membranosphaera sp. – considered herein as a probable synonym of the new species – and his Membranosphaera maastrichtica. The presence of an archaeopyle in the latter species is the principal feature (among others) that has allowed Stover and Evitt (1978, p. 44) to transfer this species from the Acritarcha to the Division Dinoflagellata. The latter authors consequently renamed the species as E. druggii. According to Stover and Evitt (1978, p. 44) who erected the genus Elytrocysta, this genus differs from the genus Chlamydophorella Cookson and Eisenack, 1958 in having solid rather than tubular processes. Therefore, we attribute the new species to the genus Elytrocysta since it has clearly solid processes. Elytrocysta elongata sp. nov. resembles Chlamydophorella wallala Cookson and Eisenack, 1960 in its shape, but differs distinctly by its solid rather than tubular processes. Chlamydophorella wallala is furthermore twice as large as E. elongata. The stratigraphical range of E. elongata and of its synonyms Chlamydophorella? aff. wallala of Slimani (1995), Elytrocysta sp. A of Slimani et al. (2011) and Membranosphaera sp. of Drugg (1967), is limited to the Campanian to Danian interval, while C. wallala is only known from older Middle and Upper Jurassic strata. Also, the continuous and common occurrence, the wide geographical repartition (USA, NW Europe) and the preservation indicate that E. elongata is autochthonous and not reworked.
Dimensions of measured specimens: Total length 25(30)35 μm, total width 16(18)20 μm, process length 1–2 μm. 14 specimens measured.
Stratigraphic range: Upper part of the Upper Campanian–Danian of Turnhout, northern Belgium (Slimani, 1995); middle part of the Upper Campanian–Uppermost Maastrichtian of Meer, northern Belgium (Slimani et al., 2011); questionable Danian of the Escarpado Canyon, California, USA (Drugg, 1967).