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Spiniferites multisphaerus
Spiniferites multisphaerus Price and Pospelova, 2014, p.107,113–115, pl.1, figs.1–13; pl.2, figs.1–12; pl.3, figs.7–9; pl.4, figs.4–9; pl.5, figs.4–11; text-fig.3.
Holotype: Price and Pospelova, 2014, pl.1, figs.1–13.
Age: late Quaternary.
Original description (Price and Pospelova, 2014):
Species Spiniferites multisphaerus sp. nov
Derivation of name. Latin multi many, and sphaerae spheres; for the characteristic central body wall structure that features multiple bubble-like elements.
Diagnosis. Oval to pear-shaped, proximochorate cyst with a pronounced apical protuberance. Wall is relatively thick and is constructed of small bubble-like elements. Processes are stubby, furcate and contain hollow bubble-like elements. Tabulation is clearly expressed and is typical of the genus. Archeopyle precingular, formed by release of plate 3’’.
Description. Proximochorate cysts with an oval to pear-shaped central body, and a pronounced apical protuberance. Often in lateral view the central body has pronounced ‘shoulders’ on the epicyst due to a change in gradient between the apical and precingular plates (e.g. Plate 1, figures 1–6; Plate 2, figures 1–6, 10– 12, Plate 5, figure 8). Central body wall thick (1.0– 2.1 µm) and consists of two layers. SEM images show the pedium connected to the telligum via columellae, forming small cavities between the two layers that vary in size (0.25–0.75 µm) and range in shape from spheroidal to ovoidal. The lower surface of the pedium is granulated (Plate 4, figure 5). In SEM images the upper surface of the tegillum is irregularly bumpy or wavy, with a pitted or reticulate surface (Plate 4, figure 4). The cavities between the two layers in brightfield microscopy give the cyst wall a pseudoreticulate appearance in plain view. Tabulation is expressed by low to moderately high (approximately half the process length) sutural septae formed between gonal processes. In some specimens, high (up 3.5 µm) septa have muri that are both proximally and distally hiate with canna that are compartmented transversely, ranging in diameter from 0.5–2.0 µm, giving the appearance of spheroidal to ovoidal bubble-like elements. In many specimens, muri appear to be absent or very reduced, with only the bubble-like elements evident. These bubble-like elements that comprise the septa range in size for a single specimen, and are often up to twice their diameter in the middle of the septae, and in some cases two or three smaller ‘bubbles’ are located on top on the large ‘bubble’ at the bottom. Processes are hollow and are commonly stubby or reduced in appearance. The stems are parallel-sided to tapering and are also composed of the bubble-like elements. The tips of the processes are highly variable in morphology between specimens as well as on a single specimen. They can be blunt but often one or more processes are distally furcated, ranging from bifurcate to multifurcate, and commonly trifurate or quadrifurcate. The tips of the pinnulae are rounded. There is no relationship between central body diameter and process length (Figure 2). Processes are predominantly gonal, but are occasionally intergonal. Tabulation is 3’-6”-6c-1v-5’’’-1P-1”” (Figure 3). The archeopyle is precingular 3’’, six-sided. Low sutural septae surround the archeopyle margin.
Dimensions. Holotype: central body length 47.7 µm, including apical protuberance 52.8 µm; central body width 42.1 µm; process length 4.4–7.7 µm; wall thickness 1.5 µm. Range: central body length 40.9 (50.1) 63.1 µm (stdev = 4.2 µm, n = 53) or including apical protuberance 42.6 (52.4) 66.5 µm (stdev = 4.6 µm, n = 50); body width 36.5 (43.6) 51.0 µm (stdev = 3.6 mm, n = 53); process length 1.5 (4.4) 8.0 µm (stdev = 1.4 µm, n = 171); wall thickness 1.0 (1.5) 2.1 µm (stdev = 0.28 µm, n = 66).
Remarks. The cyst wall and processes are rigid, and generally hold their shape well, but due to the rigidity, sections of the central body in many specimens appeared broken.
Stratigraphic range. Late Pleistocene to modern.
Comparison. Spiniferites multisphaerus sp. nov. is distinguished by its bubble-like elements that comprise the cyst wall, processes and sutural septae, which have not been observed previously in Spiniferites species of modern or older Quaternary sediments. In comparison to modern taxa, it most closely resembles S. bentorii, as both have a pronounced apical boss and ‘shoulders’ on the epicyst. It is distinguished from S. bentorii by the presence of small bubble-like elements from which it is composed. In addition, in plain view the surface of Spiniferites multisphaerus sp. nov. appears reticulated (Plate 2, figure 7; Plate 3, figures 7–9) whereas S. bentorii appears smooth to microgranular (Plate 3, figures 1–2, 4–6; Plate 5, figures 1–3). A summary of Quaternary Spiniferites taxa and their main morphological and distinguishing characteristics is given in Table 1. The characteristic bubble-like elements of Spiniferites multisphaerus sp. nov. are apparently rare in the Quaternary record, but have been encountered in taxa from older deposits. Spiniferites ristingensis Head (2007), described from the Late Pleistocene of the Baltic region, has a somewhat similar wall structure with densely distributed blisters and hollow undulations over the surface (Head 2007). It differs from Spiniferites multisphaerus sp. nov. in having longer (11–17 µm) membranous processes, a smaller central body length (39–49 µm), and a less pronounced apical protuberance. Hafniasphaera septata from the Palaeocene has a similar cyst wall appearance, albeit much thicker with a 3–7 mm outer layer (periphragm) (Hansen 1977), and processes that bear similar morphological and structural features with larger bubble-like elements comprising the process base, and smaller elements that comprise the process tips. This species lacks an apical boss, and tabulation is expressed by weakly defined sutural ridges (McClean 1971).
Holotype: Price and Pospelova, 2014, pl.1, figs.1–13.
Age: late Quaternary.
Original description (Price and Pospelova, 2014):
Species Spiniferites multisphaerus sp. nov
Derivation of name. Latin multi many, and sphaerae spheres; for the characteristic central body wall structure that features multiple bubble-like elements.
Diagnosis. Oval to pear-shaped, proximochorate cyst with a pronounced apical protuberance. Wall is relatively thick and is constructed of small bubble-like elements. Processes are stubby, furcate and contain hollow bubble-like elements. Tabulation is clearly expressed and is typical of the genus. Archeopyle precingular, formed by release of plate 3’’.
Description. Proximochorate cysts with an oval to pear-shaped central body, and a pronounced apical protuberance. Often in lateral view the central body has pronounced ‘shoulders’ on the epicyst due to a change in gradient between the apical and precingular plates (e.g. Plate 1, figures 1–6; Plate 2, figures 1–6, 10– 12, Plate 5, figure 8). Central body wall thick (1.0– 2.1 µm) and consists of two layers. SEM images show the pedium connected to the telligum via columellae, forming small cavities between the two layers that vary in size (0.25–0.75 µm) and range in shape from spheroidal to ovoidal. The lower surface of the pedium is granulated (Plate 4, figure 5). In SEM images the upper surface of the tegillum is irregularly bumpy or wavy, with a pitted or reticulate surface (Plate 4, figure 4). The cavities between the two layers in brightfield microscopy give the cyst wall a pseudoreticulate appearance in plain view. Tabulation is expressed by low to moderately high (approximately half the process length) sutural septae formed between gonal processes. In some specimens, high (up 3.5 µm) septa have muri that are both proximally and distally hiate with canna that are compartmented transversely, ranging in diameter from 0.5–2.0 µm, giving the appearance of spheroidal to ovoidal bubble-like elements. In many specimens, muri appear to be absent or very reduced, with only the bubble-like elements evident. These bubble-like elements that comprise the septa range in size for a single specimen, and are often up to twice their diameter in the middle of the septae, and in some cases two or three smaller ‘bubbles’ are located on top on the large ‘bubble’ at the bottom. Processes are hollow and are commonly stubby or reduced in appearance. The stems are parallel-sided to tapering and are also composed of the bubble-like elements. The tips of the processes are highly variable in morphology between specimens as well as on a single specimen. They can be blunt but often one or more processes are distally furcated, ranging from bifurcate to multifurcate, and commonly trifurate or quadrifurcate. The tips of the pinnulae are rounded. There is no relationship between central body diameter and process length (Figure 2). Processes are predominantly gonal, but are occasionally intergonal. Tabulation is 3’-6”-6c-1v-5’’’-1P-1”” (Figure 3). The archeopyle is precingular 3’’, six-sided. Low sutural septae surround the archeopyle margin.
Dimensions. Holotype: central body length 47.7 µm, including apical protuberance 52.8 µm; central body width 42.1 µm; process length 4.4–7.7 µm; wall thickness 1.5 µm. Range: central body length 40.9 (50.1) 63.1 µm (stdev = 4.2 µm, n = 53) or including apical protuberance 42.6 (52.4) 66.5 µm (stdev = 4.6 µm, n = 50); body width 36.5 (43.6) 51.0 µm (stdev = 3.6 mm, n = 53); process length 1.5 (4.4) 8.0 µm (stdev = 1.4 µm, n = 171); wall thickness 1.0 (1.5) 2.1 µm (stdev = 0.28 µm, n = 66).
Remarks. The cyst wall and processes are rigid, and generally hold their shape well, but due to the rigidity, sections of the central body in many specimens appeared broken.
Stratigraphic range. Late Pleistocene to modern.
Comparison. Spiniferites multisphaerus sp. nov. is distinguished by its bubble-like elements that comprise the cyst wall, processes and sutural septae, which have not been observed previously in Spiniferites species of modern or older Quaternary sediments. In comparison to modern taxa, it most closely resembles S. bentorii, as both have a pronounced apical boss and ‘shoulders’ on the epicyst. It is distinguished from S. bentorii by the presence of small bubble-like elements from which it is composed. In addition, in plain view the surface of Spiniferites multisphaerus sp. nov. appears reticulated (Plate 2, figure 7; Plate 3, figures 7–9) whereas S. bentorii appears smooth to microgranular (Plate 3, figures 1–2, 4–6; Plate 5, figures 1–3). A summary of Quaternary Spiniferites taxa and their main morphological and distinguishing characteristics is given in Table 1. The characteristic bubble-like elements of Spiniferites multisphaerus sp. nov. are apparently rare in the Quaternary record, but have been encountered in taxa from older deposits. Spiniferites ristingensis Head (2007), described from the Late Pleistocene of the Baltic region, has a somewhat similar wall structure with densely distributed blisters and hollow undulations over the surface (Head 2007). It differs from Spiniferites multisphaerus sp. nov. in having longer (11–17 µm) membranous processes, a smaller central body length (39–49 µm), and a less pronounced apical protuberance. Hafniasphaera septata from the Palaeocene has a similar cyst wall appearance, albeit much thicker with a 3–7 mm outer layer (periphragm) (Hansen 1977), and processes that bear similar morphological and structural features with larger bubble-like elements comprising the process base, and smaller elements that comprise the process tips. This species lacks an apical boss, and tabulation is expressed by weakly defined sutural ridges (McClean 1971).