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Litosphaeridium adnatum
Litosphaeridium adnatum Lucas-Clark, 2007, p.210, pl.1, figs.1–9; text-figs.7A,8.
Holotype: Lucas-Clark, 2007, pl.1, figs.1–3.
Age: late Albian.
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Original description (Lucas-Clark, 2007):
Litosphaeridium adnatum sp. nov. Plate 1, figs. 1–9; Text-Figures 7A, 8
Holotype. Plate 1, figs. 1–3. Sample PL3908; Rice Valley, California; slide FJ4, coordinates 91.5 x 10.1, England Finder reference L28/2. Carnegie Museum of Natural History #19157.
Derivation of name. After the adnate operculum that, among other factors, distinguishes this species from Litosphearidium siphoniphorum.
Diagnosis. Chorate cyst with about 20 discrete, open, bulbous to sub-cylindrical processes, including three smaller sulcal processes. Archeopyle apical, operculum adnate.
Description. Chorate apiculocavate cysts with a subspherical to ovoidal central body and a total of 18–20 discrete, hollow processes (3 or 4 on the operculum; posterior sulcal sometimes missing). Periphragm ornament granular, becoming finer to absent on the processes. Endophragm smooth. Processes sub-cylindrical, bulbous, or conical; wide and circular at the base, truncated, slightly constricted or closed at the tips. Apical and sulcal processes open or closed, others open. Open process tips sometimes thickened into a rim. Process shafts subcircular in cross-section. Sulcal processes variable; in some specimens, nearly as large as precingular processes and open, usually more slender, reduced and closed. Processes interpreted to represent B, Ci, Cu, 1u, 1i, 2–6, ai, Iu(?), II–VI, X, Y, and Z following Evittian notation. These are equivalent to 1'–3', 1a, 1"–6", as, ps, 1"'–6"', 1p, and 1"" following Kofoidian notation. Processes no more than one per plate (TextFigures 7A, 8). Cingular processes absent. Archeopyle apical, operculum adnate ventrally.
Dimensions. Central body 30–35 x 40–45 µm in diameter; processes 10–20 µm long.
Remarks. This species most closely resembles Litosphaeridium siphoniphorum subsp. siphoniphorum in overall appearance and wall ornament, but differs in having an adnate operculum and more processes, including sulcal processes. It has a more oval cyst body, and the body is not so completely covered by process bases as the body of Litosphaeridium siphoniphorum.
Occurrence. Rice Valley, Lake County, California, U.S.A. The samples are from an outlier thrust sheet of Great Valley Sequence rocks within the Central Belt of the northern California Franciscan complex, late Albian.
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Holotype: Lucas-Clark, 2007, pl.1, figs.1–3.
Age: late Albian.
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Original description (Lucas-Clark, 2007):
Litosphaeridium adnatum sp. nov. Plate 1, figs. 1–9; Text-Figures 7A, 8
Holotype. Plate 1, figs. 1–3. Sample PL3908; Rice Valley, California; slide FJ4, coordinates 91.5 x 10.1, England Finder reference L28/2. Carnegie Museum of Natural History #19157.
Derivation of name. After the adnate operculum that, among other factors, distinguishes this species from Litosphearidium siphoniphorum.
Diagnosis. Chorate cyst with about 20 discrete, open, bulbous to sub-cylindrical processes, including three smaller sulcal processes. Archeopyle apical, operculum adnate.
Description. Chorate apiculocavate cysts with a subspherical to ovoidal central body and a total of 18–20 discrete, hollow processes (3 or 4 on the operculum; posterior sulcal sometimes missing). Periphragm ornament granular, becoming finer to absent on the processes. Endophragm smooth. Processes sub-cylindrical, bulbous, or conical; wide and circular at the base, truncated, slightly constricted or closed at the tips. Apical and sulcal processes open or closed, others open. Open process tips sometimes thickened into a rim. Process shafts subcircular in cross-section. Sulcal processes variable; in some specimens, nearly as large as precingular processes and open, usually more slender, reduced and closed. Processes interpreted to represent B, Ci, Cu, 1u, 1i, 2–6, ai, Iu(?), II–VI, X, Y, and Z following Evittian notation. These are equivalent to 1'–3', 1a, 1"–6", as, ps, 1"'–6"', 1p, and 1"" following Kofoidian notation. Processes no more than one per plate (TextFigures 7A, 8). Cingular processes absent. Archeopyle apical, operculum adnate ventrally.
Dimensions. Central body 30–35 x 40–45 µm in diameter; processes 10–20 µm long.
Remarks. This species most closely resembles Litosphaeridium siphoniphorum subsp. siphoniphorum in overall appearance and wall ornament, but differs in having an adnate operculum and more processes, including sulcal processes. It has a more oval cyst body, and the body is not so completely covered by process bases as the body of Litosphaeridium siphoniphorum.
Occurrence. Rice Valley, Lake County, California, U.S.A. The samples are from an outlier thrust sheet of Great Valley Sequence rocks within the Central Belt of the northern California Franciscan complex, late Albian.
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