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Pyxidinopsis vesiculata
Pyxidinopsis vesiculata Head and Norris, 2003, p.8,11, fig.8, nos.1–20.
Holotype: Head and Norris, 2003, fig.8, nos.6–9.
Age: late Miocene–early early Pliocene.
Original description (Head and Norris, 2003)
Diagnosis: Small ovoid proximate cysts, with or without apical protuberance; surface smooth with ridges that interconnect to varying degrees to form fine irregular, non-tabular reticulum. Ridges of even height arise from widened bases and narrow distally towards crests that are entire. Small vesicles occur at the bases of some or most ridges. Archeopyle precingular 1P, formed by loss of plate 3″, has well defined angles. Operculum free.
Description: Cysts ovoid, apical protuberance of about 1 μm is rarely present (seen in three specimens, e.g., Fig. 8.19). Wall is an autophragm and has smooth surface. Continuous or discontinuous ridges form a fine, complete or incomplete irregular reticulum over entire surface of cyst. Scattered coni/verrucae may be present on specimens whose ridges are particularly discontinuous. For individual specimens with relatively complete reticulation, lumina occur in a range of sizes: smaller about 0.5–1.0 μm and larger about 1.5–3.5 μm. Ridges have smooth surface, arise from expanded (width up to about 0.5–1.0 μm) bases, and narrow distally towards crests that are entire and of generally even height, ca. 0.4–1.5 μm. Small (less than 0.5 μm) vesicles occur along bases of some or most ridges, and particularly at ridge junctions where they may occur singly or in small clusters. Ridges appear not to reflect tabulation. Between ridges, wall appears unstructured and has thickness of ca. 0.3 μm. Archeopyle precingular Type 1P (3″) and ornament extends to its borders.
Etymology: Named with reference to the presence of vesicles at ridge bases.
Type: Holotype, sample DSDP 603C-31-5, 20–22 cm; slide 2 (ROM 55084); England Finder reference F9/3. Lower Pliocene. Figure 8.6–8.9.
Measurements: Holotype: length, excluding ridges 34 μm; breadth, excluding ridges 30 μm; ridge height, ca. 0.8 μm. Range: maximum diameter, excluding ridges 23(29.1)37 μm, standard deviation, 3.2 μm; ridge height, ca. 0.4(0.8)1.5 μm. Thirty-nine specimens measured.
Occurrence - Upper Miocene through lower Lower Pliocene in DSDP Hole 603C.
Comparison - Corrudinium devernaliae n. sp. has coarser reticulation (smaller lumina ca. 2–4 μm, larger lumina ca. 7–14 μm) than P. vesiculata n. sp. (smaller lumina ca. 0.5–1.0 μm, larger lumina ca. 1.5–3.5 μm), and ornament reflecting some tabulation. The archeopyle margins are unornamented in Corrudinium devernaliae n. sp.
Holotype: Head and Norris, 2003, fig.8, nos.6–9.
Age: late Miocene–early early Pliocene.
Original description (Head and Norris, 2003)
Diagnosis: Small ovoid proximate cysts, with or without apical protuberance; surface smooth with ridges that interconnect to varying degrees to form fine irregular, non-tabular reticulum. Ridges of even height arise from widened bases and narrow distally towards crests that are entire. Small vesicles occur at the bases of some or most ridges. Archeopyle precingular 1P, formed by loss of plate 3″, has well defined angles. Operculum free.
Description: Cysts ovoid, apical protuberance of about 1 μm is rarely present (seen in three specimens, e.g., Fig. 8.19). Wall is an autophragm and has smooth surface. Continuous or discontinuous ridges form a fine, complete or incomplete irregular reticulum over entire surface of cyst. Scattered coni/verrucae may be present on specimens whose ridges are particularly discontinuous. For individual specimens with relatively complete reticulation, lumina occur in a range of sizes: smaller about 0.5–1.0 μm and larger about 1.5–3.5 μm. Ridges have smooth surface, arise from expanded (width up to about 0.5–1.0 μm) bases, and narrow distally towards crests that are entire and of generally even height, ca. 0.4–1.5 μm. Small (less than 0.5 μm) vesicles occur along bases of some or most ridges, and particularly at ridge junctions where they may occur singly or in small clusters. Ridges appear not to reflect tabulation. Between ridges, wall appears unstructured and has thickness of ca. 0.3 μm. Archeopyle precingular Type 1P (3″) and ornament extends to its borders.
Etymology: Named with reference to the presence of vesicles at ridge bases.
Type: Holotype, sample DSDP 603C-31-5, 20–22 cm; slide 2 (ROM 55084); England Finder reference F9/3. Lower Pliocene. Figure 8.6–8.9.
Measurements: Holotype: length, excluding ridges 34 μm; breadth, excluding ridges 30 μm; ridge height, ca. 0.8 μm. Range: maximum diameter, excluding ridges 23(29.1)37 μm, standard deviation, 3.2 μm; ridge height, ca. 0.4(0.8)1.5 μm. Thirty-nine specimens measured.
Occurrence - Upper Miocene through lower Lower Pliocene in DSDP Hole 603C.
Comparison - Corrudinium devernaliae n. sp. has coarser reticulation (smaller lumina ca. 2–4 μm, larger lumina ca. 7–14 μm) than P. vesiculata n. sp. (smaller lumina ca. 0.5–1.0 μm, larger lumina ca. 1.5–3.5 μm), and ornament reflecting some tabulation. The archeopyle margins are unornamented in Corrudinium devernaliae n. sp.