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Rhynchodiniopsis martonensis
Rhynchodiniopsis martonensis Bailey et al., 1997, p.239, figs.4a–b.
Holotype: Bailey et al., 1997, fig.4a.
Age: late Kimmeridgian.
Original description (Bailey et al., 1997)
Diagnosis. Dinoflagellate cyst proxumate, ellipsoidal - subpentagonal with a distinct apical horn. Autophragm thin (<1 µm), with a microgranulate outer surface and a smooth inner surface. Paratabulation indicated by variably developed parasutures, including low ridges, which may be surmounted by distally denticulate crests or isolated spines, with or without distal trabeculae. Long, blade-like acuminate spines are developed at gonal points around the paracingulum and antapically. These may also be linked distally by complex trabeculae. The archaeopyle is precingular, type P. Size range 60-120 µm.
Holotype. Slide R.6754, EF ref. Q60/3, Figure 4a.
Type locality. Kimmeridge Clay Formation (Bed 15 if Cope 1974), lower part of the Pectinatites pectinatus ammonite zone (Pectinatites eastlecottensis Subzone) at Golden Hill Quarry, Marton, North Yorkshire.
Derivation of name. After the village of Marton, North Yorkshire, England.
Description. Shape: ellipsoidal to subpentagonal. Epicyst tapers into a adistinct apical horn which is rounded distally and terminates in a solid, often complexly structured apicular extension. Wall relationships: autophragm only. Wall features: the outer surface of the autophragm is microgranular, with a smooth inner surface. Paratabulation: indicated by variable and often complex parasutural ridges and crests, including low ridges which may be surmounted by isolated spines or denticulate crests with or without proximal vacuoles and/or distal trabeculae. At gonal positions around the paracingulum and (especially) the antapex, are long, blade-like spines up to 12 µm in length. These may also be linked by distal trabeculae, which are often denticulate along their inner and outer margins. Kofoidean formula 4', 1-2a, 6", 6c, 6"', 1p, 1"". Archeopyle precingular, type P (3" only). Dimensions size range 60-110 µm. Holotype 98 µm overall length, 95 µm width.
Comparison. Rhynchodiniopsis martonense is distinguished from all other species of the genus by the presence of long, blade-like spines linked by complex trabeculae. Occurrence. Observed in small numbers from samples M1, M6, M8, M9, M10 and M11.
Holotype: Bailey et al., 1997, fig.4a.
Age: late Kimmeridgian.
Original description (Bailey et al., 1997)
Diagnosis. Dinoflagellate cyst proxumate, ellipsoidal - subpentagonal with a distinct apical horn. Autophragm thin (<1 µm), with a microgranulate outer surface and a smooth inner surface. Paratabulation indicated by variably developed parasutures, including low ridges, which may be surmounted by distally denticulate crests or isolated spines, with or without distal trabeculae. Long, blade-like acuminate spines are developed at gonal points around the paracingulum and antapically. These may also be linked distally by complex trabeculae. The archaeopyle is precingular, type P. Size range 60-120 µm.
Holotype. Slide R.6754, EF ref. Q60/3, Figure 4a.
Type locality. Kimmeridge Clay Formation (Bed 15 if Cope 1974), lower part of the Pectinatites pectinatus ammonite zone (Pectinatites eastlecottensis Subzone) at Golden Hill Quarry, Marton, North Yorkshire.
Derivation of name. After the village of Marton, North Yorkshire, England.
Description. Shape: ellipsoidal to subpentagonal. Epicyst tapers into a adistinct apical horn which is rounded distally and terminates in a solid, often complexly structured apicular extension. Wall relationships: autophragm only. Wall features: the outer surface of the autophragm is microgranular, with a smooth inner surface. Paratabulation: indicated by variable and often complex parasutural ridges and crests, including low ridges which may be surmounted by isolated spines or denticulate crests with or without proximal vacuoles and/or distal trabeculae. At gonal positions around the paracingulum and (especially) the antapex, are long, blade-like spines up to 12 µm in length. These may also be linked by distal trabeculae, which are often denticulate along their inner and outer margins. Kofoidean formula 4', 1-2a, 6", 6c, 6"', 1p, 1"". Archeopyle precingular, type P (3" only). Dimensions size range 60-110 µm. Holotype 98 µm overall length, 95 µm width.
Comparison. Rhynchodiniopsis martonense is distinguished from all other species of the genus by the presence of long, blade-like spines linked by complex trabeculae. Occurrence. Observed in small numbers from samples M1, M6, M8, M9, M10 and M11.