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Rigaudella aemula
Rigaudella aemula, (Deflandre, 1939a, p. 187–189, pl.9, fig.12; pl.10, figs.5–8; pl.11, figs.1,7), Below, 1982b, p. 139; Emendation: Below, 1982b, p.139–140
Originally Hystrichosphaeridium, subsequently Cannosphaeropsis, thirdly Adnatosphaeridium, fourthly (and now) Rigaudella.
Taxonomic junior synonym: Cannosphaeropsis paucispina, according to Below (1982b, p.139).
Holotype: Deflandre, 1938, pl.11, fig.1
Paratypes: Deflandre, 1938
Locus typicus: Villers-sur-Mer, Calvados, France
Stratum typicum: Oxfordian
Translations Deflandre, 1938 and Below, 1982: LPP
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G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP
Rigaudella aemula (Deflandre, 1939a) Below, 1982b, emend. Below, 1982b. Emendation from Below (1982b, p 140). Skolochorate cysts with spheroidal central body. Autophragm smooth. Solid, centrally located intratabular processes, which widen distally, are funnel-shaped and fenestrate or greatly slit. Processes interconnected by means of solid trabeculae. Process formula 1-4', 1-6", 0c, 0s, 2"’-5"’ (2"’-6"’), pc, 1"”, reflecting a gonyaulacoid tabulation pattern of the motile stage. Archeopyle apical with compound operculum, type (4A). Size: central body 25-45 µm, overall 60-100 µm, processes 18-25 µm.
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Original description: Deflandre 1938, p. 187-189: Hystrichosphaeridium aemulum
Description (annotated): the central body is generally spherical, ellipsoidal or lenticular, depending on flattening and angle of observation. From the central body, processes stem, some solid, some hollow, some both, that develop funnel-shaped, and split up in two or three net-forming trabeculae connecting two neighbouring processes. There are ten to fifteen processes, sometimes either all quite lean or all quite enlarged. In some cases they fuse to form a kind of bunch. The flexible and branching transversal trabeculae are solid, but certainly do not resemble those of Cannosphaeropsis utinensis O. Wetzel. The central body measures about 35 µm, but may vary from 25-45 µm. The total size is 60-90 or 100 µm. The length of the processes is 18-25 µm. The membrane of the central body and the processes seem smooth, but polluting particles render it a punctate nature.
Emended description: Below, 1982, p. 140
Skolochorate cyst with a spher- oidal central body. Autophragm smooth. Solid, centrally intra- tabular, distally widened, fenestrate or strongly split processes, interconnected by solid trabeculae. Process-formula 1'-4', 1''-6'', 0c, 0s, 2'''-5''' (2'''-6'''), pc, 1'''', reflecting a gonyaulacoid tabulation of the mobile stage. Apical archaeopyle with compound operculum, type 4A[1'-4']. (A detailed description is given of the studied material from the "Grenzglauconit" - containing the Dogger/ Malm {Callovian-Oxfordian} boundary interval - from southern Germany.)
Affinities:
Deflandre 1938, p. 188: Hystrichosphaeridium aemulum differs from Cannosphaeropsis utinensis in that the netforming trabeculae are solid, contrary to those of the latter species, which are hollow.
Stratigraphy:
Material described by Below 1982b is from the "Grenzglauconit" in southern Germany, which contains the Callovian-Oxfordian boundary interval. The boundary, based on Ammonoidea, is placed between the Quenstedtoceras lamberti Zone (Callovian zeta) and the Q. mariae Zone (Oxfordian alpha).
Williams and Bujak 1985, Adnatosphaeridium aemulum: 1. general occurrence: basis Callovian -top Berriasian; 2. Southern England and France: first appearance at the base of the "Polystephanophorus paracalathus Parazone", Early-Middle Callovian (Sarjeant 1979); 3. worldwide: occurrence since the Late Callovian (basis of the A. aemulum Zone, Williams 1977). 4. Australia; first occurrence at the basis of the R. aemula Interval Zone (=uppermost part of the Pareodinia ceratophora Superzone), containing the Callovian-Oxfordian boundary. Last occurrence at the top of the Egmontodinium torynum Interval Zone (=uppermost part of the Fromea cylindrica Superzone), latest Berriasian to possibly earliest Valanginian. An acme of R. aemula occurs at the boundary interval of the Cribroperidinium perforans Oppel Zone and the Omatia mongomeryi Range Zone (both part of the Fromea cylindrica Superzone), Early Tithonian (Helby, Morgan and Partridge 1987).
Originally Hystrichosphaeridium, subsequently Cannosphaeropsis, thirdly Adnatosphaeridium, fourthly (and now) Rigaudella.
Taxonomic junior synonym: Cannosphaeropsis paucispina, according to Below (1982b, p.139).
Holotype: Deflandre, 1938, pl.11, fig.1
Paratypes: Deflandre, 1938
Locus typicus: Villers-sur-Mer, Calvados, France
Stratum typicum: Oxfordian
Translations Deflandre, 1938 and Below, 1982: LPP
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G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP
Rigaudella aemula (Deflandre, 1939a) Below, 1982b, emend. Below, 1982b. Emendation from Below (1982b, p 140). Skolochorate cysts with spheroidal central body. Autophragm smooth. Solid, centrally located intratabular processes, which widen distally, are funnel-shaped and fenestrate or greatly slit. Processes interconnected by means of solid trabeculae. Process formula 1-4', 1-6", 0c, 0s, 2"’-5"’ (2"’-6"’), pc, 1"”, reflecting a gonyaulacoid tabulation pattern of the motile stage. Archeopyle apical with compound operculum, type (4A). Size: central body 25-45 µm, overall 60-100 µm, processes 18-25 µm.
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Original description: Deflandre 1938, p. 187-189: Hystrichosphaeridium aemulum
Description (annotated): the central body is generally spherical, ellipsoidal or lenticular, depending on flattening and angle of observation. From the central body, processes stem, some solid, some hollow, some both, that develop funnel-shaped, and split up in two or three net-forming trabeculae connecting two neighbouring processes. There are ten to fifteen processes, sometimes either all quite lean or all quite enlarged. In some cases they fuse to form a kind of bunch. The flexible and branching transversal trabeculae are solid, but certainly do not resemble those of Cannosphaeropsis utinensis O. Wetzel. The central body measures about 35 µm, but may vary from 25-45 µm. The total size is 60-90 or 100 µm. The length of the processes is 18-25 µm. The membrane of the central body and the processes seem smooth, but polluting particles render it a punctate nature.
Emended description: Below, 1982, p. 140
Skolochorate cyst with a spher- oidal central body. Autophragm smooth. Solid, centrally intra- tabular, distally widened, fenestrate or strongly split processes, interconnected by solid trabeculae. Process-formula 1'-4', 1''-6'', 0c, 0s, 2'''-5''' (2'''-6'''), pc, 1'''', reflecting a gonyaulacoid tabulation of the mobile stage. Apical archaeopyle with compound operculum, type 4A[1'-4']. (A detailed description is given of the studied material from the "Grenzglauconit" - containing the Dogger/ Malm {Callovian-Oxfordian} boundary interval - from southern Germany.)
Affinities:
Deflandre 1938, p. 188: Hystrichosphaeridium aemulum differs from Cannosphaeropsis utinensis in that the netforming trabeculae are solid, contrary to those of the latter species, which are hollow.
Stratigraphy:
Material described by Below 1982b is from the "Grenzglauconit" in southern Germany, which contains the Callovian-Oxfordian boundary interval. The boundary, based on Ammonoidea, is placed between the Quenstedtoceras lamberti Zone (Callovian zeta) and the Q. mariae Zone (Oxfordian alpha).
Williams and Bujak 1985, Adnatosphaeridium aemulum: 1. general occurrence: basis Callovian -top Berriasian; 2. Southern England and France: first appearance at the base of the "Polystephanophorus paracalathus Parazone", Early-Middle Callovian (Sarjeant 1979); 3. worldwide: occurrence since the Late Callovian (basis of the A. aemulum Zone, Williams 1977). 4. Australia; first occurrence at the basis of the R. aemula Interval Zone (=uppermost part of the Pareodinia ceratophora Superzone), containing the Callovian-Oxfordian boundary. Last occurrence at the top of the Egmontodinium torynum Interval Zone (=uppermost part of the Fromea cylindrica Superzone), latest Berriasian to possibly earliest Valanginian. An acme of R. aemula occurs at the boundary interval of the Cribroperidinium perforans Oppel Zone and the Omatia mongomeryi Range Zone (both part of the Fromea cylindrica Superzone), Early Tithonian (Helby, Morgan and Partridge 1987).