Back
Avellodinium flagellatum
Avellodinium flagellatum, Davey, 1987
Holotype: Davey, 1987, pl.1, fig.1-2
Locus typicus: Papuan Basin, Papua New Guinea
Stratum typicum: Valanginian
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original description: [Davey, 1987, p. 35]:
Diagnosis:
Shape: The body is typically subspherical, but is often distorted.
Wall: The two thin wall layers are closely appressed, except where the periphragm forms the sutural ridges and processes. The surface is smooth to scabrate.
Paratabulation: This is well defined by low ridges and is gonyaulacacean, probably 3-4', 5", 6", 6c, 5-6'', 1p, 1''''.
Processes: The processes are sutural, long and thin and mainly gonal in position. The gonal processes are more strongly developed than the sutural processes which are mainly confined to the hypotract. The latter bifurcate and the gonal processes trifurcate towards their distal ends to give rise to thin, flexuous spines or threads. An additional, distal bifurcation may occur.
Archaeopyle: Combination, epicystal, Type tAtP always developed with the two cyst halves typically separate. Archaeopyle suture immediately anterior to the cingulum.
Description:
The wall of the cyst is relatively thin and so specimens are often broken or distorted to some extent. In addition, the long flexuous processes have an obscuring effect making it very difficult to determine precisely the tabulation. It is presumed to be, however, very similar to that occurring in A. falsificum Duxbury 1977 and in the genus Spiniferites Mantell 1850. Trifurcation and bifurcation of the processes tends to be rather irregular and this, together with the flexuous nature of the processes, generally gives this species an untidy appearance.
Dimensions:
Ranges in µm:
Body diameter 67x60 (complete specimen)
Body width 36-60
Length of processes 9-29
Affinities:
Davey, 1987, p. 35: Avellodinium flagellatum is most comparable to A. falsificum from the Early Cretaceous of northwest Europe. It differs significantly in being larger, having a thinner wall, bearing longer, more flexuous processes, which are extremely fine distally, and in possessing sutural processes.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Notes:
G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.
Avellodinium flagellatum Davey, 1988, has the archeopyle suture immediately anterior to the cingulum. It differs from A.falsificum in being much larger, having a thinner wall, bearing longer more flexuous processes, which are very fine distally and in possessing sutural processes.
Size: overall 67 x 60 µm, width 36-60 µm, processes 9-29 µm.
Holotype: Davey, 1987, pl.1, fig.1-2
Locus typicus: Papuan Basin, Papua New Guinea
Stratum typicum: Valanginian
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original description: [Davey, 1987, p. 35]:
Diagnosis:
Shape: The body is typically subspherical, but is often distorted.
Wall: The two thin wall layers are closely appressed, except where the periphragm forms the sutural ridges and processes. The surface is smooth to scabrate.
Paratabulation: This is well defined by low ridges and is gonyaulacacean, probably 3-4', 5", 6", 6c, 5-6'', 1p, 1''''.
Processes: The processes are sutural, long and thin and mainly gonal in position. The gonal processes are more strongly developed than the sutural processes which are mainly confined to the hypotract. The latter bifurcate and the gonal processes trifurcate towards their distal ends to give rise to thin, flexuous spines or threads. An additional, distal bifurcation may occur.
Archaeopyle: Combination, epicystal, Type tAtP always developed with the two cyst halves typically separate. Archaeopyle suture immediately anterior to the cingulum.
Description:
The wall of the cyst is relatively thin and so specimens are often broken or distorted to some extent. In addition, the long flexuous processes have an obscuring effect making it very difficult to determine precisely the tabulation. It is presumed to be, however, very similar to that occurring in A. falsificum Duxbury 1977 and in the genus Spiniferites Mantell 1850. Trifurcation and bifurcation of the processes tends to be rather irregular and this, together with the flexuous nature of the processes, generally gives this species an untidy appearance.
Dimensions:
Ranges in µm:
Body diameter 67x60 (complete specimen)
Body width 36-60
Length of processes 9-29
Affinities:
Davey, 1987, p. 35: Avellodinium flagellatum is most comparable to A. falsificum from the Early Cretaceous of northwest Europe. It differs significantly in being larger, having a thinner wall, bearing longer, more flexuous processes, which are extremely fine distally, and in possessing sutural processes.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Notes:
G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.
Avellodinium flagellatum Davey, 1988, has the archeopyle suture immediately anterior to the cingulum. It differs from A.falsificum in being much larger, having a thinner wall, bearing longer more flexuous processes, which are very fine distally and in possessing sutural processes.
Size: overall 67 x 60 µm, width 36-60 µm, processes 9-29 µm.