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Avellodinium lepidum
Avellodinium lepidum, Backhouse, 1988
Holotype: Backhouse, 1988, pl.19, figs.6a-b
Locus typicus: Perth Basin, Western Australia
Stratum typicum: Late Valanginian-Early Aptian
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Original description: [Backhouse, 1988, p. 75]:
Description:
Chorate cysts, body ovoid to subspherical. Endophragm smooth, 1 µm thick, periphragm appressed to endophragm except where it forms trifurcate gonal processes or parasutural features. Gonal processes sometimes connected by low parasutural septa. One or two bifurcate intergonal parasutural processes situated on longer parasutures whether parasutural septa are evident or not. Processes 12 to 25 µm long, similar in length on one specimen, 1 to 2 µm thick near the base, bifurcating one-half to two-thirds of the distance from the base into slender spines which bifurcate again near the tip.
Paratabulation indicated by low parasutural septa, and by position of gonal and intergonal processes, formula: 4", 6", Xc, 5""", 1p, 1"""", paraplates 1""" to 5""" in the 2""" to 6""" paraplate positions.
Paracingulum 5 µm wide indicated by low septa and sometimes by fused gonal processes, offset approximately one cingulum width.
Archeopyle combination epicystal, type [tAtP], often attached at parasulcal tab.
Dimensions:
Cyst body length of holotype approximately 54 µm, width approximately 57 µm.
Range of cyst body length (15 specimens) 42(50)61 µm, width 37(44)57 µm.
Affinities:
Ctenidodinium panneum (Norris) Lentin and Williams 1973, C. tenellum Deflandre 1938, C. cumulum (Norris) Lentin and Williams 1973, and C. elegantulum Millioud 1969 all possess spinose parasutural septa, but in each case the spines are more numerous than those of A. lepidum and are not furcate.
A. lepidum is distinguished from A. falsificum Duxbury 1977 by possessing intergonal processes and lower parasutural septa.
Holotype: Backhouse, 1988, pl.19, figs.6a-b
Locus typicus: Perth Basin, Western Australia
Stratum typicum: Late Valanginian-Early Aptian
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original description: [Backhouse, 1988, p. 75]:
Description:
Chorate cysts, body ovoid to subspherical. Endophragm smooth, 1 µm thick, periphragm appressed to endophragm except where it forms trifurcate gonal processes or parasutural features. Gonal processes sometimes connected by low parasutural septa. One or two bifurcate intergonal parasutural processes situated on longer parasutures whether parasutural septa are evident or not. Processes 12 to 25 µm long, similar in length on one specimen, 1 to 2 µm thick near the base, bifurcating one-half to two-thirds of the distance from the base into slender spines which bifurcate again near the tip.
Paratabulation indicated by low parasutural septa, and by position of gonal and intergonal processes, formula: 4", 6", Xc, 5""", 1p, 1"""", paraplates 1""" to 5""" in the 2""" to 6""" paraplate positions.
Paracingulum 5 µm wide indicated by low septa and sometimes by fused gonal processes, offset approximately one cingulum width.
Archeopyle combination epicystal, type [tAtP], often attached at parasulcal tab.
Dimensions:
Cyst body length of holotype approximately 54 µm, width approximately 57 µm.
Range of cyst body length (15 specimens) 42(50)61 µm, width 37(44)57 µm.
Affinities:
Ctenidodinium panneum (Norris) Lentin and Williams 1973, C. tenellum Deflandre 1938, C. cumulum (Norris) Lentin and Williams 1973, and C. elegantulum Millioud 1969 all possess spinose parasutural septa, but in each case the spines are more numerous than those of A. lepidum and are not furcate.
A. lepidum is distinguished from A. falsificum Duxbury 1977 by possessing intergonal processes and lower parasutural septa.