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Labyrinthodinium
From Williams et al., 2017:
[Labyrinthodinium, Piasecki, 1980, p. 67
Type species: Labyrinthodinium truncatum, Piasecki, 1980 (pl.2, figs.9–11)]
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Original description: [Piasecki, 1980]:
Diagnosis:
Small chorate cysts with spherical main body and apical archaeopyle. The cyst wall is two layered, and periphragma forms a closed or open reticulum of anastomosing crests. The smaller crests support the larger ones, which form membraneous processes of equal length.
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Modified description:
Stover and Williams 1987, p. 139:
Synopsis:
Cysts proximochorate, subspherical; endophragm and periphragm appressed except where the periphragm forms few to numerous processes; all or most processes connected by membraneous septa which form an imperfect reticulum; archeopyle apical, type [tA], operculum free.
Description:
Shape: Subspherical.
Wall relationships: Endophragm and periphragm appressed except where the latter forms processes.
Wall features: Periphragm smooth or faintly ornamented; processes few to many, of uniform height but differ in width, typically with expanded tips; all or most processes joined by thin, membraneous septa whose height is equal to or less than that of the processes, and which form an imperfect, small- to large-mesh reticulum.
Archeopyle: Apical, type [tA], operculum free; principal archeopyle suture does not cut across septa.
Paratabulation: Indicated by archeopyle only.
Paracingulum: Not indicated.
Parasulcus: Not indicated.
Size: Small to intermediate, overall diameter about 35 µm to 65 µm.
Affinities:
Labyrinthodinium is similar to Epiplosphaera Klement 1960, but differs in having a less well-developed reticulum and in possessing distinct processes, of which some may be free of connecting septa.
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Notes:
G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.
Labyrinthodinium Piasecki, 1980. Synopsis from Stover and Williams (1987, p.139). Cysts proximochorate, subspherical; endophragm and periphragm appressed except where the periphragm forms few to numerous processes; all or most processes connected by membranous septa which form an imperfect reticulum; archeopyle apical, type (tA), operculum free.
[Labyrinthodinium, Piasecki, 1980, p. 67
Type species: Labyrinthodinium truncatum, Piasecki, 1980 (pl.2, figs.9–11)]
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original description: [Piasecki, 1980]:
Diagnosis:
Small chorate cysts with spherical main body and apical archaeopyle. The cyst wall is two layered, and periphragma forms a closed or open reticulum of anastomosing crests. The smaller crests support the larger ones, which form membraneous processes of equal length.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Modified description:
Stover and Williams 1987, p. 139:
Synopsis:
Cysts proximochorate, subspherical; endophragm and periphragm appressed except where the periphragm forms few to numerous processes; all or most processes connected by membraneous septa which form an imperfect reticulum; archeopyle apical, type [tA], operculum free.
Description:
Shape: Subspherical.
Wall relationships: Endophragm and periphragm appressed except where the latter forms processes.
Wall features: Periphragm smooth or faintly ornamented; processes few to many, of uniform height but differ in width, typically with expanded tips; all or most processes joined by thin, membraneous septa whose height is equal to or less than that of the processes, and which form an imperfect, small- to large-mesh reticulum.
Archeopyle: Apical, type [tA], operculum free; principal archeopyle suture does not cut across septa.
Paratabulation: Indicated by archeopyle only.
Paracingulum: Not indicated.
Parasulcus: Not indicated.
Size: Small to intermediate, overall diameter about 35 µm to 65 µm.
Affinities:
Labyrinthodinium is similar to Epiplosphaera Klement 1960, but differs in having a less well-developed reticulum and in possessing distinct processes, of which some may be free of connecting septa.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Notes:
G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.
Labyrinthodinium Piasecki, 1980. Synopsis from Stover and Williams (1987, p.139). Cysts proximochorate, subspherical; endophragm and periphragm appressed except where the periphragm forms few to numerous processes; all or most processes connected by membranous septa which form an imperfect reticulum; archeopyle apical, type (tA), operculum free.