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Callaiosphaeridium trycherium

Callaiosphaeridium trycherium, Duxbury, 1980

Holotype:Duxbury 1980, pl.11, fig.6
Locality: Speeton Clay, Speeton, England
Age: Barremian

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Original description: [Duxbury, 1980, p.114]:

Diagnosis:
A spheroidal to ovoidal dinoflagellate cyst with a smooth to finely granular surface. bears six tubular paracingular processes which have several secondary, flexuous spines near their distal terminations. The epi- and hypocystal areas bear distinctive, light parasutural crests which outline a typically gonaulacacean paratabulation pattern. The parasutural crests are distally irregular and possess variously-grouped spines along their distal margins suggesting the terminal furcations of gonal and parasutural processes. Individual gonal and parasutural processes cannot, however, be distinguished. Parasutural crests occasionally connect tubular paracingular processes to trifurcate gonal areas, suggesting that the tubular processes are themselves gonal or parasutural in position.
The archeopyle is epicystal.

Dimensions:
Holotype--73 x 77 µm. Overall--87 (77) 70 x 87 (79) 67 µm.

Affinities:
Near their proximal edge, the parasutural crests of this species have a vacuolar appearance as have the parasutural crests in Callaiosphaeridium asymmetricum (Deflandre & Courteville, 1939) Davey & Williams, 1966. The high parasutural crests and lack of individually distinguishable epi- and hypocystal processes distinguish this species from Callaiosphaeridium asymmetricum.

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Remarks:
G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.

Callaiosphaeridium trycherium Duxbury, 1980, has six tubular cingular processes which have flexuous spines near their distal terminations. The epi- and hypocystal areas bear distinctive, high parasutural crests which outline a typical gonyaulacacean tabulation. The parasutural crests are distally irregular and possess variously-grouped spines along their distal margins suggesting the terminal furcations of gonal and parasutural processes. However, individual processes cannot be distinguished. Parasutural crests occasionally connect tubular paracingular processes to trifurcate gonal areas. Archeopyle epicystal. Near their proximal edge, the parasutural crests of this species have a vacuolar appearance as in C.asymmetricum. The high parasutural crests and lack of individually distinguishable epi and hypocystal processes, however, distinguish C. trycherium from C. asymmetricum.
Size: overall 87-70 x 87-67 µm.
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