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Hystrichosphaeridium phoenix
Hystrichosphaeridium? phoenix Duxbury 1980
Now Surculosphaeridium?. Originally Hystrichosphaeridium?, subsequently (and now) Surculosphaeridium?.
Duxbury, 1980, questionably included this species in Hystrichosphaeridium.
Holotype: Duxbury, 1980, pl.13, figs.5,6, text-fig.9
Locus typicus: Speeton, England.
Stratum typicum: Barremian
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Original diagnosis: Duxbury, 1980, p. 124
A chorate cyst with a small, smooth central body which is spheroidal, though usually extensively folded and which bears long (up to 3/4 main body diameter), solid processes. The processes are smooth and may number up to 20 per individual. Each process flares proximally, and distally divides into a number (usually 6--8) of slender, flat spines. The overall diameter of the process terminations may exceed the main body radius.
Observed Dimensions: Holotype--76 x 73 µm. Overall--84 (71) 57 x 76 (65) 52 µm.
Duxbury. 1980, p. 124: Hystrichosphaeridium recurvatum and Melitasphaeridium choanophorum both have hollow processes with distal spines (or fringes with spines) around the distal tubular margins. This contrasts with the solid processes of Hystrichosphaeridium phoenix. Bacchidinium polypes and Taleisphaera hydra possess solid processes but the number of such processes is markedly greater than in Hystrichosphaeridium phoenix.
Also, the first two taxa have a constantly greater main body/overall diameter ratio than the latter. Taleisphaera hydra has angularity to the main body and penitabular crests and neither of these features is demonstrated by Hystrichosphaeridium phoenix.
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Remarks: Heilmann-Clausen and Thomsen 1995:
The archaeopyle-type of H.? phoenix is unknown, as it has been explained by Duxbury(1980) and BELOW (1982d). The uncertainty has not been clarified since then, and a definite generic assignment of H. ? phoenix is still not possible.
H. ? phoenix was transferred to the genus Surculosphaeridium by Lentin & Williams (1981) and this was (tentatively) maintained by Sarjeant (1984). However, judging from the process-morphology there is little affinity of H. ? phoenix with typical species in Surculosphaeridium. The processes in Surculosphaeridium are branched irTegularly and they are often deeply furcate. The processes in H. ? phoenix are composed of a simple tubiform shaft with a palmate branching pattern at the distal end. Affinities rather lie with species and genera mentioned by Duxbury ( 1980) and Below (1982d), in particular with Hystrichosphaeridium duplum Lentin & Williams, 1989 nom. subst. pro H. palmatum (White, 1842), Melitasphaeridium Harland & Hill, 1979 spp. and Kleithriasphaeridium? sarmentum (Davey, 1979) Below, 1982d. The present author therefore supports BELOW"S (1982d) rejection of transferring this species to Surculosphaeridium, in spite of the reasonings of Sarjeant (1984).
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Now Surculosphaeridium?. Originally Hystrichosphaeridium?, subsequently (and now) Surculosphaeridium?.
Duxbury, 1980, questionably included this species in Hystrichosphaeridium.
Holotype: Duxbury, 1980, pl.13, figs.5,6, text-fig.9
Locus typicus: Speeton, England.
Stratum typicum: Barremian
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Original diagnosis: Duxbury, 1980, p. 124
A chorate cyst with a small, smooth central body which is spheroidal, though usually extensively folded and which bears long (up to 3/4 main body diameter), solid processes. The processes are smooth and may number up to 20 per individual. Each process flares proximally, and distally divides into a number (usually 6--8) of slender, flat spines. The overall diameter of the process terminations may exceed the main body radius.
Observed Dimensions: Holotype--76 x 73 µm. Overall--84 (71) 57 x 76 (65) 52 µm.
Duxbury. 1980, p. 124: Hystrichosphaeridium recurvatum and Melitasphaeridium choanophorum both have hollow processes with distal spines (or fringes with spines) around the distal tubular margins. This contrasts with the solid processes of Hystrichosphaeridium phoenix. Bacchidinium polypes and Taleisphaera hydra possess solid processes but the number of such processes is markedly greater than in Hystrichosphaeridium phoenix.
Also, the first two taxa have a constantly greater main body/overall diameter ratio than the latter. Taleisphaera hydra has angularity to the main body and penitabular crests and neither of these features is demonstrated by Hystrichosphaeridium phoenix.
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Remarks: Heilmann-Clausen and Thomsen 1995:
The archaeopyle-type of H.? phoenix is unknown, as it has been explained by Duxbury(1980) and BELOW (1982d). The uncertainty has not been clarified since then, and a definite generic assignment of H. ? phoenix is still not possible.
H. ? phoenix was transferred to the genus Surculosphaeridium by Lentin & Williams (1981) and this was (tentatively) maintained by Sarjeant (1984). However, judging from the process-morphology there is little affinity of H. ? phoenix with typical species in Surculosphaeridium. The processes in Surculosphaeridium are branched irTegularly and they are often deeply furcate. The processes in H. ? phoenix are composed of a simple tubiform shaft with a palmate branching pattern at the distal end. Affinities rather lie with species and genera mentioned by Duxbury ( 1980) and Below (1982d), in particular with Hystrichosphaeridium duplum Lentin & Williams, 1989 nom. subst. pro H. palmatum (White, 1842), Melitasphaeridium Harland & Hill, 1979 spp. and Kleithriasphaeridium? sarmentum (Davey, 1979) Below, 1982d. The present author therefore supports BELOW"S (1982d) rejection of transferring this species to Surculosphaeridium, in spite of the reasonings of Sarjeant (1984).
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