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Hystrichosphaeridium recurvatum
From Fensome et al., 2019:
Hystrichosphaeridium recurvatum (White, 1842, p.39, pl.4, fig.12) Lejeune-Carpentier, 1940, p.B221–B222. Holotype: White, 1842, pl.4, fig.12. Originally Xanthidium tubiferum var. recurvatum (Appendix A), subsequently (and now) Hystrichosphaeridium recurvatum. Nomenclatural junior synonyms: Xanthidium tubiferum var. palmatum [subsequently Hystrichosphaeridium palmatum (White), an illegitimate name], Xanthidium tubiferum var. palmaforme and Hystrichosphaeridium duplum, since they all have the same holotype as Hystrichosphaeridium recurvatum. White (1842, p.39) named "The twelfth ... species of the genus Xanthidium ... the Tubiferum recurvatum or palmaforme — the curved or palm-formed Tubiferum", thus presenting two epithets in his text. To compound matters, the single illustration was labelled "X. tubiferum palmatum". Since prior to 1953 alternative names were allowed under the ICN, and since White (1842) provided a description and illustration, the taxon was validly published. The correct name would be that chosen by the first subsequent author to make such a choice, and this was Bronn (1848, p.1375), who used the name Xanthidium palmatum, at species rank. When Downie and Sarjeant (1965, p.121) transferred Xanthidium palmatum to Hystrichosphaeridium, they created an illegitimate combination — a junior homonym of Hystrichosphaeridium palmatum Deflandre and Courteville. Hence, since Xanthidium tubiferum var. recurvatum had been raised to specific rank, as Hystrichosphaeridium recurvatum, by Lejeune-Carpentier (1940), "recurvatum" becomes the correct epithet as long as the epithet "palmatum" remains unavailable. Age: Late Cretaceous.
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Original description White, 1842:
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Emended description Lejeune-Carpentier, 1940:
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Supplemental description: Hultberg, 1985, p. 134
Chorate cyst, composed of endophragm and periphragm, appressed between processes. The surface of both endophragm and periphragm is smooth. The shape of the cyst is elongate ellipsoidal. Paratabulation is expressed by intratabular hollow, slender processes, which are open distally. The process-bases are circular. The process-tips are digitate, with the digiti bending towards the cyst. The gonyaulacacean, process-formula: 4', 6'', 6c, 1p, 6''', 1''''. The archeopyle is apical, type tA. Operculum free. The paracingulum is indicated by six processes, which, in contrast to what is found in many other species, are not flat-based. Parasulcus is not indicated. Size - 62-78 µm (diameter).
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G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.
Hystrichosphaeridium recurvatum (White, 1842) Lejeune-Carpentier, 1940. Davey and Williams (1966b, p.67-68) described this species as having a subspherical central body with moderate number of slender tubiform processes. Length of latter between that of radius and diameter of central body. Processes open distally, terminating with a few short, orthogonal or recurved spines. The processes on an individual, even the sulcals, do not vary much in size and width. Distally the processes terminate in a rosette of short spines. Size: holotype diameter of central body 32 by 25 µm, maximum overall 75 µm, length of processes 18-30 µm.
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Hystrichosphaeridium recurvatum (White, 1842, p.39, pl.4, fig.12) Lejeune-Carpentier, 1940, p.B221–B222. Holotype: White, 1842, pl.4, fig.12. Originally Xanthidium tubiferum var. recurvatum (Appendix A), subsequently (and now) Hystrichosphaeridium recurvatum. Nomenclatural junior synonyms: Xanthidium tubiferum var. palmatum [subsequently Hystrichosphaeridium palmatum (White), an illegitimate name], Xanthidium tubiferum var. palmaforme and Hystrichosphaeridium duplum, since they all have the same holotype as Hystrichosphaeridium recurvatum. White (1842, p.39) named "The twelfth ... species of the genus Xanthidium ... the Tubiferum recurvatum or palmaforme — the curved or palm-formed Tubiferum", thus presenting two epithets in his text. To compound matters, the single illustration was labelled "X. tubiferum palmatum". Since prior to 1953 alternative names were allowed under the ICN, and since White (1842) provided a description and illustration, the taxon was validly published. The correct name would be that chosen by the first subsequent author to make such a choice, and this was Bronn (1848, p.1375), who used the name Xanthidium palmatum, at species rank. When Downie and Sarjeant (1965, p.121) transferred Xanthidium palmatum to Hystrichosphaeridium, they created an illegitimate combination — a junior homonym of Hystrichosphaeridium palmatum Deflandre and Courteville. Hence, since Xanthidium tubiferum var. recurvatum had been raised to specific rank, as Hystrichosphaeridium recurvatum, by Lejeune-Carpentier (1940), "recurvatum" becomes the correct epithet as long as the epithet "palmatum" remains unavailable. Age: Late Cretaceous.
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Original description White, 1842:
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Emended description Lejeune-Carpentier, 1940:
---------------------------------------------------------------------------------------------------
Supplemental description: Hultberg, 1985, p. 134
Chorate cyst, composed of endophragm and periphragm, appressed between processes. The surface of both endophragm and periphragm is smooth. The shape of the cyst is elongate ellipsoidal. Paratabulation is expressed by intratabular hollow, slender processes, which are open distally. The process-bases are circular. The process-tips are digitate, with the digiti bending towards the cyst. The gonyaulacacean, process-formula: 4', 6'', 6c, 1p, 6''', 1''''. The archeopyle is apical, type tA. Operculum free. The paracingulum is indicated by six processes, which, in contrast to what is found in many other species, are not flat-based. Parasulcus is not indicated. Size - 62-78 µm (diameter).
--------------------------------------------------
G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.
Hystrichosphaeridium recurvatum (White, 1842) Lejeune-Carpentier, 1940. Davey and Williams (1966b, p.67-68) described this species as having a subspherical central body with moderate number of slender tubiform processes. Length of latter between that of radius and diameter of central body. Processes open distally, terminating with a few short, orthogonal or recurved spines. The processes on an individual, even the sulcals, do not vary much in size and width. Distally the processes terminate in a rosette of short spines. Size: holotype diameter of central body 32 by 25 µm, maximum overall 75 µm, length of processes 18-30 µm.
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