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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:
The eleventh and last species of the genus Xanthidium, and the third of the Tubifera, I have named Tubiferum recurvatum or palmaforme, the curved or palm-formed Tubiferum ; it differs from the two preceding in having the tentacula decorated at their terminations with a cluster of smaller curved processes, diverging from the orifice of each tentaculum, and inclining back in the form of a cluster of palm-leaves, from four to six in number. Next to Tubiferwm simplex this is the most rare of all the species : the average of their diameter, measuring as before from the ends of the opposite tentacula, is from 1/330 to 1/280 of an inch.
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Emended description Lejeune-Carpentier, 1940 (translated from French):
Hystrichosphaeridium recurvatum (White).
This is a form of which Reade (1839, pl. I, fig. 9) had already published a recognizable image, but simply under the name tubiferum Ehrbg.
H. H. White (1842, p. 83) called it Tubiferum recurvatum or palmaforme; we will retain only the first of these two names here. H. recurvatum is a well-characterized species, and White's text and figure (pl. 7, fig. 11) are sufficient, we believe, to identify it. This is fortunate, as our efforts to obtain communication of the old English material have been unsuccessful. At least two of the three specimens inserted by G. Deflandre (1987) in his plate XIII (figs. 2 and 4) clearly belong to H. recurvatum, and he attributes them to H. tubiferum Ehrbg. in the broad sense.
The shell of H. recurvatum is usually more clearly ellipsoidal than that of H. tubiferum. It is somewhat smaller; the major diameter of our specimens measures approximately 25 to 33 µ. The tubes, all of roughly the same caliber, reach a length exceeding this major diameter. The base that supports them is not very wide, but, on most of our specimens, is strongly domed, with a rounded outline. Toward their distal portion, the tubes thin out regularly, then become roughly cylindrical. The end, which is not widened and whose walls are not spread out, bears a rosette of small, very distinct spiniform extensions, all curving similarly towards the tube. The total number of tubes, according to our best pieces, is about 30.
Of several hundred flint tubifers of Senonian and Maastrichtian age, obtained from both Hainaut and the Cretaceous basin of Limburg, only about fifteen indisputably belong to H. recurvatum. The species therefore does not appear to be much more common in Belgium than it would be in England, according to H. H. White. The text by G. Deflandre (loc. cit) suggests that it is found more frequently in French flints.
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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:
The eleventh and last species of the genus Xanthidium, and the third of the Tubifera, I have named Tubiferum recurvatum or palmaforme, the curved or palm-formed Tubiferum ; it differs from the two preceding in having the tentacula decorated at their terminations with a cluster of smaller curved processes, diverging from the orifice of each tentaculum, and inclining back in the form of a cluster of palm-leaves, from four to six in number. Next to Tubiferwm simplex this is the most rare of all the species : the average of their diameter, measuring as before from the ends of the opposite tentacula, is from 1/330 to 1/280 of an inch.
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Emended description Lejeune-Carpentier, 1940 (translated from French):
Hystrichosphaeridium recurvatum (White).
This is a form of which Reade (1839, pl. I, fig. 9) had already published a recognizable image, but simply under the name tubiferum Ehrbg.
H. H. White (1842, p. 83) called it Tubiferum recurvatum or palmaforme; we will retain only the first of these two names here. H. recurvatum is a well-characterized species, and White's text and figure (pl. 7, fig. 11) are sufficient, we believe, to identify it. This is fortunate, as our efforts to obtain communication of the old English material have been unsuccessful. At least two of the three specimens inserted by G. Deflandre (1987) in his plate XIII (figs. 2 and 4) clearly belong to H. recurvatum, and he attributes them to H. tubiferum Ehrbg. in the broad sense.
The shell of H. recurvatum is usually more clearly ellipsoidal than that of H. tubiferum. It is somewhat smaller; the major diameter of our specimens measures approximately 25 to 33 µ. The tubes, all of roughly the same caliber, reach a length exceeding this major diameter. The base that supports them is not very wide, but, on most of our specimens, is strongly domed, with a rounded outline. Toward their distal portion, the tubes thin out regularly, then become roughly cylindrical. The end, which is not widened and whose walls are not spread out, bears a rosette of small, very distinct spiniform extensions, all curving similarly towards the tube. The total number of tubes, according to our best pieces, is about 30.
Of several hundred flint tubifers of Senonian and Maastrichtian age, obtained from both Hainaut and the Cretaceous basin of Limburg, only about fifteen indisputably belong to H. recurvatum. The species therefore does not appear to be much more common in Belgium than it would be in England, according to H. H. White. The text by G. Deflandre (loc. cit) suggests that it is found more frequently in French flints.
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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).
--------------------------------------------------
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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