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Tenua hystrix
From Fensome et al., 2019:
Tenua hystrix Eisenack, 1958a, p.410, pl.23, figs.1–4; text-fig.10. Emendation: Sarjeant, 1985a, p.94–95, as Tenua hystrix; Fensome et al., 2019a, p.48.
Holotype: Eisenack, 1958a, pl.23, fig.1; Sarjeant, 1985a, pl.10, fig.5; Sarjeant, 1992b, fig.1; Fauconnier and Masure, 2004, pl.80, fig.3; Fensome et al., 2019a, fig.18F.
Originally (and now) Tenua Eisenack, subsequently Cyclonephelium.
Taxonomic junior synonyms: Tenua hystricella, according to Eisenack and Kjellström (1972, p.1039) — however, Fensome et al. (2019a, p.37) considered Tenua hystricella to be a taxonomic junior synonym of Circulodinium distinctum; Cyclonephelium (as Cerbia) tabulatum, according to
Sarjeant (1985a, p.95–96) and Sarjeant (1992b, p.681) — however, by retaining Cerbia, Duxbury (2002, p.76,78) retained Cerbia tabulata by implication; Palaeohystrichophora (al. Cyclonephelium) brevispinosa, Cyclonephelium distinctum var. brevispinatum, Canningia americana, and Canningia insignis, all according to Fensome et al. (2019a, p.48). Backhouse (1988, p.83) considered Circulodinium hirtellum to be a possible taxonomic junior synonym of this species. NIA.
Locus typicus: N Germany
Stratum typicum: Aptian
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Translation Eisenack, 1958: Sarjeant, 1985
Original diagnosis: Eisenack, 1958, p.410
A species of Tenua of 75-105 µm length and about 65-97 µm breadth. The spinelets are, on the sarne individual, mostly rather constant in length, varying however-from 2-10 µm length; they are at their tips either thickened in knoblike fashion or briefly branched; only rarely do the short, clublike branch-prongs show secondary division.
Emended diagnosis: Sarjeant, 1985, p.95
Proximate, lenticular cysts, penitabulate and consisting of autophragm only. Ambitus subpolygonal, of variable breadth, with a strong antapical outbulge to the left, and a faint antapical swelling to the right, of the sulcal region in some specimens, both swellings reduced in others: apex smoothly rounded. Peniplates outlined by single or double rows of very short solid spinelets, their length only around 1/15 of the central body cross-measurement. Spinelets distally oblate to capitate or bifid, with very short branches subparallel to the autoblast surface, symmetrical or (rarely) asymmetrical. Penitabulation ?', 6", 5c, 5''', 1p, 1'''', 1-?s. Archaeopyle apical (type tA): operculum typically free, rarely attached.
Dimensions: Holotype (in dorsoventral orientation): overall length (apex lacking) 86 µm, overall breadth 97 µm. Figured specimen (in slightly oblique lateral view): overall length (apex attached) 75 µm, overall breadth 66 µm. Range of dimensions (all orientations); overall length 56-105 µm, overall breadth 48-95 µm. Sixty specimens measured.
Supplemental description: Mao Shaozhi and Norris, 1988, p.33: Cyclonephelium hystrix
Cyst dorsoventrally flattened, truncated-circular to semicircular in shape with no apical plates, usually more or less asymmetrical. Wall surface covered with stout, rigid, and densely and uniformly distributed nontabular processes; expanded proximally and slightly expanded or capitate distally; usually 1 to 2 µm (rarely up to 5 µm) long, 0.5 to 2 µm wide. Archeopyle apical, type (tA).
Operculum usually detached; archeopyle suture zigzag with accessory sutures indicating six precingular plates.
Emended description fensome et al., 2019a:
Emended description. A species of Tenua with very short isolated spines or projections, which are terminally acuminate to blunt or briefly bifid. The spines are present, but may be reduced in density and/or length, on the dorsal and ventral surfaces, and may show weak penitabular alignment. Cyst antapically rounded or asymmetrical with rounded protuberances.
Comments. Eisenack (1958, p. 410) gave the following diagnosis for Tenua hystrix. "A species of Tenua 75–105 μ long and some 65–95 μm wide. In a single specimen, the spines are mostly of rather similar length, varying however from about 2–10 μ in length; they are either only slightly knobbed distally or weakly divided, only rarely do the short, thick prongs have secondary branches …. [Translation]"
The species description is here emended to mention the possibility of weakly developed penitabular distribution of the spines. See under the genus Tenua and earlier sections of this paper for further discussion. Pocock (1962, p. 81) provided the following description for Palaeohystrichophora brevispinosa:
"Theca more or less isodiametric, covered by short spines; transverse furrow equatorial, broad, marked by two rows of short spines; epitheca conical, terminated by a tuft of slightly longer spines than those covering the rest of the theca; epitheca terminated by two short blunt processes, one slightly longer and sharper than the other; the theca commonly encloses a spherical cyst about half the diameter of the theca; yellow green spherical organic bodies are also frequently present."
The inner body (“cyst”) described by Pocock (1962) is probably a misinterpretation of folds on the cyst wall, as the cyst is clearly an areoligeracean with a single wall layer and low ornamentation, as confirmed in a re-examination by Jansonius (1986). Isolated spines are the dominant form of ornament on the holotype, although, as Jansonius (1986) noted, occasional processes are connected. The line drawing of the holotype of Circulodinium brevispinosum by Jansonius (1986) appears to show a reduction of ornament mid-ventrally, but this is not evident in the re-illustration of the holotype by Fauconnier & Masure (2004, pl. 14, figs 7–8). We consider Canningia americana to be indistinguishable from Tenua hystrix, as is Circulodinium brevispinatum, which was described as a subspecies of Cyclonephelium2836
distinctum by Millioud (1969). Millioud (1969, p. 427) provided no details of the spines other than that they are less than 2 μm long. This species accommodates forms of Tenua with short, usually blunt projections typically <4 μm long. Tenua anaphrissa has longer, generally hair-like processes. The ambital outline of both species, as conceived herein, is variable.
Stratigraphical occurrence. Eisenack (1958) described Tenua hystrix from the Aptian of northern Germany. Costa & Davey (1992) placed the LAD if this species in the latest Maastrichtian. He Chengquan (1991) recorded Canningia insignis from the Cenomanian of China. Tenua (as Palaeohystrichophora) brevispinosa was first described from the upper Barremian and Aptian of western Canada. Pöthe de Baldis & Ramos (1983) described the species Canningia americana from the lower Aptian of Argentina. The type material of Cyclonephelium distinctum var. brevispinatum is from the Berriasian to lower Aptian of France.
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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.
Tenua hystrix Eisenack, 1958, emend Sarjeant, 1985a. Emendation from Sarjeant (1985a, p.94-95), Proximate lenticular cysts, penitabulate and consisting of autophragm only. Ambitus subpolygonal, of variable breadth, with a strong antapical outbulge to the left, and a faint antapical swelling to the right, of the sulcal region in some specimens, both swellings reduced in others: apex smoothly rounded. Peniplates outline by single or double rows of very short solid spinelets, their length only around 1/15th of the central body cross-measurement. Spinelets distally oblate to capitate or bifid with very short branches subparallel to the autoblast surface, symmetrical or (rarely) asymmetrical. Operculum rarely attached. Size: holotype overall length, without operculum, 86 µm, width 97 µm, range, overall length 56-105 µm, overall width 48-95 µm.
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Tenua hystrix Eisenack, 1958a, p.410, pl.23, figs.1–4; text-fig.10. Emendation: Sarjeant, 1985a, p.94–95, as Tenua hystrix; Fensome et al., 2019a, p.48.
Holotype: Eisenack, 1958a, pl.23, fig.1; Sarjeant, 1985a, pl.10, fig.5; Sarjeant, 1992b, fig.1; Fauconnier and Masure, 2004, pl.80, fig.3; Fensome et al., 2019a, fig.18F.
Originally (and now) Tenua Eisenack, subsequently Cyclonephelium.
Taxonomic junior synonyms: Tenua hystricella, according to Eisenack and Kjellström (1972, p.1039) — however, Fensome et al. (2019a, p.37) considered Tenua hystricella to be a taxonomic junior synonym of Circulodinium distinctum; Cyclonephelium (as Cerbia) tabulatum, according to
Sarjeant (1985a, p.95–96) and Sarjeant (1992b, p.681) — however, by retaining Cerbia, Duxbury (2002, p.76,78) retained Cerbia tabulata by implication; Palaeohystrichophora (al. Cyclonephelium) brevispinosa, Cyclonephelium distinctum var. brevispinatum, Canningia americana, and Canningia insignis, all according to Fensome et al. (2019a, p.48). Backhouse (1988, p.83) considered Circulodinium hirtellum to be a possible taxonomic junior synonym of this species. NIA.
Locus typicus: N Germany
Stratum typicum: Aptian
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Translation Eisenack, 1958: Sarjeant, 1985
Original diagnosis: Eisenack, 1958, p.410
A species of Tenua of 75-105 µm length and about 65-97 µm breadth. The spinelets are, on the sarne individual, mostly rather constant in length, varying however-from 2-10 µm length; they are at their tips either thickened in knoblike fashion or briefly branched; only rarely do the short, clublike branch-prongs show secondary division.
Emended diagnosis: Sarjeant, 1985, p.95
Proximate, lenticular cysts, penitabulate and consisting of autophragm only. Ambitus subpolygonal, of variable breadth, with a strong antapical outbulge to the left, and a faint antapical swelling to the right, of the sulcal region in some specimens, both swellings reduced in others: apex smoothly rounded. Peniplates outlined by single or double rows of very short solid spinelets, their length only around 1/15 of the central body cross-measurement. Spinelets distally oblate to capitate or bifid, with very short branches subparallel to the autoblast surface, symmetrical or (rarely) asymmetrical. Penitabulation ?', 6", 5c, 5''', 1p, 1'''', 1-?s. Archaeopyle apical (type tA): operculum typically free, rarely attached.
Dimensions: Holotype (in dorsoventral orientation): overall length (apex lacking) 86 µm, overall breadth 97 µm. Figured specimen (in slightly oblique lateral view): overall length (apex attached) 75 µm, overall breadth 66 µm. Range of dimensions (all orientations); overall length 56-105 µm, overall breadth 48-95 µm. Sixty specimens measured.
Supplemental description: Mao Shaozhi and Norris, 1988, p.33: Cyclonephelium hystrix
Cyst dorsoventrally flattened, truncated-circular to semicircular in shape with no apical plates, usually more or less asymmetrical. Wall surface covered with stout, rigid, and densely and uniformly distributed nontabular processes; expanded proximally and slightly expanded or capitate distally; usually 1 to 2 µm (rarely up to 5 µm) long, 0.5 to 2 µm wide. Archeopyle apical, type (tA).
Operculum usually detached; archeopyle suture zigzag with accessory sutures indicating six precingular plates.
Emended description fensome et al., 2019a:
Emended description. A species of Tenua with very short isolated spines or projections, which are terminally acuminate to blunt or briefly bifid. The spines are present, but may be reduced in density and/or length, on the dorsal and ventral surfaces, and may show weak penitabular alignment. Cyst antapically rounded or asymmetrical with rounded protuberances.
Comments. Eisenack (1958, p. 410) gave the following diagnosis for Tenua hystrix. "A species of Tenua 75–105 μ long and some 65–95 μm wide. In a single specimen, the spines are mostly of rather similar length, varying however from about 2–10 μ in length; they are either only slightly knobbed distally or weakly divided, only rarely do the short, thick prongs have secondary branches …. [Translation]"
The species description is here emended to mention the possibility of weakly developed penitabular distribution of the spines. See under the genus Tenua and earlier sections of this paper for further discussion. Pocock (1962, p. 81) provided the following description for Palaeohystrichophora brevispinosa:
"Theca more or less isodiametric, covered by short spines; transverse furrow equatorial, broad, marked by two rows of short spines; epitheca conical, terminated by a tuft of slightly longer spines than those covering the rest of the theca; epitheca terminated by two short blunt processes, one slightly longer and sharper than the other; the theca commonly encloses a spherical cyst about half the diameter of the theca; yellow green spherical organic bodies are also frequently present."
The inner body (“cyst”) described by Pocock (1962) is probably a misinterpretation of folds on the cyst wall, as the cyst is clearly an areoligeracean with a single wall layer and low ornamentation, as confirmed in a re-examination by Jansonius (1986). Isolated spines are the dominant form of ornament on the holotype, although, as Jansonius (1986) noted, occasional processes are connected. The line drawing of the holotype of Circulodinium brevispinosum by Jansonius (1986) appears to show a reduction of ornament mid-ventrally, but this is not evident in the re-illustration of the holotype by Fauconnier & Masure (2004, pl. 14, figs 7–8). We consider Canningia americana to be indistinguishable from Tenua hystrix, as is Circulodinium brevispinatum, which was described as a subspecies of Cyclonephelium2836
distinctum by Millioud (1969). Millioud (1969, p. 427) provided no details of the spines other than that they are less than 2 μm long. This species accommodates forms of Tenua with short, usually blunt projections typically <4 μm long. Tenua anaphrissa has longer, generally hair-like processes. The ambital outline of both species, as conceived herein, is variable.
Stratigraphical occurrence. Eisenack (1958) described Tenua hystrix from the Aptian of northern Germany. Costa & Davey (1992) placed the LAD if this species in the latest Maastrichtian. He Chengquan (1991) recorded Canningia insignis from the Cenomanian of China. Tenua (as Palaeohystrichophora) brevispinosa was first described from the upper Barremian and Aptian of western Canada. Pöthe de Baldis & Ramos (1983) described the species Canningia americana from the lower Aptian of Argentina. The type material of Cyclonephelium distinctum var. brevispinatum is from the Berriasian to lower Aptian of France.
--------------------------------------------------
G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.
Tenua hystrix Eisenack, 1958, emend Sarjeant, 1985a. Emendation from Sarjeant (1985a, p.94-95), Proximate lenticular cysts, penitabulate and consisting of autophragm only. Ambitus subpolygonal, of variable breadth, with a strong antapical outbulge to the left, and a faint antapical swelling to the right, of the sulcal region in some specimens, both swellings reduced in others: apex smoothly rounded. Peniplates outline by single or double rows of very short solid spinelets, their length only around 1/15th of the central body cross-measurement. Spinelets distally oblate to capitate or bifid with very short branches subparallel to the autoblast surface, symmetrical or (rarely) asymmetrical. Operculum rarely attached. Size: holotype overall length, without operculum, 86 µm, width 97 µm, range, overall length 56-105 µm, overall width 48-95 µm.
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