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Tenua hystrix

Tenua hystrix Eisenack, 1958a, p.410, pl.23, figs.1–4; text-fig.10. Emendation: Sarjeant, 1985a, p.94–95, as Tenua hystrix.

Originally (and now) Tenua Eisenack, 1958, subsequently Cyclonephelium.
Taxonomic junior synonyms: Tenua hystricella, according to Eisenack and Kjellström (1972, p.1039); Cyclonephelium (as Cerbia) tabulatum, according to Sarjeant (1985a, p.95–96) and Sarjeant (1992b, p.681).
Backhouse (1988, p.83) considered Circulodinium hirtellum to be a possible taxonomic junior synonym of this species.

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.
Locus typicus: N Germany
Stratum typicum: Aptian
Translation Eisenack, 1958: Sarjeant, 1985

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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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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.
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