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Spiniferella cornuta

Spiniferella cornuta (Gerlach, 1961, p.180, pl.27, figs.10–12) Stover and Hardenbol, 1994, p.38. Emendation: Stover and Hardenbol, 1994, p.38–39, as Spiniferella cornuta.

Originally Hystrichosphaera, subsequently Spiniferites, thirdly (and now) Spiniferella
Holotype: Gerlach, 1961, pl.27, figs.10–12.
Age: middle Oligocene–middle Miocene.
Plate 6, Figures 37a-c

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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.

Spiniferella cornuta (Gerlach, 1961) Stover and Hardenbol, 1991. Emended diagnosis from Stover and Hardenbol (1994, p.38-39). Cysts skolochorate with ellipsoidal bodies bearing parasutural septa, gonal and intergonal spiniferate processes and a prominent apical horn. Endophragm much thicker than periphragm and uniformly minutely granulate. The thin, smooth to faintly ornamented periphragm appressed to endophragm except where parasutural features, processes and an apical horn are developed. Apical horn long, wider proximally than distally and with two supr-like projections, one at about mid-length, the other at about two-thirds the horn length from the base of the horn. Parasutural septa of low to moderate height, straight or concave between processes and merge imperceptibly with process bases. Processes trifurcate when gonal, bifurcate when intergonal. Paratabulation 3-4', 6", 6c, 5"’, 1p, 1"”. Septum between 1' and 4' may be reduced or absent. 6" contacts 1'. Paracingulum offset by about 11/2 cingular width. Size: overall length 95-115 µm, central body length 50-56 µm, width 42-47 µm, apical horn 31-46 µm, process length 12-17 µm, endophragm 2.5-3.5 µm thick.
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Synonymy
1961 - Hystrichosphaera cornuta GERLACH, p. 180-181, pl. 27, figs. 10-12. 1970 -
Spiniferites cornutus (Gerlach 1961) SARJEANT, p. 76.

Emended description: Stover and Hardenbol, 1994, p. 38-39
Cysts skolochorate with ellipsoidal bodies (length greater than width) bearing parasutural septa, gonal and intergonal spiniferate processes and a prominent apical horn. Endophragm much thicker than periphragm and uniformly minutely granulate. The thin, smooth to faintly ornamented periphragm appressed to endophragm except where parasutural features, processes and an apical horn are developed. Apical horn long, wider proximally than distally and with two spur-like projections, one at about mid-length, the other at about two-thirds the horn length from the base of the horn. Parasutural septa of low to moderate height, straight or concave between processes and merge imperceptibly with process bases. Process stalks beyond septa tapered distally, relatively narrow and with trifurcate or bifurcate tips on gonal and intergonal processes, respectively. The archeopyle is precingular, formed by the release of paraplate 3''; operculum monoplacoid and secate.
Paratabulation expressed clearly by the parasutural septa, gonyaulacoid, formula: 3-4', 6'', 6c, 5''', 1p, 1''''. Septum between paraplates 1' and 4' may be reduced or absent. Last precingular paraplate subquadrangular to pentangular and in substantial contact with paraplate 1'. Hypocystal paratabulation pattern arranged in the standard sexiform pattern.
Paracingulum laevorotatory, delimited by two, equatorial, parallel, transverse septa divided into six rectangular paraplates by short longitudinal septa. Anterior ends of paracingulum offset by approximately 1 l/2 cingular widths.
Size: intermediate to large; overall length 95 to 115µm, body length 50 to 56 µm, body width 42 to 47 µm, apical horn 31 to 46 µm long, process length 12 to 17 µm, endophragm 2.5 to 3.5 µm wide.

Type
Holotype: specimen illustrated by Gerlach (1961, pl. 27, figs. 10-12) from the Emsburen-7 borehole, Germany, at 182 meters. The holotype was reported initially from Middle Oligocene strata which are now regarded as probably Lower Oligocene (Rupelian).

Occurrence
Spiniferella cornuta occurs virtually throughout the Boom Formation. Although specimens have been reported (as Spiniferites cornutus) from throughout the Paleogene, it is uncertain whether or not they possess features diagnostic of Spiniferella cornuta. Presently, the species is known unequivocally from the Lower Oligocene (Rupelian) only.
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