Back
Wilsonidium ornatum
Wilsonidinium ornatum (Wilson, 1967) Lentin and Williams, 1976
Originally Wetzeliella, subsequently (and now) Wilsonidium, thirdly Rhombodinium?.
Stover and Evitt, 1978, questionably transferred this species to Rhombodinium Gocht, 1955. Lentin and Williams, 1981, retained it in Wilsonidium.
Holotype: Wilson, 1967, fig.33
Locus typicus: Waipawa, Hawkes Bay, New Zealand
Stratum typicum: Early Eocene (Mangaorapan)
--------------------------------------------------
G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999
Wilsonidium ornatum (Wilson, 1967c) Lentin and Williams, 1976. According to Wilson (1967c, p.481), Wilsonidium lineidentatum has a pentagonal pericyst with the left antapical horn always being longer than the right. The ornamentation consists of short, rectangular pillars (length 1-3 Fm), arranged in rows and usually capped by fairly stout membranous fibre. There are small rectangular perforations especially on the pericyst margin. Size: Length 124-156 Fm. The archeopyle appears to be hyperepeliform. Size: length pericyst 124-156 µm, width 135-151 µm, endocyst length 74-99um, width 102-88 µm, apical horn 25-30 µm, left antapical horn 8-14 µm, right antapical horn 22-25 µm, lateral horn 22-25 µm.
--------------------------------------------------
Original description: Wilson, 1967, p.481, 492: Wetzeliella (Wetzeliella) ornata
Periphragm pentagonal, angular, with five well developed horns although left antapical horn substantially shorter than right. Ornament very distinctive, comprises short, rectangular pillars (1=1-3 Á) arranged in rows and usually capped by a fairly stout membranous fibre. The small rectangular perforations (I up to 3 Á) so formed are especially apparent along the periphragm margin. Archeopyle large, trapezium-shaped. Capsule large, circular. Tabulation not clear although process rows appear to correspond to sutures. Transverse girdle always present.
Dimensions: Holotype: l = 156 µm h = 151 µm, capsule 99 µm X 102 µm, apical horn 30 µm, Ieft antapical horn 14 µm, right antapical horn 25 µm, side horns 25 µm. Another specimen (SM 123): l124 µm, b=135 Ám, capsule 74 µm X 88 µm, ap. h. 25 µm, l. ant. h. 8 µm, r. ant. h. 22 µm, lat. h. 22 µm.
Affinities:
Wilson, 1967, p.492: Wetzeliella (Wetzeliella) ornata
This species is of the same general type as Wetzeliella (W.) clathrata Eis., W. (W.) coelothrypa Williams and Downie, and W. (W.) edwardsii Wilson since the processes are linked distally. It is readily distinguished by the very short length of the processes and the small rectangular nature of the perforations so formed.
Originally Wetzeliella, subsequently (and now) Wilsonidium, thirdly Rhombodinium?.
Stover and Evitt, 1978, questionably transferred this species to Rhombodinium Gocht, 1955. Lentin and Williams, 1981, retained it in Wilsonidium.
Holotype: Wilson, 1967, fig.33
Locus typicus: Waipawa, Hawkes Bay, New Zealand
Stratum typicum: Early Eocene (Mangaorapan)
--------------------------------------------------
G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999
Wilsonidium ornatum (Wilson, 1967c) Lentin and Williams, 1976. According to Wilson (1967c, p.481), Wilsonidium lineidentatum has a pentagonal pericyst with the left antapical horn always being longer than the right. The ornamentation consists of short, rectangular pillars (length 1-3 Fm), arranged in rows and usually capped by fairly stout membranous fibre. There are small rectangular perforations especially on the pericyst margin. Size: Length 124-156 Fm. The archeopyle appears to be hyperepeliform. Size: length pericyst 124-156 µm, width 135-151 µm, endocyst length 74-99um, width 102-88 µm, apical horn 25-30 µm, left antapical horn 8-14 µm, right antapical horn 22-25 µm, lateral horn 22-25 µm.
--------------------------------------------------
Original description: Wilson, 1967, p.481, 492: Wetzeliella (Wetzeliella) ornata
Periphragm pentagonal, angular, with five well developed horns although left antapical horn substantially shorter than right. Ornament very distinctive, comprises short, rectangular pillars (1=1-3 Á) arranged in rows and usually capped by a fairly stout membranous fibre. The small rectangular perforations (I up to 3 Á) so formed are especially apparent along the periphragm margin. Archeopyle large, trapezium-shaped. Capsule large, circular. Tabulation not clear although process rows appear to correspond to sutures. Transverse girdle always present.
Dimensions: Holotype: l = 156 µm h = 151 µm, capsule 99 µm X 102 µm, apical horn 30 µm, Ieft antapical horn 14 µm, right antapical horn 25 µm, side horns 25 µm. Another specimen (SM 123): l124 µm, b=135 Ám, capsule 74 µm X 88 µm, ap. h. 25 µm, l. ant. h. 8 µm, r. ant. h. 22 µm, lat. h. 22 µm.
Affinities:
Wilson, 1967, p.492: Wetzeliella (Wetzeliella) ornata
This species is of the same general type as Wetzeliella (W.) clathrata Eis., W. (W.) coelothrypa Williams and Downie, and W. (W.) edwardsii Wilson since the processes are linked distally. It is readily distinguished by the very short length of the processes and the small rectangular nature of the perforations so formed.