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Wanaea enoda
Wanaea enoda Riding and Helby, 2001b, p.39, figs.2A–I.
Holotype: Riding and Helby, 2001b, fig.2H.
Age: late Bathonian–mid Callovian.
Original description (Riding & Helby, 2001b):
Wanaea enoda sp.nov. (Figs 2A-I)
Prevous autralian usage
M.P. 491 – Helby
Wanaea enoda – Helby.
Description: An intermediate sized, acavate species of Wanaea lacking demonstrable paracingular differentiation. Hypocyst subconical, subtriangular in dorsoventral and lateral views; sometimes with a rounded antapical horn which is sometimes slightly inclined. The epicyst is domed; the degree of convexity variable (see dimensions). The autophragm is thin (c. 0.5 µm thick) and generally smooth to irregularly scabrate, shallow concavity. Simple operculum normally attached ventrally.
Dimensions (µm, n=26): Min.(Mean)Max.
Length of the entire cyst: 61 (72) 82
Length of the epicyst: 12 (22) 40
Length of the hypocyst: 40 (59) 75
Equatorial width of the hypocyst (in lateral view): 60 (75) 94
Width of the antapical horn (at midpoint): 4 (7) 12.
The measured specimens are from a conventional core sample at 2066.02m in Magobu Island-1 well.
Comments: The description above is based on a single sample. Despite this limitation the general morphology is accurately covered with the single exception that in the other material the cyst wall may be slightly thicker (up to 1 µm). the shape of the hypocyst is somewhat variable. Some specimens are relatively wide, whereas other markedly elongate. In the Magobu Island-1 well specimens, the autophragm is thin and flimsy, however this species is surprisingly not especially susceptible to mechanical distortion. The development o and antapical horn is variable. Some individuals have a relatively distinct, short horn and others have subtriangular hypocyst which lack a well differentiated antapical protrusions. No accessory Archeopyle sutures have been observed o the epicyst.
Comparison: this distinctive species of Wanaea is characterized by its acavate organisation, the domes nature of the epicyst and its thin, smooth autophragm. Wanaea enoda differs from younger species of the genus by lacking a posterior paracingular flange. It is most similar to Wanaea lacuna sp. nov. in size, shape and autophragm morphology, however, W. enoda is acavate. It differs form other acingulate Wanaea species such as W. verrucosa sp. nov. and W. zoharensis in possessing a smooth autophragm. The lack of a paracingular crest and partial paratabulation together with a domed epicyst differentiates Wanaea enoda from W. acollaris.
Derivation of name: From the Latin enodis, meaning free of knots and referring to the lack of ornamentation on the autophragm.
Holotype and type locality: Fig. 2H, CPC 35848, from a conventional core sample in Magobu Island-1 well at 2066.02m
Statigraphical distribution: Wanaea enoda ranges from the Bathonian base of the Wanaea verrucosa Zone (7ciaiii) to the Callovian basal Wanaea digitate Zone (7bi) (figs 11, 12; Foster, this volume; Helby & Partridge, in prep.)
Holotype: Riding and Helby, 2001b, fig.2H.
Age: late Bathonian–mid Callovian.
Original description (Riding & Helby, 2001b):
Wanaea enoda sp.nov. (Figs 2A-I)
Prevous autralian usage
M.P. 491 – Helby
Wanaea enoda – Helby.
Description: An intermediate sized, acavate species of Wanaea lacking demonstrable paracingular differentiation. Hypocyst subconical, subtriangular in dorsoventral and lateral views; sometimes with a rounded antapical horn which is sometimes slightly inclined. The epicyst is domed; the degree of convexity variable (see dimensions). The autophragm is thin (c. 0.5 µm thick) and generally smooth to irregularly scabrate, shallow concavity. Simple operculum normally attached ventrally.
Dimensions (µm, n=26): Min.(Mean)Max.
Length of the entire cyst: 61 (72) 82
Length of the epicyst: 12 (22) 40
Length of the hypocyst: 40 (59) 75
Equatorial width of the hypocyst (in lateral view): 60 (75) 94
Width of the antapical horn (at midpoint): 4 (7) 12.
The measured specimens are from a conventional core sample at 2066.02m in Magobu Island-1 well.
Comments: The description above is based on a single sample. Despite this limitation the general morphology is accurately covered with the single exception that in the other material the cyst wall may be slightly thicker (up to 1 µm). the shape of the hypocyst is somewhat variable. Some specimens are relatively wide, whereas other markedly elongate. In the Magobu Island-1 well specimens, the autophragm is thin and flimsy, however this species is surprisingly not especially susceptible to mechanical distortion. The development o and antapical horn is variable. Some individuals have a relatively distinct, short horn and others have subtriangular hypocyst which lack a well differentiated antapical protrusions. No accessory Archeopyle sutures have been observed o the epicyst.
Comparison: this distinctive species of Wanaea is characterized by its acavate organisation, the domes nature of the epicyst and its thin, smooth autophragm. Wanaea enoda differs from younger species of the genus by lacking a posterior paracingular flange. It is most similar to Wanaea lacuna sp. nov. in size, shape and autophragm morphology, however, W. enoda is acavate. It differs form other acingulate Wanaea species such as W. verrucosa sp. nov. and W. zoharensis in possessing a smooth autophragm. The lack of a paracingular crest and partial paratabulation together with a domed epicyst differentiates Wanaea enoda from W. acollaris.
Derivation of name: From the Latin enodis, meaning free of knots and referring to the lack of ornamentation on the autophragm.
Holotype and type locality: Fig. 2H, CPC 35848, from a conventional core sample in Magobu Island-1 well at 2066.02m
Statigraphical distribution: Wanaea enoda ranges from the Bathonian base of the Wanaea verrucosa Zone (7ciaiii) to the Callovian basal Wanaea digitate Zone (7bi) (figs 11, 12; Foster, this volume; Helby & Partridge, in prep.)