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Evittia
From Williams et al., 2017:
[Evittia, Brito, 1967, p. 477; Emendations: Lister, 1970, p. 66–67; Eiserhardt, 1992, p. 24; Sarjeant and Vavrdova, 1997, p. 20.
Acritarch genus.
For synonymy see Fensome et al., 1990.
Type species: Evittia sommeri, Brito, 1967 (pl.1, fig.9)]
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Original description: [Brito, 1967, p. 477]:
Genus Evittia Brito, new genus
Evittia BRITO, 1966, p. 78 (nomen nudum).
Diagnosis: Acritarchs with triangular to polygonal vesicles having the general structure of Veryhachium but with the processes typically ramified, although some of the processes on a specimen may have simple tips.
Comparison: In general appearance, this new genus most closely resembles Veryhachium and Wilsonastrum, but differs from both in having ramified processes. These digitiform ramifications may be regular or irregular. Evittia does not have the bristle-like projection characteristic of Wilsonastrum.
Type of the genus: Evittia sommeri Brito, n. sp.
Other species referred to the genus: The following species, all formerly placed in Veryhachium, are here reattributed to Evittia:
V. asturiae Cramer, 1964
V. josefae Cramer, 1964
V. rabiosum Cramer, 1964
V. sartbernardense Martin, 1966
V. thyrae Cramer, 1964
V. tolontolum Cramer, 1964
V. torrestionense Cramer, 1964
V. trispinoramosum Stockmans and Willibre, 1962
It is at present uncertain whether ? V. cazurrum Cramer, 1965, belongs here.
Derivation of name: This new genus is dedicated to Professor W. R. Evitt of Stanford University.
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Emended diagnosis: [Lister, 1970, ex Sarjeant and Vavrdova, 1997]:
"Vesicle hollow, subspherical to polygonal, single-walled; vesicle wall may be smooth or sculptured; processes are heteromorphic, hollow, invariably granulate to echinate, communicating with the vesicle cavity. Excystment by cryptosuture, apical or near equatorial."
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Emended diagnosis: [Sarjeant and Vavrdova, 1997, p. 20]:
Vesicle hollow, subpolygonal to polygonal; eilyma single-layered or apparently so. Surface of eilyma laevigate, granulate to echinate. Number of processes low (ca. 4-12), their broad bases modifying but not controlling the vesicle outline. Processes always broad and short, dividing distally into a low number of rather blunt branches, sometimes secondarily branched but not showing ramification. The processes are hollow, their cavities communicating directly with the vesicle cavity. Excystment by cryptosuture, apical or near equatorial.
Remarks: As initially defined, Evittia embraced triangular forms with branching processes. Following the revision of the genus Frankea by Servais 1993 and of the Veryhachium group by Sarjeant and Stancliffe 1994, such species are now referred to Frankea, two further transfers to that genus being made herein. Evittia differs from the members of the Veryhachium and Pulvinosphaeridium groups in the form and number of its processes, their brevity and the fact that they do not modify the vesicle outline.
Evittia differs from Vogtlandia in having a vesicle whose outline may be modified, but is not determined, by the shape of the processes and in having processes whose distal extremities branch or ramify less elaborately. This genus differs from Multiplicisphaeridium in that the processes show essentially one order of branching and from Martinsphaeridium and Ammonidium in the much lower number and greater thickness of the processes. It differs from Tylotopalla in the lesser number of the processes and in the fact that the vesicle is not essentially spheroidal.
[Evittia, Brito, 1967, p. 477; Emendations: Lister, 1970, p. 66–67; Eiserhardt, 1992, p. 24; Sarjeant and Vavrdova, 1997, p. 20.
Acritarch genus.
For synonymy see Fensome et al., 1990.
Type species: Evittia sommeri, Brito, 1967 (pl.1, fig.9)]
------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original description: [Brito, 1967, p. 477]:
Genus Evittia Brito, new genus
Evittia BRITO, 1966, p. 78 (nomen nudum).
Diagnosis: Acritarchs with triangular to polygonal vesicles having the general structure of Veryhachium but with the processes typically ramified, although some of the processes on a specimen may have simple tips.
Comparison: In general appearance, this new genus most closely resembles Veryhachium and Wilsonastrum, but differs from both in having ramified processes. These digitiform ramifications may be regular or irregular. Evittia does not have the bristle-like projection characteristic of Wilsonastrum.
Type of the genus: Evittia sommeri Brito, n. sp.
Other species referred to the genus: The following species, all formerly placed in Veryhachium, are here reattributed to Evittia:
V. asturiae Cramer, 1964
V. josefae Cramer, 1964
V. rabiosum Cramer, 1964
V. sartbernardense Martin, 1966
V. thyrae Cramer, 1964
V. tolontolum Cramer, 1964
V. torrestionense Cramer, 1964
V. trispinoramosum Stockmans and Willibre, 1962
It is at present uncertain whether ? V. cazurrum Cramer, 1965, belongs here.
Derivation of name: This new genus is dedicated to Professor W. R. Evitt of Stanford University.
------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Emended diagnosis: [Lister, 1970, ex Sarjeant and Vavrdova, 1997]:
"Vesicle hollow, subspherical to polygonal, single-walled; vesicle wall may be smooth or sculptured; processes are heteromorphic, hollow, invariably granulate to echinate, communicating with the vesicle cavity. Excystment by cryptosuture, apical or near equatorial."
------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Emended diagnosis: [Sarjeant and Vavrdova, 1997, p. 20]:
Vesicle hollow, subpolygonal to polygonal; eilyma single-layered or apparently so. Surface of eilyma laevigate, granulate to echinate. Number of processes low (ca. 4-12), their broad bases modifying but not controlling the vesicle outline. Processes always broad and short, dividing distally into a low number of rather blunt branches, sometimes secondarily branched but not showing ramification. The processes are hollow, their cavities communicating directly with the vesicle cavity. Excystment by cryptosuture, apical or near equatorial.
Remarks: As initially defined, Evittia embraced triangular forms with branching processes. Following the revision of the genus Frankea by Servais 1993 and of the Veryhachium group by Sarjeant and Stancliffe 1994, such species are now referred to Frankea, two further transfers to that genus being made herein. Evittia differs from the members of the Veryhachium and Pulvinosphaeridium groups in the form and number of its processes, their brevity and the fact that they do not modify the vesicle outline.
Evittia differs from Vogtlandia in having a vesicle whose outline may be modified, but is not determined, by the shape of the processes and in having processes whose distal extremities branch or ramify less elaborately. This genus differs from Multiplicisphaeridium in that the processes show essentially one order of branching and from Martinsphaeridium and Ammonidium in the much lower number and greater thickness of the processes. It differs from Tylotopalla in the lesser number of the processes and in the fact that the vesicle is not essentially spheroidal.