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Psaligonyaulax deflandrei
Psaligonyaulax deflandrei Sajeant, 1966; Emendation: Sarjeant, 1982b, p.45–46, as Psaligonyaulax deflandrei.
Originally (and now) Psaligonyaulax, subsequently Gonyaulacysta (combination illegitimate). Below, 1981 transferred this species to Gonyaulacysta Deflandre, 1964; however, the specific name Gonyaulacysta deflandrei (Sarjeant, 1966) Below, 1981 is an illegitimate name since it is a jr. homonym of Gonyaulacysta deflandrei Riley in Fisher and Riley, 1980. Lentin and Williams, 1981 retained this species in Psaligonyaulax.
Tax. sr. synonym of Gonyaulacysta extensa Clarke and Verdier, 1967, according to Clarke et al., 1968.
Holotype: Sarjeant, 1966, pl. 14, figs.7-8, text-fig. 35; Jan du Chene et al., 1986, pl.85, figs.3-4, pl. 86, figs. 1-3
Locus typicus: Fetchum Mill, Surrey, England
Stratum typicum: Cenomanian
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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.
Psaligonyaulax deflandrei Sarjeant, 1966b, emend. Sarjeant, 1982b. P.deflandrei has a spindle shaped pericyst truncated posteriorly and with the apex prolonged into a broad-based, narrow-tipped horn. Bicavate with epipericoel somewhat longer and larger than hypopericoel. Endocyst spheroidal to broadly ovoidal. Parasutures marked by raised crests, entire or serrate to irregularly to regularly denticulate distally. Paraplate 4' has a short boundary with 6". Surface of periphragm smooth to minutely granular, bearing an irregular scatter of tubercles. Archeopyle precingular, resulting from loss of 3". Sarjeant (1982b) emended the diagnosis to correct the paratabulation formula, supply more detail concerning the ventral paraplate pattern and the character of the crests, and stress the absence of an opisthopyle. Tabulation is 2a, 4', 6", 6c, 6"’, 1p, 1"”. Paraplate 4' contacts 6" and as. No opisthopyle. Size: overall length 72-82 µm, width 43-60 µm.
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Original diagnosis: Sarjeant, 1966, p. 137
A Psaligonyaulax having a spindle-shaped outline, truncated posteriorly, with ovoidal inner body. Apical pericoel surmounted by bifid horn, antapical pericoel flattened. Tabulation 4', 1a, 6", 6c, 6''', 1p, 1''''. Crests of moderate height with smooth or denticulate edges. Cingulum broad, strongly spiral: sulcus narrower but widening posteriorly. Surfaces of endophragm and periphragm smooth or only minutely granular: an irregular scatter of tubecles may be present on periphragm.
Dimensions: holotype: overall length 75 µm, breadth 44 µm; length of inner body 35 µm, breadth 40 µm. Range of dimensions: overall lengths 72 to 82 µm, breadths 43 to 60 µm.
Original description: Sarjeant, 1966, p.138
The apical horn is more or less conical, a bifid appearance being imparted by the apical junction of crests separating the four apical plates. Plate 1' is narrow and elongate, occupying the anterior prolongation of the sulcus; the anterior intercalary plate is also rather elongate. Six precingular and six postcingular plates are present: plate 1''' is very reduced and elongate. A posterior intercalary plate separates plates 1''' and 2''' from the single plate occupying the antapex.
The cingulum forms a laevorotatory spiral such that its two ends differ in antero-posterior position by three times its width: six cingular plates are present. The sulcus is constricted in its median portion, but widens considerably as it approaches the antapex.
The crests are in part smooth, in part denticulate: they are sometimes very finely perforate. A scatter of tubercles may be present, their number and distribution varying considerably between individuals.
Plate 3" is consistently lost in archaeopyle formation: its absence is not always obvious in unstained specimens, as a result of the delicacy and transparency of the shell.
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Emended diagnosis: Sarjeant 1982b p. 45-46
Proximate dinoflagellate cyst, spindle-shaped in ambitus but truncated posteriorly and with apex prolonged into a broad-based, narrow-tipped horn. Bicavate, with epipericoel longer and somewhat larger than the hypopericoel. Endoblast spheroidal to very broadly ovoidal. Parasutures marked by raised crests, entire or serrate to irregularly to regularly denticulate distally. Paratabulation 2a, 4', 6", 6c, 6"', lp, 1""; sulcus not subdivided into paraplates. Paraplate 4' is elongate, longer than 1' and having only a short boundary with 6"; the latter paraplate is almost triangular, with a convex right lateral and a straight to slightly concave left lateral boundary. Cingulum laevorotatory, its two ends differing in anteroposterior position by almost twice its width. The sulcus shows a slight narrowing and flexure between the two ends of the cingulum, then widens posteriorly to the antapex. Paraplate 1 "" is reduced and elongate; it and paraplate 2"' are separated from the antapex by paraplate 1 p. Surface of periphragm smooth to minutely granular, bearing an irregular scatter of tubercles. Paraplate 1"" is large and convex, unperforated by an opisthopyle. Archaeopyle single-plate precingular, formed by loss of paraplate 3".
Holotype: Sarjeant, 1966, p. 114: figs. 7-8, text-fig. 34; Sarjeant 1982b: pl. 11 figs. 1-3.
Locus typicus: Surrey, England
Stratum typicum: Late Cretaceous (Cenomanian)
DISCUSSION: The diagnosis is emended to correct the paratabulation formula, supply more detail concerning the ventral paraplate pattern and the character of the crests, and stress the absence of an opisthopyle. The stratigraphical range of this species is from the Early Cretaceous (Late Aptian) to early Late Cretaceous (Turonian). Its geographical range is intriguing; most records are from northwest Europe (England, France, Belgium and the Netherlands), whereas there is only one other Northern Hemisphere record, from the Scotian Shelf offshore from eastern Canada (Barss et al., 1979) and only one from the Southern Hemisphere, from New Zealand (Wilson, 1976). A palaeocurrent temperature control on its distribution may thus be hypothesized. The form placed into this species by Foucher (1975a) appears of such dissimilar morphology as to merit attribution to another genus (perhaps Triblastula?)
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Originally (and now) Psaligonyaulax, subsequently Gonyaulacysta (combination illegitimate). Below, 1981 transferred this species to Gonyaulacysta Deflandre, 1964; however, the specific name Gonyaulacysta deflandrei (Sarjeant, 1966) Below, 1981 is an illegitimate name since it is a jr. homonym of Gonyaulacysta deflandrei Riley in Fisher and Riley, 1980. Lentin and Williams, 1981 retained this species in Psaligonyaulax.
Tax. sr. synonym of Gonyaulacysta extensa Clarke and Verdier, 1967, according to Clarke et al., 1968.
Holotype: Sarjeant, 1966, pl. 14, figs.7-8, text-fig. 35; Jan du Chene et al., 1986, pl.85, figs.3-4, pl. 86, figs. 1-3
Locus typicus: Fetchum Mill, Surrey, England
Stratum typicum: Cenomanian
--------------------------------------------------
G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.
Psaligonyaulax deflandrei Sarjeant, 1966b, emend. Sarjeant, 1982b. P.deflandrei has a spindle shaped pericyst truncated posteriorly and with the apex prolonged into a broad-based, narrow-tipped horn. Bicavate with epipericoel somewhat longer and larger than hypopericoel. Endocyst spheroidal to broadly ovoidal. Parasutures marked by raised crests, entire or serrate to irregularly to regularly denticulate distally. Paraplate 4' has a short boundary with 6". Surface of periphragm smooth to minutely granular, bearing an irregular scatter of tubercles. Archeopyle precingular, resulting from loss of 3". Sarjeant (1982b) emended the diagnosis to correct the paratabulation formula, supply more detail concerning the ventral paraplate pattern and the character of the crests, and stress the absence of an opisthopyle. Tabulation is 2a, 4', 6", 6c, 6"’, 1p, 1"”. Paraplate 4' contacts 6" and as. No opisthopyle. Size: overall length 72-82 µm, width 43-60 µm.
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Original diagnosis: Sarjeant, 1966, p. 137
A Psaligonyaulax having a spindle-shaped outline, truncated posteriorly, with ovoidal inner body. Apical pericoel surmounted by bifid horn, antapical pericoel flattened. Tabulation 4', 1a, 6", 6c, 6''', 1p, 1''''. Crests of moderate height with smooth or denticulate edges. Cingulum broad, strongly spiral: sulcus narrower but widening posteriorly. Surfaces of endophragm and periphragm smooth or only minutely granular: an irregular scatter of tubecles may be present on periphragm.
Dimensions: holotype: overall length 75 µm, breadth 44 µm; length of inner body 35 µm, breadth 40 µm. Range of dimensions: overall lengths 72 to 82 µm, breadths 43 to 60 µm.
Original description: Sarjeant, 1966, p.138
The apical horn is more or less conical, a bifid appearance being imparted by the apical junction of crests separating the four apical plates. Plate 1' is narrow and elongate, occupying the anterior prolongation of the sulcus; the anterior intercalary plate is also rather elongate. Six precingular and six postcingular plates are present: plate 1''' is very reduced and elongate. A posterior intercalary plate separates plates 1''' and 2''' from the single plate occupying the antapex.
The cingulum forms a laevorotatory spiral such that its two ends differ in antero-posterior position by three times its width: six cingular plates are present. The sulcus is constricted in its median portion, but widens considerably as it approaches the antapex.
The crests are in part smooth, in part denticulate: they are sometimes very finely perforate. A scatter of tubercles may be present, their number and distribution varying considerably between individuals.
Plate 3" is consistently lost in archaeopyle formation: its absence is not always obvious in unstained specimens, as a result of the delicacy and transparency of the shell.
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Emended diagnosis: Sarjeant 1982b p. 45-46
Proximate dinoflagellate cyst, spindle-shaped in ambitus but truncated posteriorly and with apex prolonged into a broad-based, narrow-tipped horn. Bicavate, with epipericoel longer and somewhat larger than the hypopericoel. Endoblast spheroidal to very broadly ovoidal. Parasutures marked by raised crests, entire or serrate to irregularly to regularly denticulate distally. Paratabulation 2a, 4', 6", 6c, 6"', lp, 1""; sulcus not subdivided into paraplates. Paraplate 4' is elongate, longer than 1' and having only a short boundary with 6"; the latter paraplate is almost triangular, with a convex right lateral and a straight to slightly concave left lateral boundary. Cingulum laevorotatory, its two ends differing in anteroposterior position by almost twice its width. The sulcus shows a slight narrowing and flexure between the two ends of the cingulum, then widens posteriorly to the antapex. Paraplate 1 "" is reduced and elongate; it and paraplate 2"' are separated from the antapex by paraplate 1 p. Surface of periphragm smooth to minutely granular, bearing an irregular scatter of tubercles. Paraplate 1"" is large and convex, unperforated by an opisthopyle. Archaeopyle single-plate precingular, formed by loss of paraplate 3".
Holotype: Sarjeant, 1966, p. 114: figs. 7-8, text-fig. 34; Sarjeant 1982b: pl. 11 figs. 1-3.
Locus typicus: Surrey, England
Stratum typicum: Late Cretaceous (Cenomanian)
DISCUSSION: The diagnosis is emended to correct the paratabulation formula, supply more detail concerning the ventral paraplate pattern and the character of the crests, and stress the absence of an opisthopyle. The stratigraphical range of this species is from the Early Cretaceous (Late Aptian) to early Late Cretaceous (Turonian). Its geographical range is intriguing; most records are from northwest Europe (England, France, Belgium and the Netherlands), whereas there is only one other Northern Hemisphere record, from the Scotian Shelf offshore from eastern Canada (Barss et al., 1979) and only one from the Southern Hemisphere, from New Zealand (Wilson, 1976). A palaeocurrent temperature control on its distribution may thus be hypothesized. The form placed into this species by Foucher (1975a) appears of such dissimilar morphology as to merit attribution to another genus (perhaps Triblastula?)
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