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Energlynia kyrbasia
Energtynia kyrbasia "*kyrbasia" Sarjeant, 1976b, p.166,168,170,172, figs.1-16. Holotype: Sarjeant, 1976b, figs.1,6-7. Taxonomic senior synonym: Wanaea (subsequently Energlynia) acollaris, according to Fenton and Fisher (1978, p.236). The nomenclatural type of the genus Energlynia remains the holotype of Energlynia kyrbasia. Age: Late Bathonian.
Original diagnosis: Sarjeant, 1976, p. 166
A species of Energlynia having a broadly ovoidal cyst, somewhat flattened ventrally, with the epitract low-arched and markedly smaller than the high-arched hypotract. A poorly marked apical horn may be developed, short and rounded; the antapical horn is, in contrast, much larger and more conspicuous, seen to be asymmetric in position when the hypotract is in lateral view. The antapical horn may be prolonged by a spine, which may or may not show distal branching. Tabulation poorly marked by faint lines on the surface or by rows of short spinelets, which may show distal linkage (especially on the borders of the cingulum) or may lack such linkage; alternatively, there may be no indication of the tabulation. Surface typically laevigate, rarely with an irregular scatter of coarse granules or very short spinelets or with an infrareticulate patterning.
Original description: Sarjeant, 1976, p. 168, 170, 172
This species is a relatively abundant component of the assemblage examined. In almost all cases, the specimens observed consisted of a hypotract, with or without the associated or attached remains of an epitract; only one complete cyst was seen. The hypotract is not only markedly longer (about 50¦/o longer) than the epitract but also appears slightly thicker-walled; the antapical horn is so marked a feature that, from parallels with other Jurassic genera with pronounced apical horns, the hemicysts were taken to be epitracts until a close study of archaeopyle formation and tabulation vestiges proved otherwise. A further, initially misleading feature was the presence of a spine at the horn tip, suggesting comparisons with the apical horn of the genus Imbatodinium Vozzhennikova, 1967; no similar "horn extensions" on antapical horns have hitherto been reported.
Sutures between plate-areas are marked by lines of spinelets, by low ridges, or not at all; the tabulation is thus at best inconspicuous and in no case has it proved possible for me to determine all the plate-areas of even a half-shell with complete confidence. The tabulation here presented was worked out from study of many specimens. It is in part illustrated by Figs. 1--5; but I am unwilling as yet to reconstruct the tabulation of a complete cyst, since several points of uncertainty remain (see discussion, below). Special difficulties result from the facts that the hypotract is usually encountered in exact or oblique lateral view, and that the epitract (where present at all) is most often incomplete, folded or torn and has quite often partially or wholly slipped inside the hypotract (see for example Figs. 5, 9,13,16).
The epitract has the form of a low dome, distinctly lower-arched than a hemisphere. An apical horn appears to be usually present but may not always be developed; it is rather broad and short and can only be seen clearly in exceptionally favourable specimens (such as Paratype III, Figs. 2, 14). The apical plate-areas are all small. The first (1") is elongate and situated in the anterior prolongation of the sulcus; the character, and even the number, of the other apical plate-areas could not be determined. A small intercalary plate-area (1 a) is present on the dorsal surface; a rather larger intercalary plate-area (2 a) is present to the right of the sulcus, between the apical series and plate-area 6", causing a reduction in the size of the latter. The precingular plate-areas are otherwise of comparable size; they are progressively lost in archaeopyle formation, plate-area 3" apparently being lost first. Archaeopyle formation is completed by ventral severance of the remaining plates, at or about midventral position. This does not always take place, however; many specimens were encountered in which the whole (or, more usually, a part) of the epitract remains attached.
The cingulum forms part of the hypotractal hemicyst; it may be bordered by relatively long spinelets which may exhibit distal linkage. Though boundaries traversing the cingulum could regularly be detected, marginal folding (particularly in specimens where a portion of the epitract remained attached to the hypotract) meant that the number of cingular plate-areas could not be established with any certainty. Because of the widely gaping opening, the hemicysts were very often compressed towards the position of the cingulum, exaggerating their apparent breadth.
The hypotract is consistently high-domed; specimens seen in lateral view may have almost the profile of a truncated cone, but more often they appear as hemi-ovoids. The antapical horn is consistently conspicuous, rather nipple-like and rounded distally. In dorsoventral view it appears centrally situated; in lateral view, however, it is seen to be offset towards the ventral side and typically sloping in that direction. In some specimens (one-fifth to one-quarter of those observed), a spine arises from its tip; this may be short or moderately long, simple or capitate. Whether such a spine was always developed but has usually been broken off subsequently, or whether it was not consistently developed, is hard to say; certainly several of the specimens seen afforded no vestige of an indication of the former presence of such a spine.
Six postcingular plate-areas are developed; plate-area 1""" is reduced to accommodate a moderately large posterior intercalary plate-area. Although crests traversing the antapical horn were frequently observed, in no case was I able to determine the tabulation on both sides of the horn with any certainty; but at least two antapical plate-areas, possibly three, were present. The sulcus is quite narrow and apparently extends from apex to antapex; it is indicated not just by the bordering sutures, but also by a slight inflexure of the surface of the cyst.
Dimensions: Holotype: epitract c. 53 Ám in diameter, hypotract length 49 Ám overall, breadth c. 63 Ám, length of antapical horn 6 Ám. Paratype l: length 52 Ám (epitract 18 Ám, hypotract 34 Ám, length of antapical horn c. 4 Ám), breadth 50 Ám. Paratype Il: length of hypotract 35 Ám overall, breadth 40 Ám, length of antapical horn 5.5 Ám (epitract not measurable). Paratype III: length of hypotract 49 Ám overall, breadth 52 Ám, length of antapical horn 6 Ám, length of antapical spine c. 5 Ám (epitract not measurable). Paratype IV (slightly oblique): overall length c. 70 Ám (epitract c. 16 Ám, hypotract c. 52 Ám, apical horn c. 2 Ám, antapical horn c. 6 Ám), breadth 51 Ám. Range of dimensions of hypotracts; overall length 34--59 Ám (mean 44 Ám), breadth 35--70 Ám (mean 55.5 Ám), length of antapical horn 3.5--7 Ám (mean 5 Ám), length of antapical spine (where present) 1--5 Ám (mean 2.5 Ám). Number of specimens measured: 24.
Original diagnosis: Sarjeant, 1976, p. 166
A species of Energlynia having a broadly ovoidal cyst, somewhat flattened ventrally, with the epitract low-arched and markedly smaller than the high-arched hypotract. A poorly marked apical horn may be developed, short and rounded; the antapical horn is, in contrast, much larger and more conspicuous, seen to be asymmetric in position when the hypotract is in lateral view. The antapical horn may be prolonged by a spine, which may or may not show distal branching. Tabulation poorly marked by faint lines on the surface or by rows of short spinelets, which may show distal linkage (especially on the borders of the cingulum) or may lack such linkage; alternatively, there may be no indication of the tabulation. Surface typically laevigate, rarely with an irregular scatter of coarse granules or very short spinelets or with an infrareticulate patterning.
Original description: Sarjeant, 1976, p. 168, 170, 172
This species is a relatively abundant component of the assemblage examined. In almost all cases, the specimens observed consisted of a hypotract, with or without the associated or attached remains of an epitract; only one complete cyst was seen. The hypotract is not only markedly longer (about 50¦/o longer) than the epitract but also appears slightly thicker-walled; the antapical horn is so marked a feature that, from parallels with other Jurassic genera with pronounced apical horns, the hemicysts were taken to be epitracts until a close study of archaeopyle formation and tabulation vestiges proved otherwise. A further, initially misleading feature was the presence of a spine at the horn tip, suggesting comparisons with the apical horn of the genus Imbatodinium Vozzhennikova, 1967; no similar "horn extensions" on antapical horns have hitherto been reported.
Sutures between plate-areas are marked by lines of spinelets, by low ridges, or not at all; the tabulation is thus at best inconspicuous and in no case has it proved possible for me to determine all the plate-areas of even a half-shell with complete confidence. The tabulation here presented was worked out from study of many specimens. It is in part illustrated by Figs. 1--5; but I am unwilling as yet to reconstruct the tabulation of a complete cyst, since several points of uncertainty remain (see discussion, below). Special difficulties result from the facts that the hypotract is usually encountered in exact or oblique lateral view, and that the epitract (where present at all) is most often incomplete, folded or torn and has quite often partially or wholly slipped inside the hypotract (see for example Figs. 5, 9,13,16).
The epitract has the form of a low dome, distinctly lower-arched than a hemisphere. An apical horn appears to be usually present but may not always be developed; it is rather broad and short and can only be seen clearly in exceptionally favourable specimens (such as Paratype III, Figs. 2, 14). The apical plate-areas are all small. The first (1") is elongate and situated in the anterior prolongation of the sulcus; the character, and even the number, of the other apical plate-areas could not be determined. A small intercalary plate-area (1 a) is present on the dorsal surface; a rather larger intercalary plate-area (2 a) is present to the right of the sulcus, between the apical series and plate-area 6", causing a reduction in the size of the latter. The precingular plate-areas are otherwise of comparable size; they are progressively lost in archaeopyle formation, plate-area 3" apparently being lost first. Archaeopyle formation is completed by ventral severance of the remaining plates, at or about midventral position. This does not always take place, however; many specimens were encountered in which the whole (or, more usually, a part) of the epitract remains attached.
The cingulum forms part of the hypotractal hemicyst; it may be bordered by relatively long spinelets which may exhibit distal linkage. Though boundaries traversing the cingulum could regularly be detected, marginal folding (particularly in specimens where a portion of the epitract remained attached to the hypotract) meant that the number of cingular plate-areas could not be established with any certainty. Because of the widely gaping opening, the hemicysts were very often compressed towards the position of the cingulum, exaggerating their apparent breadth.
The hypotract is consistently high-domed; specimens seen in lateral view may have almost the profile of a truncated cone, but more often they appear as hemi-ovoids. The antapical horn is consistently conspicuous, rather nipple-like and rounded distally. In dorsoventral view it appears centrally situated; in lateral view, however, it is seen to be offset towards the ventral side and typically sloping in that direction. In some specimens (one-fifth to one-quarter of those observed), a spine arises from its tip; this may be short or moderately long, simple or capitate. Whether such a spine was always developed but has usually been broken off subsequently, or whether it was not consistently developed, is hard to say; certainly several of the specimens seen afforded no vestige of an indication of the former presence of such a spine.
Six postcingular plate-areas are developed; plate-area 1""" is reduced to accommodate a moderately large posterior intercalary plate-area. Although crests traversing the antapical horn were frequently observed, in no case was I able to determine the tabulation on both sides of the horn with any certainty; but at least two antapical plate-areas, possibly three, were present. The sulcus is quite narrow and apparently extends from apex to antapex; it is indicated not just by the bordering sutures, but also by a slight inflexure of the surface of the cyst.
Dimensions: Holotype: epitract c. 53 Ám in diameter, hypotract length 49 Ám overall, breadth c. 63 Ám, length of antapical horn 6 Ám. Paratype l: length 52 Ám (epitract 18 Ám, hypotract 34 Ám, length of antapical horn c. 4 Ám), breadth 50 Ám. Paratype Il: length of hypotract 35 Ám overall, breadth 40 Ám, length of antapical horn 5.5 Ám (epitract not measurable). Paratype III: length of hypotract 49 Ám overall, breadth 52 Ám, length of antapical horn 6 Ám, length of antapical spine c. 5 Ám (epitract not measurable). Paratype IV (slightly oblique): overall length c. 70 Ám (epitract c. 16 Ám, hypotract c. 52 Ám, apical horn c. 2 Ám, antapical horn c. 6 Ám), breadth 51 Ám. Range of dimensions of hypotracts; overall length 34--59 Ám (mean 44 Ám), breadth 35--70 Ám (mean 55.5 Ám), length of antapical horn 3.5--7 Ám (mean 5 Ám), length of antapical spine (where present) 1--5 Ám (mean 2.5 Ám). Number of specimens measured: 24.