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Thalassiphora balcanica
From Fensome et al., 2019:
Thalassiphora balcanica Balteş, 1971, p.6, pl.3, figs.3–7.
Emendation: Mudie et al., 2019, VRp.17,19–21.
Holotype: Balteş, 1971, pl.3, figs.3–7 (lost according to Mudie et al., 2019, VRp.17).
Neotype: Mudie et al., pl.4, figs.1–13, designated by Mudie et al, VRp.19.
Originally (and now) Thalassiphora, subsequently Disphaeria, thirdly Subathua (combination not validly published), fourthly Spiniferites. Taxonomic senior synonym: Pterospermopsis (as and now Thalassiphora) pelagica, according to Stover and Evitt (1978, p.194) — however, Sütő-Szentai (2000, p.162) retained Thalassiphora (as Spiniferites) balcanica.
Williams et al. (2017, p.809) retained this species in Thalassiphora as its morphology clearly accords with that genus rather than with Spiniferites. Age: Early Pliocene.
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Emended diagnosis: Mudie, P. J. et al., 2019:
A large camocavate,“winged” (pterate) species of Thalassiphora resembling Thalassiphora subreticulata as seen in lateral view but with an irregularly perforate
periphragm that may include a few large claustra and is narrower in the apical area, giving it a notched appearance. The periphragm has rod-like thickenings in the apical area and folds in the hypocystal area, the latter being expanded, appearing sub-rectangular in dorso-ventral view and box-shaped in SEM images. The periphragm surrounds one-third or more of the ventral endocyst surface and has open perforations that are not crossed by microfibrils. The endocyst is ovoid to sub-rhomboidal with a microreticulate to smooth endophragm.
Emended description: Mudie, P. J. et al., 2019:
Shape: The pericyst outline is irregularly rounded to polygonal in lateral view and suboval to subrectangular in dorso-ventral view; it envelops a darker, centrally located endocyst that is ovoid to subrhomboidal and usually has a diameter about 50 percent that of the pericyst. The ventral pericyst opening exposes about half to one-third of the ventral surface; this opening is difficult to see in LM images, but is clearly visible using SEM. In lateral view, which is the most common cyst orientation, the pericyst may appear bilaterally wing-like, with a low boss at the apex, giving the anterior pericyst area a notched appearance that is emphasised by short rod-like folds or thickenings in the dorso-apical area. In dorso-ventral view, the pericyst appears notably asymmetrical, being reduced in the apical area and expanded into a flaring or a sub-rectangular, partly enclosed antapical structure.
Wall structure: The periphragm is attached dorso-laterally and is thin, fibrous, quasi-reticulate, and irregularly perforate, with openings variable in size, sometimes including a few large epicystal and hypocystal claustra. There may be low sutural ridges on the periphragm dorsally and equatorially. In lateral view, many periphragm perforations tend to be elongate and increase in size away from the endocyst attachment area. In ventral view, the wide, inrolled periphragm margin displays broad, narrow openings that are oriented parallel to the ventral opening. Between perforations, the periphragm is microreticulate, but the margins of the perforations are smooth, sometimes slightly raised and are not crossed by fibrils. The endophragm is relatively thin (about 3 μm), with a typically microreticulate but occasionally microgranular surface. Some SEM images show that the endophragm texture may also be fibrillar.
Archeopyle: The camerate P3” archeopyle is notably reduced, with its margins in penitabular position. The archeopyle may be closed, but is usually
open; the operculum lacks a spine.
Tabulation: Paratabulation is difficult to discern because of its variable expression in Thalassiphora balcanica; for example, on the endocyst, the cingulum may either be clearly marked by low septa and wart-like ornament or it is barely discernable in some LM or SEM images. The ventral endocyst surface apparently lacks any trace of tabulation. When present, low ridges, sometimes flanked by occasional verrucae may mark cingular plate boundaries, presumably 2/3c, 3/4c, and 4/5c; other verrucae may be present on dorsal and lateral surfaces but are absent on the ventral surface. In dorsal or lateral view, the narrow, shallow cingulum clearly extends onto the
periphragm as a band lacking perforations, and SEM images may show other linear, non-perforate areas of the periphragm but in contrast to the interpretation of Sütoné
Szentai (2004), they are neither consistently expressed nor clearly related to tabulation, and more high-resolution SEM studies are needed to interpret the hints of cingular and epicystal paratabulation on the periphragm. In dorso-lateral view, low ridges also persistently delineate plates *4”’ and *1””, and membranous projections, folds or low ridges may mark the intersection of the *3”’/*4”’ and *4”’/*5”’ boundaries with *1””. Some SEM images of Thalassiphora balcanica, suggest the presence of a
mid-dorsal *4”’/*5”’ suture, but two rotated LM images of the neotype appear to suggest neutral torsion. In the apical area, LM images often appear to show two periphragm “wings” that are supported by folds or projections on the ventro-lateral sides of a small apical boss, most likely at the junctions of plates 2’ and 2” and 3’and 4”. In dorsal view, a third short apical projection suggests reflection of four apical plates. SEM images, however, show that the boss can be low or absent and that the periphragm extends continuously over the ventro-apical area, with short membranous septa or sutural ridges marking the dorsal apical area, and P1’ may be faintly traced on the periphragm. The high-resolution SEM images clearly show that the apical features previously interpreted as solid trifurcate processes (Sütó-Szentai 2000; Sütoné Szentai 2004) are simple short, membranous septa with blunt or crenulated tips.
Dimensions: Mudie, P. J. et al., 2019:
Balteş’s (1971) Romanian material: total cyst length 120−130 μm; endocyst = 90−100 μm, archeopyle = 35−45 μm. In Hungarian samples, total length has been reported as 80−110 μm, with the length of the inner body being 80 to 90 μm (e.g. Sütő 1994 pl. VI, fig. 1).
In northern Croatian samples, endocyst length = 51.8 (67.3) 82.2 μm; total cyst length = 69.3 (92.8) 115.1 μm for 30 specimens. It is likely that the slightly smaller sizes reported here for some Croatian cysts are because silicone oil was used as a mounting medium rather than glycerine which causes some swelling, hence enlargement (Cushing, 2011)
Affinities: Mudie, P. J. et al., 2019:
Thalassiphora balcanica differs from Galeacysta etrusca in being larger, without prominent dorsal tabulation and in having few or no very large periphragm openings (claustra). Thalassiphora balcanica also has reduced apical wing-development that gives the periphragm a notched rather than inflated helmet-shaped appearance. Lophocysta and Pterocysta have a prominent periphragm crest with parasutural ribs and openings that indicate paratabulation and cover only the middle part of the
ventral area (the part that is typically open in Thalassiphora). Lophocysta also has small gonal processes.
Thalassiphora balcanica Balteş, 1971, p.6, pl.3, figs.3–7.
Emendation: Mudie et al., 2019, VRp.17,19–21.
Holotype: Balteş, 1971, pl.3, figs.3–7 (lost according to Mudie et al., 2019, VRp.17).
Neotype: Mudie et al., pl.4, figs.1–13, designated by Mudie et al, VRp.19.
Originally (and now) Thalassiphora, subsequently Disphaeria, thirdly Subathua (combination not validly published), fourthly Spiniferites. Taxonomic senior synonym: Pterospermopsis (as and now Thalassiphora) pelagica, according to Stover and Evitt (1978, p.194) — however, Sütő-Szentai (2000, p.162) retained Thalassiphora (as Spiniferites) balcanica.
Williams et al. (2017, p.809) retained this species in Thalassiphora as its morphology clearly accords with that genus rather than with Spiniferites. Age: Early Pliocene.
---------------------------------------------------------------------------------------------------
Emended diagnosis: Mudie, P. J. et al., 2019:
A large camocavate,“winged” (pterate) species of Thalassiphora resembling Thalassiphora subreticulata as seen in lateral view but with an irregularly perforate
periphragm that may include a few large claustra and is narrower in the apical area, giving it a notched appearance. The periphragm has rod-like thickenings in the apical area and folds in the hypocystal area, the latter being expanded, appearing sub-rectangular in dorso-ventral view and box-shaped in SEM images. The periphragm surrounds one-third or more of the ventral endocyst surface and has open perforations that are not crossed by microfibrils. The endocyst is ovoid to sub-rhomboidal with a microreticulate to smooth endophragm.
Emended description: Mudie, P. J. et al., 2019:
Shape: The pericyst outline is irregularly rounded to polygonal in lateral view and suboval to subrectangular in dorso-ventral view; it envelops a darker, centrally located endocyst that is ovoid to subrhomboidal and usually has a diameter about 50 percent that of the pericyst. The ventral pericyst opening exposes about half to one-third of the ventral surface; this opening is difficult to see in LM images, but is clearly visible using SEM. In lateral view, which is the most common cyst orientation, the pericyst may appear bilaterally wing-like, with a low boss at the apex, giving the anterior pericyst area a notched appearance that is emphasised by short rod-like folds or thickenings in the dorso-apical area. In dorso-ventral view, the pericyst appears notably asymmetrical, being reduced in the apical area and expanded into a flaring or a sub-rectangular, partly enclosed antapical structure.
Wall structure: The periphragm is attached dorso-laterally and is thin, fibrous, quasi-reticulate, and irregularly perforate, with openings variable in size, sometimes including a few large epicystal and hypocystal claustra. There may be low sutural ridges on the periphragm dorsally and equatorially. In lateral view, many periphragm perforations tend to be elongate and increase in size away from the endocyst attachment area. In ventral view, the wide, inrolled periphragm margin displays broad, narrow openings that are oriented parallel to the ventral opening. Between perforations, the periphragm is microreticulate, but the margins of the perforations are smooth, sometimes slightly raised and are not crossed by fibrils. The endophragm is relatively thin (about 3 μm), with a typically microreticulate but occasionally microgranular surface. Some SEM images show that the endophragm texture may also be fibrillar.
Archeopyle: The camerate P3” archeopyle is notably reduced, with its margins in penitabular position. The archeopyle may be closed, but is usually
open; the operculum lacks a spine.
Tabulation: Paratabulation is difficult to discern because of its variable expression in Thalassiphora balcanica; for example, on the endocyst, the cingulum may either be clearly marked by low septa and wart-like ornament or it is barely discernable in some LM or SEM images. The ventral endocyst surface apparently lacks any trace of tabulation. When present, low ridges, sometimes flanked by occasional verrucae may mark cingular plate boundaries, presumably 2/3c, 3/4c, and 4/5c; other verrucae may be present on dorsal and lateral surfaces but are absent on the ventral surface. In dorsal or lateral view, the narrow, shallow cingulum clearly extends onto the
periphragm as a band lacking perforations, and SEM images may show other linear, non-perforate areas of the periphragm but in contrast to the interpretation of Sütoné
Szentai (2004), they are neither consistently expressed nor clearly related to tabulation, and more high-resolution SEM studies are needed to interpret the hints of cingular and epicystal paratabulation on the periphragm. In dorso-lateral view, low ridges also persistently delineate plates *4”’ and *1””, and membranous projections, folds or low ridges may mark the intersection of the *3”’/*4”’ and *4”’/*5”’ boundaries with *1””. Some SEM images of Thalassiphora balcanica, suggest the presence of a
mid-dorsal *4”’/*5”’ suture, but two rotated LM images of the neotype appear to suggest neutral torsion. In the apical area, LM images often appear to show two periphragm “wings” that are supported by folds or projections on the ventro-lateral sides of a small apical boss, most likely at the junctions of plates 2’ and 2” and 3’and 4”. In dorsal view, a third short apical projection suggests reflection of four apical plates. SEM images, however, show that the boss can be low or absent and that the periphragm extends continuously over the ventro-apical area, with short membranous septa or sutural ridges marking the dorsal apical area, and P1’ may be faintly traced on the periphragm. The high-resolution SEM images clearly show that the apical features previously interpreted as solid trifurcate processes (Sütó-Szentai 2000; Sütoné Szentai 2004) are simple short, membranous septa with blunt or crenulated tips.
Dimensions: Mudie, P. J. et al., 2019:
Balteş’s (1971) Romanian material: total cyst length 120−130 μm; endocyst = 90−100 μm, archeopyle = 35−45 μm. In Hungarian samples, total length has been reported as 80−110 μm, with the length of the inner body being 80 to 90 μm (e.g. Sütő 1994 pl. VI, fig. 1).
In northern Croatian samples, endocyst length = 51.8 (67.3) 82.2 μm; total cyst length = 69.3 (92.8) 115.1 μm for 30 specimens. It is likely that the slightly smaller sizes reported here for some Croatian cysts are because silicone oil was used as a mounting medium rather than glycerine which causes some swelling, hence enlargement (Cushing, 2011)
Affinities: Mudie, P. J. et al., 2019:
Thalassiphora balcanica differs from Galeacysta etrusca in being larger, without prominent dorsal tabulation and in having few or no very large periphragm openings (claustra). Thalassiphora balcanica also has reduced apical wing-development that gives the periphragm a notched rather than inflated helmet-shaped appearance. Lophocysta and Pterocysta have a prominent periphragm crest with parasutural ribs and openings that indicate paratabulation and cover only the middle part of the
ventral area (the part that is typically open in Thalassiphora). Lophocysta also has small gonal processes.