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Turbiosphaera sarrisii
From Fensome et al., 2019:
Turbiosphaera sarrisii (Archangelsky, 1969a, p.411, pl.2, figs.5–7) Fensome et al., 2019a, p.55.
Holotype: Archangelsky, 1969a, pl.2, figs.6–7; Fensome et al., 2019a, figs.20E–F.
Originally Polystephanephorus?, subsequently Senoniasphaera?, thirdly (and now) Turbiosphaera.
Questionable assignment: Fensome et al. (2019a. p.55).
Age: Eocene.
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Original description: [Archangelsky, 1969a] (translated from Spanish):
Polystephanephorus (?) sarrisii n. sp.
Pl. II, figs. 5, 6, 7
DIAGNOSIS. Subspherical to oval body, composed of an inner membrane (1.5 μ) thicker than the outer membrane; outer membrane giving rise to membranous processes, frequently tubuliform, generally perforated, which narrow towards the apex or are typically cylindrical. Number of processes: about 12; processes of variable width, but all of similar length; processes sometimes united by very delicate distal trabeculae, generally laminar. Apical archeopyle.
HOLOTYPE: microscope slide no. 709, coordinates 30.2/100.3.
MEASUREMENTS: body length: 43 μ; width of body: 40 μ; archeopyle: 23 μ; processes: 14 μ
DISTRIBUTION: Río Turbio Formation, D-15, level 687-689 m. Eocene.
OTHER MEASUREMENTS (specimens from the same provenance): body length: 43-61 μ (15 ex.); body width: 34-51 μ (15 ex.); archeopyle: 22-36 μ (10 ex.); length of processes: 10-17 μ.
DISCUSSION AND COMPARISONS. This curious species appears to be restricted exclusively to a single level, in well D-15; the frequency of the material allows its diagnosis with relative ease. More problematic, however, is the generic assignment. Indeed, the species most similar to ours is undoubtedly Cannosphaeropsis urnaformis Cookson (1953) and Deflandre and Cookson (1955), from the Tertiary of Australia. It was transferred to the genus Polystephanephorus by Sarjeant (1961), who typified it with a Jurassic species from Europe, P. calathus. According to the genus definition, the tubular processes are formed by the union of individual processes that meet distally by trabeculae that form a distal ring. In our case, these distal rings can occasionally be seen, but the individual processes cannot; instead, the tubes are formed by highly perforated membranes. Possibly, the degree of concrescence of the individual processes in this species reached a state similar to that sometimes observed in Turbiosphaera filosa. We also do not know the archeopyle in the European and Australian forms. Therefore, the reference of our taxon to Polystephanephorus is made with reservations.
Our specimens are in many respects similar to those described as Cannosphaeropsis urnaformis Cookson, a species originally assigned to the Lower to Middle Eocene and now uncertainly placed in the Oligocene of Australia. Our specimens have a similar body and appendage size, which may very occasionally be joined distally by very delicate trabeculae (as mentioned by Deflandre and Cookson, 1955, p. 284). The membranes of the appendages or processes are frequently perforated; in our species, we do not observe the widening of the processes toward the distal sector, which gives them an urn-like appearance in the Australian species. This difference is considered valid for the creation of a new species for the Patagonian individuals.
The presence of an archeopyle in our specimens, and its absence in the Australian ones, may be due to rather fortuitous causes (as is the case with Aiora fenestrata, for example). The archeopyle, from what has been observed, appears to be apical (see Plate 2, Figs. 5 and 7).
This species is dedicated to Dr. Miguel Sarris, geologist at Yacimientos Carboníferos Fiscales.
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Comments Fensome et al., 2019a:
Archangelsky (1969) considered that this species has an apical archaeopyle. However, G. R. Guerstein (personal communication 2017) noted that a restudy of the type material confirmed that this species has a precingular archaeopyle. Following suggestions by Archangelsky (1969), Gonzalez Estebenet et al. (2015, 2016) considered Senoniasphaera sarrisii to be an extreme member of the Turbiosphaera filosa complex (their morphotype 1). These authors considered the morphological variation within the Turbiosphaera filosa complex to parallel the variation described by Benedek & Gocht (1981 and references therein) and Pross (2001) for Thalassiphora pelagica. However, Gonzalez Estebenet et al. (2015, 2016) made no formal taxonomic proposals, so for now we questionably transfer Senoniasphaera? sarrisii to Turbiosphaera.
Stratigraphical occurrence. The type material is from the Eocene of Argentina.
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Emended description Guerstein et al., 2023:
Emended diagnosis: A species of Turbiosphaera characterised by short, taeniate intratabular processes distally connected to one another by a delicate membrane. Cingular processes isolated, taenite, small, and rectangular. Archaeopyle precingular represented by the plate 3″. Description: Chorate, subspheroidal to subovoidal central body with wall formed by two layers. The endophragm is thicker than the periphragm, the latter forming very short taeniate processes. Pre- and postcingular processes intratabular to penitabular, small, and of uniform length but variable width; they are generally interconnected, forming continuous or discontinuous perforate membranes (Plate I, 1–3). Wellpreserved specimens show one membrane joining the apical and precingular processes and another developed on the hypocystal processes (Plate III, 1, 4). Archaeopyle precingular, type P, formed by the loss of plate 3″. When present, the operculum has several small isolated processes. (Plate III, 2–3).
Dimensions: Holotype. Length of the central body 43 μm, width of central body 40 μm, maximum diameter of the archaeopyle 23 μm, length of processes 14 μm. Ranges: length of central body 43–61 μm (15 specimens), width of central body 34–51 μm (15 specimens), diameter of the archaeopyle 22–36 μm (10 specimens), length of processes 10–17 μm. The dimensions of our specimens fit within the size ranges provided in the protologue.
Remarks and comparisons: Archangelsky (1968) considered that the species most similar to Turbiosphaera sarrisii is Cannosphaeropsis urnaformis (now Emmetrocysta urnaformis) from the Cenozoic of Australia. He also added that the degree of development of individual processes in his material was similar to that observed in some of the specimens in his circumscription of Turbiosphaera filosa (considered as Turbiosphaera archangelskyi herein) from the Río Turbio Formation. In transferring Turbiosphaera sarrisii questionably to Senoniasphaera, Stover and Evitt (1978, p. 80) noted that it “… lacks tubiform processes with ring trabeculae [sic] characteristic of Polystephanephorus and some other genera. Illustrations show continuous ectophragm; assignment to Senoniasphaera very uncertain because of inconsistencies between description and illustrations.” Archangelsky (1968) interpreted this species as having an apical archaeopyle (pl. II, figs. 5 and 7), and it seems that this interpretation was followed by Stover and Evitt's in their attribution of the species to Senoniasphaera? However, several specimens observed in the present restudy of the type material confirm the presence of a precingular archaeopyle, supporting its transfer to Turbiosphaera, as proposed, albeit tentatively, by Fensome et al. (2019a). Following Archangelsky's (1968) acknowledgement that the processes of this species were similar to those of Turbiosphaera filosa (i.e. material now recognised as Turbiosphaera archangelskyi) and our observation that the species has a precingular archaeopyle, we confirm the generic assignment to Turbiosphaera and emend the diagnosis primarily to include mention of a precingular archaeopyle.
Turbiosphaera sarrisii (Archangelsky, 1969a, p.411, pl.2, figs.5–7) Fensome et al., 2019a, p.55.
Holotype: Archangelsky, 1969a, pl.2, figs.6–7; Fensome et al., 2019a, figs.20E–F.
Originally Polystephanephorus?, subsequently Senoniasphaera?, thirdly (and now) Turbiosphaera.
Questionable assignment: Fensome et al. (2019a. p.55).
Age: Eocene.
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Original description: [Archangelsky, 1969a] (translated from Spanish):
Polystephanephorus (?) sarrisii n. sp.
Pl. II, figs. 5, 6, 7
DIAGNOSIS. Subspherical to oval body, composed of an inner membrane (1.5 μ) thicker than the outer membrane; outer membrane giving rise to membranous processes, frequently tubuliform, generally perforated, which narrow towards the apex or are typically cylindrical. Number of processes: about 12; processes of variable width, but all of similar length; processes sometimes united by very delicate distal trabeculae, generally laminar. Apical archeopyle.
HOLOTYPE: microscope slide no. 709, coordinates 30.2/100.3.
MEASUREMENTS: body length: 43 μ; width of body: 40 μ; archeopyle: 23 μ; processes: 14 μ
DISTRIBUTION: Río Turbio Formation, D-15, level 687-689 m. Eocene.
OTHER MEASUREMENTS (specimens from the same provenance): body length: 43-61 μ (15 ex.); body width: 34-51 μ (15 ex.); archeopyle: 22-36 μ (10 ex.); length of processes: 10-17 μ.
DISCUSSION AND COMPARISONS. This curious species appears to be restricted exclusively to a single level, in well D-15; the frequency of the material allows its diagnosis with relative ease. More problematic, however, is the generic assignment. Indeed, the species most similar to ours is undoubtedly Cannosphaeropsis urnaformis Cookson (1953) and Deflandre and Cookson (1955), from the Tertiary of Australia. It was transferred to the genus Polystephanephorus by Sarjeant (1961), who typified it with a Jurassic species from Europe, P. calathus. According to the genus definition, the tubular processes are formed by the union of individual processes that meet distally by trabeculae that form a distal ring. In our case, these distal rings can occasionally be seen, but the individual processes cannot; instead, the tubes are formed by highly perforated membranes. Possibly, the degree of concrescence of the individual processes in this species reached a state similar to that sometimes observed in Turbiosphaera filosa. We also do not know the archeopyle in the European and Australian forms. Therefore, the reference of our taxon to Polystephanephorus is made with reservations.
Our specimens are in many respects similar to those described as Cannosphaeropsis urnaformis Cookson, a species originally assigned to the Lower to Middle Eocene and now uncertainly placed in the Oligocene of Australia. Our specimens have a similar body and appendage size, which may very occasionally be joined distally by very delicate trabeculae (as mentioned by Deflandre and Cookson, 1955, p. 284). The membranes of the appendages or processes are frequently perforated; in our species, we do not observe the widening of the processes toward the distal sector, which gives them an urn-like appearance in the Australian species. This difference is considered valid for the creation of a new species for the Patagonian individuals.
The presence of an archeopyle in our specimens, and its absence in the Australian ones, may be due to rather fortuitous causes (as is the case with Aiora fenestrata, for example). The archeopyle, from what has been observed, appears to be apical (see Plate 2, Figs. 5 and 7).
This species is dedicated to Dr. Miguel Sarris, geologist at Yacimientos Carboníferos Fiscales.
---------------------------------------------------------------------------------------------------
Comments Fensome et al., 2019a:
Archangelsky (1969) considered that this species has an apical archaeopyle. However, G. R. Guerstein (personal communication 2017) noted that a restudy of the type material confirmed that this species has a precingular archaeopyle. Following suggestions by Archangelsky (1969), Gonzalez Estebenet et al. (2015, 2016) considered Senoniasphaera sarrisii to be an extreme member of the Turbiosphaera filosa complex (their morphotype 1). These authors considered the morphological variation within the Turbiosphaera filosa complex to parallel the variation described by Benedek & Gocht (1981 and references therein) and Pross (2001) for Thalassiphora pelagica. However, Gonzalez Estebenet et al. (2015, 2016) made no formal taxonomic proposals, so for now we questionably transfer Senoniasphaera? sarrisii to Turbiosphaera.
Stratigraphical occurrence. The type material is from the Eocene of Argentina.
---------------------------------------------------------------------------------------------------
Emended description Guerstein et al., 2023:
Emended diagnosis: A species of Turbiosphaera characterised by short, taeniate intratabular processes distally connected to one another by a delicate membrane. Cingular processes isolated, taenite, small, and rectangular. Archaeopyle precingular represented by the plate 3″. Description: Chorate, subspheroidal to subovoidal central body with wall formed by two layers. The endophragm is thicker than the periphragm, the latter forming very short taeniate processes. Pre- and postcingular processes intratabular to penitabular, small, and of uniform length but variable width; they are generally interconnected, forming continuous or discontinuous perforate membranes (Plate I, 1–3). Wellpreserved specimens show one membrane joining the apical and precingular processes and another developed on the hypocystal processes (Plate III, 1, 4). Archaeopyle precingular, type P, formed by the loss of plate 3″. When present, the operculum has several small isolated processes. (Plate III, 2–3).
Dimensions: Holotype. Length of the central body 43 μm, width of central body 40 μm, maximum diameter of the archaeopyle 23 μm, length of processes 14 μm. Ranges: length of central body 43–61 μm (15 specimens), width of central body 34–51 μm (15 specimens), diameter of the archaeopyle 22–36 μm (10 specimens), length of processes 10–17 μm. The dimensions of our specimens fit within the size ranges provided in the protologue.
Remarks and comparisons: Archangelsky (1968) considered that the species most similar to Turbiosphaera sarrisii is Cannosphaeropsis urnaformis (now Emmetrocysta urnaformis) from the Cenozoic of Australia. He also added that the degree of development of individual processes in his material was similar to that observed in some of the specimens in his circumscription of Turbiosphaera filosa (considered as Turbiosphaera archangelskyi herein) from the Río Turbio Formation. In transferring Turbiosphaera sarrisii questionably to Senoniasphaera, Stover and Evitt (1978, p. 80) noted that it “… lacks tubiform processes with ring trabeculae [sic] characteristic of Polystephanephorus and some other genera. Illustrations show continuous ectophragm; assignment to Senoniasphaera very uncertain because of inconsistencies between description and illustrations.” Archangelsky (1968) interpreted this species as having an apical archaeopyle (pl. II, figs. 5 and 7), and it seems that this interpretation was followed by Stover and Evitt's in their attribution of the species to Senoniasphaera? However, several specimens observed in the present restudy of the type material confirm the presence of a precingular archaeopyle, supporting its transfer to Turbiosphaera, as proposed, albeit tentatively, by Fensome et al. (2019a). Following Archangelsky's (1968) acknowledgement that the processes of this species were similar to those of Turbiosphaera filosa (i.e. material now recognised as Turbiosphaera archangelskyi) and our observation that the species has a precingular archaeopyle, we confirm the generic assignment to Turbiosphaera and emend the diagnosis primarily to include mention of a precingular archaeopyle.