Back
Turnhosphaera
From Fensome et al., 2019:
Turnhosphaera Slimani, 1994, p.62. Type: Yun Hyesu, 1981, pl.9, fig.1, as Disphaeria hypoflata.
---------------------------------------------------------------------------------------------------
Original description: [Slimani, 1994]: (Translation: LPP):
Diagnosis:
In dorsoventral view the cyst is composed of a hypopericyst which follows the subcircular to oval outline of the endocyst, and a prominent epipericyst, subhexagonal in outline, forming an epipericoel.
Proximate, acavate cyst; the subspheroidal to ovoidal endocyst with often a small apical boss, and the pericyst are in close contact in the complete hypocystal area. From the paracingulum the two walls part and form a large epipericoel enclosed by a large prominent and dorsally open epipericyst. The enophragm and periphragm are smooth, scabrate or granulate. Parasutural crests are located on the periphragm which indicate a complete or partial paratabulation. The crests are smooth, perforate, straight, undulate to distally crenulate; they are generally low and may on the hypocyst develop or not into prominent crest.
The archaeopyle is precingular type P (3`` only); an endoarchaeopyle with a free or attached operculum; a dorsal opening in the periphragm representing a precingular periarchaeopyle with a free monotabular operculum.
The paratabulation is gonyaulacoid: 4`, 6``, 3-6c, 4-5```, 1````, xs. The paracingulum is indicated by 3 to 6 rectangular paraplates. The parasulcus is indicated ventrally by a surface which extends from the apex to the antapex.
The size is intermediate to large, 50-80 µm in diameter.
Affinities:
Turnhosphaera differs from all cavate genera described up till now in the combination of the following characteristics: an epicavate tabulate cyst, a precingular type P(3``) archaeopyle with a narrow endoarchaeopyle and a large periarchaeopyle and the absence of processes. Invertocysta Edwards, 1984, most closely resembles turnhosphaera, but, referring to the original description: "the bowl- or saucer-shaped periphragm opens toward the dorsal side and is appressed to the endophragm midventrally"; this genus has a circumcavate cyst with and endocyst and pericyst which are in contact midventrally. Flandrecysta Slimani, 1994, also has a pericoel, but it is developed on the ventral side of the cyst and is connected to the exterior by a large ventral opening, and it has processes. Wilsonisphaera Slimani, 1994, has an endophragm and periphragm separated by a large pericoel, but connected post-ventrally by a large membranous process.
Turnhosphaera Slimani, 1994, p.62. Type: Yun Hyesu, 1981, pl.9, fig.1, as Disphaeria hypoflata.
---------------------------------------------------------------------------------------------------
Original description: [Slimani, 1994]: (Translation: LPP):
Diagnosis:
In dorsoventral view the cyst is composed of a hypopericyst which follows the subcircular to oval outline of the endocyst, and a prominent epipericyst, subhexagonal in outline, forming an epipericoel.
Proximate, acavate cyst; the subspheroidal to ovoidal endocyst with often a small apical boss, and the pericyst are in close contact in the complete hypocystal area. From the paracingulum the two walls part and form a large epipericoel enclosed by a large prominent and dorsally open epipericyst. The enophragm and periphragm are smooth, scabrate or granulate. Parasutural crests are located on the periphragm which indicate a complete or partial paratabulation. The crests are smooth, perforate, straight, undulate to distally crenulate; they are generally low and may on the hypocyst develop or not into prominent crest.
The archaeopyle is precingular type P (3`` only); an endoarchaeopyle with a free or attached operculum; a dorsal opening in the periphragm representing a precingular periarchaeopyle with a free monotabular operculum.
The paratabulation is gonyaulacoid: 4`, 6``, 3-6c, 4-5```, 1````, xs. The paracingulum is indicated by 3 to 6 rectangular paraplates. The parasulcus is indicated ventrally by a surface which extends from the apex to the antapex.
The size is intermediate to large, 50-80 µm in diameter.
Affinities:
Turnhosphaera differs from all cavate genera described up till now in the combination of the following characteristics: an epicavate tabulate cyst, a precingular type P(3``) archaeopyle with a narrow endoarchaeopyle and a large periarchaeopyle and the absence of processes. Invertocysta Edwards, 1984, most closely resembles turnhosphaera, but, referring to the original description: "the bowl- or saucer-shaped periphragm opens toward the dorsal side and is appressed to the endophragm midventrally"; this genus has a circumcavate cyst with and endocyst and pericyst which are in contact midventrally. Flandrecysta Slimani, 1994, also has a pericoel, but it is developed on the ventral side of the cyst and is connected to the exterior by a large ventral opening, and it has processes. Wilsonisphaera Slimani, 1994, has an endophragm and periphragm separated by a large pericoel, but connected post-ventrally by a large membranous process.