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Hystrichokolpoma fimbriatum
Hystrichokolpoma fimbriatum Morgenroth, 1968
Now Conneximura. Originally Hystrichokolpoma?, subsequently Danea, thirdly (and now) Conneximura.
Morgenroth, 1968, questionably included this species in Hystrichokolpoma.
Holotype: Morgenroth, 1968, pl.45, figs.7-8
Age: Danian
Original diagnosis: Morgenroth, 1968, p.547-548
A species of ?Hystrichokolpoma with following process scheme: ?6', 6'', ?7, 7''', ?2 sulcal plates, 1''''. The thin-walled theca ellipsoidal in outline. Surface smooth. Delicate processes at all specimens with deep slits, process distribution therefore difficult to determine. Bases of processes granulate. Girdle weakly anticlockwise spiral. The horseshoe-shaped archaeopyle situated below the apex on the dorsal side and corresponds to process 3''. The ventral situated sulcal area seems to be differentiated by several processes, but are not determinably in the current material.
Dimensions: Theca length 37 Ám (31 Ám/ 50), breadth 32 Ám (25 Ám/ 36 Ám); 50 specimens measured.
Revised description: May, 1980, p.46
Cyst bilayered, spherical to ovoidal, bearing simulate, broad-based, polygonal, parallel-sided, hollow, fimbriate, and open processes. Fimbriate walls often connect corner positions of processes with adjacent gonal positions of plate equivalents, and also outline cingular and sulcal areas. Endophragm and periphragm generally closely appressed. Endophragm smooth, thicker than periphragm, measuring ca. 2 Ám; periphragm smooth to faintly scabrate, often wrinkled or rippled near base of fimbriate walls, measures ca. 1 Ám thick. Processes, formed of periphragm, may be completely intratabular except where they abut against the margin of cingulum and sulcus; reflect tabulation of 1', 6", 6c, 5''', 1p, 1''''. Processes formed of thin, delicate, somewhat distally-shredded walls, draped between more solid, spinelike corner supports. Similar walls also outline cingulum and sulcus.
The combination of process walls and all additional walls imparts a complex, netlike appearance to cyst surface. A large triradiate apical spine, located between the four apical plate equivalents, possibly reflects the position of an apical pore closing platelet. Antapical process bears a thick, punctate inner base, and is noticeably thicker walled and more solidly constructed than the other processes. Cingulum levorotatory, composed of six plate equivalents, outlined by fimbriate walls and low sutural ridges. Sulcus, angularly outlined by high fimbriate walls, extends from near the apex to near the antapex. Archeopyle precingular (Type P), horseshoeshaped, often slightly gabled at anterior margin.
Discussion: Although many of the basic morphological features of C. fimbriata (Morgenroth, 1968) were reported by Morgenroth (1968, p. 547 to 548), the complex positioning of the many walls was not discussed. This unique feature distinguishes Conneximura from other genera, and C. fimbriata from other species. Morgenroth (1968) observed a precingular archeopyle, and therefore placed a question mark before his generic assignment, identifying it as ?Hystrichokolpoma fimbriata.
Dimensions: Observed range (30 specimens measured): length main body 40--60 µm; width 37-54 µm; process length 13--19 µm. Wall layers ca. 3 µm; endophragm thicker than periphragm.
Emended description: Marheinecke, 1992, p.112-113
Cyst habitus sphaeroidal to ovaloidal. Wall composed of pedium and luxuria. Luxuria develops ornamentation, processes and septae, which may be finate or nonfinate. Areation gonyaulax-type. Processes gonal or in some cases intergonal. Surface of central body smooth.
Septae consist of conflate, claudate muri. Septae striate and often weakly folded. Between the processes, especially in the apical and antapical region, the septae may reach the higth of the processes and may give the impression of large, hollow processes.
Processes gonal, intergonal or intraareate. Processes develop, as in Spiniferites, by the fusion of usually three septae. Processes at the bases hollow. Processes taper towards the closed, distal ends. Processes always simple, never furcate.
Areation: 1pr, 4', 6'', 6c, 5(6?)''. 1p, 1''''.
Archaeopyle: 3'', operculum secate.
Affinities:
Morgenroth, 1968, p.548: ?H. fimbriata differs from H. bifomoides in the type of processes.
May, 1980, p.46: In certain respects, such as process development, C. fimbriata (Morgenroth) is similar to Hystrichokolpoma or Systematophora, but it is separated from these because of its precingular archeopyle (Type P). The closest relationships are seen in other Gonyaulax types with precingular archeopyles, and walls about plate-margins, e.g. Acanthogonyaulax, Leptodinium, and Psaligonyaulax. These, however, lack simulate processes and fimbriate secondary walls connecting gonal positions of plate margins with corner positions of polygonal processes.
Now Conneximura. Originally Hystrichokolpoma?, subsequently Danea, thirdly (and now) Conneximura.
Morgenroth, 1968, questionably included this species in Hystrichokolpoma.
Holotype: Morgenroth, 1968, pl.45, figs.7-8
Age: Danian
Original diagnosis: Morgenroth, 1968, p.547-548
A species of ?Hystrichokolpoma with following process scheme: ?6', 6'', ?7, 7''', ?2 sulcal plates, 1''''. The thin-walled theca ellipsoidal in outline. Surface smooth. Delicate processes at all specimens with deep slits, process distribution therefore difficult to determine. Bases of processes granulate. Girdle weakly anticlockwise spiral. The horseshoe-shaped archaeopyle situated below the apex on the dorsal side and corresponds to process 3''. The ventral situated sulcal area seems to be differentiated by several processes, but are not determinably in the current material.
Dimensions: Theca length 37 Ám (31 Ám/ 50), breadth 32 Ám (25 Ám/ 36 Ám); 50 specimens measured.
Revised description: May, 1980, p.46
Cyst bilayered, spherical to ovoidal, bearing simulate, broad-based, polygonal, parallel-sided, hollow, fimbriate, and open processes. Fimbriate walls often connect corner positions of processes with adjacent gonal positions of plate equivalents, and also outline cingular and sulcal areas. Endophragm and periphragm generally closely appressed. Endophragm smooth, thicker than periphragm, measuring ca. 2 Ám; periphragm smooth to faintly scabrate, often wrinkled or rippled near base of fimbriate walls, measures ca. 1 Ám thick. Processes, formed of periphragm, may be completely intratabular except where they abut against the margin of cingulum and sulcus; reflect tabulation of 1', 6", 6c, 5''', 1p, 1''''. Processes formed of thin, delicate, somewhat distally-shredded walls, draped between more solid, spinelike corner supports. Similar walls also outline cingulum and sulcus.
The combination of process walls and all additional walls imparts a complex, netlike appearance to cyst surface. A large triradiate apical spine, located between the four apical plate equivalents, possibly reflects the position of an apical pore closing platelet. Antapical process bears a thick, punctate inner base, and is noticeably thicker walled and more solidly constructed than the other processes. Cingulum levorotatory, composed of six plate equivalents, outlined by fimbriate walls and low sutural ridges. Sulcus, angularly outlined by high fimbriate walls, extends from near the apex to near the antapex. Archeopyle precingular (Type P), horseshoeshaped, often slightly gabled at anterior margin.
Discussion: Although many of the basic morphological features of C. fimbriata (Morgenroth, 1968) were reported by Morgenroth (1968, p. 547 to 548), the complex positioning of the many walls was not discussed. This unique feature distinguishes Conneximura from other genera, and C. fimbriata from other species. Morgenroth (1968) observed a precingular archeopyle, and therefore placed a question mark before his generic assignment, identifying it as ?Hystrichokolpoma fimbriata.
Dimensions: Observed range (30 specimens measured): length main body 40--60 µm; width 37-54 µm; process length 13--19 µm. Wall layers ca. 3 µm; endophragm thicker than periphragm.
Emended description: Marheinecke, 1992, p.112-113
Cyst habitus sphaeroidal to ovaloidal. Wall composed of pedium and luxuria. Luxuria develops ornamentation, processes and septae, which may be finate or nonfinate. Areation gonyaulax-type. Processes gonal or in some cases intergonal. Surface of central body smooth.
Septae consist of conflate, claudate muri. Septae striate and often weakly folded. Between the processes, especially in the apical and antapical region, the septae may reach the higth of the processes and may give the impression of large, hollow processes.
Processes gonal, intergonal or intraareate. Processes develop, as in Spiniferites, by the fusion of usually three septae. Processes at the bases hollow. Processes taper towards the closed, distal ends. Processes always simple, never furcate.
Areation: 1pr, 4', 6'', 6c, 5(6?)''. 1p, 1''''.
Archaeopyle: 3'', operculum secate.
Affinities:
Morgenroth, 1968, p.548: ?H. fimbriata differs from H. bifomoides in the type of processes.
May, 1980, p.46: In certain respects, such as process development, C. fimbriata (Morgenroth) is similar to Hystrichokolpoma or Systematophora, but it is separated from these because of its precingular archeopyle (Type P). The closest relationships are seen in other Gonyaulax types with precingular archeopyles, and walls about plate-margins, e.g. Acanthogonyaulax, Leptodinium, and Psaligonyaulax. These, however, lack simulate processes and fimbriate secondary walls connecting gonal positions of plate margins with corner positions of polygonal processes.