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Krutzschidinium spinosum
Krutzschidinium spinosum Strauss, 1991
Name not validly published: lodgment of holotype not specified. Strauss (1991a, p.57) considered this species to be a possible taxonomic junior synonym of Wetzeliella (now Apectodinium) summissa.
Holotype: Strauss, 1991, pl.1, a-b; text-fig.4b
Paratypes: Strauss, 1991
Locus typicus: Well L÷derburg, Engeln-Brown Coal Basin, Central Germany
Stratum typicum: Middle Eocene
Original description: Strauss, 1991, p. 54, 56
Diagnosis: A species of Krutzschidinium with characteristic bulbose ending spines, which together with discontinous membraneous ridges incompletely delineate a tabulation typical for the genus. The most frequently observed dorsal paratabulation style seems to be a penta one, but the quadra-(and hexa?) style are probably present, too. Archaeopyle of variable type: 3I (1a-3a), I (2a) and ? tAtI.
Description/Discussion: Strongly dorsoventrally flattened cornucavate cysts with pentagonal-rounded shape, which may be either somewhat elongated or compressed in apical-antapical direction.
The horns, whose general shape is roughly triangular, may be branched irregulary by spine-like processes, arising from the periphragm at the parasutures. They are sharply set off from the cyst body but may be difficult to recognize in oblique view.
The sutural arranged spines may be numerous and relatively long (up to 10 Ám), but additionally specimen with sparsely distributed tiny processes (0.5-4 Ám) occur. The reduction of process-density and -lenght is often connected with a more bellied outline of the cyst and appears to be controlled by environmental variations. The arrangement of spine-like processes and the discontinuous membraneous ridges incompletely delineate a peridinoid paratabulation with penta-, probably quadra- (and hexa?) dorsal styles. Position and run of parasutural ridges are often very difficult to be observed under the light microscope, because many parasutures are only indicated by one or two spine bases and therefore often obscured by irregular periphragmal folds.
Even observations with interference-phase-contrast microscope and with SEM cannot always elucidate the dorsal patterns as shown in the schemes at Fig. 3, because most of the observed specimen were intensively folded or crumpled.
Paracingulum and parasulcus are not indented and weakly delineated by spinose crests. If the specimen is in oblique position with wrinkled and folded phragma layers paracingulum and parasulcus often cannot easily be discerned.
Periphragm endophragm without any ornamentation besides the spiny processes and closely appressed. Except at the horn bases, occasionally very narrow ambital pericoels occur.
The ventral surface seems to display an ortho-tabulation style, but this has to be proved by further examinations.
Examining about 50 specimens for archaeopyle structure, the 3I (1a-3a)-type appeared to be by far the most common. The tAtI-type could not easily be recognized because many epicysts were damaged by accidental ruptures after detachment of operculum. This type is represented by very few individuals, the apical parts of which may have been cut off along the anterior boundary of precingulars. A remarkable percentage of the observed cysts showed operculi in situ with no or almost no split of archaeopyle sutures. Simple I (2a) types rarely occur.
Dimensions: endocyst length 51(63)74 Ám; endocyst width 44(57)68 Ám; pericyst length 63(80)95 Ám; pericyst width 50(65)78 Ám, horns (apical and antapicals are nearly equal in length, measured together) 7(12)17 Ám, length of spine-like processes 0.5(7)10 Ám, (25 specimens measured).
Name not validly published: lodgment of holotype not specified. Strauss (1991a, p.57) considered this species to be a possible taxonomic junior synonym of Wetzeliella (now Apectodinium) summissa.
Holotype: Strauss, 1991, pl.1, a-b; text-fig.4b
Paratypes: Strauss, 1991
Locus typicus: Well L÷derburg, Engeln-Brown Coal Basin, Central Germany
Stratum typicum: Middle Eocene
Original description: Strauss, 1991, p. 54, 56
Diagnosis: A species of Krutzschidinium with characteristic bulbose ending spines, which together with discontinous membraneous ridges incompletely delineate a tabulation typical for the genus. The most frequently observed dorsal paratabulation style seems to be a penta one, but the quadra-(and hexa?) style are probably present, too. Archaeopyle of variable type: 3I (1a-3a), I (2a) and ? tAtI.
Description/Discussion: Strongly dorsoventrally flattened cornucavate cysts with pentagonal-rounded shape, which may be either somewhat elongated or compressed in apical-antapical direction.
The horns, whose general shape is roughly triangular, may be branched irregulary by spine-like processes, arising from the periphragm at the parasutures. They are sharply set off from the cyst body but may be difficult to recognize in oblique view.
The sutural arranged spines may be numerous and relatively long (up to 10 Ám), but additionally specimen with sparsely distributed tiny processes (0.5-4 Ám) occur. The reduction of process-density and -lenght is often connected with a more bellied outline of the cyst and appears to be controlled by environmental variations. The arrangement of spine-like processes and the discontinuous membraneous ridges incompletely delineate a peridinoid paratabulation with penta-, probably quadra- (and hexa?) dorsal styles. Position and run of parasutural ridges are often very difficult to be observed under the light microscope, because many parasutures are only indicated by one or two spine bases and therefore often obscured by irregular periphragmal folds.
Even observations with interference-phase-contrast microscope and with SEM cannot always elucidate the dorsal patterns as shown in the schemes at Fig. 3, because most of the observed specimen were intensively folded or crumpled.
Paracingulum and parasulcus are not indented and weakly delineated by spinose crests. If the specimen is in oblique position with wrinkled and folded phragma layers paracingulum and parasulcus often cannot easily be discerned.
Periphragm endophragm without any ornamentation besides the spiny processes and closely appressed. Except at the horn bases, occasionally very narrow ambital pericoels occur.
The ventral surface seems to display an ortho-tabulation style, but this has to be proved by further examinations.
Examining about 50 specimens for archaeopyle structure, the 3I (1a-3a)-type appeared to be by far the most common. The tAtI-type could not easily be recognized because many epicysts were damaged by accidental ruptures after detachment of operculum. This type is represented by very few individuals, the apical parts of which may have been cut off along the anterior boundary of precingulars. A remarkable percentage of the observed cysts showed operculi in situ with no or almost no split of archaeopyle sutures. Simple I (2a) types rarely occur.
Dimensions: endocyst length 51(63)74 Ám; endocyst width 44(57)68 Ám; pericyst length 63(80)95 Ám; pericyst width 50(65)78 Ám, horns (apical and antapicals are nearly equal in length, measured together) 7(12)17 Ám, length of spine-like processes 0.5(7)10 Ám, (25 specimens measured).