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Lacrymodinium
From Fensome et al., 2019:
Lacrymodinium, Albert et al., 1986, p.305–307.
Type: Albert et al., 1986, pl.1, figs.1–2,4, as Lacrymodinium warrenii.
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Original description: [Albert et al., 1986]:
Description:
Shape: proximate cyst outline in dorso-ventral view variably pyriform, drawn out apically into a stout horn of variable length; antapex broadly convex, without horns.
Wall relations: wall layering inconspicuous in the light microscope; without prominent cavation.
Wall features: clearly expressed, low to moderately high parasutural ridges; crests generally denticulate, hirsute-spinose, or serrate, but may be smooth; surface between ridges with indistinct features of low relief sparsely spinose, or smooth.
Paratabulation: partiform gonyaulacoid paratabulation pattern (Evitt 1985) clearly indicated by parasutural features. Epicyst paratabulation pattern exsert, with a single, pentagonal, middorsal, anterior intercalary (4v) separated from subjacent precingular (4h) by a rectilinear parasuture. Hypocyst paratabulation pattern partiform.
Archeopyle: formed by loss of anterior intercalary paraplate (4v), Type I.
Paracingulum: indicated by rectangular, transversely elongated paraplates (seven in the type species).
Parasulcus: longitudinally elongate area, wider antapically than apically, confined mainly to hypocyst; paraplates commonly differentiated.
Size: intermediate (approximately 40-100 µm).
Affinities:
As represented by the type species, the shape and superficial appearance of Lacrymodinium is similar to Pareodinia Deflandre 1947, Pluriarvalium Sarjeant 1962, and Paragonyaulacysta Johnson & Hills 1973. Lacrymodinium differs from all of these by having only a single anterior intercalary paraplate. In addition, it differs from Pareodinia by having paratabulation fully expressed by parasutural ridges and from Paragonyaulacysta and Pluriarvalium in details of paratabulation. It should be noted, however, that Sarjeant (1962) and Wiggins (1975, as Pareodinia osmingtonense) have interpreted the paratabulation of Pluriarvalium osmingtonense differently, partly because of different material, and that some of the characteristics of the species of Paragonyaulacysta most similar to Lacrymodinium (P. borealis and P. capillosa) 3 were described by Brideaux and Fisher (1976) with uncertainty (oral commun., W. W. Brideaux). Our specimens establish clearly that Lacrymodinium has only a single anterior intercalary paraplate, which forms the archeopyle, and only three apicals, whose proportions and contacts with adjacent paraplates are rather unusual. Although Mr. Wiggins kindly permitted us to examine some of his original material, we believe a fully convincing comparison of our species with Pluriarvalium osmingtonense, as well as with the two species of Paragonyaulacysta, and thereby a convincing generic comparison of Lacrymodinium with Pluriarvalium and Paragonyaulacysta, must await information on details not now available for species of the last two genera. Because the scanning electron microscope has left little doubt about the details of paratabulation of the Lacrymodinium specimens we have studied, we feel justified in attributing these specimens to a new genus, although eventually some degree of synonymy at specific or generic levels may be shown upon resolution of uncertain details in the other species to which the specimens show some similarity.
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Notes:
G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.
Lacrymodinium Albert et al., 1986, has the tabulation 3`, 2a, 6", 6c, 6"', 1p, 1"'', 1ps. It has an exsert 1` and a partiform hypocyst, with 6"' being of comparable size to 1"'. The two anterior intercalary plates are both five sided and the archeopyle is formed from the loss of 1a. The genus is included in the family Pareodiniaceae by Fensome et al. (1993).
Lacrymodinium, Albert et al., 1986, p.305–307.
Type: Albert et al., 1986, pl.1, figs.1–2,4, as Lacrymodinium warrenii.
---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original description: [Albert et al., 1986]:
Description:
Shape: proximate cyst outline in dorso-ventral view variably pyriform, drawn out apically into a stout horn of variable length; antapex broadly convex, without horns.
Wall relations: wall layering inconspicuous in the light microscope; without prominent cavation.
Wall features: clearly expressed, low to moderately high parasutural ridges; crests generally denticulate, hirsute-spinose, or serrate, but may be smooth; surface between ridges with indistinct features of low relief sparsely spinose, or smooth.
Paratabulation: partiform gonyaulacoid paratabulation pattern (Evitt 1985) clearly indicated by parasutural features. Epicyst paratabulation pattern exsert, with a single, pentagonal, middorsal, anterior intercalary (4v) separated from subjacent precingular (4h) by a rectilinear parasuture. Hypocyst paratabulation pattern partiform.
Archeopyle: formed by loss of anterior intercalary paraplate (4v), Type I.
Paracingulum: indicated by rectangular, transversely elongated paraplates (seven in the type species).
Parasulcus: longitudinally elongate area, wider antapically than apically, confined mainly to hypocyst; paraplates commonly differentiated.
Size: intermediate (approximately 40-100 µm).
Affinities:
As represented by the type species, the shape and superficial appearance of Lacrymodinium is similar to Pareodinia Deflandre 1947, Pluriarvalium Sarjeant 1962, and Paragonyaulacysta Johnson & Hills 1973. Lacrymodinium differs from all of these by having only a single anterior intercalary paraplate. In addition, it differs from Pareodinia by having paratabulation fully expressed by parasutural ridges and from Paragonyaulacysta and Pluriarvalium in details of paratabulation. It should be noted, however, that Sarjeant (1962) and Wiggins (1975, as Pareodinia osmingtonense) have interpreted the paratabulation of Pluriarvalium osmingtonense differently, partly because of different material, and that some of the characteristics of the species of Paragonyaulacysta most similar to Lacrymodinium (P. borealis and P. capillosa) 3 were described by Brideaux and Fisher (1976) with uncertainty (oral commun., W. W. Brideaux). Our specimens establish clearly that Lacrymodinium has only a single anterior intercalary paraplate, which forms the archeopyle, and only three apicals, whose proportions and contacts with adjacent paraplates are rather unusual. Although Mr. Wiggins kindly permitted us to examine some of his original material, we believe a fully convincing comparison of our species with Pluriarvalium osmingtonense, as well as with the two species of Paragonyaulacysta, and thereby a convincing generic comparison of Lacrymodinium with Pluriarvalium and Paragonyaulacysta, must await information on details not now available for species of the last two genera. Because the scanning electron microscope has left little doubt about the details of paratabulation of the Lacrymodinium specimens we have studied, we feel justified in attributing these specimens to a new genus, although eventually some degree of synonymy at specific or generic levels may be shown upon resolution of uncertain details in the other species to which the specimens show some similarity.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Notes:
G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.
Lacrymodinium Albert et al., 1986, has the tabulation 3`, 2a, 6", 6c, 6"', 1p, 1"'', 1ps. It has an exsert 1` and a partiform hypocyst, with 6"' being of comparable size to 1"'. The two anterior intercalary plates are both five sided and the archeopyle is formed from the loss of 1a. The genus is included in the family Pareodiniaceae by Fensome et al. (1993).