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Dracodinium
From Williams et al., 2017:
[Dracodinium, Gocht, 1955, p. 87; Emendations: Bujak et al., 1980, p.28; Williams et al., 2015, p.303.
Taxonomic senior synonym: Wetzeliella, by implication in Williams and Downie (1966b, p.195), who transferred the "type species" of Dracodinium, Dracodinium solidum, to Wetzeliella — however, Costa and Downie (1979, p.36) and Lentin and Williams (1989, p.121) retained Dracodinium.
Type species: Dracodinium solidum, Gocht, 1955 (text-figs.3a–b)]
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Original description: [Gocht, 1955]: (Translation Gocht, 1955: LPP):
Diagnosis:
Dinoflagellates with approximately kite-shaped outline, well developed lateral horns and partially reduced antapical horns. Apex more or less rounded, more rarely slightly pointed (distinction from Wetzeliella); only exceptionally an indication of a small apical tip. Shell untabulated, often provided with bristles; no development of furrows. Inside always a circular to more or less elliptical capsule.
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Emended description:
Bujak et al., 1980, p. 28:
Diagnosis:
Pericyst ambitus triangular to subtriangular. Apex rounded or with a greatly reduced apical horn. Pericingular horns well developed. Antapex prolonged into one prominent left antapical horn that is usually acuminate. The right antapical horn is strongly reduced or absent. Length of epipericyst considerably less than length of hypopericyst. Endocyst ambitus circular to oval. Cornucavate pericoels always present, sometimes connected by an ambital pericoel of variable width. Periphragm smooth, chagrinate, granulate, verrucate; may possess simple or branched processes that are distally open or closed. Endophragm of variable thickness up to several microns, surface laevigate, chagrinate, granulate, or verrucate. Paratabulation indeterminate except for the archaeopyle. Pericingulum and perisulcus poorly defined. Pericingulum sometimes indicated by an indentation at the extremities of the pericingular horns. Periarchaeopyle intercalary, resulting from the loss of the second anterior intercalary paraplate 2a. Perioperculum detached. Endoarchaeopyle the same size as the periarchaeopyle and involving intercalary paraplate 2a, or considerably broader than the periarchaeopyle and resulting from the loss of three intercalary paraplates (1a-3a).
Endoperculum detached.
Affinities:
Gocht, 1955 erected the genus Dracodinium for forms differing from Wetzeliella Eisenack, 1938, in not having an apical horn. He stated that the archaeopyle was variable and could be apical. Williams and Downie, 1966, p. 195, transferred the single species of Dracodinium, D. solidum, to Wetzeliella, thus making Dracodinium a junior synonym of Wetzeliella.
Lentin and Williams, 1976, p. 158 also considered Dracodinium to be a junior synonym of Wetzeliella and Gocht`s specimens of Dracodinium solidum with an apical archaeopyle were interpreted as being quadra 2a intercalary.
The present authors advocate retention of the genus Dracodinium for forms differing from Wetzeliella in having a triangular to subtriangular pericyst outline with a single prominent antapical horn, and in lacking a distinct apical horn.
Dracodinium differs from Rhombodinium Gocht, 1955, as emended by Bujak, 1979, in pericyst and endocyst outline and mode of archaeopyle formation. Rhombodinium has a rhomboidal pericyst and endocyst and a soleiform periarchaeopyle and endoarchaeopyle in which the opercula remain attached anteriorly along side Q1.
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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.
Dracodinium Gocht, 1955, emend. Bujak et al., 1980. From the emendation of Bujak et al. (1980, p.28). Pericyst ambitus triangular to subtriangular. Apex rounded or with a greatly reduced apical horn., pericingular horns well developed. Antapex prolonged into one prominent left antapical horn that is usually acuminate. The right antapical horn is strongly reduced or absent. Length of epipericyst considerably less than length of hypopericyst. Endocyst ambitus circular to oval. Cornucavate pericoels always present, sometimes connected by an ambital pericoel of variable width. Periphragm smooth, chagrinate, granulate, verrucate; may possess simple or branched processes that are distally open or closed. Endophragm of variable thickness up to several microns, surface laevigate, chagrinate, granulate, or verrucate. Paratabulation indeterminate except for the archeopyle. Pericingulum and perisulcus poorly defined. Percingulum sometimes indicated by an indentation at the extremities of the pericingular horns. Periarcheopyle intercalary, resulting from the loss of the second anterior intercalary paraplate 2a. Perioperculum detached. Endoarcheopyle the same size as the periarcheopyle and involving intercalary paraplate 2a, or considerably broader than the periarcheopyle and resulting from the loss of three intercalary paraplates (1a-3a). Endoperculum detached. The archeopyle is latiepeliform.
[Dracodinium, Gocht, 1955, p. 87; Emendations: Bujak et al., 1980, p.28; Williams et al., 2015, p.303.
Taxonomic senior synonym: Wetzeliella, by implication in Williams and Downie (1966b, p.195), who transferred the "type species" of Dracodinium, Dracodinium solidum, to Wetzeliella — however, Costa and Downie (1979, p.36) and Lentin and Williams (1989, p.121) retained Dracodinium.
Type species: Dracodinium solidum, Gocht, 1955 (text-figs.3a–b)]
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original description: [Gocht, 1955]: (Translation Gocht, 1955: LPP):
Diagnosis:
Dinoflagellates with approximately kite-shaped outline, well developed lateral horns and partially reduced antapical horns. Apex more or less rounded, more rarely slightly pointed (distinction from Wetzeliella); only exceptionally an indication of a small apical tip. Shell untabulated, often provided with bristles; no development of furrows. Inside always a circular to more or less elliptical capsule.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Emended description:
Bujak et al., 1980, p. 28:
Diagnosis:
Pericyst ambitus triangular to subtriangular. Apex rounded or with a greatly reduced apical horn. Pericingular horns well developed. Antapex prolonged into one prominent left antapical horn that is usually acuminate. The right antapical horn is strongly reduced or absent. Length of epipericyst considerably less than length of hypopericyst. Endocyst ambitus circular to oval. Cornucavate pericoels always present, sometimes connected by an ambital pericoel of variable width. Periphragm smooth, chagrinate, granulate, verrucate; may possess simple or branched processes that are distally open or closed. Endophragm of variable thickness up to several microns, surface laevigate, chagrinate, granulate, or verrucate. Paratabulation indeterminate except for the archaeopyle. Pericingulum and perisulcus poorly defined. Pericingulum sometimes indicated by an indentation at the extremities of the pericingular horns. Periarchaeopyle intercalary, resulting from the loss of the second anterior intercalary paraplate 2a. Perioperculum detached. Endoarchaeopyle the same size as the periarchaeopyle and involving intercalary paraplate 2a, or considerably broader than the periarchaeopyle and resulting from the loss of three intercalary paraplates (1a-3a).
Endoperculum detached.
Affinities:
Gocht, 1955 erected the genus Dracodinium for forms differing from Wetzeliella Eisenack, 1938, in not having an apical horn. He stated that the archaeopyle was variable and could be apical. Williams and Downie, 1966, p. 195, transferred the single species of Dracodinium, D. solidum, to Wetzeliella, thus making Dracodinium a junior synonym of Wetzeliella.
Lentin and Williams, 1976, p. 158 also considered Dracodinium to be a junior synonym of Wetzeliella and Gocht`s specimens of Dracodinium solidum with an apical archaeopyle were interpreted as being quadra 2a intercalary.
The present authors advocate retention of the genus Dracodinium for forms differing from Wetzeliella in having a triangular to subtriangular pericyst outline with a single prominent antapical horn, and in lacking a distinct apical horn.
Dracodinium differs from Rhombodinium Gocht, 1955, as emended by Bujak, 1979, in pericyst and endocyst outline and mode of archaeopyle formation. Rhombodinium has a rhomboidal pericyst and endocyst and a soleiform periarchaeopyle and endoarchaeopyle in which the opercula remain attached anteriorly along side Q1.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Notes:
G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.
Dracodinium Gocht, 1955, emend. Bujak et al., 1980. From the emendation of Bujak et al. (1980, p.28). Pericyst ambitus triangular to subtriangular. Apex rounded or with a greatly reduced apical horn., pericingular horns well developed. Antapex prolonged into one prominent left antapical horn that is usually acuminate. The right antapical horn is strongly reduced or absent. Length of epipericyst considerably less than length of hypopericyst. Endocyst ambitus circular to oval. Cornucavate pericoels always present, sometimes connected by an ambital pericoel of variable width. Periphragm smooth, chagrinate, granulate, verrucate; may possess simple or branched processes that are distally open or closed. Endophragm of variable thickness up to several microns, surface laevigate, chagrinate, granulate, or verrucate. Paratabulation indeterminate except for the archeopyle. Pericingulum and perisulcus poorly defined. Percingulum sometimes indicated by an indentation at the extremities of the pericingular horns. Periarcheopyle intercalary, resulting from the loss of the second anterior intercalary paraplate 2a. Perioperculum detached. Endoarcheopyle the same size as the periarcheopyle and involving intercalary paraplate 2a, or considerably broader than the periarcheopyle and resulting from the loss of three intercalary paraplates (1a-3a). Endoperculum detached. The archeopyle is latiepeliform.