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Hystrichokolpoma
From Fensome et al., 2019:
Hystrichokolpoma, Klumpp, 1953, p.388.
Emendations: Williams and Downie, 1966a, p.176; Zevenboom and Santarelli in Zevenboom, 1995, p.136; Foucher in Fauconnier and Masure, 2004, p.281.
Type: Klumpp, 1953, pl.17, figs.3,5a, as Hystrichokolpoma cinctum.
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Original description: [Klumpp, 1953]: (Translation: Stover and Evitt, 1978, p. 54):
Diagnosis:
The shell is almost round, divided by a girdle-like zone into two separate halves. The lower consists of six plates with inflated processes, between which in the middle there is an opening. The upper part carries four humped plates adjacent to the girdle and one field with thin spines as on girdle. A smaller plate with a hollow process, longer than the bags [i.e., bag-like inflated processes], forms the apical field.
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Emended description:
Williams and Downie, 1966:
Diagnosis:
Chorate cyst bearing two types of intratabular processes, large types with expanded bases, and slender ones. Large processes have proximally a quadrate cross section reflecting plate outline. Slender processes delimiting well marked cingular and sulcal zone. Cingulum helocoid reflected tabulation of 4`, 6``, 6g, 5```, 1p, 1````. Archaeopyle tetratabular.
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Modified description:
Stover and Evitt 1978, p. 54-55:
Synopsis:
Cysts skolochorate, gonyaulacacean; body subspherical with hollow, distally open, intratabular processes of two shapes; those in
paracingular and parasulcal areas typically much narrower than others; archeopyle apical, Type tA.
Description:
Shape: Body subspherical.
Wall relationships: Endophragm and periphragm appressed between processes.
Wall features: Parasutural areas are narrow strips between expanded process bases and may be expressed additionally by low parasutural ridges or periphragmal thickenings on some forms. Intratabular processes of two different shapes. Most processes more or less cylindrical to vasiform; may have significantly expanded bases (penitabular) and constricted distal ends. Paracingular and most parasulcal processes narrower than others; periphragm, including processes, smooth, faintly striate, or scabrate. Profiles of processes differ considerably among species, but fairly constant within a species.
Paratabulation: Expressed by separate processes or by small groups of processes having a common base; gonyaulacacean, process formula: 4`, 6``, 6-12c, 5-6```, 1p, 1````, 2-5s.
Archeopyle: Apical, Type tA; outline of principal archeopyle suture often nearly smooth.
Paracingulum: Each paraplate indicated by single or multiple processes. The latter have a common base and are normally slender, tapered, expanded slightly distally, and much narrower than those on other parts of the cyst. Parasulcus: Indicated by two to five isolated intratabular processes; anterior and posterior processes larger than other parasulcal processes.
Size: Intermediate to large.
Affinities:
Hystrichokolpoma differs from Florentinia in having an apical archeopyle rather than a precingular or combination Type tA+P archeopyle. It differs from Hystrichosphaeridium in possessing processes of two different shapes rather than of a single shape. Achilleodinium, which has processes like those on Hystrichokolpoma, has a precingular archeopyle rather than an apical archeopyle.
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Emended description Nelissen et al., 2025:
Emended diagnosis: The generic description of Hystrichokolpoma Klumpp 1953 is here emended to include species characterized by a distinct, robust, periphragmal membrane connecting the pre- and postcingular processes, overarching the cingular region (“cingular cavation”). The morphologically related genus Cousteaudinium de Verteuil and Norris, 1996 is distinctly circumcavate.
Full emendation: Species within the genus Hystrichokolpoma possess a gonyaulacacean, sexiform tabulation with dextral torsion. The cysts bear large, distally open penitabular processes situated on the apical, precingular, postcingular, and antapical plates. Processes on the paracingulum and parasulcus are markedly narrower, are often elongate, and may be distally open or closed. Here, we expand on the latter by including species in which the pre- and postcingular processes are connected with a periphragmal membrane overarching the cingular region. As a result of this overarching membrane in the cingular region, the cingular and sulcal processes become less visible and appear absent in some individuals. The archeopyle is apical, typically formed by the loss of a single plate.
Remarks. The morphologically related genus Oligokolpoma (Fensome et al., 2009) differs from Hystrichokolpoma emend. nov. by lacking any reflection of the cingular and sulcal plates.
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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.
Hystrichokolpoma Klumpp, 1953, emend. Williams and Downie, 1966a, emend. Zevenboom and Santarelli in Zevenboom, 1995, was emended by Zevenboom and Santarelli in Zevenboom (1995) to include taxa lacking cingular and sulcal processes. The genus is characterised by large, distally open penitabular processes on the apical, precingular, postcingular and antapical plates and much narrower, often elongate, distally open or closed processes on the paracingulum and parasulcus. The tabulation is gonyaulacacean, sexiform, with dextral torsion. The archeopyle is apical.
Hystrichokolpoma, Klumpp, 1953, p.388.
Emendations: Williams and Downie, 1966a, p.176; Zevenboom and Santarelli in Zevenboom, 1995, p.136; Foucher in Fauconnier and Masure, 2004, p.281.
Type: Klumpp, 1953, pl.17, figs.3,5a, as Hystrichokolpoma cinctum.
---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original description: [Klumpp, 1953]: (Translation: Stover and Evitt, 1978, p. 54):
Diagnosis:
The shell is almost round, divided by a girdle-like zone into two separate halves. The lower consists of six plates with inflated processes, between which in the middle there is an opening. The upper part carries four humped plates adjacent to the girdle and one field with thin spines as on girdle. A smaller plate with a hollow process, longer than the bags [i.e., bag-like inflated processes], forms the apical field.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Emended description:
Williams and Downie, 1966:
Diagnosis:
Chorate cyst bearing two types of intratabular processes, large types with expanded bases, and slender ones. Large processes have proximally a quadrate cross section reflecting plate outline. Slender processes delimiting well marked cingular and sulcal zone. Cingulum helocoid reflected tabulation of 4`, 6``, 6g, 5```, 1p, 1````. Archaeopyle tetratabular.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Modified description:
Stover and Evitt 1978, p. 54-55:
Synopsis:
Cysts skolochorate, gonyaulacacean; body subspherical with hollow, distally open, intratabular processes of two shapes; those in
paracingular and parasulcal areas typically much narrower than others; archeopyle apical, Type tA.
Description:
Shape: Body subspherical.
Wall relationships: Endophragm and periphragm appressed between processes.
Wall features: Parasutural areas are narrow strips between expanded process bases and may be expressed additionally by low parasutural ridges or periphragmal thickenings on some forms. Intratabular processes of two different shapes. Most processes more or less cylindrical to vasiform; may have significantly expanded bases (penitabular) and constricted distal ends. Paracingular and most parasulcal processes narrower than others; periphragm, including processes, smooth, faintly striate, or scabrate. Profiles of processes differ considerably among species, but fairly constant within a species.
Paratabulation: Expressed by separate processes or by small groups of processes having a common base; gonyaulacacean, process formula: 4`, 6``, 6-12c, 5-6```, 1p, 1````, 2-5s.
Archeopyle: Apical, Type tA; outline of principal archeopyle suture often nearly smooth.
Paracingulum: Each paraplate indicated by single or multiple processes. The latter have a common base and are normally slender, tapered, expanded slightly distally, and much narrower than those on other parts of the cyst. Parasulcus: Indicated by two to five isolated intratabular processes; anterior and posterior processes larger than other parasulcal processes.
Size: Intermediate to large.
Affinities:
Hystrichokolpoma differs from Florentinia in having an apical archeopyle rather than a precingular or combination Type tA+P archeopyle. It differs from Hystrichosphaeridium in possessing processes of two different shapes rather than of a single shape. Achilleodinium, which has processes like those on Hystrichokolpoma, has a precingular archeopyle rather than an apical archeopyle.
---------------------------------------------------------------------------------------
Emended description Nelissen et al., 2025:
Emended diagnosis: The generic description of Hystrichokolpoma Klumpp 1953 is here emended to include species characterized by a distinct, robust, periphragmal membrane connecting the pre- and postcingular processes, overarching the cingular region (“cingular cavation”). The morphologically related genus Cousteaudinium de Verteuil and Norris, 1996 is distinctly circumcavate.
Full emendation: Species within the genus Hystrichokolpoma possess a gonyaulacacean, sexiform tabulation with dextral torsion. The cysts bear large, distally open penitabular processes situated on the apical, precingular, postcingular, and antapical plates. Processes on the paracingulum and parasulcus are markedly narrower, are often elongate, and may be distally open or closed. Here, we expand on the latter by including species in which the pre- and postcingular processes are connected with a periphragmal membrane overarching the cingular region. As a result of this overarching membrane in the cingular region, the cingular and sulcal processes become less visible and appear absent in some individuals. The archeopyle is apical, typically formed by the loss of a single plate.
Remarks. The morphologically related genus Oligokolpoma (Fensome et al., 2009) differs from Hystrichokolpoma emend. nov. by lacking any reflection of the cingular and sulcal plates.
----------------------------------------------------------------------------------------------------------------------------
Notes:
G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.
Hystrichokolpoma Klumpp, 1953, emend. Williams and Downie, 1966a, emend. Zevenboom and Santarelli in Zevenboom, 1995, was emended by Zevenboom and Santarelli in Zevenboom (1995) to include taxa lacking cingular and sulcal processes. The genus is characterised by large, distally open penitabular processes on the apical, precingular, postcingular and antapical plates and much narrower, often elongate, distally open or closed processes on the paracingulum and parasulcus. The tabulation is gonyaulacacean, sexiform, with dextral torsion. The archeopyle is apical.