Back
Muderongia
From Williams et al., 2017:
[Muderongia, Cookson and Eisenack, 1958, p. 40–41; Emendation: Monteil, 1991b, p. 470–471.
Tax. jun. syn.: Phoberocysta, according to Monteil (1991b, p.470) — however, Poulsen (1996, p.56) retained Phoberocysta; Pseudomuderongia, according to Helby (1987, p.297) and Stover and Williams (1987, p.181). Helby (1987, p.298) considered the "modified description" provided by Stover and Evitt (1978, p.66) to represent an emendation of Muderongia.
Type species: Muderongia mcwhaei, Cookson and Eisenack, 1958 (pl.6, fig.2)] ; emend. Helby, 1987
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original description: [Cookson and Eisenack, 1958]:
Diagnosis:
Test flattened, bilaterally symmetrical, composed of a thin outer membrane and an internal body or capsule. The outer membranes prolonged into four equidistant horns and crossed by a narrow shallow girdle. A longitudinal furrow is not developed.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Modified description:
Stover and Evitt, 1978, p. 66-67:
Synopsis:
Cysts proximate, generally cornucavate, body ceratioid with an apical, two cingular, and two antapical horns, of which one may be reduced or absent; proximal part of cingular horns in line with paracingulum, distal part directed antapically; periphragm smooth or weakly ornamented; archeopyle apical, Type tA; parasulcal notch offset.
Description:
Shape: Ceratioid; generally rhomboidal with an apical, two cingular, and two unequally developed antapical horns. Proximal part of cingular horns straight and in line with paracingulum, distal part directed antapically; the two parts commonly form an obtuse angle, and a short projection is typically present at the apex of the angle.
Wall relationships: Cysts generally cornucavate; a narrow antapical pericoel may be present.
Wall features: Parasutural features commonly absent; faint parasutural lines, low ridges, or ornamentation present on some species. Periphragm smooth or ornamented with scabrae or small spines; endophragm smooth or scabrate.
Paratabulation: Indicated by archeopyle, occasionally also by faint parasutural features; formula: 4`, 6``, 6c, 6```, 1p, 1```.
Archeopyle: Apical, Type tA; principal archeopyle suture zigzag; parasulcal notch offset; operculum free.
Paracingulum: Position indicated by cingular horns; other indications generally lacking or expressed as faint, parallel, transverse lines.
Parasulcus: Generally not indicated.
Size: Intermediate to large.
Affinities:
Muderongia differs from Phoberocysta in having a smooth to weakly ornamented periphragm, whereas the periphragm on Phoberocysta is ornamented with numerous irregularly shaped processes.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Emended description:
Monteil, 1991:
Synopsis:
Cysts proximate to proximochorate, compressed dorsoventrally, two-layered, cornucavate to circumcavate; pericyst ceratioid, asymmetrical or symmetrical, with usually 5 or 4 prominent horns: 1 apical, 2 lateral and 2 or 1 antapical; endocyst oval to rhombic or pentangular. Periphragm bearing processes or not. Gonyaulacacean paratabulation rarely completely indicated by low ornamental features or by processes; formula ?pr, 4`, 0a, (sic, 6`` missing here,) 6c, 6```, 1````, 1p, 3s (with rs, ls and ps fused). Archaeopyle apical, type (4A).
Diagnosis:
Shape: Cysts proximate to proximochorate, compressed dorsoventrally. Pericyst ceratioid, asymmetrical or symmetrical, with usually 5 or 4 prominent horns: 1 apical (Type AP I), 2 lateral (Types L I, II or IV) and 2 antapical (Types ATP I, II or III), the right one being always reduced or absent. Horns indented or not, normal or tapered, with distal extremities closed, rounded or pointed, sometimes perforated-scalloped or perforated-ragged. Proximal extremities of horns narrow or wide; endocyst oval to rhombic, sometimes with eccentric antapex extending in the left antapical horn, or pentangular, sometimes with a protrusion at the base of the horns or stretching out up to the middle part of the five horns.
Wall relationships: Cysts two-layered, cornucavate to delphicavate or circumcavate.
Wall features: Periphragm thin, psilate to scabrate, sometimes folded, microperforate, perfortae, spinous, or bearing processes; endophragm thin, psilate to granulate.
Archaeopyle: Apical, type (4A), angular margin; parasulcal notch marked. Operculum free.
Paratabulation: Indicated by archaeopyle and sometimes by low ridges or septa, and rarely by verrucae, by folds of periphragm and/or finely perforated areas. Formula: ?pr, 4`, 0a, 6``, 6c, 6```, 1````, 1p, 3s (with rs, ls and ps fused). fm (De Cruz and Monteil, in progress). More or less clearly expressed by distribution and type of processes (stages I to IV), when those are present.
Pericingulum: Marked by indentation of lateral horns and, generally, by parallel transverse structures. Endocingulum not observed.
Perisulcus: Marked by parasulcal notch offset, appearing sinuous when discernible. Exceptionally, perisulcal area clearly subdivided. Endosulcus not observed.
Size: Intermediate to large, length of pericyst 85-260 µm.
Affinities:
Muderongia differs from Odontochitina and Xenascus in having 5 or 4 horns rather than 3.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Poulsen 1996, p. 56, 59:
Remarks:
Monteil 1991 emended this genus to allow the inclusion of species with processes (i.e. species belonging to Phoberocysta) and circumcavate types. The emendation by Monteil is not followed in this study. Monteil (199lb) regards the stratigraphic succession of Senoniasphaera tabulata, Muderongia simplex, M. Iongicorna, and M. tabulata as having great value in the subdivision of the Late Kimmeridgian to Early Valanginian interval. Stratigraphic information for the Tithonian-Valanginian is found in Monteil (1992).
Re-attributed species and specimens:
The specimens figured by Monteil (1991b, pl. 1, figs. 3 a-c) as Senoniasphaera tabulata Backhouse and Helby 1987 (originally Muderongia sp. A of Davey 1979, p. 64, pl. 2, figs. 4-5), and the transfer of Muderongia sp. A of Davey 1979, p. 30, pl. 9, figs. 2-3 to Muderongia longicorna Monteil 1991b are here regarded as belonging to Muderongia simplex.
The specimens figured by Monteil (1991b) on pl. 2, figs. 4-5, as Muderongia tabulata (Raynaud 1978) Monteil 1991b are here regarded as a form of M. simplex with a short antapical horn. Such forms were included in the original description of M. tomaszowensis.
*Phoberocysta neocomica and *P. tabulata Raynaud 1978, which were transferred to Muderongia by Monteil (1991b) are herein retained in Phoberocysta, the latter genus being characterized by forms with pronounced spines. Lentin and Williams (1993) regarded P. neocomica as a taxonomic senior synonym of Muderongia tomaszowensis. This is also not followed here. The specimen figured by Monteil (1991b, pl. 2, fig. 3) as Muderongia longicorna is here regarded as a Phoberocysta species.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Notes:
G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.
Muderongia Cookson and Eisenack, 1958, emend. Monteil, 1991b. Helby (1987) recognized two groups in this genus. One is characterized by robust, broad based, cingular horns with variable development of the distal extremities of postcingular paraplates comprising the horns. The group includes Muderongia perforata, M.simplex, M.testudinaria, M.australis, M.tomaszowensis, M.macwhaei and M.staurota . The right antapical horn is variably developed. The apical and antapical horns are of relatively short to moderate length and their extremities are often rounded. There is considerable overlap of the species in this group. Group two includes Muderongia extensiva, M.tetracantha and M.imparilis and is characterized by a single, elongate, pointed antapical horn; long, antapically inclined, postcingular extensions of the cingular horns and a long, pointed, apical horn, resembling that of Odontochitina operculata. Monteil (1991b, p.470), in a major study and emendation of Muderongia , provided the following synopsis. Cysts proximate to proximochorate, compressed dorsoventrally, two-layered, cornucavate to circumcavate; pericyst ceratioid, asymmetrical or symmetrical with usually 5 or 4 prominent horns: 1 apical, 2 lateral, and 2 or 1 antapical; endocyst oval to rhombic or pentangular. Periphragm bearing processes or not. Gonyaulacacean paratabulation rarely completely indicated by low ornamental features or by processes; formula ?pr, 4`, 0a, 6", 6c, 6"', 1"'', 1p, 3s (with rs, ls and ps fused). Archeopyle apical, type (4A)
[Muderongia, Cookson and Eisenack, 1958, p. 40–41; Emendation: Monteil, 1991b, p. 470–471.
Tax. jun. syn.: Phoberocysta, according to Monteil (1991b, p.470) — however, Poulsen (1996, p.56) retained Phoberocysta; Pseudomuderongia, according to Helby (1987, p.297) and Stover and Williams (1987, p.181). Helby (1987, p.298) considered the "modified description" provided by Stover and Evitt (1978, p.66) to represent an emendation of Muderongia.
Type species: Muderongia mcwhaei, Cookson and Eisenack, 1958 (pl.6, fig.2)] ; emend. Helby, 1987
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original description: [Cookson and Eisenack, 1958]:
Diagnosis:
Test flattened, bilaterally symmetrical, composed of a thin outer membrane and an internal body or capsule. The outer membranes prolonged into four equidistant horns and crossed by a narrow shallow girdle. A longitudinal furrow is not developed.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Modified description:
Stover and Evitt, 1978, p. 66-67:
Synopsis:
Cysts proximate, generally cornucavate, body ceratioid with an apical, two cingular, and two antapical horns, of which one may be reduced or absent; proximal part of cingular horns in line with paracingulum, distal part directed antapically; periphragm smooth or weakly ornamented; archeopyle apical, Type tA; parasulcal notch offset.
Description:
Shape: Ceratioid; generally rhomboidal with an apical, two cingular, and two unequally developed antapical horns. Proximal part of cingular horns straight and in line with paracingulum, distal part directed antapically; the two parts commonly form an obtuse angle, and a short projection is typically present at the apex of the angle.
Wall relationships: Cysts generally cornucavate; a narrow antapical pericoel may be present.
Wall features: Parasutural features commonly absent; faint parasutural lines, low ridges, or ornamentation present on some species. Periphragm smooth or ornamented with scabrae or small spines; endophragm smooth or scabrate.
Paratabulation: Indicated by archeopyle, occasionally also by faint parasutural features; formula: 4`, 6``, 6c, 6```, 1p, 1```.
Archeopyle: Apical, Type tA; principal archeopyle suture zigzag; parasulcal notch offset; operculum free.
Paracingulum: Position indicated by cingular horns; other indications generally lacking or expressed as faint, parallel, transverse lines.
Parasulcus: Generally not indicated.
Size: Intermediate to large.
Affinities:
Muderongia differs from Phoberocysta in having a smooth to weakly ornamented periphragm, whereas the periphragm on Phoberocysta is ornamented with numerous irregularly shaped processes.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Emended description:
Monteil, 1991:
Synopsis:
Cysts proximate to proximochorate, compressed dorsoventrally, two-layered, cornucavate to circumcavate; pericyst ceratioid, asymmetrical or symmetrical, with usually 5 or 4 prominent horns: 1 apical, 2 lateral and 2 or 1 antapical; endocyst oval to rhombic or pentangular. Periphragm bearing processes or not. Gonyaulacacean paratabulation rarely completely indicated by low ornamental features or by processes; formula ?pr, 4`, 0a, (sic, 6`` missing here,) 6c, 6```, 1````, 1p, 3s (with rs, ls and ps fused). Archaeopyle apical, type (4A).
Diagnosis:
Shape: Cysts proximate to proximochorate, compressed dorsoventrally. Pericyst ceratioid, asymmetrical or symmetrical, with usually 5 or 4 prominent horns: 1 apical (Type AP I), 2 lateral (Types L I, II or IV) and 2 antapical (Types ATP I, II or III), the right one being always reduced or absent. Horns indented or not, normal or tapered, with distal extremities closed, rounded or pointed, sometimes perforated-scalloped or perforated-ragged. Proximal extremities of horns narrow or wide; endocyst oval to rhombic, sometimes with eccentric antapex extending in the left antapical horn, or pentangular, sometimes with a protrusion at the base of the horns or stretching out up to the middle part of the five horns.
Wall relationships: Cysts two-layered, cornucavate to delphicavate or circumcavate.
Wall features: Periphragm thin, psilate to scabrate, sometimes folded, microperforate, perfortae, spinous, or bearing processes; endophragm thin, psilate to granulate.
Archaeopyle: Apical, type (4A), angular margin; parasulcal notch marked. Operculum free.
Paratabulation: Indicated by archaeopyle and sometimes by low ridges or septa, and rarely by verrucae, by folds of periphragm and/or finely perforated areas. Formula: ?pr, 4`, 0a, 6``, 6c, 6```, 1````, 1p, 3s (with rs, ls and ps fused). fm (De Cruz and Monteil, in progress). More or less clearly expressed by distribution and type of processes (stages I to IV), when those are present.
Pericingulum: Marked by indentation of lateral horns and, generally, by parallel transverse structures. Endocingulum not observed.
Perisulcus: Marked by parasulcal notch offset, appearing sinuous when discernible. Exceptionally, perisulcal area clearly subdivided. Endosulcus not observed.
Size: Intermediate to large, length of pericyst 85-260 µm.
Affinities:
Muderongia differs from Odontochitina and Xenascus in having 5 or 4 horns rather than 3.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Poulsen 1996, p. 56, 59:
Remarks:
Monteil 1991 emended this genus to allow the inclusion of species with processes (i.e. species belonging to Phoberocysta) and circumcavate types. The emendation by Monteil is not followed in this study. Monteil (199lb) regards the stratigraphic succession of Senoniasphaera tabulata, Muderongia simplex, M. Iongicorna, and M. tabulata as having great value in the subdivision of the Late Kimmeridgian to Early Valanginian interval. Stratigraphic information for the Tithonian-Valanginian is found in Monteil (1992).
Re-attributed species and specimens:
The specimens figured by Monteil (1991b, pl. 1, figs. 3 a-c) as Senoniasphaera tabulata Backhouse and Helby 1987 (originally Muderongia sp. A of Davey 1979, p. 64, pl. 2, figs. 4-5), and the transfer of Muderongia sp. A of Davey 1979, p. 30, pl. 9, figs. 2-3 to Muderongia longicorna Monteil 1991b are here regarded as belonging to Muderongia simplex.
The specimens figured by Monteil (1991b) on pl. 2, figs. 4-5, as Muderongia tabulata (Raynaud 1978) Monteil 1991b are here regarded as a form of M. simplex with a short antapical horn. Such forms were included in the original description of M. tomaszowensis.
*Phoberocysta neocomica and *P. tabulata Raynaud 1978, which were transferred to Muderongia by Monteil (1991b) are herein retained in Phoberocysta, the latter genus being characterized by forms with pronounced spines. Lentin and Williams (1993) regarded P. neocomica as a taxonomic senior synonym of Muderongia tomaszowensis. This is also not followed here. The specimen figured by Monteil (1991b, pl. 2, fig. 3) as Muderongia longicorna is here regarded as a Phoberocysta species.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Notes:
G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.
Muderongia Cookson and Eisenack, 1958, emend. Monteil, 1991b. Helby (1987) recognized two groups in this genus. One is characterized by robust, broad based, cingular horns with variable development of the distal extremities of postcingular paraplates comprising the horns. The group includes Muderongia perforata, M.simplex, M.testudinaria, M.australis, M.tomaszowensis, M.macwhaei and M.staurota . The right antapical horn is variably developed. The apical and antapical horns are of relatively short to moderate length and their extremities are often rounded. There is considerable overlap of the species in this group. Group two includes Muderongia extensiva, M.tetracantha and M.imparilis and is characterized by a single, elongate, pointed antapical horn; long, antapically inclined, postcingular extensions of the cingular horns and a long, pointed, apical horn, resembling that of Odontochitina operculata. Monteil (1991b, p.470), in a major study and emendation of Muderongia , provided the following synopsis. Cysts proximate to proximochorate, compressed dorsoventrally, two-layered, cornucavate to circumcavate; pericyst ceratioid, asymmetrical or symmetrical with usually 5 or 4 prominent horns: 1 apical, 2 lateral, and 2 or 1 antapical; endocyst oval to rhombic or pentangular. Periphragm bearing processes or not. Gonyaulacacean paratabulation rarely completely indicated by low ornamental features or by processes; formula ?pr, 4`, 0a, 6", 6c, 6"', 1"'', 1p, 3s (with rs, ls and ps fused). Archeopyle apical, type (4A)