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Muderongia asymmetrica
Muderongia asymmetrica Brideaux, 1977; emend. Monteil, 1991
Originally (and now) Muderongia, subsequently Pseudomuderongia.
Jain and Khowaja-Ateequzzaman, 1984, transferred this species to Pseudomuderongia Jain and Khowaja-Ateequzzaman, 1984. Stover and Williams, 1987, retained it in Muderongia.
Holotype: Brideaux, 1977, pl.15, fig.9, pl.16, fig.1
Locus typicus: Richardson Mountains, Mackenzie, Canada
Stratum typicum: Aptian-Albian
Original diagnosis: Brideaux, 1977, p. 40
Shape: Pericyst ambitus elongate, the main portion pentagonal to subrhombic; epipericyst prolonged into a long, tapering apical horn; hypopericyst prolonged antapically to form a longer tapering left antapical horn and a shorter, tapering to acuminate right antapical horn; laterally, hypopericyst produced to form a shorter right postcingular and longer left postcingular horn. Left antapical horn from one and one-half to three times the length of the right antapical horn; right postcingular horn distinctly longer and up to four times as long as the left postcingular horn; right postcingular horn broad at the base but tapering abruptly at about half its length.
Endocyst ambitus follows that of pericyst, but extends only slightly or not at all into the apical, postcingular and antapical horns. One apical, two lateral and two antapical pericoels formed in the broad sense; ambital pericoel not developed; dorso-ventral compression.
Phragma: Periphragm about 1.0 Ám thick, of constant thickness; surface smooth or granulate. Endophragm thin, less than 0.5 Ám thick, of constant thickness.
Paratabulation: Evident only in the formation of the archeopyle, denoted by the zig-zag shape of the archeopyle outline-details of paratabulation not observed.
Archeopyle/operculum: Peri- and endoarcheopyle formed by the loss of the apical part of the peri- and endocyst; perioperculum presumably simple, detached, as is endoperculum; detached opercula not observed. Formula. A/A.
Pericingulum/perisulcus. Not observed.
Dimensions: Pericyst width (2 complete specimens), 103, 118 Ám; pericyst width (excluding postcingular horns), 43-58 Ám; left postcingular horn, 12-38 Ám; right postcingular horn, 15-33 Ám; left antapical horn, 25-60 Ám; right antapical horn, 10-35 Ám.
Emended diagnosis: Monteil, 1991, p. 472
Cysts proximate, compressed dorso-ventrally, two-layered, cornucavate. Pericyst ceratioid, asymmetrical, with 5 prominent tapered horns: 1 apical (axial, type AP l); 2 inequal lateral (bent, type L ll), indented; 2 inequal antapical (not joined, type ATP lll). Left lateral horn shorter (up to four times) than the right one. Left antapical horn longer (up to one and one-half to three times) than the right one. Distal extremities of horns closed and pointed; proximal extremities narrow to wide. The right lateral horn is always wider than the other one. Endocyst rhombic or pentangular, sometimes with a protrusion at the base of the horns. Periphragm thin, psilate to scabrate. Endophragm thin, psilate to granulate. Archeopyle apical, type (4A), with angular margin. Operculum free. Paratabulation marked only by archeopyle and by pericingulum. Pericingulum indicated by indentation of lateral horns. Perisulcus not observed.
Affinities:
Brideaux, 1977, p. 40: Muderongia asymmetrica is distinguished from other species of the genus by its possession of two developed antapical horns and by the pairing of long left antapical and short right postcingular horns and short right antapical and long left postcingular horns. "Pseudoceratium sp. A" of Davis (1963, p. 130, Pl. 10, figs. 9-12; unpubl. thesis) possesses a shorter and broader apical horn and postcingular and antapical horns in equal-sized pairs.
Monteil, 1991, p. 472: Muderongia asymmetrica emend. differs from M. testudinaria emend in having an asymmetrical rather than symmetrical ambitus.
Originally (and now) Muderongia, subsequently Pseudomuderongia.
Jain and Khowaja-Ateequzzaman, 1984, transferred this species to Pseudomuderongia Jain and Khowaja-Ateequzzaman, 1984. Stover and Williams, 1987, retained it in Muderongia.
Holotype: Brideaux, 1977, pl.15, fig.9, pl.16, fig.1
Locus typicus: Richardson Mountains, Mackenzie, Canada
Stratum typicum: Aptian-Albian
Original diagnosis: Brideaux, 1977, p. 40
Shape: Pericyst ambitus elongate, the main portion pentagonal to subrhombic; epipericyst prolonged into a long, tapering apical horn; hypopericyst prolonged antapically to form a longer tapering left antapical horn and a shorter, tapering to acuminate right antapical horn; laterally, hypopericyst produced to form a shorter right postcingular and longer left postcingular horn. Left antapical horn from one and one-half to three times the length of the right antapical horn; right postcingular horn distinctly longer and up to four times as long as the left postcingular horn; right postcingular horn broad at the base but tapering abruptly at about half its length.
Endocyst ambitus follows that of pericyst, but extends only slightly or not at all into the apical, postcingular and antapical horns. One apical, two lateral and two antapical pericoels formed in the broad sense; ambital pericoel not developed; dorso-ventral compression.
Phragma: Periphragm about 1.0 Ám thick, of constant thickness; surface smooth or granulate. Endophragm thin, less than 0.5 Ám thick, of constant thickness.
Paratabulation: Evident only in the formation of the archeopyle, denoted by the zig-zag shape of the archeopyle outline-details of paratabulation not observed.
Archeopyle/operculum: Peri- and endoarcheopyle formed by the loss of the apical part of the peri- and endocyst; perioperculum presumably simple, detached, as is endoperculum; detached opercula not observed. Formula. A/A.
Pericingulum/perisulcus. Not observed.
Dimensions: Pericyst width (2 complete specimens), 103, 118 Ám; pericyst width (excluding postcingular horns), 43-58 Ám; left postcingular horn, 12-38 Ám; right postcingular horn, 15-33 Ám; left antapical horn, 25-60 Ám; right antapical horn, 10-35 Ám.
Emended diagnosis: Monteil, 1991, p. 472
Cysts proximate, compressed dorso-ventrally, two-layered, cornucavate. Pericyst ceratioid, asymmetrical, with 5 prominent tapered horns: 1 apical (axial, type AP l); 2 inequal lateral (bent, type L ll), indented; 2 inequal antapical (not joined, type ATP lll). Left lateral horn shorter (up to four times) than the right one. Left antapical horn longer (up to one and one-half to three times) than the right one. Distal extremities of horns closed and pointed; proximal extremities narrow to wide. The right lateral horn is always wider than the other one. Endocyst rhombic or pentangular, sometimes with a protrusion at the base of the horns. Periphragm thin, psilate to scabrate. Endophragm thin, psilate to granulate. Archeopyle apical, type (4A), with angular margin. Operculum free. Paratabulation marked only by archeopyle and by pericingulum. Pericingulum indicated by indentation of lateral horns. Perisulcus not observed.
Affinities:
Brideaux, 1977, p. 40: Muderongia asymmetrica is distinguished from other species of the genus by its possession of two developed antapical horns and by the pairing of long left antapical and short right postcingular horns and short right antapical and long left postcingular horns. "Pseudoceratium sp. A" of Davis (1963, p. 130, Pl. 10, figs. 9-12; unpubl. thesis) possesses a shorter and broader apical horn and postcingular and antapical horns in equal-sized pairs.
Monteil, 1991, p. 472: Muderongia asymmetrica emend. differs from M. testudinaria emend in having an asymmetrical rather than symmetrical ambitus.