Back
Muderongia extensiva
Muderongia extensiva Duxbury, 1977
Tax. jr. synonym of Muderongia macwhaei Cookson and Eisenack, 1958, according to Monteil, 1991.- however, Poulsen (1996, p.57) retained Muderongia extensiva.
Holotype: Duxbury, 1977, pl.15, fig.10
Locus typicus: Speeton, England
Stratum typicum: Valanginian-Early Hauterivian
Original diagnosis: Duxbury, 1977, p.54
A species of Muderongia with four very prominent horns, one apical, two lateral and one antapical. The last is slightly offset from the antapical pole. Ille lateral horns are long and extend almost at right angles from the test. They are distally notched and these notches probably reflect the cingulum. Anteriorly, the distal extremes of the cingular notches are produced into short spines. In contrast, they are posteriorly produced into long, backwardly-directed spines. These curve slightly towards the main body of the cyst and taper to sharp points.
Observed Dimensions: Holotype (complete) 227 x 165 Ám. Complete specimens-- Overall 227x165 Ám. Archeopyle formed--Overall 132(119)99 x 171(149)12 Ám.
Poulsen 1996 p.57 Pl. 23, Fig. 1
Muderongia extensiva Duxbury, 1977, p. 54-55, pl. 15, fig. 10.
Remarks. Monteil (1991b) regarded Muderongia extensiva Duxbury 1977 as a taxonomic junior synonym of Muderongia macwhaei Cookson and Eisenack 1958, which he found to be a useful index fossil for the Early Valanginian of south-east France. The cingular horns on the holotype of M. macwhaei extend in an oblique angle from the cyst body, whereas the proximal part of the cingular horns on M. extensiva extend almost at right angles from the cyst body. Therefore, Monteil"s synonymy between these two species is not followed here and the two species are retained separately.
Recorded occurrence. Denmark: Skagen-2 borehole, 820 ft., Pseudoceratium pelliferum Zone, latest Ryazanian to earliest Valanginian.
Tax. jr. synonym of Muderongia macwhaei Cookson and Eisenack, 1958, according to Monteil, 1991.- however, Poulsen (1996, p.57) retained Muderongia extensiva.
Holotype: Duxbury, 1977, pl.15, fig.10
Locus typicus: Speeton, England
Stratum typicum: Valanginian-Early Hauterivian
Original diagnosis: Duxbury, 1977, p.54
A species of Muderongia with four very prominent horns, one apical, two lateral and one antapical. The last is slightly offset from the antapical pole. Ille lateral horns are long and extend almost at right angles from the test. They are distally notched and these notches probably reflect the cingulum. Anteriorly, the distal extremes of the cingular notches are produced into short spines. In contrast, they are posteriorly produced into long, backwardly-directed spines. These curve slightly towards the main body of the cyst and taper to sharp points.
Observed Dimensions: Holotype (complete) 227 x 165 Ám. Complete specimens-- Overall 227x165 Ám. Archeopyle formed--Overall 132(119)99 x 171(149)12 Ám.
Poulsen 1996 p.57 Pl. 23, Fig. 1
Muderongia extensiva Duxbury, 1977, p. 54-55, pl. 15, fig. 10.
Remarks. Monteil (1991b) regarded Muderongia extensiva Duxbury 1977 as a taxonomic junior synonym of Muderongia macwhaei Cookson and Eisenack 1958, which he found to be a useful index fossil for the Early Valanginian of south-east France. The cingular horns on the holotype of M. macwhaei extend in an oblique angle from the cyst body, whereas the proximal part of the cingular horns on M. extensiva extend almost at right angles from the cyst body. Therefore, Monteil"s synonymy between these two species is not followed here and the two species are retained separately.
Recorded occurrence. Denmark: Skagen-2 borehole, 820 ft., Pseudoceratium pelliferum Zone, latest Ryazanian to earliest Valanginian.