Diplopora johnsoni and Selliporella neocomiensis are often considered synonymous. The two taxa share the same pattern consisting in a cylindrical, articulated biomineralised skeleton bearing whorls of short primary laterals followed by numerous long, trichophorous, secondary laterals. An exhaustive study, entailing a review of Praturlon's type-material of Diplopora johnsoni, displays the different framework and biometry between them. Therefore, the two species are considered separate taxa. Moreover, a controversial generic attribution of the two taxa is highlighted in literature: Selliporella neocomiensis has been attributed to both the genus Pseudoclypeina and to the genus Selliporella, while Diplopora johnsoni has been assigned to the genus Pseudoclypeina. Regarding the comparison between the genera Selliporella and Pseudoclypeina, and their respective type species, there is no doubt that Diplopora johnsoni and Selliporella neocomiensis display the closest affinity with Selliporella (short primary laterals and trichophorous secondary laterals) and not with Pseudoclypeina (long phloiophorous primary laterals and phloiophorous secondary laterals). Thus, the two taxa are ascribed to the genus Selliporella. The former species is named Selliporella johnsonii n.comb. Further relevant results show that Selliporella johnsonii and Selliporella neocomiensis display a different chronostratigraphic distribution. In the Apennine Carbonate Platform (southern Apennines, Italy), Selli-porella johnsonii has been well calibrated through high-resolution C-isotope stratigraphy and biostratigraphy as revealed in previous studies. This taxon constitutes a peculiar bioevent set between the end of the Weissert event and the Valanginian−Hauterivian boundary, thus may serve as a possible instrument in locating the Weissert event in the field. On the other hand, Selliporella neocomiensis found in the Getic Carbonate Platform (South Carpathians, Romania), appears to characterise the Berriasian stage.
Selliporella johnsonii (Praturlon) nov.comb. and Selliporella neocomiensis (Radoičić) (green algae, Dasycladales), taxonomic reconsideration and chronostratigraphic calibration
Amodio S.
;
2021-01-01
Abstract
Diplopora johnsoni and Selliporella neocomiensis are often considered synonymous. The two taxa share the same pattern consisting in a cylindrical, articulated biomineralised skeleton bearing whorls of short primary laterals followed by numerous long, trichophorous, secondary laterals. An exhaustive study, entailing a review of Praturlon's type-material of Diplopora johnsoni, displays the different framework and biometry between them. Therefore, the two species are considered separate taxa. Moreover, a controversial generic attribution of the two taxa is highlighted in literature: Selliporella neocomiensis has been attributed to both the genus Pseudoclypeina and to the genus Selliporella, while Diplopora johnsoni has been assigned to the genus Pseudoclypeina. Regarding the comparison between the genera Selliporella and Pseudoclypeina, and their respective type species, there is no doubt that Diplopora johnsoni and Selliporella neocomiensis display the closest affinity with Selliporella (short primary laterals and trichophorous secondary laterals) and not with Pseudoclypeina (long phloiophorous primary laterals and phloiophorous secondary laterals). Thus, the two taxa are ascribed to the genus Selliporella. The former species is named Selliporella johnsonii n.comb. Further relevant results show that Selliporella johnsonii and Selliporella neocomiensis display a different chronostratigraphic distribution. In the Apennine Carbonate Platform (southern Apennines, Italy), Selli-porella johnsonii has been well calibrated through high-resolution C-isotope stratigraphy and biostratigraphy as revealed in previous studies. This taxon constitutes a peculiar bioevent set between the end of the Weissert event and the Valanginian−Hauterivian boundary, thus may serve as a possible instrument in locating the Weissert event in the field. On the other hand, Selliporella neocomiensis found in the Getic Carbonate Platform (South Carpathians, Romania), appears to characterise the Berriasian stage.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
