During an investigation of the marine phototrophic biodiversity of the Ross Sea, a crustose coralline alga was collected from two sites in Tethys Bay. The alga formed thin crusts adherent to cobbles at ~20 m depth and showed morpho-anatomical features typical of the order Hapalidiales, family Hapalidiaceae (cell fusions, zonate tetrasporangia produced in multiporate conceptacles, and apical plugs). Molecular phylogenies based on the psbA, rbcL and 18S rRNA genes showed that this alga formed a lineage in the family Hapalidiaceae for which a formal assignment at genus level was not yet available. The only other known member of the lineage was a coralline from the Balleny Islands, named as Hapalidiaceae sp. ASG448A, for which psbA and 18S rRNA sequences were deposited in GenBank without identification at genus and species level. Based on our results, we describe this lineage as the new genus Tethysphytum Sciuto, Moschin & Moro, with the single species Tethysphytum antarcticum Sciuto, Moschin & Moro. At present, morpho-anatomical characters do not allow for the discrimination of Tethysphytum from other similar genera of Hapalidiaceae. The discovery of a new genus suggests that the diversity of coralline algae in Antarctica may have been underestimated and that molecular data will be essential for future taxonomic assessments of this group within this region.
Tethysphytum antarcticum gen. et sp. nov. (Hapalidiales, Rhodophyta), a new non geniculate coralline alga from Terra Nova Bay (Ross Sea, Antarctica): morpho-anatomical characterization and molecular phylogeny
ALONGI Giuseppina;
2021-01-01
Abstract
During an investigation of the marine phototrophic biodiversity of the Ross Sea, a crustose coralline alga was collected from two sites in Tethys Bay. The alga formed thin crusts adherent to cobbles at ~20 m depth and showed morpho-anatomical features typical of the order Hapalidiales, family Hapalidiaceae (cell fusions, zonate tetrasporangia produced in multiporate conceptacles, and apical plugs). Molecular phylogenies based on the psbA, rbcL and 18S rRNA genes showed that this alga formed a lineage in the family Hapalidiaceae for which a formal assignment at genus level was not yet available. The only other known member of the lineage was a coralline from the Balleny Islands, named as Hapalidiaceae sp. ASG448A, for which psbA and 18S rRNA sequences were deposited in GenBank without identification at genus and species level. Based on our results, we describe this lineage as the new genus Tethysphytum Sciuto, Moschin & Moro, with the single species Tethysphytum antarcticum Sciuto, Moschin & Moro. At present, morpho-anatomical characters do not allow for the discrimination of Tethysphytum from other similar genera of Hapalidiaceae. The discovery of a new genus suggests that the diversity of coralline algae in Antarctica may have been underestimated and that molecular data will be essential for future taxonomic assessments of this group within this region.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
