Sunday, February 23, 2020

[Phycology • 2020] Pyropia meridionalis • An Appraisal of the Genus Pyropia (Bangiales, Rhodophyta) from southern Africa based on A Multi-gene Phylogeny, Morphology and Ecology, including the Description of A New Species

Pyropia meridionalis M.M. Reddy, R.J. Anderson et J.J. Bolton

in Reddy, De Clerck, Leliaert, et al., 2020. 

• An appraisal of the genus Pyropia from southern Africa was carried out using an integrative taxonomic approach.
• A new, kelp-associated, species was described from the region.
• Species boundaries were confirmed for two other species of Pyropia endemic to the region.
• Species-level relationships of southern African Pyropia were considered in a global phylogenetic context.

Since its reinstatement, the diversity of the genus Pyropia has never been fully assessed in the Benguela Marine Province in southern Africa (South Africa and Namibia), although it has been included in previous, more general biodiversity assessments. The aim of the present study was to revisit the diversity and identity of species of Pyropia from the region, using an integrative taxonomic approach, including a multigene phylogeny, morphological characterisation and ecological data. The phylogenetic affinities of southern African Pyropia to other species around the world were assessed using three unlinked loci (cox1, rbcL, nSSU rDNA). A species first collected on the South African coast ca. 60 years ago is described as a new species, Pyropia meridionalis, and extended descriptions and further information provided on the distribution and ecology for two previously described species endemic to the Benguela Marine Province: Py. saldanhae and Pyaeodis. Lastly, the identity and occurrence of Py. gardneri, a species widely distributed in North America, could not be confirmed in South Africa, while the cosmopolitan Pysuborbiculata likely occurs in the region but is currently lacking molecular data. The phylogenetic relationships between species from southern Africa and other species occurring in the Southern Hemisphere support the notion of historic connectivity in the Southern Ocean, but also indicate a much more complex historical biogeographical history as some clades are deeply divergent while others are more closely related.

Keywords: Bangiales, Integrated taxonomy, Molecular systematics

Morphological and anatomical features of Pyropia meridionalis sp. nov. 
a) Pymeridionalis attached to its host Cymbula compressa; b) General morphology (holdfast inset); c) Surface view of cells along the thallus margin; d) Surface view of non-reproductive cells; e) non-reproductive in cross section of thallus, showing blade thickness; f) Rhizoidal cells near thallus base; g) Surface view of reproductive cells; h) Cross section of thallus showing female reproductive cells with distinct trichogynes on opposite ends; i) Female reproductive cells (larger & elliptical) and spermatia (lanceolate to fusiform); j) Zygotosporangium.

Pyropia meridionalis M.M. Reddy, R.J. Anderson et J.J. Bolton sp. nov.

Etymology: This species is named for its distribution along the coastline of southern Africa, (meridionalis in Latin means southern).

 Maggie M. Reddy, Olivier De Clerck, Frederik Leliaert, Robert J. Anderson and John J.Bolton. 2020. An Appraisal of the Genus Pyropia (Bangiales, Rhodophyta) from southern Africa based on A Multi-gene Phylogeny, Morphology and Ecology, including the Description of Pyropia meridionalis sp. nov. South African Journal of Botany. 131; 18-32. DOI: 10.1016/j.sajb.2019.12.027