Sporolithon franciscanum sp. nov. (Sporolithales, Rhodophyta), a New Rhodolith-Forming Species from Northeast Brazil

Luis Alfredo S Leão,Leonardo T Salgado,Walter H Adey,Michel B Jesionek,Renato C Pereira,Ricardo G Bahia,Gabriel Johnson

doi:10.3390/d12050199

Abstract

This paper describes Sporolithon franciscanum, a new rhodolith-forming species of non-geniculate coralline algae found at depths between 47–52 m near the São Francisco river mouth, the second largest and the most extensive drainage basin in Brazil, and also at the Abrolhos Bank, in the world´s largest rhodolith beds. DNA sequences from plastidial psbA and rbcL markers indicate that the species is unique compared to all other Sporolithon species that have thus far been sequenced. Since morpho-anatomical features of the new species are shared with some other Sporolithon species, its identification was only confirmed by DNA sequences.

Highlights

Coralline red algae (Corallinophycidae, Rhodophyta) have as their main feature the deposition of calcium carbonate polymorphs on their cell walls [1,2,3,4]
The phylogram shows that Sporolithon franciscanum formed a highly supported (93/0.99, Maximum Likelihood (ML) and Bayesian Inference (BI)) clade sister to S. eltorensis and an Australian Sporolithon sp
Taxonomic inventories are becoming even more urgent to support local conservation and management actions directed towards rhodolith beds

Summary

Introduction

Coralline red algae (Corallinophycidae, Rhodophyta) have as their main feature the deposition of calcium carbonate polymorphs (calcite, dolomite, magnesite, aragonite, calcite with low magnesium content) on their cell walls [1,2,3,4]. Non-geniculate coralline algae are considered one of the most difficult groups within the Rhodophyta in terms of taxonomic identification [5,6,7]. This perception can be attributed largely to the fact that, unlike most seaweeds, they have a calcified thallus that requires specific and time-consuming laboratory methods for taxonomic analyses [8]. Most identification from order (Corallinales, Hapalidiales, Sporolithales) to species level requires analyses of characteristics related to the reproductive structures (conceptacles or calcified compartments) from the tetra/bisporophytic phases [9]. In most cases morpho-anatomical identification in coralline algae is based on a combination of both vegetative and reproductive characteristics [9]

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Conclusion