FIGURES 7–13 in Sporolithon yoneshigueae sp. nov. (Sporolithales, Corallinophycidae, Rhodophyta), a new rhodolith-forming coralline alga from the southwest Atlantic

FIGURES 7–13. Tetrasporangial anatomy of Sporolithon yoneshigueae. 7. Magnified surface view of a protuberance showing a sorus with large tetrasporangial compartment pores (RB 505770). Scale bar = 500 μm. 8. SEM of the surface of a sorus showing tetrasporangial compartment pores (RB 569425). Scale bar = 80 μm. 9. SEM of a single tetrasporangial compartment pore surrounded by 24 rosette cells that are slightly raised towards the pore opening (RB 569425). Note the mucilage ring that forms inward of the rosette cells, which only partially occludes the pore (arrow). Scale bar = 30 μm. 10. Vertical section of the outer thallus showing numerous tetrasporangial compartments buried in distinct layers (RB 505770). Note the distinct layers of elongate cells at the base of tetrasporangial compartments. Scale bar = 300 μm. 11. Magnified view of the thallus showing the paraphyses (arrows) between tetrasporangial compartments (RB 505770). Scale bar = 60 μm. 12. Vertical section of the outer thallus showing a raised sorus (RB 505770). Note the tetrasporangial compartment bearing a single tetrasporangium (t) and an apical pore plug (arrow). Scale bar = 50 μm. 13. Magnified view of the base of a tetrasporangial compartment showing a tetrasporangium (t) subtended by a single stalk cell (arrow) (RB 505770). Scale bar = 25 μm.