Sporolithon yoneshigueae Bahia, Amado-Filho, Maneveldt & W.H.Adey, 2015

Sporolithon yoneshigueae Bahia, Amado-Filho, Maneveldt & W.H.Adey , sp. nov. ( Figs. 2–13 View FIGURES 2–6 View FIGURES 7–13 )

Etymology: " yoneshigueae " in honor of Brazilian phycologist Dr. Yocie Yoneshigue-Valentin for her invaluable contributions to the marine sciences.

Diagnosis: With the characteristics of the genus Sporolithon ; differing from all other species by tetrasporangial compartments that characteristically have larger pore diameters (≥ 35 μm) and consequently have greater numbers of rosette cells surrounding the tetrasporangial compartment pores (≥ 19).

Holotype: Brazil, Bahia, Plataforma Continental de Abrolhos , 17º48`35``S; 38º11`03``W, 28 m depth, GM Amado Filho, 23.x.2008. The holotype here selected is deposited at Jardim Botânico do Rio de Janeiro ( RB 569425 ). GoogleMaps

Isotypes: two isotype specimens have been selected ( RB 569426 , RB 569427 ) .

Paratypes: Brazil, Espírito Santo, Cadeia Vitória-Trindade, Banco Jaseur , 20°29'17'' S; 30°06'07'' W, 66 m depth (GM Amado Filho, 12.iii.2009, RB 505770 , RB 569466 , RB 569468 ) GoogleMaps ; Brazil, Espírito Santo, Cadeia Vitória-Trindade, Banco Davis , 20°34'42'' S, 34°46'12'' W, 57 m depth (GM Amado Filho, 14.ii.2011, RB 569467 ) GoogleMaps ; Brazil, Bahia, Plataforma Continental de Abrolhos , 17º54`01``S; 37º54`56``W, 52 m depth (GM Amado Filho, 11.iii.2012, RB 570782 ). GoogleMaps Brazil, Bahia, Plataforma Continental de Abrolhos , 17º48`35``S; 38º11`03``W, 28 m depth (DS Cajueiro Filho, 27.x.2013, RB 600359 , RB 600360 , RB 600362 ) GoogleMaps .

Distribution: Southeastern Brazil: Vitória-Trindade Chain and Espírito Santo State; northeastern Brazil: Abrolhos Bank ( Fig. 1 View FIGURE 1 ).

Representative specimens examined: In addition to the type specimens designated above, the following specimens were also examined: Espírito Santo State, Brazil (19º37`S; 39º27W, 46–77 m depth, NY Tomita, date unknown, SP 138576 , as Sporolithon mediterraneum , slides only) GoogleMaps ; Espírito Santo State, Brazil (20º10`S; 40 º02`W, 60 m depth, NY Tomita, date unknown, SP 114638 , SP 114641 , SP 114642 , as Sporolithon mediterraneum , slides only) GoogleMaps .

Morphological/Anatomical Analysis

Habit: Thalli non-geniculate, free-living and forming rhodoliths of up to 15 cm in diameter ( Figs. 2–3 View FIGURES 2–6 ) produced by successive, multiple overgrowing thalli. Crusts firmly adherent and when freshly collected, living thalli are pink to deep purple in colour. Thalli measure 1000–2500 μm thick and are warty to lumpy to fruticose ( Figs. 2–3 View FIGURES 2–6 ). Thalli bear numerous irregularly shaped protuberances that measure 2–15 mm in length and 2–13 mm in diameter ( Figs. 2–3 View FIGURES 2–6 ).

Vegetative anatomy: Thalli dorsiventral, monomerous; haustoria absent ( Fig. 4 View FIGURES 2–6 ). Hypothallus plumose (noncoaxial), comprising 5–13 layers of cells. Hypothallial cells predominantly cylindrical, 10–30 μm in length by 5–15 μm in diameter. Perithallial cells squat to square to rectangular, 5–25 μm in length by 4–15 μm in diameter ( Figs. 4–5 View FIGURES 2–6 ). Cells of contiguous filaments joined by both cell fusions and secondary pit connections ( Fig. 6 View FIGURES 2–6 ); cell fusions predominate by a ratio of 2–3:1. Subepithallial initials squat to square, 6–8 μm in length by 12–15 μm in diameter, typically as long as their immediate inward derivatives ( Fig. 5 View FIGURES 2–6 ). Epithallial cells occurring in a single layer, flattened and flared ( Fig. 5 View FIGURES 2–6 ), 2–4 μm in length by 5–8 μm in diameter.

Reproductive anatomy: Gametangial plants not observed.

Tetrasporangia occurring individually in calcified compartments that are aggregated in superficial sori. Sori raised 5–8 cells above the surrounding vegetative thallus ( Figs. 7–13 View FIGURES 7–13 ) and located predominantly at the tips of protuberances ( Fig. 7 View FIGURES 7–13 ). Tetrasporangial compartments elliptical to rounded, 140–210 μm in height and 70–130 μm in diameter, separated from one another by 1–11 paraphyses composed of 5–8 elongate cells ( Fig. 11 View FIGURES 7–13 ). Individual compartments formed on a distinct basal layer of elongate cells ( Figs. 10–13 View FIGURES 7–13 ). Compartment pores are large, 35–43 μm in diameter and surrounded by 19–24 rosette cells ( Figs. 7–9 View FIGURES 7–13 ) that are partly occluded by a mucilage ring around the pore opening ( Figs. 8–9 View FIGURES 7–13 ). Tetrasporangia cruciately divided, 90–140 μm in length by 80–100 μm in diameter ( Figs. 12–13 View FIGURES 7–13 ). Tetrasporangia bear apical pore plugs and are subtended by a single stalk cell measuring 20–40 μm in length by 25–50 μm in diameter ( Figs. 12–13 View FIGURES 7–13 ). Entire senescent tetrasporangial sori become buried in distinct layers in the thallus by overgrowing vegetative tissue ( Fig. 10 View FIGURES 7–13 )