Lithophyllum stictaeforme (Areschoug) Hauck, 1877: 292

Tâmega, Frederico T. S., Riosmena-Rodriguez, Rafael, Mariath, Paula Spotorno-Oliveira Rodrigo, Khader, Samir & Figueiredo, Marcia A. O., 2015, Taxonomy and distribution of non-geniculate coralline red algae (Corallinales, Rhodophyta) on rocky reefs from Ilha Grande Bay, Brazil, Phytotaxa 192 (4), pp. 267-278 : 270-272

Lithophyllum stictaeforme (Areschoug) Hauck, 1877: 292

( Figs. 6–9 )

Basionym:— Melobesia stictaeformis Areschoug in J. Agardh, 1852: 517.

Lectotype:— S (unnumbered); designated and illustrated in Athanasiadis (1999: 738, Fig. 1 ).

Type locality:—Mediterranean Sea ( Athanasiadis 1999: 738, Fig. 1 )

Homotypic synonyms:— Lithophyllum expansum f. stictaeformis (Areschoug) Foslie, 1900: 18 .

Heterotypic synonyms:— Dermatolithon bermudense (Foslie & M.Howe) Foslie & M.Howe in Foslie, 1909: 58; Lithophyllum bermudense Foslie & M.Howe, 1906: 132 ; Lithophyllum expansum f. agariciforme Hauck, 1885: 269 ; Lithophyllum frondosum (Dufour) G. Furnari, Cormaci & Alongi, 1996: 120 ; Lithophyllum grandiusculum (Montagne) Woelkerling, Penrose & Y.M.Chamberlain, 1993b: 326 ; Melobesia frondosa Dufour, 1861: 39 ; Pseudolithophyllum expansum f. decumbens Foslie (publication date unknown, see Guiry & Guiry 2014); Pseudolithophyllum expansum f. strictaeforme Philippi (publication date unknown, see Guiry & Guiry 2014); Tenarea bermudensis (Foslie & M.Howe) Adey, 1970: 6 ; Titanoderma bermudense (Foslie & M.Howe) Woelkerling, Y.M.Chamberlain & P.C.Silva, 1985: 333 .

Material examined:— BRAZIL. Rio de Janeiro State, Rochedo de São Pedro (23º03’43.74” S, 44º31’46.26” W, 30.x.2003, F. T. de S. Tâmega & M. A. de O. Figueiredo, RB 587134 ; RB 587135 ) .

the central columella (C) and peripherally arranged, zonately divided tetrasporangia (te) (RB 587135). Scale bar = 50 μm.

Description:—Thalli non-geniculate, encrusting to warty ( Fig. 6 ); 268–1161 μm thick; internal construction monomerous ( Fig. 7 ) with hypothallial cells composed of non-palisade cells; single layer of rounded to elliptical, dark-staining epithallial cells ( Fig. 8 ) 3–4 μm in length and 5–10 μm in diameter; subepithallial initials square to rectangular and measure 6–14 μm in length and 6–13 μm in diameter ( Fig. 8 ); perithallial cells square to rectangular and measure 4–16 μm in length and 3–11 μm in diameter; hypothallial cells square to rectangular and measure 6–21 μm in length and 4–12 μm in diameter. Cells of adjacent perithallial and hypothallial filaments joined by secondary pit connections ( Fig. 8 ); cell fusions not observed.

Gametangial thalli appear to be diocieous although female thalli have not been observed. Spermantangial conceptacle chambers 128–140 μm in diameter and 60–80 μm in height. Spermatangial systems distributed on the conceptacle floor.

Mature tetrasporangial conceptacles uniporate and raised above the surrounding thallus surface; conceptacle roofs 6–8 cells thick ( Fig. 9 ); conceptacle external diameter 180–210 μm; chambers 290–360 μm in diameter and 109–174 μm in height. A prominent central columella is present and zonately divided tetrasporangia, that at maturity measure 75–91 μm in length and 27–41 μm in diameter, are located peripherally to it ( Fig. 9 ); the conceptacle floor located 14–18 cells below the thallus surface.

Remarks:—Specimens ascribed to L. stictaeforme in this study show similarities in their tetrasporangial conceptacle characteristics with those previously reported for the species in Australia ( Woelkerling et al. 1993a, Ringeltube & Harvey 2000, Harvey et al. 2009), the Mediterranean ( Furnari, Cormaci & Alongi 1996) and Brazil ( Nunes et al. 2008, Villas-Boas et al. 2009), with only minor differences in the conceptacle roof thickness and the depth of the conceptacle floor ( Table 2). However, of the Brazilian material, far greater variation was observed.

Ecological observations:—The species is found in the subtidal zone ranging from 3–8 m depth.

Geographical distribution:—The species has been widely reported from the Atlantic, Indian and Pacific oceans. See Guiry & Guiry (2014) for a detailed distribution list. In Brazil the species has been reported from Bahia ( Nunes et al. 2008) and Espírito Santo ( Villas-Boas et al. 2009).

Distribution within the study sites:—Rochedo de São Pedro (23º03’43.74” S, 44º31’46.26” W), Parcel dos Meros (23º09’57.32” S, 44º30’49.02” W), Ponta do Acaiá (23º10’29.88” S, 44º22’47.45” W) and Queimada Grande Island (23º05’10.26” S, 44º19’38.27” W).

Subfamily: Hydrolithoideae A.Kato & M.Baba in Kato et al., 2011: 669

Figures

FIGURE 1. Ilha Grande Bay with study sites: Rochedo de São Pedro (1), Parcel dos Meros (2), Flechas Island (3), Ponta do Acaiá (4) Queimada Grande Island (5), Jorge Grego Island (6) and Comprida Island (7).

FIGURE 6–9. Lithophyllum stictaeforme. FIGURE 6. External morphology (RB 587134). Scale bar = 1 cm. FIGURE 7. Longitudinal section showing monomerous thallus construction (white arrow) (RB 587135). Scale bar = 100 μm. FIGURE 8. Longitudinal section showing a single layer of rounded to elliptical epithallial cells (e), subepithallial initials (s) and secondary pit connections between adjacent filaments (white arrow) (RB 587135). Scale bar = 10 μm. FIGURE 9. Longitudinal section through a tetrasporangial conceptacle showing