Spongites fruticulosus Kützing (1841: 33)

Tâmega, Frederico T. S., Spotorno-Oliveira, Paula, Coutinho, Ricardo & Bassi, Davide, 2016, Taxonomic assessment of fossil Holocene coralline red algae (Rhodophyta, Corallinales, Hapalidiales) from southwestern Atlantic, Phytotaxa 245 (4), pp. 237-250 : 241-242

Spongites fruticulosus Kützing (1841: 33) (Figs. 7–9)

Lectotype: — L ( Rijksherbarium , Leiden, Netherlands L 943.8.134).

Type locality: —Mediterranean Sea ( Silva et al. 1996).

Synonyms: —Complete reference in Basso & Rodondi (2006).

Age: —Prainhas do Pontal —3,370 –3,185 Cal yrs B. P. (2σ).

FIGURE 7–9. Spongites fruticulosus , sample IEAPM 00334, Arraial do Cabo.

7) Monomerous internal construction with a multistratose ventral cell filaments (v, arrow); scale bar = 50 μm.

8–9) Tangential and oblique longitudinal sections of uniporate conceptacles, with a cylindrical conical pore canal (pc, arrows). (8—scale bar = 200 μm, 9—scale bar = 100 μm).

FIGURE 10–11. Spongites yendoi , sample IEAPM 00335, Arraial do Cabo.

10) Encrusting thalli with several tangential oblique longitudinal section of conceptacles (c, arrow); scale bar = 500 μm.

11) Nearly longitudinal sections of uniporate conceptacles showing the pore canal (pc, arrow); scale bar = 200 μm.

Material examined: — BRAZIL. Rio de Janeiro State,Arraial do Cabo, Prainhas do Pontal (22°59’18.8” S, 42°00’47.1” W, 2.14 m above sea level, 14 August 2014, F. T. de S. Tâmega & P. S-Oliveira, IEAPM 00333, IEAPM 00334).

Description: —Thalli non-geniculate, fruticose; internal organization monomerous with a multistratose ventral core of cell filaments composed of rectangular cells (Fig. 7), 10–20 μm in length and 5–10 μm in diameter; dorsal cell filaments with rectangular cells 6–10 μm in length and 6–10 μm in diameter. Cells of adjacent cell filaments joined by cell fusions; secondary pit connections not observed. Empty uniporate conceptacles and flush with, to raised above the surrounding thallus surface (Figs. 8–9); conceptacle chambers 320–350 μm in diameter and 175–210 μm in height (Figs. 8–9). No epithallial cells were identified.

Remarks: —The absence of genicula, the co-occurrence of cell fusions and uniporate conceptacles in the studied specimens indicate that the thalli belong to the Corallinaceae , subfamily Mastophoroideae ( Braga 2003, Harvey et al. 2003, Braga et al. 2005). Because the uniporate conceptacles have no contents, it is not possible to determine whether the plants are tetrasporangial or gametangial. The vegetative and reproductive characters preserved in the studied material correspond to those considered diagnostic for Spongites Kützing ( Harvey & Woelkerling 2007). Studied specimens ascribed to S. fruticulosus show similarities in their conceptacle characteristics with those previously reported for the species in the Mediterranean Sea ( Basso & Rodondi 2006), Australia ( Penrose 1991, Woelkerling 1996, Ringeltaube & Harvey 2000) and Brazil ( Tâmega et al. 2014b), with only minor differences in the conceptacle chamber height and diameter ( Table 3).

Geographical distribution: —See Guiry & Guiry (2015) for a detailed distribution list.