Placospongia giseleae sp. nov.

(Fig. 2; Tab. 1)

Material examined. Holotype. UFBA 4051, Praia de Aratuba, Recife das Caramuanas, Vera Cruz, 13º08’S – 38º45’W, Bahia State, Brazil, 1–2 m deep, January 30, 2013, coll. Cavalcanti, F. & Neves, E.

Paratype. UFBA 4050, Paciência de Terra, Baía de Camamu, Maraú, 13°57’29.19”S – 38°54’47.95”W, Bahia State, Brazil, 18–20 m deep, October 23rd, 2012, coll. Menegola, C. & Guimarães, R.

UFPE POR 1446, Cabo de Santo Agostinho, Praia Enseada dos corais, 8º19’0.34’’S – 34º56’51.92’’W, Pernambuco State, Brazil, intertidal zone, November 29th, 2012, coll. Pinheiro, U.

Diagnosis. Megascleres tylostyles I range from 650 to 1200 µm; Tylostyles II range from to 220 to 740 µm. Microscleres selenasters and acanthomicrorhabds.

Description. Encrusting sponge (Based on Holotype UFBA 4051 measurements: 72.31 150 mm length x 55.09 mm width and 4.05 mm thickness), covered by smooth and rigid cortical plates, separated by contractible grooves. Color in life light brown or dark brown (Fig. 2A), retained after alcohol preservation (Fig. 2B). Consistency is hard like a stone. Texture rugose, due to cortical plates. Oscules retracted after collection.

Skeleton. Cortex composed of densely packed selenasters, with acanthomicrorhabds in ectosomal surface, over the selenaster crust. Choanosome with tylostyle bundles outwardly disposed, supporting the cortex, emerging from a basal layer of selenasters. Selenasters in different developmental stages and acanthomicrorhabds widely scattered in choanosome (Fig. 2C).

Spicules. Megascleres. Tylostyles in two size categories. Tylostyles I (Fig. 2D), large, straight, with prominent tyles (Fig. 2E) and blunt points (Fig. 2F) (860–1033.5–1200 µm/7.5–11.9–15 µm). Tylostyles II (Fig. 2G), small, straight, with hastate ends (Fig. 2I) (220–402.9–740 µm / 5–6.9–10 µm).

Microscleres. Selenasters in distinct growth stages, bean-shaped, oval or spherical (Fig. 2J) (35–59.5–71 µm / 22–45.1–52 µm) and young selenasters (Fig. 2K) (20–26.9–33 µm/8–13.2–20 µm). Curved/sinuous or straight acanthomicrorhabds (Fig. 2L), densely spined (6–9.1–11 µm/2–2.2–3 µm).

Ecology. Encrusting sponges, found on the underside of rocks, at 0–20 m depths.

Distribution. Southwest Atlantic, Brazil. Recorded from Northeast Brazil, Bahia State, Baía de Todos os Santos (Vera Cruz, Recife de Caramuanas, Aratuba beach) and south coast (Baía de Camamu, Maraú, Paciência da Terra). Pernambuco State, south coast (Cabo de Santo Agostinho, Praia Enseada dos Corais).

Etymology. The specific epithet is dedicated to Dr. Gisele Lôbo Hajdu, for her important contribution in teaching/guiding dozens of biology students from South America and Europe since the 90’s, in phylogeography, ecology, taxonomy and molecular biology of sponges.

Remarks. Placospongia giseleae sp. nov. is similar to the Pacific species P. santodomingoae, because of the similar spicule categories, showing tylostyles I with blunt ends and tylostyles II with hastate ends like and microscleres selenasters and acanthomicrorhabds are present. Nevertheless, the new species is unique by tylostyles I having twice the size (860–1033.5–1200/7.5–11.9–15µm) in comparison to the Pacific species (430–605.5–660/13– 15.5–20 µm). In addition, in P. giseleae sp. nov., tylostyles II are considerably longer (220–402.9–740 / 5–6.9–10 µm), when compared to tylostyles II of P. santodomingoae (240–290/5–8 µm).

Microrhabds are considerably smaller in Brazilian species (6–9.1–11/2–2.2–3 µm), than in P. santodomingoae (8–12.3–18/2.5–2.7–3.5 µm) (Table 1). Selenasters measurements are also different, in the new species 35–59.5– 71/22–45.1–52 µm, being approximately the minimum size of the Pacific species (80–84.8–90/60–67.3–75µm).

Besides the morphological differences between these two species P. giseleae sp. nov. is found at coral reefs from tropical regions, while P. santodomingoae is exclusively found in anchialine pools from Indonesia. Therefore, the considerable distance between the Southwestern Atlantic and the Indo-Pacific Ocean, gives further evidence of specific distinctness, considering the limited dispersal ability of this genus (Nichols & Barnes (2005).

The differences between the species recorded to the Caribbean Sea and the new species are mainly related to additional microscleres: (1) P. caribica presents spherasters, spirasters and oxyasters; (2) P. melobesioides shows spherules; (3) P. intermedia has spherasters and spirasters; (4). Furthermore, P. ruetzleri and the Brazilian species P. cristata has as additional microscleres, spirasters and spherasters, respectively. P. giseleae sp. nov. differs from all previous species by having only selenasters and acanthomicrorhabds as microscleres in spicule composition.