Tethya brasiliana, Ribeiro, Suzi M. & Muricy, Guilherme, 2004

Ribeiro, Suzi M. & Muricy, Guilherme, 2004, Four new sympatric species of Tethya (Demospongiae: Hadromerida) from Abrolhos Archipelago (Bahia State, Brazil), Zootaxa 557, pp. 1-16 : 4-7

Tethya brasiliana sp. nov.

( Fig. 2 A–B, 3, Table 1 )

Holotype. UFRJPOR 4670 A, Redonda Island, Abrolhos Archipelago, Bahia State, Brazil, 30/x/1997, intertidal zone, coll. G. Muricy.

Paratypes. UFRJPOR 4670b and UFRJPOR 4676 (Redonda Is., 30/x/1997, coll. G. Muricy), MNRJ 5309 (between Redonda and Siriba Islands, 03/iii/2002, 1.5 m depth, coll. E. Vilanova), MNRJ 5310 (Siriba Is., 04/iii/2002, coll. E. Esteves), MNRJ 5312a–c (Ilha Redonda, 03/iii/2002, coll. S. Ribeiro), MNRJ 5313 (Siriba Is., 02/iii/2002, colls. S. Ribeiro & E. Esteves), MNRJ 5314 (Siriba Is., 03/iii/2002, colls. E. Esteves & G. Muricy, 0.5 m depth), MNRJ 5317a–b (Redonda Is., 03/iii/2002, coll. S. Ribeiro), MNRJ 5318 (Siriba Is., 02/iii/2002, colls. S. Ribeiro & E. Esteves), MNRJ 5319 (Redonda Is., 02/iii/ 2002, coll. G. Muricy), all from Abrolhos Archipelago, and from intertidal zone when depth is not specified.

Diagnosis. Tethya green or yellow externally and yellowish orange internally. Micrasters are strongylasters, microspherasters and microoxyasters.

Description. Body spherical or hemispherical ( Fig. 2 A–B, 3A), 0.7–2.5 cm in diameter, 0.4–2.5 cm high. Colour in life yellow or green externally, yellowish orange internally; it becomes whitish or pinkish in alcohol. Surface covered by well­developed or flattened tubercles. Buds supported by stalks (up to 1 mm long) or attached to sponge surface. Oscules dispersed, hardly visible (up to 1 mm in diameter), retracted in alcohol. Cortex firm, choanosome soft.

Cortical skeleton ( Fig. 3 B–C). Cortical layer 750–2000 m thick. Megasclere bundles with terminal fans, 625–1500 m; sometimes they may be branched in up to five brushes. Spherasters and tylasters are abundant and distributed throughout the cortex. Lacunae may be rare or abundant (100–300 mm in diameter).

Choanosomal skeleton ( Fig. 3 B). Strongylasters uncommon. Spherasters and strongylasters distributed more densely in the outer choanosome, becoming rare towards the center of the sponge.

Spicules ( Table 1 ). Main strongyloxea, 448–852– 1475 m long by 2–11– 29 m wide ( Fig. 3 D). Accessory strongyloxea, 243–430–809 x 2 –5.5– 11 m. Spherasters with acerate rays, rarely bifurcate, 13–84 m in diameter ( Fig. 3 E); ratio between ray length and center diameter (R/C) varied from 0.3–1.0. Strongylasters with isodiametric rays, 7–10– 13 m in diameter (Fig. E, G). Microspherasters 9–10– 12 m in diameter ( Fig. 3 F). Microoxyasters 6–9– 13 m in diameter ( Fig. 3 H).

Distribution and ecology. Provisionally endemic from Abrolhos Archipelago, Brazil, in and between Redonda and Siriba Islands. This species is relatively common in shallow water, from the intertidal zone to 1.5 m depth. It is only found on the undersurface of boulders and on cavities, sheltered from direct sunlight. Polychaetes, bryozoans and calcareous fragments were found over the sponge surface.

Main Accessory Spherasters Strongy­ Micro­ Micro­ Specimens strongyloxeas strongyloxeas lasters oxyasters spherasters Etymology. The name brasiliana refers to the colours of this species (yellow and green) which are the same of the Brazilian national flag, and also to the distribution of the species, provisionally endemic from Brazil.

Remarks. Tethya californiana de Laubenfels, 1932 and Tethya seychellensis sensu Bergquist & Kelly­Borges 1991 (non Wrigth 1881) also have microoxyasters similar to those of the new species. However, both T. californiana and T. seychellensis have a distinct skeletal organization: Tethya californiana has cavities regularly distributed in both the cortex and the choanosome, which are not found in T. brasiliana sp. nov.; Tethya seychellensis sensu Bergquist & Kelly­Borges (1991) has oxyasters, which are absent in T. brasiliana sp. nov. The new species is caracterized by its spicular composition, especially by the shape of its micrasters (strongylasters, microspherasters and microoxyasters). Tethya brasiliana sp. nov. is the only species of the genus in which the micrasters are a combination of strongylasters, microspherasters and microoxyasters.

Figures

FIGURE 2. In situ close­ups of three species of Tethya from Abrolhos Archipelago, Brazil. A, B, Tethya brasiliana sp. nov. (paratypes); C, Tethya ignis sp. nov. (holotype); D, Tethya rubra sp. nov. (holotype).

FIGURE 3. Tethya brasiliana sp. nov. A, preserved holotype (UFRJPOR 4670 A); B and C, architecture of the ectosome and choanosome; D, strongyloxea; E, spherasters and strongylasters; F, microspheraster; G, strongylaster and microoxyaster; H, microoxyaster. B – D, LM; E – H, SEM.

Tables

TABLE 1. Measurements of spicules of Tethya brasiliana sp. nov. (m). Main and accessory strongyloxeas, n = 30. Microscleres and width of strongyloxeas, n = 10. Underlined numbers indicate mean values. ** Holotype.

	lenght width	lenght	width	diameter	R/C	diameter	diameter	diameter
MNRJ 4670a**	721–972–1475 8–14–18	360–434–556	2–5–8	18–41–60	0.5–0.7–1.0	7–11–13	8–11–13	10–11–12
MNRJ 5314	448–551–692 2–6–11	243–323–400	2–3–5	13–22–34	0.5–0.7–1.0	10–12–13	7–10–11	10–11–12
MNRJ 5317a	597–708–975 5–7–11	321–395–458	2–3–5	15–36–50	0.6–0.7–0.8	10–12–13	9–11–13	9–10–12
MNRJ 5318	682–792–926 8–11–13	273–392–546	2–5–8	18–33–47	0.5–0.7–0.8	10–11–13	10–11–13	9–11–12
UFRJPOR 4676	775–945–1219 11–13–24	439–520–800	5–7–8	18–26–40	0.5–0.8–1.0	7–9–11	6–8–11	10–11–12
MNRJ 5309	700–887–1619 13–17–29	419–523–809	7–10–11	18–55–84	0.3–0.5–0.6	10–11–13	8–9–11	9–11–12
UFRJPOR 5319	809–983–1229 8–11–19	341–449–702	4–5–7	13–18–30	0.4–0.7–1.0	7–8–10	7–8–10	9–10–11
MNRJ 5313	750–984–1475 8–9–13	321–404–692	5–6–7	18–30–47	0.5–0.7–1.0	8–10–13	8–10–13	9–10–12