Biemna trisigmata, Mothes, Beatriz, De, Maurício A. & Campos, 2004

Mothes, Beatriz, De, Maurício A. & Campos, 2004, North coast of Brazil (Demospongiae, Poecilosclerida), Zootaxa 639, pp. 1-7 : 4-6

Biemna trisigmata sp. nov.

( Figs. 2 A–B; 3A–F)

Holotype. MCNPOR 1897, off coast Amapá State, 02°57'00"N – 49°04'00"W, 76 m depth, coll. R/V ‘Almirante Saladanha’, 25.XI.1968. Sand substratum.

Comparative material. Biemna oxeata Van Soest & Stentoft, 1988 – ZMAPOR 5420 (holotype), Barbados (fragment deposited in MCNPOR 2593); Biemna tubulata (Dendy, 1905) sensu Van Soest, 1984 – ZMAPOR 3520, Puerto Rico (fragment deposited in MCNPOR 2618); B. microacanthosigma Mothes, Hajdu, Lerner & Van Soest (in press) – MCNPOR 1898, Amapá State, Brazil.

Diagnosis. Biemna trisigmata sp. nov. differs from other West Atlantic species of Biemna by the presence of styles, raphides, three categories of sigmas and two categories of microxeas.

Description. Specimen massive, irregular, with lobular processes ( Fig. 2 A): 4.5 cm width, 3.0 cm length, 3.0 cm thickness, larger lobe 2.0 cm high. Smooth surface. Oscules on the apical portion of the lobes, 0.3 cm in diameter. Pores aligned, arranged in superficial small grooves, parallel to each other; near to oscules the grooves are arranged in convergence. Preserved material: consistency slightly compressible and friable; colour dark brown.

Skeleton ( Fig. 2 B). Ectosome: membraneous surface, without specialized spiculation. Spicule bundles protuding on the surface. Choanosome: renieroid­like reticulate, with spicules arranged in ascending bundles of 7–10 spicules, 285–427.5 m apart, forming brushes near the surface and connected by single spicules or transverse tracts, 3–7 spicules wide. Microscleres scattered throughout the choanosome.

Spicules. Styles ( Figs. 2 C, 2F)— Basal portion slightly curved, sharp­pointed or with slightly stepped extremities ( Fig. 2 D), rarely mucronate; 313.5­ 350. 7 ­370.5 / 6.9­ 13. 8 ­ 18.4 m. Raphides ( Figs. 2 E, 2F, 2L) — Hair­like, relatively long and slender, straight or recurved, occur singly or in bundles within the skeleton; more than 92 m long, <1.0 m wide. Sigmas occur in three size categories ( Figs. 2 E, 2F); most are C­ or S­shaped, all with microspined extremities: I ( Figs. 2 G) – 46­ 48. 3 ­50.6 / <2.3 m; II ( Figs. 2 H) – 27.6­ 30. 3 ­34.5 / 2.3 m; III ( Fig. 2 I) – 9.2­ 10. 7 ­13.8 / <1.1 m. Microxeas in two size categories ( Figs. 2 E, 2F); straight and smooth, with hastate points, occur singly within the skeleton: I ( Fig. 2 J) – 102.5­ 113. 3 ­127.5 / 2.5; II ( Fig. 2 K) – 47.5­ 55. 5 ­62.5 / 1.25.

Etymology. The species name refers to the presence of three size categories of sigmas.

Remarks. The species of Biemna previously known from the tropical West Atlantic are B. tubulata (Dendy, 1905) sensu Van Soest, 1984 , cited from Bonaire and Puerto Rico, characterized by the presence of styles and two categories of sigmas, raphides and commas; B. microstyla De Laubenfels, 1950 , recorded from the Bermudas Archipelago, which differs in having styles, raphides and one category of sigmas; and B. oxeata Van S o es t & Stentoft, 1988 described from Barbados, is distinct from the others by the presence of oxeas. B. caribea Pulitzer­Finali, 1986 , recorded from Puerto Rico, approaches B. tubulata [Van Soest pers. comm.], and the former is now considered to be the proper name. B. cribaria ( Alcolado & Gotera, 1986) recorded from Cuba, and cited later from Jamaica by Lehnert & Van Soest, (1998, 1999), is very similar to B. oxeata [Van Soest pers. comm.], and must be considered as a senior synonym for this latter.

Only one species of Biemna has been previously reported for the Brazilian coast. B. microacanthosigma Mothes, Hajdu, Lerner & Van Soest (in press) differs from the new species here described mainly by the dimensions of styles and two categories of sigmas. The new species differs from all these above mentioned species by its characteristic presence of three categories of sigmas and two size categories of microxeas.

Finally, the new species bears a similar spicular conjuct to Biemna saucia Hooper, Capon & Hodder, 1991 (Northwest Australia), but it differs from that species in having smaller spicules and by the disjunct distribution, and the coespicificity of both would be highly imprabable, due to their markedly disjunct distribution. Another Biemna species which presents three categories sigmas is Biemna ehrenbergi (Keller, 1889) , recorded from the Red Sea and South Arabia ( Sultanate of Oman) by Van Soest & Beglinger, 2002.

TABLE 1. Tropical West Atlantic species of Biemna .

Sigma I 46 ­ 48. 3 ­50.6 / <2.3 75.7­ 92. 2 ­112.8 / 4.5 27­ 29. 4 ­33 5­30 * Remeasured.

** Measurements from Literature.