Biemna spinomicroxea, Mothes, Beatriz, Campos, Maurício, Lerner, Cléa, Carraro, João Luís, Van, Rob W. M. & Soest, 2005

Mothes, Beatriz, Campos, Maurício, Lerner, Cléa, Carraro, João Luís, Van, Rob W. M. & Soest, 2005, A new species of Biemna Gray, 1867 (Demospongiae, Poecilosclerida) from the north coast of Brazil, Zootaxa 1087, pp. 39-44 : 41

Biemna spinomicroxea sp. nov.

Figs. 2 A–I

Material examined. Holotype MCNPOR 1887, off the coast of Amapá State: 03°56'00" N – 50°00'07" W, 81 m depth; coll. R/V ‘Almirante Saldanha’, 07.XII.1968; substratum sand.

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, 2004 – MCNPOR 1898, Amapá State, Brazil; B. trisigmata Mothes & Campos, 2004 – MCNPOR 1897, Amapá State, Brazil.

Description. Massive, irregular but slightly lobate, internally cavernous ( Fig. 2 A). Measurements: 3.5 cm length, 2.0 cm width and 2.0 cm thick. Surface hispid, from to protruding spicules. Oscules scattered over the surface, the larger ones measuring 0.2 cm in diameter. Consistency of preserved material soft, easily compressible. Colour alive unknown, in alcohol light brown.

Skeleton ( Fig. 2 B). Plumoreticulate, not differentiated into ectosomal or choanosomal skeleton. Megascleres arranged in ascending tracts, 3–5 spicules thick, at 190–332.5 m distance from each other, widening slightly near the surface and connected by single spicules or transverse tracts 1–3 spicules thick. Only nodal spongin present. Between the spicule tracts, some microscleres are found randomly distributed.

Spicules. Oxeas ( Fig. 2 C­D): slightly curved, rarely straight; extremities lightly stepped, a few slightly strongylote; length: 370.5– 409. 4 – 437 m, width: 9.2– 11. 6 – 13.8 m. Sigmas ( Fig. 2 E­F): shallow­curved, with long­spined extremities; length: 16.1– 17. 6 – 20.7 m, width: 1.0 m. Microxeas in two sizes ( Fig. 2 G­I): larger ( Fig. 2 G­H), straight, microspined; length: 103– 133. 4 – 152 m, width: 2.3– 3.2 – 4.6 m; Smaller ( Fig. 2 I), smooth, slightly curved, a few straight; length: 87.5– 113. 7 – 152.5 m, width: less than 2.5 m.

Remarks. Until now there were five valid species of genus Biemna known in the tropical West Atlantic: B. microstyla de Laubenfels, 1950 ; B. cribaria ( Alcolado & Gotera, 1986) (senior synonym of B. oxeata Van Soest & Stentoft, 1988 ); B. caribea Pulitzer­ Finali, 1986 (“ B. tubulata (Dendy, 1905) ” sensu Van Soest, 1984); B. microacanthosigma Mothes, Hajdu, Lerner & Van Soest, 2004 ; B. trisigmata Mothes & Campos, 2004 ; the new species, B. spinomicroxea , brings the number to six. The latter species shares the oxeote megascleres with B. cribaria , which however lacks microxeas and has two size categories of sigmas. The remaining Biemna species have styles as megascleres.

Etymology. The specific name is given to signal the presence of a spined microxea.

Figures

FIGURE 2. Biemna spinomicroxea sp. n. (Holotype, MCNPOR 1887). A. Specimen preserved in alcohol (scale bar = 0.5 cm); B. Skeletal arrangement (scale bar = 300 µm); C. Oxea (scale bar = 100 µm); D. Detail of oxea extremities (scale bar = 10 µm); E. Spiny sigma (scale bar = 5 µm); F. Detail of sigma extremity (scale bar = 2 µm); G. Microxea I (scale bar = 20 µm); H. Detail of microxea I extremity (scale bar = 2 µm); I. Microxea II (scale bar = 20 µm).