Guancha ramosa, Azevedo, Fernanda, Hajdu, Eduardo, Willenz, Philippe & Klautau, Michelle, 2009

Guancha ramosa View in CoL sp. nov.

( Figs. 4 View FIGURE 4 A–D, 9B; Table 4 View TABLE 4 )

Type material. IZUA-POR-0116 = MNRJ 10336 (holotype / alcohol), MNRJ 10313 and MNRJ 10314 (paratypes / alcohol).

Type locality. Quintupeu Fjord, X th Region, Chile.

Material examined. IZUA-POR-0116 = MNRJ 10336; North side entrance to Quintupeu Fjord; collected by E.H. & Ph.W.; 10 October 2006; -12 to - 15 m. MNRJ 10313, MNRJ 10314; in front of HSFS; collected by E.H. & Ph.W.; 9 October 2006; - 17.2 m. MNRJ 10414; Reñihue Fjord; collected by G.L.H.; 16 October 2006; - 17.2 m.

Colour. Light beige in life and in alcohol.

Etymology. Latin ramosus (= branching). Describing its external morphology.

Description. Cormus composed of a peduncle and a clathroid body formed by fragile, irregular and loosely anastomosed tubes (20 x 12 x 0.5 mm). Oscula are localised at the end of large tubes on the surface, giving a ramified appearance to this Guancha ( Figs. 4 View FIGURE 4 A, 9B). The skeleton of the clathroid body has no special organisation. It is composed of regular and sub regular triactines ( Fig. 4 View FIGURE 4 B). The peduncle is formed by true tubes, with choanoderm, but the portion that attaches to the substrate may be solid. A special skeleton composed uniquely of parasagittal triactines forms the peduncle ( Fig. 4 View FIGURE 4 C). The unpaired actine of these spicules is always basipetally oriented.

Spicules ( Table 4 View TABLE 4 ). Triactine of the peduncle [paired actines 60.6 (±5.3) / 4.4 (±0.7), unpaired actine 101.3 (±10.9) / 4.9 (±0.6) µm]: Parasagittal. Actines are cylindrical with rounded tips. Paired actines are undulated while the unpaired actine is straight and about twice longer ( Fig. 4 View FIGURE 4 D).

(MNRJ 10313, MNRJ 10314).

Spicule Length (µm) Width (µm) n Triactines from clathroid 46.8 63.3 6.2 85.8 3.4 1.0 - body (regular)

Triactine of the clathroid body [70.3 (±8.8) / 4.6 (±0.7) µm]: Regular (equiangular and equiradiate) or subregular. Actines are cylindrical and slightly undulated with rounded tips ( Fig. 4 View FIGURE 4 D).

Ecology. Specimens were collected on hard substrate attached to a mollusc (Bivalve) shell.

Remarks. This is the first report on Guancha for Chile. G. r a m o s a sp. nov. can be differentiated from other species of the genus mainly by the organisation of the cormus. The clathroid body in guanchas is usually well defined, composed of tightly anastomosed tubes. The only exceptions are G. arnesenae Rapp, 2006 , G. camura Rapp, 2006 (both originally described from Norway) and now G. ramosa sp. nov., which have loosely anastomosed tubes. G. ramosa sp. nov. can be easily distinguished from G. arnesenae because the latter has only tripodic parasagittal triactines in the skeleton, while G. r a m o s a sp. nov. has parasagittal as well as regular triactines. G. ramosa sp. nov. differs from G. c a m u r a, because it does not have the horn-shaped triactines characteristic of the latter. Furthermore, the dimensions of the spicules are very different [G. r a m o s a sp. nov. triactine from peduncle: paired actines 60.6 (±5.3) / 4.4 (±0.7) µm, unpaired actine 101.3 (±10.9) / 4.9 (±0.6) µm, triactine from clathroid body 70.3 (±8.8) / 4.6 (±0.7) µm; G. arnesenae triactine from peduncle: paired actines 63.0 (±5.0) / 9.5 (±1.1) µm, unpaired actine 135.0 (±12.0) / 10.8 (±1.2) µm, triactine from clathroid body: paired actines 78.0 (±13.0) / 8.4 (±1.1) µm, unpaired actine 131.0 (±18.0) / 9.38 (±1.2) µm; G. camura triactine from peduncle: paired actines 94.0 (±7.0) / 9.3 (±1.2) µm, unpaired actine 135.0 (±12.0) / 10.6 (±1.3) µm, triactine from clathroid body: 114.0 (±12.0) / 9.6 (±1.2) µm].