Mycale (Paresperella) vitellina, Van, Rob W. M., 2009

Van, Rob W. M., 2009, New sciophilous sponges from the Caribbean (Porifera: Demospongiae), Zootaxa 2107, pp. 1-40 : 34

Mycale (Paresperella) vitellina sp.n.

( Figs 14 A–E)

? Mycale (Paresperella) sp. in: Hajdu & Rützler, 1998: 766, fig. 16a–c.

Holotype. ZMA Por. 0 5389, Curaçao, Barbara Beach, 12.065°N - 68.855°W, under coral rubble, 1–3 m, 03- 06-1984, coll. J.H. Stock & J.J. Vermeulen.

Paratypes. ZMA Por. 21076, Curaçao, Cornelis Baai, 12.084°N - 68.897°W, under coral rubble, 3.5 m, 13-03-1989, coll. E. Meesters & P. Willemse # C23-9; ZMA Por. 21086, Curaçao, Cornelis Baai, 12.084°N - 68.897°W, under coral rubble, 4 m, 03-03-1989, coll. E. Meesters & P. Willemse #C6-12.

Additonal material (not belonging to the type series). Curaçao, Cornelis Baai, 12.084°N - 68.897°W, under coral rubble, 3.5 m, 1989, coll. E. Meesters & P. Willemse # C6-12; Curaçao, Cornelis Baai, 12.084°N - 68.897°W, under coral rubble, 3.5 m, 1989, coll. E. Meesters & P. Willemse # C20-9; Curaçao, Blauwbaai, 12.131°N - 68.987°W, under coral rubble, 35 m, 27-02-1989, coll. E. Meesters & P. Willemse #B19A1.

Description. Thin encrustation under coral rubble, up to 3 mm in thickness and several mm 2 in widest expansion. Consistency soft, fragile. Color: described by collectors as‘egg-yellow’, light yellow, transparant orange.

Skeleton. Plumose, thin wavy bundles of megascleres carrying the surface membrane in which scattered megascleres are arranged tangentially, with many microscleres inbetween, notably numerous rosettes of the larger anisochelae.

Spicules. Styles, anisochelae, spined sigmas and toxas.

Styles ( Figs 14 A–B) relatively long and flexuous, without conspicuous subterminal constriction (looking like proper styles rather than mycalostyles), 276- 307.7 -348 x 1.5- 2.7 -3.5 µm.

Sigmas ( Fig. 14 C), relatively large, thin, asymmetrical with prominent long teeth on the outer curve of the larger/upper part, 78- 86.4 -93 µm long, 1.5- 2.3 -3 µm in thickness.

Anisochelae I ( Fig. 14 D), usually forming rosettes of 65–70 µm diameter, with relatively pointed larger alae, 21- 26.9 -30 µm; anisochelae II ( Fig. 14 E), not forming rosettes, usually more rare than anisochelae I, thin and inconspicuous, 10- 12.8 -15 µm.

Ecology. Under coral rubble, 1– 35 m.

Etymology. Vitellinus (Latin) = like the yolk of an egg, referring to the color of the sponge.

Remarks. A provisional description of the holotype, ZMA Por. 0 5389, was already provided by Hajdu & Rützler (1998: 766) in a discussion of isolated spined sigmas found in material of another Mycale species ( M. citrina ) from Belize. These authors also mention the presence of an isolated toxa of 34 µm long, but this could not be confirmed from the present investigation of this and other specimens quoted above, so presumably the toxa was foreign. The serrated sigmas in the Belize material were of similar size and shape, which may indicate the presence of M. (P.) vitellina n. sp. in Belize.

The present species is the second Central Western Atlantic species of the subgenus Paresperella . On paper, the Brazilian Mycale (Paresperella) spinosigma ( Boury-Esnault, 1973 as Paresperella ) appears quite similar to our new species, sharing all spicule types. The Brazilian specimen, however, possessed styles neatly larger, without overlap (400–627 µm), the anisochelae I and II likewise were larger (37–53 µm and 16–19 µm), while the spined sigmas were clearly smaller (37–68 µm), although a few apparently reach 156 µm (?). Boury-Esnault (l.c.) also records a separate category of oxeas, larger than the styles (600–821 µm), which are an unusual spicule type for Mycale . The Brazilian specimen was reported from approx. 100 m depth. Combined, these differences are judged to be of specific level, but both species are considered closely related if Boury-Esnault's (l.c.) description is accurate. Curiously, however, Hajdu & Rützler (1998) failed to find anisochelae in the holotype of M. spinosigma (MNHN D NBE 968), whereas serrated sigmas were quite rare. Combined with their findings of isolated serrated sigmas in Mycale citrina , they arrived at the hypothesis that the serrated sigmas were possible contaminations in a specimen of uncertain affinity. The presence of M. (P.) spinosigma in Brazil waters needs to be confirmed.

Figures

FIGURE 14. Mycale (Paresperella) vitellina n. sp., SEM images of spicules (Holotype ZMA Por. 05389). A – B. Style and details of the apices; C. Spined sigma; D – E. Large and small palmate chela categories.