Desmacella annexa Schmidt, 1870

Cavalcanti, Thaynã, Santos, George Garcia & Pinheiro, Ulisses, 2015, Desmacella Schmidt, 1870 from Brazil: Description of two new species and a review of records (Desmacellida: Demospongiae: Porifera), Zootaxa 4034 (2), pp. 364-374 : 371

Desmacella annexa Schmidt, 1870

( Figures 1 , 4 , Table 1)

For full synonymy see Muricy et al. 2011.

Specimens examined. MNRJ 2860 (Hajdu et al. 2004), São Paulo State (25º 36.988’ S; 45º 13.571’ W), Brazil, 153 m depth, REVIZEE South, trawl, station 6686 (28) (13/I/1998), det. E. Hajdu et al.

External morphology ( Fig. 4 A). Fragments, thinly encrusting 2 x 1 cm (length x width). Oscules were not found, vaguely hispid surface, consistency is fragile and colour cream in ethanol.

Skeleton ( Fig. 4 B). There is no special ectosomal skeleton. Choanosomal skeleton formed by large tylostyles making massive plumose bundles; well developed spongin fibres. Abundant sigmas (I and II) appear to be randomly distributed. Toxiform microxeas were not recognized.

Spicules ( Fig. 4 C–I). Tylostyles (286– 392.5 –521 x 3 – 8.1 –14 µm, length x width): long, thin, erect and smooth ( Fig. 4 C–D); Sigmas I (19– 29.8 –38 µm, chord length) and Sigmas II: (9– 11.6 –14 µm, chord length) thin, abundant and terminally microspined ( Fig. 4 F, G, I); Toxiform microxeas (54– 76.7 –90 µm, length) long, thin, curved and microspined ( Fig. 4 E, H).

Geographical distribution. Florida ( Schmidt 1870), South and West Iceland ( Stephens 1921), Adriatic Sea ( Pansini 1987), Mediterranean ( Vacelet 1969), Naples ( Pulitzer-Finali 1978), Spain ( Bibiloni 1981), Azores ( Boury-Esnault & Lopes 1985), Barbados (van Soest & Stentoft 1988), Alboran Sea ( Boury-Esnault et al. 1994; Sitj & Maldonado 2014) and Aegean Sea ( Voultsiadou 2005). Brazil: São Paulo State: off Guarujá and off Ilhabela (Hajdu et al. 2004; Hajdu & Lopes 2007; Muricy et al. 2011).

Remarks. Van Soest & Stentoft (1988) described the typical morphology of D. annexa . The species’ spicules consist of tylostyles, two categories of sigmas and toxiform microxeas. Here, we provide for the first time illustrations using scanning electron microscopy of D. annexa , the microspination of its sigmas and toxiform microxeas. The presence of microspination on microscleres is also observed in other species of Desmacella such as D. austini Lehnert et al. (2005 , from the Pacific coast of Canada) ( Lehnert et al. 2005) and Desmacella aff. pumilio (from Campos Basin, Brazil) ( Cosme & Hajdu 2010). Desmacella austini has microspines on the tips of its two categories of sigmas, while Desmacella aff. pumilio has microspines on the tips of one category of sigma. We believe that this new feature probably occur in other populations of D. annexa , however this hypothesis can be confirmed only with SEM images. Records biogeographically akin to the Floridian type locality, such as the Brazilian ones (see Hajdu et al. 2004), are likely conspecific. Nevertheless, the other more disjunct records need to be reviewed with great care.

Figures

FIGURE 1. Location of the collection sites of Desmacella species from Brazil. (1) Desmacella microsigmata sp. nov. (Rio Grande do Norte State); (2) Desmacella tylovariabilis sp. nov. (Rio de Janeiro State); (3) Desmacella annexa (São Paulo State).

FIGURE 4. Desmacella annexa (MNRJ 2860) in SEM. A, preserved specimen; B, thick section showing the ectosome and choanosome; C, size variation of tylostyles; D, tylostyle base; E, size variation of toxiform microxeas; F, sigma I and sigma II; G, details of sigma I microspines; H, details of toxiform microxea microspines; I, details of sigma II microspines. Scale bars: A = 1 cm; B = 200 µm; C = 100 µm; D = 10 µm; E = 20 µm; F = 10 µm; G – H = 2 µm; I = 1 µm.