Desmacella microsigmata, Cavalcanti, Thaynã, Santos, George Garcia & Pinheiro, Ulisses, 2015

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 : 366-367

Desmacella microsigmata sp. nov.

( Figures 1 , 2 , Table 1)

Type locality: Brazil, Rio Grande do Norte State, Potiguar Basin.

Type specimens: Holotype. UFPEPOR 1759, Bacia Potiguar (04° 36.6848’ S; 036° 46.6926’ W), Rio Grande do Norte State, Brazil, depth 157 m, trawl, coll. Petrobrás, (21/V/2011).

Diagnosis. Desmacella microsigmata sp. nov. is an encrusting sponge, characterized by the presence of tylostyles (286.3 x 3.9 µm, length x width) with elliptical tyles situated at varied positions at their bases, and small sigmas with microspined ends (14.6 µm, chord length).

External morphology ( Fig. 2 A). Encrusting sponge, 1 x 1.5 cm (length x width) ( Fig. 2 A). Hispid surface, consistency is fragile, oscules were not seen, colour in situ is unknown, brownish-purple in ethanol. The specimens were collected in the same dredge as Aiolochroia crassa ( Hyatt, 1875) and stored in the same container. It is possible that the A. crassa pigments stained the Desmacella specimens ( Cavalcanti et al. 2014).

Skeleton ( Fig. 2 B). The ectosomal skeleton consists in terminations of the ascending choanosomal tracts. Choanosomal skeleton is composed of poor spongin fibres and tylostyles forming bouquets of spicules projecting through the surface. Sigmas are randomly distributed.

Spicules ( Fig. 2 C–F). Tylostyles (177– 286.3 –425 x 2 – 3.9 –7 µm, length x width): long, thin, smooth, straight to slightly curved, with elliptical tyles situated at varied positions at their bases ( Fig. 2 C, F); Sigmas (12– 14.6 –19 µm, chord length): small, thin, abundant and with microspined ends ( Fig. 2 D, E).

Ecology. The specimens of Desmacella microsigmata sp. nov. was found associated with the bryozoan Canda alsia Winston, Vieira & Woollacott, 2014 .

Distribution ( Fig. 1 ). Brazil: Northeastern Region: Rio Grande do Norte State: off Potiguar Basin.

Etymology. The species name refers to the small size of the sigma.

Remarks. Desmacella microsigmata sp. nov. belongs to the genus by the possession of tylostyles and sigmas, and a skeleton consisting of plumose bundles of tylostyles. Desmacella microsigmata sp. nov. differs from other Atlantic species by its elliptical tyles with variously located along the basal part of the shaft of the megasclere and dimensions of the spicules. The new species differs from D. annexa , D. digitata , D. polysigmata , D. pumilio and D. vicina by having just one category of sigmas. Desmacella grimaldii , D. informis , D. inornata , D. suberitoides , D. topsenti , D. vagabunda and, D. vestibularis are distinguished by the possession of larger tylostyles and sigmas bigger than those of D. microsigmata sp. nov. (see Table 1). The new species differs from D. infundibuliformis , D. jania and D. meliorata , by the encrusting growth form of the new species and its tiny sigmas (see Table 1). Desmacella peachi sensu Ferrer-Hernandez (1914) is distinguished from D. microsigmata sp. nov. by the presence of raphides, sinuous tylostyles and lacking sigmas. Finally, in spite of D. corrugata ’s description ( Bowerbank, 1866, from Azores) not having included the dimensions of its spicules, it can still be differentiated from D. microsigmata sp. nov. due to the former’s tylostyles lacking variously located subterminal tyles.

TABLE 1. Comparative micrometric data on the spicules, shape, colour and overview of distribution of the living species of Desmacella Schmidt, 1870 from Atlantic Ocean. Values are in micrometres (µm), expressed as follows: minimum–maximum or minimum– mean –maximum length/width. References are numbered in parentheses and listed after the table.

Desmacella tylovariabilis sp. nov. Rio de Janeiro State ( Brazil) Massive / Beige (fixed) 315– 616.0 –1050/ 6–11.0–16 25– 34.2 –48 - -

/ 1130

inornata ( Bowerbank, 1866) 1,4 Aegean Sea, Alboran Sea, Amorphous / Dirty gray 190–1000 / 6–18 20 –45 - -

Azores, Western (dried) Mediterranean / 100–270

jania Verrill, 1907 1,10 Bermuda, Caribbean Sea, Massive and irregularly 220–250 (styles to tylostyles) 37–40 - -

Mexico / not recorded lobulate / White (dried)

meliorata Wiedenmayer , Bahamas, Caribbean Sea / Lobular / Crimson red 210–230 / 3.5–4.5 37 / 2 - - 1,11 not recorded

......continued on the next page TABLE 1. (Continued) References: (1) Lehnert et al. (2005); (2) Topsent (1936); (3) van Soest & Stentoft (1988); (4) Bowerbank (1866); (5) Lévi, (1960); (6) Topsent (1890); (7) Stephens (1916); (8) Vosmaer (1885); (9) Fristedt (1887); (10) Verril (1907); (11) Wiedenmayer (1977); (12) Ferrer-Hernandez (1914); (13) Van Soest (1984); (14) Schmidt (1870); (15) Burton (1932); (16) Burton (1930); (17) Wilson 1904).

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 2. Desmacella microsigmata sp. nov. (UFPEPOR 1759) in SEM. A, preserved specimen; B, thick section showing the ectosome and choanosome; C, size variation of tylostyles; D, sigma; E, details of microspines on the tip of a sigma; F, variation of tylostyle bases. Scale bars: A = 1 cm; B = 200 µm; C = 100 µm; D = 5 µm; E = 2 µm; F = 10 µm.