Ernstia multispiculata, Klautau, 2017

Klautau, Michelle, 2017, Taxonomy and phylogeny of calcareous sponges (Porifera: Calcarea: Calcinea) from Brazilian mid-shelf and oceanic islands, Zootaxa 4311 (3), pp. 301-344 : 325-327

Ernstia multispiculata sp. nov.

( Figs 11 A–I; Table 12)

Diagnosis. Ernstia with white cormus formed by irregular and tightly anastomosed tubes. Skeleton with two size categories of triactines and tetractines. Actines are slightly conical or conical with sharp tips.

Material examined (One specimen). Holotype: UFRJPOR 6688, Barretinha , Rocas Atoll , Rio Grande do Norte State, 3 m depth, coll. A. Padua, 18 July 2011.

Etymology. In reference to the presence of several size categories of triactines and tetractines.

Colour. white in life and light beige in ethanol.

Morphology. The only specimen is small, with soft and fragile consistency. The cormus is composed of irregular and tightly anastomosed tubes ( Fig 11 A). water-collecting tubes were not observed.

Anatomy. No cells with granules were present. The skeleton has no special organization and is composed of two size categories of both triactines and tetractines ( Fig 11 B). Triactines and tetractines are present in the same proportion.

Spicules ( Figure 11 ; Table 12). Triactine I. Equiangular and equiradiate. Actines are slightly conical, straight, with sharp tips ( Figs 11 C, D).

Specimen Spicule Length (µm) Width (µm) n Min mean sd max min mean sd max

UFRJPOR 6688 (H) Triactine I 78.3 122.6 24.1 162.0 6.8 11.7 2.8 18.9 35 Triactine II 175.5 205.2 17.91 226.8 8.1 20.9 4.8 27.0 17 Tetractine I 75.6 120.2 24.8 156.6 6.8 11.4 2.7 16.2 29 Apical 32.4 52.5 15.4 89.1 4.1 5.5 1.1 8.1 23 Tetractine II 170.1 207.2 19.5 253.8 17.6 20.9 2.1 24.3 30 Apical 27.0 54.2 15.3 94.5 4.1 5.3 0.4 5.4 30 Triactine II. Equiangular and equiradiate. Actines are conical, straight, with sharp tips ( Fig 11 E).

Tetractine I. Equiangular and equiradiate. Actines are slightly conical, straight, with sharp tips ( Figs 16 F, G). The apical actine is very thin, almost cylindrical, smooth and sharp ( Fig 11 I).

Tetractine II. Equiangular and equiradiate. Actines are conical, straight, with sharp tips ( Fig 11 H). The apical actine is very thin, slightly conical, smooth and sharp.

Ecology. The single specimen was collected in a small tide pool in Rocas Atoll, at 3 m of depth.

Distribution. Rocas Atoll, off NE Brazil.

Remarks. Including the new species described above, 11 species of Ernstia are recognized to date (see Remarks on the description of Ernstia citrea sp. nov.). The presence of more than one size category of triactine and of tetractine differentiates E. multispiculata sp. nov. from all the others. The new species shares its white colour with E. quadriradiata , E. tetractina and perhaps also with E. sagamiana , E. septentrionalis , and E. sueziana (whose colours alive are unknown; Hôzawa 1929; Rapp et al. 2001; Klautau & Valentine, 2003). The new species can be differentiated from E. quadriradiata , E. tetractina , and E. sagamiana by the proportion between triactines and tetractines. while in those known species of Ernstia , tetractines are much more abundant than triactines, in E. multispiculata sp. nov. they are equally abundant. The new species can be differentiated from E. sagamiana also by the presence of diactines only in the latter; and from E. septentrionalis by the absence of granular cells, and by its spicules with conical instead of cylindrical actines. It can be distinguished from E. sueziana by the cormus formed by loosely anatomosed tubes in that species, and by tightly anastomosed tubes in the new one.

Figures

FIGURE 11. Ernstia multispiculata sp. nov. A—Holotype after fixation. B—Section. C—Triactine I. D—Triactine II. E— Triactine III. F—Tetractine I. G—Tetractine II. H—Tetractine III. I—Tetractine I (ap: apical actine).

FIGURE 16. In situ photographs of eight Calcinea species studied. A— Arturia trindadensis sp. nov. (MNRJ 7372); B— Borojevia trispinata sp. nov. (MNRJ 8569); C— Clathrina aurea; D, C. lutea sp. nov.; E— Ernstia citrea sp. nov.; F— E. rocasensis sp. nov.; G— E. sanctipauli sp. nov. (MNRJ 3584); H— E. solaris sp. nov. (MNRJ 7374). Photos by the authors.