Ernstia sanctipauli, 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 : 329-331

Ernstia sanctipauli sp. nov.

( Figs 13 A–I; Table 14)

Diagnosis. Ernstia with white cormus formed by irregular and loosely anastomosed tubes. water-collecting tubes are present. Skeleton composed of three size categories each, of triactines and of tetractines. The cormus is white and composed of loosely anastomosed tubes with water-collecting tubes.

Material examined ( One specimen). Holotype: UFRJPOR 6432, Belmont Island west cliff, São Pedro e São Paulo Archipelago, Brazil, 10 m depth, coll. E. Lanna and L. A. Pessoa, 27 April 2011.

Etymology. From the type locality, São Pedro e São Paulo Archipelago.

Colour. white in life and beige in ethanol.

Morphology. Consistency fragile. The tubes collapse after fixation. The cormus is composed of irregular and loosely anastomosed tubes ( Fig 13 A). water-collecting tubes are present, and they converge to an apical osculum (5 x 3 mm).

Anatomy. Cells with granules were not found. The skeleton has no special organization ( Fig 13 B). It is formed by triactines and tetractines, both in three size categories. The medium size triactines are the most abundant spicules.

Spicules ( Figure 13 ; Table 14). Triactines I ( Fig 13 C), Triactines II ( Fig 13 D), and Triactines III ( Fig 13 E): Equiangular and equiradiate. Actines are conical and straight, with sharp tips. The only difference among these spicules is the size ( Table 14).

Specimen Spicule Length (µm) Width (µm) n

min mean sd max min mean sd max

UFRJPOR 6432 (H) Triactine I 35.1 48.6 11.0 67.5 8.1 8.6 1.0 10.8 13 Triactine II 72.9 89.4 10.7 108.0 8.1 10.2 0.9 10.8 28 Triactine III 116.1 142.4 19.6 180.9 10.8 15.8 3.5 21.6 19 Tetractine I 35.1 57.5 10.6 67.5 5.4 8.2 1.0 9.5 13 Apical 18.9 83.2 30.1 135.0 2.7 4.0 0.7 5.4 20 Tetractine II 70.2 91.4 12.5 108.0 8.1 10.3 0.8 12.2 30 Apical 29.7 81.7 29.7 124.2 2.7 4.1 1.0 5.4 15 Tetractine III 110.7 136.3 23.2 183.6 10. 14.7 3.5 21.6 17 Apical 37.8 91.3 24.3 113.4 4.1 5.3 0.3 5.4 15 Tetractines I ( Fig 13 F), Tetractines II ( Fig 13 G), and Tetractines III ( Fig 13 H): Equiangular and equiradiate. Actines are conical and straight, with sharp tips. The apical actine is thinner and longer or shorter than the basal ones. It is cylindrical (needle-like), sharp, smooth and straight ( Fig 13 I). The only difference among these spicules is the size ( Table 14).

Ecology. The single specimen was found at 10 m depth in a small crevice. The species seems to be rare. Associated organisms were not found.

Distribution. São Pedro e São Paulo Archipelago, off NE Brazil.

Remarks. Ernstia sanctipauli sp. nov. can be differentiated from almost all other species of Ernstia by the presence of more than one size category of spicules. The only other white species of Ernstia with more than one size category each, of triactines and tetractines is E. multispiculata sp. nov., which has two. Besides the presence of an additional size category of spicules in E. sanctipauli sp. nov., both species can be distinguished by the cormus, which is formed by tightly anastomosed tubes without water-collecting tubes in E. multispiculata sp. nov. and by loosely anastomosed tubes with water-collecting tubes in E. sanctipauli sp. nov.

Figures

FIGURE 13. Ernstia sanctipauli 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).