Clathrina insularis, 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 : 317-318

Clathrina insularis sp. nov.

( Figs 6 A–F; Table 7)

Diagnosis. Clathrina yellow alive and brown in ethanol. Cormus formed by irregular and loosely anastomosed tubes and two categories of triactines, one with cylindrical actines and another with conical actines. Subregular spicules are also present.

Material examined (Nine specimens, all from Fernando de Noronha Archipelago , Pernambuco State). Holotype: UFRJPOR 6532, Cagarras, 15 m depth, coll. F. Azevedo & G. Rodríguez, 27 June 2011 . Paratypes: UFRJPOR 6536, same data as holotype. UFRJPOR 6529, Ilha do Meio, 15 m depth, coll. F. Azevedo & G. Rodríguez, 27 June 2011 . Additional material: UFRJPOR 6527, 6533, Cagarras, 15 m depth, coll. F. Azevedo & G. Rodríguez, 27 June 2011. UFRJPOR 6530, 6531, 6534, 6537, Ilha do Meio , 15 m depth, coll. F. Azevedo & G. Rodríguez, 27 June 2011 .

Etymology. From the Latin Ïnsula (= island), after the known distribution of this species, which is at least provisionally restricted only to islands in NE Brazil.

Colour. Yellow in life and brown in ethanol.

Morphology. Shape thinly encrusting, consistency soft and delicate ( Fig 6 A). The anastomosis of the cormus is loose and irregular with thin tubes (not larger than 4 mm in diameter). Oscula are small apical elevations of variable diameter (not higher than 1 mm). water-collecting tubes are absent.

Anatomy. Cells with granules were not found. The skeleton is composed of two categories of triactines without organization ( Fig 6 B).

Spicules. ( Figure 6 ; Table 7) Triactines I: Equiangular and equiradiate. Actines are conical, sometimes slightly undulated, with sharp tips ( Fig 6 C).

Specimen Spicule Length (µm) Width (µm) n

min mean sd max min mean sd max

UFRJPOR 6532 (H) Triactine I 47.5 76.4 12.5 97.5 5.0 6.1 0.8 7.5 30 Triactine II 100.0 121.7 10.3 140.0 6.3 6.8 0.7 8.8 30 UFRJPOR 6529 (P) Triactine I 50.0 70.0 13.1 90.0 5.0 6.8 0.8 8.8 30 Triactine II 102.5 123.1 10.1 150.0 6.3 7.4 0.7 8.8 30 UFRJPOR 6536 (P) Triactine I 42.5 66.8 13.7 97.5 3.8 7.3 1.1 8.8 30 Triactine II 115.0 135.2 9.7 162.5 7.5 8.4 1.1 10.0 30 Triactines II: Regular or subregular. These spicules are larger than the triactines I. Actines are cylindrical, sometimes slightly undulated with sharp tips ( Figs 6 D, E, F).

Ecology. Specimens were common on the ceiling of small caves and other shaded environments, about 15 m depth.

Distribution. Fernando de Noronha Archipelago, off NE Brazil.

Remarks. There is no other yellow species of Clathrina with two categories of triactines as C. insularis sp. nov. Besides, yellow clathrinas frequently have triactines with rounded tips, while the new species has sharp tips. The only yellow clathrinas that have spicules with sharp tips are C. chrysea Borojevic & Klautau, 2000 and C. luteoculcitella wörheide & Hooper, 1999 (see C. mutabilis sp. nov. below), however, both have tightly anastomosed tubes, while in the new species they are loosely anastomosed. Moreover, C. luteoculcitella also has diactines.

Figures

FIGURE 6. Clathrina insularis sp. nov. A—Holotype after fixation. B—Section. C—Triactine I. D, E—Triactine II (regular). F—Triactine II (subregular).