Taxonomy of calcareous sponges (Porifera, Calcarea) from Potiguar Basin, NE Brazil Author Lanna, Emilio Author Cavalcanti, Fernanda F. Author Cardoso, Lilian Author Muricy, Guilherme Author Klautau, Michelle text Zootaxa 2009 1973 1 27 journal article 10.5281/zenodo.185084 6ac345dd-90c1-44f8-83b0-b1fae7ae5ecf 1175-5326 185084 Leucetta potiguar sp. nov. Diagnosis. Leucetta light pink with white elevated oscula, and atrium frequently reduced to a system of exhalant canals that open directly into the osculum. Surface is smooth and the skeleton is composed of two size categories of triactines and tetractines. FIGURE 4. Leucetta floridana (UFPEPOR 200). A—live specimen in situ ; B—transversal section of the body (cx—cortex, at—atrium); C—tangential section of the cortex; D—apical actines of tetractines penetrating the atrium; E—triactine I; F—triactine II; G—tetractine I; H—tetractine II. Type material. (EXAMINED) HOLOTYPE : UFPEPOR 569, Urca do Tubarão, Guamaré ( 04º50’52.7”S – 36º27’02.1”W ), depth: 10 m , coll. G. Muricy, 04/III/2007 . PARATYPES : UFPEPOR 588, Risca das Bicudas, Caissaras, Rio Grande do Norte state ( 04º57’00.9”S – 36º07’49.7”W ), depth: 10 m , coll. F. Moraes, 05/III/2007 . UFPEPOR 591, Risca das Bicudas, Caissaras ( 04º57’00.9”S – 36º07’49.7”W ), depth: 10 m , coll. G. Muricy, 05/III/2007 . Type locality. Potiguar Basin, Rio Grande do Norte state, Brazil . Etymology. The adjective potiguar derives from the Native Brazilian tribe which inhabited Rio Grande do Norte state. In Tupi language, potiguar means “shrimp eater”, in reference to the major item in the diet of that tribe. Description. Light pink sponge with white-ringed oscula in life, becoming white to beige in ethanol. Shape massive and lobate (Fig. 5A). The largest specimen is 4.0 x 5.0 x 2.0 cm. Surface is smooth. Oscula are without crown but elevated and white-ringed; they are dispersed over the surface of the lobes (Fig. 5A). Atrial cavity is frequently absent or strongly reduced. The aquiferous system is leuconoid, with spherical choanocyte chambers. The skeleton has no special organisation (Fig. 5B). There are two size categories of equiangular and equiradiate triactines (I and II) and tetractines (I and II) (Figs. 5B-G). Triactines I are the most abundant spicules while giant tetractines (tetractines II) are very rare (often absent). The atrial skeleton is composed of tetractines I. TABLE 4. Spicule measurements of Leucetta potiguar sp. nov. (individual actines, in Μm); H, holotype; P, paratypes; s, standard deviation.

Spicule	Actine	Length	Width	n
Min Mean	s	Max	Mean	s
Triactine I
UFPEPOR 569 (H)	basal	122.2 148.8	14.4	182.0	14.4	1.8	30
UFPEPOR 588 (P)	109.2 144.8	17.8	174.2	14.0	1.7	30
UFPEPOR 591 (P)	72.8 135.3	24.5	176.8	13.4	2.1	30
All specimens	72.8 142.9	6.9	182.0	13.9	0.5	-
Triactine II
UFPEPOR 569 (H)	basal	346.5 579.3	199.7	1,102.5	71.8	24.9	30
UFPEPOR 588 (P)	231.0 474.1	126.5	703.5	56.2	16.4	20
UFPEPOR 591 (P)	145.6 586.6	258.9	1,050.0	77.2	34.1	30
All specimens	145.6 546.6	62.9	1,102.5	68.4	10.9	-
Tetractine I
UFPEPOR 569 (H)	basal	98.8 147.2	20.3	195.0	13.5	1.5	30
UFPEPOR 588 (P)	132.0 173.4	21.4	214.5	16.4	2.7	30
UFPEPOR 591 (P)	99.0 147.1	23.1	207.9	16.0	3.0	30
All specimens	98.8 155.9	15.1	214.5	15.3	1.5	-
UFPEPOR 569 (H)	apical	33.8 80.4	44.7	243.0	5.7	2.2	21
Tetractine II
UFPEPOR 569 (H)	basal	630.0 698.3	96.5	766.5	84.0	0	0 2
UFPEPOR 588 (P)	- 472.5	-	-	63.0	-	0 1
UFPEPOR 591 (P)	236.3 403.1	127.4	653.3	58.7	11.6	11
All specimens	236.3 524.6	154.4	766.5	68.6	13.5	-

Spicules ( Table 4 ). Triactines I: equiradiate and equiangular. Actines are conical with sharp tips [72.8–142.9 (±6.9)–182.0 / 13.9 (±0.5) µm (n = 3 specimens )] (Fig. 5C). Triactines II: equiradiate and equiangular. Actines are conical with sharp tips [145.6–546.6 (±62.9)–1,102.5 / 68.4 (±10.9) µm (n = 3 specimens )] (Fig. 5D). Tetractines I: equiradiate and equiangular. Actines are conical and sharp. The basal actines are straight or curved [98.8–155.9 (±15.1)–214.5 / 15.3 (±1.5) µm (n = 3 specimens )]. The apical actine is conical or cylindrical and sharp [33.8–80.4 (±44.7)–243.0 / 5.7 (±2.2) µm (n = 1 specimen , 21 spicules)] (Fig. 5E–F). Tetractines II: equiradiate and equiangular. Actines are conical with sharp tips [236.3–524.6 (±154.4)–766.5 / 68.6 (±13.5) µm (n = 3 specimens )]. The apical actine is shorter than the basal ones, straight, conical and sharp (Fig. 5G). FIGURE 5. Leucetta potiguar sp. nov. (UFPEPOR 569). A—live specimen in situ ; B—transversal section of the body; C—triactine I; D—triactine II; E, F —tetractine I; G— tetractine II. Known distribution. Brazil : Rio Grande do Norte ( Potiguar Basin) and Ceará (Valderrama et al . in press as Leucetta sp.). Ecology. Sponge photophilous, living on horizontal substrata. Some specimens were found associated to hydrozoans. Remarks. Molecular analyses showed high levels of genetic divergence between the new species and L. floridana (2.4 to 3.1%; Valderrama et al . in press ), suggesting that they are different species. Leucetta potiguar sp. nov. is morphologically similar to L. floridana , from which it can be distinguished by its colour in vivo (light pink), surface (smooth), oscula (white-ringed, elevated) and its atrium frequently absent or reduced, whereas L. floridana is light blue and has a rough, ridged surface, simple, flush oscula, and a large atrium. The only other species of Leucetta in the Atlantic is L. imberbis ( Duchassaing & Michelotti, 1864 ) . The original description of that species reported the presence of only triactines in its skeleton, but Burton (1963) mentioned also the presence of tetractines. However, even if L. imberbis has tetractines as L. potiguar sp. nov. , a very important characteristic that differentiates them is the pink colour of our species, while L. imberbis is white alive.