Leucascus simplex Dendy, 1892

Klautau, Michelle, Lopes, Matheus Vieira, Guarabyra, Bruna, Folcher, Eric, Ekins, Merrick & Debitus, Cécile, 2020, Calcareous sponges from the French Polynesia (Porifera: Calcarea), Zootaxa 4748 (2), pp. 261-295 : 277-278

Leucascus simplex Dendy, 1892

( Fig 7 ; Table 7)

Synonyms. Leucascus simplex, Dendy 1892: 77 , Kirk 1897: 313, Dendy 1913: 9, Dendy & Row 1913: 731, Row & Hôzawa 1931: 742, Cavalcanti et al. 2013: 277. Leucetta chagosensis, Hall et al. 2013: 500 .

Type locality. Port Phillip Heads , Australia

Material examined. UFRJPOR 6451 = MNHN-IP- 2018-22 — Tahiti, Society Islands, Station ST12 (17°31.30’ S– 149°33.40’W), depth: 10 m, coll. C. Debitus , 23/III/2009, P2. UFRJPOR 6456 = MNHN-IP- 2018-27 — Hiva Oa, Marquesas Islands, Station MHO05 (9° 42.553’ S– 139° 01.18’ W), depth: 15 m, coll. C. Debitus , 08/IX/2009, P167. Other material. UFRJPOR 6458 = MNHN-IP- 2018-29 — Moorea, Society Islands, Station M01 (17°29.681’ S– 149°51.717’ W), depth: 8 m, coll. C. Debitus , 04/XII/2010, P221. UFRJPOR 8919 = MNHN-IP- 2018-60 — Tahiti, Society Islands, Station ST52 (17°47.147’ S– 149°25.359’ W), depth: 30 m, coll. S. Petek , 21/IV/2013, P480˗ST52. UFRJPOR 8921 = MNHN-IP- 2018-62 — Tahiti, Society Islands, Station ST27 (17°46.642’ S– 149°24.236’ W), depth: 20 m, coll. S. Petek , 12/IV/2013, P480˗ST27.

Colour. White alive and beige to light yellow in ethanol ( Fig 7A ).

Morphology and anatomy. Sponge massive, almost spherical. Sometimes there is more than one “sphere” attached to another ( Figs 7A, B ). Each sphere has an apical osculum sometimes surrounded by membrane. The cormus is formed by regular and tightly anastomosed tubes covered by a continuous, smooth, delicate cortex. The tubes near the surface are more parallel to each other than in the middle of the choanosome. The atrial cavity is large and delimited by endopinacoderm. Aquiferous system solenoid. The skeleton is composed of triactines and tetractines ( Fig 7C ). Triactines are more abundant than the tetractines. The atrial skeleton is composed of tetractines only.

Spicules ( Table 7)

Triactines. Regular to sagittal. Actines are slightly conical with sharp tips ( Fig 7D ). Size: 102.5/ 8.7 µm.

Tetractines. Regular to sagittal. Actines are slightly conical with sharp tips ( Fig 7E ). The apical actine is very thin (needle-like), cylindrical and sharp, covered with very short spines ( Fig 7F ). Size: 96.7/ 8.1 µm (basal actine); 72.8/ 2.7 µm (apical actine).

Geographical distribution. Tahiti and Moorea, Society Islands; Hiva Oa, Marquesas Islands. XPirae (Tahiti- ST12). Mataeia (Rautirae. Tahiti-ST27). Mataeia (Aifa. Tahiti-ST52). Opunohu (Moorea). Hanamenu (Hiva Oa). French Polynesia and Marquesas Islands ( Hall et al. 2013).

Remarks. The specimens from French Polynesia have spicules with sharp tips, while in the holotype they are blunt. Besides, in the holotype the tetractines are rare, while in the specimens from French Polynesia they are abun- dant (although still less abundant than the triactines). The spicules from the french polynesian specimens are also thinner than those of the holotype [Triactines: 83.2–102.9 (±6.7)–114.4/ 11.7–13.3 (±0.9)– 15.9 µm; Tetractines: 72.8–100.1 (±9.2)–117.0/ 10.4–12.1 (±1.0)– 14.3 µm (basal), 26.0–42.3 (±8.8)–65.0/ 2.6–4.0 (±1.0)– 5.2 µm (apical)] ( Table 7). In our C-LSU molecular tree L. simplex is sister species of L. flavus .

Figures

FIGURE 7. Leucascus simplex (UFRJPOR 6451). A—Specimen in situ. B—Fixed specimen. C—Cross-section of the choanosome. D—Triactine. E—Tetractine. F—Apical actine of two tetractines. Abbreviation: at = atrium; cx = cortex.