Artemisina brasili, Cavalcanti, Thaynã, Santos, George Garcia, Hajdu, Eduardo & Pinheiro, Ulisses, 2016

Cavalcanti, Thaynã, Santos, George Garcia, Hajdu, Eduardo & Pinheiro, Ulisses, 2016, A new shallow water species of Artemisina Vosmaer, 1885 (Microcionidae, Demospongiae; Porifera) from Northeastern Brazil, Zootaxa 4184 (2), pp. 386-390 : 386-387

Artemisina brasili sp. nov.

Type specimens: Holotype. UFPEPOR 2124, Pontas de Pedra (07°37’00’’S – 34°48’51’’W), Goiana Municipality , Pernambuco State, Brazil, intertidal, coll. T. Cavalcanti and G.G. Santos (26/XI/2015) . Paratypes. UFPEPOR 2123 (31/ VIII/2015), UFPEPOR 2125 (26/XI/2015), MNRJ 20790 (23/XII/2015), collected at the type locality.

Description of specimens ( Fig. 1 A–C, 2A–D). Encrusting sponge (0.5–1.0 mm thick), with elongated papillae 2–5 mm long ( Fig. 1 A–B), easily detachable from substrate. Conulose and hispid surface. Consistency soft and compressible. Small oscules (0.2–0.5 mm) observed on papillae. Colour in life dull red ( Fig. 1 A), slowly fading in ethanol over about 30 days, becoming gray.

Skeleton: ( Fig. 1 C). Ectosome with subtylostyles piercing the surface, forming discrete spicule bundles. Choanosomal skeleton in a confused halichondroid reticulation with multispicular ascending megascleres bundles. Microscleres are randomly distributed.

Spicules: ( Fig. 2 A–D; Table 1). Subtylostyles (145– 298.3 –428 / 2– 3.5 –6 µm): elongated, smooth, slightly curved, stylote forms are present but rare ( Fig. 2 A–B); Palmate isochelae (14– 17.4 –21 µm): smooth, lightly curved and abundant ( Fig. 2 C); Toxas (51– 57.9 –67 µm): wing-shaped, thin, smooth and rare ( Fig. 2 D).

Distribution and ecology. Known only from the type locality: Pontas de Pedra beach (Goiana Municipality, Pernambuco State, Northeastern Region, Brazil), intertidal zone. Paratype UFPEPOR 2123 was found associated with the bryozoan Amathia vidovici Heller, 1867 . All specimens were growing on sandy rocky substrate.

Etymology. The specific name honors the first author’ son Nilton Brasil Câmara Neto.

Discussion. Artemisina brasili sp. nov. may be mistaken for the subgenus Clathria (Axosuberites) Topsent, 1893 , also with echinating spicules absent. However, species of Clathria (A.) all have well differentiated axial and extra-axial skeletal architecture. This is markedly distinct from the architecture seen in A. brasili sp. nov. which has a confused halichondroid reticulation and ascending bundles. This latter arrangement is diagnostic for Artemisina . Table 1 compares the new Brazilian species to the known species of Artemisina reported from the Atlantic. The combination of dull red colour, presence of papillae, and its spicule set comprising subtylostyles (145–428 µm), palmate isochelae (14–21 µm) and thin toxas (51–67 µm) sets it apart from every other species. A one-by-one comparison follows. The new species differs from A. erecta by the combination of styles and subtylostyles, smaller isochelae and larger toxas. It is distinguished from A. incrustans by the presence in the latter of two categories of subtylostyles and isochelae, and absence of toxas. It differs from A. melana due to the occurrence of styles and subtylostyles (microspined heads) as megascleres in the Caribbean species. Artemisina melanoides can be easily distinguished from the new species by its thinly encrusting habit, black live color, two categories of megascleres of distinct morphology and dimensions, as well as slightly larger toxas. Artemisina vulcani differs by its massive shape and two categories of styles. Artemisina transiens appears to be the most similar to the new species sharing the presence of subtylostyles, palmate isochelae and toxas of comparable dimensions, but differs by the rounded shape, white colour, and the presence of spines in the bases of its substylostyles (styles sensu Topsent, 1892: 95; see Table 1).

Figures

FIGURE 1. Artemisina brasili sp. nov. (UFPEPOR 2124 and MNRJ 20790). A, specimens in situ (MNRJ 20790); specimen freshly collected; B, detail of papillae and surface (UFPEPOR 2124); C, thick section showing the ectosome and choanosome; A – B = 1 cm; C = 200 µm.

FIGURE 2. Spicule complement of Artemisina brasili sp. nov. in SEM (UFPEPOR 2124, holotype). A, size variation of subtylostyles; B, details of subtylostyles; C, palmate isochelae; D, light microscope images of toxas (arrows). Scale bars: A = 100 µm; B = 5 µm; C = 5 µm; D = 50 µm.