Oceanapia spinisphaera Hajdu, Desqueyroux-Faundez, Carvalho, Lobo-Hajdu and Willenz 2013, sp. nov.
Creators: name: Hajdu, Eduardo
name: Desqueyroux-Faúndez, Ruth
name: Carvalho, Mariana De Souza
name: Lôbo-Hajdu, Gisele
name: Willenz, Philippe
Publisher: name: Zenodo
Year: 2013
Subjects: Biodiversity
Taxonomy
Animalia
Porifera
Demospongiae
Haplosclerida
Phloeodictyidae
Oceanapia
Oceanapia spinisphaera

description: Oceanapia spinisphaera Hajdu, Desqueyroux-Faúndez, Carvalho, Lôbo-Hajdu and Willenz sp. nov.
(Figs. 2F, 5F–I; Tab. 5)
Oceanapia spinisphaera Willenz and Desqueyroux-Faúndez (2009, nomen nudum) in Willenz et al. (2009: 156)
Type material. Holotype. RBINSc-IG 32233-POR 9913, Copihue Channel (50˚20’23.10’’S–75˚22’39.20’’W, Chilean Patagonia), 24 m depth, coll. Ph. Willenz and E. Atwood, 09 March 2006 —fragment from holotype: MHNG 52781.
Diagnosis. Oceanapia guaiteca sp. nov. is the only species of Oceanapia in the southern (eastern and western) as well as the Tropical and Subtropical eastern Pacific, and the Temperate south-western Atlantic, which is full of rudimentary, radially disposed fistules, and has a single category of oxeote megascleres 200–384 µm long and 2.4– 18 µm thick, as well as a single category of sigmas 15–18 µm long.
Description (Fig. 2F). Massive, globular sponge. The single specimen collected (holotype) was 10 cm in diameter. External surface strongly spiny, covered by short, translucent, fine fistulae (0.5–1 cm high). Firm consistency. Oscula are scattered and can be larger than 0.5 cm in diameter. Live-colour is whitish-rose, becoming whitish grey in ethanol.
Skeleton (Fig. 5F–G). Ectosomal, a mostly unispicular reticulation with sparse short paucispicular tracts of oxeas. Sigmas abound in the meshes. Choanosomal skeleton, dense, irregular network of strong multispicular fibres, with irregular or elongate meshes and a dense connecting network of free oxeas and sigmas. The latter are much less common than in the ectosome. Young oxeas are quite common, the smaller of which as thin as raphides. Fistule skeleton formed by longitudinal multispicular tracts of oxeas with irregular elongated meshes.
Spicules (Figs. 5H–I). Megascleres, oxeas, acerate tips, 200– 334.4 –384 µm long and 2.4– 12.3 –18 µm thick. Microscleres, sigmas, 15– 18.2 –20 µm long and 1 µm thick.
Distribution and ecology. So far known only from Canal Copihue, Madre de Dios Archipelago, 50°20’ S. On the horizontal bottom among abundant hydrocorals (Errina antarctica) in a cold water coral reef-like structure, 24 m deep.
Etymology. The name ‘spinisphaera’ is derived from the species acanthose (‘spina’, Latin for thorn), spherical habit (‘sphaera’, Latin for sphere).
Remarks. Our decision to classify the former two new species in Oceanapia rested on their possession of fistulae, albeit quite short in O. spinisphaera sp. nov., their dense choanosome with conspicuous multispicular tracts intermingled to abundant free oxeas, and the possession of sigmas by both. They are markedly distinct in overall living appearance, but a superficial examination of their spicule content might lead to mistaken identifications of either of the two. Curiously, the possession of a single category of sigmas of similar morphology and dimensions is shared by both, but does not occur in any other Oceanapia considered below. Both can be confidently set apart through the possession by O. guaiteca sp. nov. of a neatly fistulose habit, where fistules represent an important proportion of the sponge overall diameter, and by its stouter and larger, mostly only gently curved oxeote/strongylote megascleres. On the contrary, O. spinisphaera sp. nov. fistules are rudimentary, and albeit abundant, do not represent a major proportion of the sponge’s overall diameter. The latter species also has megascleres which are mostly oxeote, as well as shorter and more slender, and which can be markedly bent, sometimes more than once. A few markedly thinner oxeas observed in this species’ holotype have been partially equated with a second category of oxeas and partially with an additional category of microscleres, raphids, by Willenz et al. (2009). We judge now that these are most likely simply rare, young forms of the main oxeote megascleres.
Table 5 briefly summarises the descriptive information available for all species of Oceanapia hitherto recorded from the South-eastern Pacific, its neighbouring areas, and other areas deemed to have closer historical affinities to it, to which the new species described here are compared with. In total, ten species of Oceanapia are known from these regions, viz.: O. aberrans, O. arcifera, O. bacillifera, O. enigmatica, O. eumitum, O. fistulosa, O. kirkpatricki, O. microtoxa, O. oleracea and O. pacifica. Only three of these were described with any microscleres, and given the abundance of these in our material, it is judged unlikely that they might have been overlooked. O. arcifera has been described with a category of toxas; O. kirkpatricki with two categories of raphides, the largest of which composed of enormous spicules, nearly twice as long as the megascleres; and O. microtoxa, with a diverse set of microscleres comprising three categories of sigmas and two of toxas. None of these species comes minimally close to either new species as judged from their microsclere content.
The remaining species in Table 5 do not have microscleres. Given the small set of specimens considered in our descriptions, especially in the case of O. spinisphaera sp. nov., known from a single individual, it cannot be completely ruled out that additional specimens might prove devoid of microscleres. For that reason, the comparison is extended here to the habit and megasclere complement of these. Of the seven remaining species, five can be set apart from the new species described by the further possession of megascleres, which are either too small or too large when contrasted to those in the new species. These are O. aberrans, O. enigmatica, O. eumitum, O. oleracea and O. pacifica.
1 Temperate South America, Southern Oceans, Tropical Eastern Pacific, New Zealand, and the southern sector of the Temperate Northern Pacific (Spalding et al. 2007).
Oceanapia bacillifera and O. fistulosa require a closer inspection. The first of these, originally reported from a few broken off fragments, has a fistulose habit where fistules may reach over 10 mm in width, and is likely a form similar to that described by Bowerbank (1873) for O. fistulosa. These sponges, albeit of different species, are also abundant on the north-eastern Brazilian shelf where they exhibit a somewhat psammobyontic habit, with a nearly spherical body variably embedded in the sandy bottom, the fistules pointing mostly upwards beyond the sand. This is a totally different life-strategy to both described new species, which are typically rocky-bottom dwellers, possibly adapted to very slight silting. This life strategy is also observed in O. isodictyiformis (Carter, 1882) and O. nodosa (George & Wilson, 1919), as illustrated in de Weerdt (1985) and Muricy and Ribeiro (1999), respectively. On top of its distinct habit, if only for the stouter fistules, O. bacillifera has strongyles as the sole megascleres, alike the Tropical western Atlantic species O. bartschi (de Laubenfels, 1934), a trait that could point to another Transisthmian syster-pair (cf. Rhabderemia, van Soest & Hooper 1993, Hajdu & Desqueyroux-Faúndez 2008; Asteropus, Carvalho 2008 O. fistulosa has a markedly distinct habit and oxeote megascleres which are rather smaller than those found in both new species—300 µm long in Dendy (1924) and only 180–233 µm long, as made out from Bergquist and Warne’s (1980, Pl. 11c).
description: Published as part of Hajdu, Eduardo, Desqueyroux-Faúndez, Ruth, Carvalho, Mariana De Souza, Lôbo-Hajdu, Gisele & Willenz, Philippe, 2013, Twelve new Demospongiae (Porifera) from Chilean fjords, with remarks upon sponge-derived biogeographic compartments in the SE Pacific, pp. 1-64 in Zootaxa 3744 (1) on pages 27-29, DOI: 10.11646/zootaxa.3744.1.1, http://zenodo.org/record/5271084