Suberites cranium 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
Suberitida
Suberitidae
Suberites
Suberites cranium

description: Suberites cranium Hajdu, Desqueyroux-Faúndez, Carvalho, Lôbo-Hajdu and Willenz sp. nov.
(Figs. 2A, 3A–E, Tabs. 1 –2)
Suberites cranium Hajdu et al. (2009, nomen nudum) in Willenz et al. (2009: 113)
Type material. Holotype. IZUA-POR 140, Piedra Lille (43°10’58.60”S – 73°38’27.20”W, Quellon, Chiloé Island, Chilean Patagonia), 16 m depth, coll. E. Hajdu and Ph. Willenz, 04 March 2005 —fragments from the holotype: MHNG 64112, MNRJ 8889 and RBINSc–IG 32232–POR 8889. Paratypes. MNRJ 8897, 8899, south of Melinka (43°53’56.70”S – 73°45’16.70”W, Ascension Island, Guaitecas Archipelago, Chilean Patagonia), 10–16 m depth, coll. E. Hajdu, Ph. Willenz and G. Lôbo-Hajdu, 06 March 2005 ―fragments of paratypes: MHNG 61426, 61427 and RBINSc-IG 32232-POR 8897, 8899; respectively. MNRJ 8944, Isla Laurel (44°00’50’’S – 73°48’14’’W, Guaitecas Archipelago, Chilean Patagonia), 15–19 m depth, coll. E. Hajdu, Ph. Willenz and G. Lôbo-Hajdu, 07 March 2005 ―fragments of paratype: MHNG 61428 and RBINSc-IG 32232-POR 8944.
Comparative material. Suberites puncturatus Thiele, 1905 — MHNG 32888 (fragment from holotype ZMB 3275,), microscopical preparations of dissociated spicules and thick sections.
Suberites ruber Thiele, 1905 — MHNG 32891 (fragment from holotype ZMB 3274), microscopical preparations of dissociated spicules and thick sections.
Diagnosis. Suberites cranium sp. nov. is the only Suberites known to occur in Chile which has a nearly hemispherical body shape and two categories of tylostyles, mostly straight or only slightly bent and sharply pointed.
Description (Fig. 2A). Massive, nearly hemispherical, almost totally smooth, velvety, and with a firm consistency. Usually about 5 cm in diameter, and about 4 cm high. A few, scattered, short, at times membranous, volcaniform projections (ca. 5 mm high) bear small oscula on top (ca. 4 mm across). Frequently these appear to be contracted on live specimens. Live-colour is yellowish-beige, which may bear carmine spots, turning greyish beige in ethanol.
Skeleton (Fig. 3A –A’). Ectosomal skeleton, a dense palisade of tylostyles (ca. 300–700 µm thick). Choanosomal skeleton, also with a dense pack of tylostyles separable in two clearly distinguishable layers. Subectosomal skeleton, mostly radially disposed (ca. 550–1000 µm thick); and a confused, thicker, central layer, where tylostyles are strewn in great confusion.
Spicules (Figs. 3B–E; Table 1). Megascleres, tylostyles in two size categories; (I) smaller, ectosomal, stout, irregular roundish heads, occasionally subterminal or lacking (Figs. 3 B–C), 120–288 µm long and 1.6–15 µm thick, with sharp apex; (II) larger, choanosomal, stout, irregular roundish heads, occasionally subterminal or lacking (Figs. D–E), 296–720 µm long and 4.8–16 µm thick, with sharp apex.
Distribution and ecology. So far known from a narrow zone in the outer Chilean fjords region, between 43ºS (Quellon, southern Chiloé) and 44ºS (Melinka and Isla Laurel, in the Guaitecas Archipelago). The species occurs on nearly vertical rocky substrate, between 10 and 19 m depth, frequently isolated individuals can be seen sticking out from a thin layer of silt.
Etymology. The name ‘cranium’ is a noun in apposition, which conveys the species’ bald head shape.
Remarks. This is a very conspicuous sponge, hard to be mistaken in situ for any other found so far in the Chilean fjords region. The genus Suberites which includes 73 valid species (van Soest et al. 2013) is allegedly cosmopolitan in distribution, but is commonest in cold temperate waters. Table 2 briefly summarises the descriptive information available for all species of Suberites this far recorded from the Chile –Peruvian region, as well as from other biogeographic areas deemed closely related to it. Affinity has been postulated mostly on the basis of geographic adjacency, with the exception of northern and southern New Zealand, included for their known Trans-Pacific historical biogeographic relationships (Sluys 1994, Carvalho 2008, Hajdu & Desqueyroux-Faúndez 2008, see biogeographic remarks below). No species of Suberites has thus far been recorded from either the Central Pacific or the Eastern Tropical Pacific.
Out of 21 species of Suberites known this far from the areas listed above, seven are set apart from the new species for their possession of tylostyles which can be much larger (1000 µm or larger) than those of S. cranium sp.nov: S. axiatus, S. caminatus, S. massa, S. microstomus, S. mollis, S. perfectus and S. stellatus. Four species were described with additional diactines, and are clearly distinct too: S. australiensis, S. ficus, S. mineri and S. strongylatus. Suberites tortuosus sensu Cuartas (1986a; as S. tortuosa var. austral) was reported to possess styles in addition to tylostyles, but these could be simply malformed tylostyles. The species differs further from S. cranium sp. nov. by its massive-ridged habit, as well as by its tylostyles, which albeit reported as pertaining to two size categories, are neither as small as the smallest ones in the new species, neither as large as the largest ones.
Of the remaining species, S. affinis, S. anastomosus and S. carnosus were reported with a single variable category of tylostyles. Both former ones are New Zealand species, and it is highly unlikely that either would be spread across the entire southern Pacific Ocean. Brøndsted ([1923] 1924a) reported that spicules in S. affinis and S. anastomosus are considerably thinner than those reported here for the new species (7–8 µm and 7–11 µm, vs. 1.6– 16 µm, respectively). Furthermore, the specimens of S. affinis are attached through a narrow base, being pear or club-shaped, while all the specimens seen of S. cranium sp. nov. were nearly hemispherical. The habit of S. anastomosus is also distinct in presenting anastomosing branches and a clearly discernible ectosomal membrane over large and numerous subectosomal cavities. The latter species has been associated with genus Pseudosuberites Topsent, 1896 by Burton (1930) and Bergquist (1968), but the recent focus on a tangential ectosomal skeleton and single category of tylostyles as diagnostic features of Pseudosuberites (van Soest 2002a) argues for a different placement. Assignment to Suberites appears to be the best option, and is thus endorsed here.
Suberites carnosus, on the other hand, is a North-eastern Atlantic species subsequently reported from several far apart areas around the globe. The species is in need of a taxonomic revision as it may well contain a series of cryptic undetected species. The report by Burton (1934), based on specimens from the Falklands/ Malvinas Islands, did not furnish any descriptive data wherefrom affinities of his material could be inferred. Consequently, Ackers et al. (2007) description has been adopted as a proxy for S. carnosus ’ morphology. According to these authors the species has thin tylostyles under 500 µm long, which is quite less than the observed values for S. cranium sp. nov.
Suberites cupuloides, as redescribed in Bergquist (1968), possesses a quite comparable set of spicules, differing in maximum achieved width and mean length of the larger category of tylostyles. These are minor points of distinction, but in association with the species’ erect-massive habit with conspicuous large, rounded lobes, and known occurrence on the south-western Pacific only, indicates that both are not cospecific. Further support for this hypothesis stems from Bergquist’s (1961, 1968) mention of “loose, subplumose, ascending fibres of extremely variable diameter” in the choanosome of S. cupuloides, which is quite comparable to what is seen in S. aurantiaca (Duchassaing and Michelotti, 1864) for instance. This kind of architecture has been associated with the old concept of Laxosuberites Topsent, 1896 (cf. Topsent 1938), a genus no longer considered valid (van Soest 2002a), and is not present in the new species reported upon here, which has a dense and confused choanosomal architecture.
Suberites latus comes very close to S. cranium sp. nov. in overall morphology. Lambe (1892) reported the north-eastern Pacific sponge as subhemispherical and possessing tylostyles in rather similar size categories as those described here. The species has subsequently been merged into S. suberia (Montagu, 1818), originally from the north-eastern Atlantic, on account of the finding of a few centrotylote microstrongyles, upon reexamination of the original series of specimens (Lambe 1893). Later, de Laubenfels (1932) identified Californian specimens as belonging to this species, which he preferred to treat as a subspecies of suberia, within genus Ficulina Gray, 1867. He failed to find any centrotylote microstrongyles, and neither did he clearly distinguish two size classes of tylostyles, having reported them as 70–590 µm long and 5–12 µm thick. We concur with van Soest et al. (2013) in recognizing the status of Lambe’s sponge as distinct from S. suberia and as the minor points of distinction in comparison to the Chilean species we list the irregularly subhemispherical habit illustrated by Lambe (1892, Pl. III, fig. 7), the ability to produce centrotylote microstrongyles, even if not widespread, and the possibility of being bright-orange alive, if de Laubenfels’ (1930) material is indeed cospecific. In support of this decision we add the failure to recover any S. latus -like sponges in the vast area comprised between California (ca. 37ºN) and the Chilean fjords region (ca. 43ºS), in spite of considerable sampling conducted in latter years (Desqueyroux-Faúndez & van Soest 1997, Gómez et al. 2002, Hajdu et al. 2006 b, Carvalho 2008, Hooker 2008, Willenz et al. 2009).
Finally, two Chilean species of Suberites were described by Thiele (1905), S. puncturatus (Fig. 4A) and S. ruber (Fig. 4B). Both have tylostyles with dimensions comparable to those reported here from S. cranium sp. nov. Suberites puncturatus, from Coquimbo (ca. 30ºS), is easily discernible from the new species though, as it has a thickly encrusting habit, and its smaller tylostyles, actually tylostrongyles, are frequently rather markedly bent, sometimes twice. As highlighted by Thiele (1905), the species’ ectosome is marked by abundant pores, which render the overall architecture neatly reticulated in tangential view. This arrangement penetrates into both the subectosomal and outer choanosomal regions and is notoriously distinct from that which is observed in S. cranium sp. nov. as described above. Suberites ruber was described with a light-red live colour, and irregularly cushion-like in habit. Reexamination of the type material revealed that its choanosomal tylostyles are often sinuous, and that slender young forms, also sinuous and bearing markedly irregular heads abound. Thiele (1905) has referred to S. ruber ’s slight cavernous structure due to the common subectosomal and choanosomal aquiferous canals, which is a further point of distinction from S. cranium sp. nov.
The species reported upon here is thus considered well differentiated from other Suberites occurring in the Chilean-Peruvian area, its adjacent biogeographic provinces in the south-eastern Pacific and south-western Atlantic, or in additional areas, which albeit located farther away, have traditionally been regarded as possibly sharing faunistic elements with the marine temperate Chilean biota.
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 7-9, DOI: 10.11646/zootaxa.3744.1.1, http://zenodo.org/record/5271084