(Vosmaer, 1885)

Species Overview

Hemigellius arcofer (Vosmaer, 1885) is a thickly fan-shaped sponge, with a coarse fibrous structure. It occurs only in deep water in the Northern Atlantic N of 60°N

Taxonomic Description

Colour: Greyish-yellow (in alcohol).
Shape, size, surface and consistency: Fan-shaped, firmly attached to stones; size up to 15 x 8.5 x 3 cm.Towards the top the thickness gradually tapers to 1 cm. Strongly fibrous; at the surface of the fan, the spicule fibers are more or less tangentially orientated, but with numerous fibres projecting through the surface; numerous circular and oval canal openings of 1-4 mm are situated at both sides of the fan, giving the surface a very open and loose appearance; part of these openings is covered by a thin, transparent dermal membrane. Consistency: soft, fragile.
Spicules: (hemigellius_arcofer_spics.jpg) Megascleres: Oxeas, robust, slightly curved, with long, sharp points: 450-650 x 15-22 µm. Microscleres: Sigmas, slightly and unevenly curved, but with strongly curved points, abundant: 12-28 x 1.0-1.9 µm; toxas, rather thick, robust, evenly bent, with recurved apices, numerous: 95-180 x 3.0-6.8 µm.
Skeleton: Ectosome: part of the choanosomal spicule fibres becomes tangentially oriented at the surface. They form an irregular reticulation around the canal openings. Choanosome: the choanosomal skeleton is a rather close-meshed reticulation of strong multispicular primary lines, 125-400 µm thick. These are irregularly connected by unispicular secondary lines. Spongin very scarce, confined to the nodes of the spicules.
Ecology: Deeper than 70 m, on stones.
Distribution: Trondheim (Norway), Spitsbergen, between Iceland and Faroe; Barents Sea, Kara Sea, Greenland, Gulf of St. Lawrence, Baffinland.
Etymology: arcofer (Latin) = carrying a bow, referring to the possession of toxas.
Type specimen information: The lectotype is ZMA POR. 6075, W. Barents Exp. 20°77'71" N 49°37'5" E, 170 fms (=306 m).

Remarks

Hemigellius arcofer is characterized by its robust toxas of variable size. In habit it is quite similar to Hemigellius pumiceus, but this species has much thinner toxas, which lack the recurved apices. Apart from this H. pumiceus has no sigmata, and much larger oxeas.
The conspecificity of Gelliodes plexa and Gelliodes consimilis with H. arcofer has already been suggested by Burton (1948), and is confirmed by De Weerdt and Van Soest (1987). The spicules, both megascleres and microscleres, of the type specimen of G. consimilis are somewhat larger than those of G. plexa. The similarity in habit, skeletal architecture and form of the spicula of three species is, however, evident.
Burton (1932) considered Gellius esperi Arnesen (1903) also a synonym of H. arcofer. Arnesen's description of the species strongly resembles that of H. arcofer. The species was described as fan-shaped, 20 x 15 cm, with a choanosomal skeleton consisting of coarse, multispicular primary lines. Megascleres evenly bent oxeas, 450-560 x 16 µm and smaller oxeas of 300 µm. Microscleres sigmas of 8 µm and toxas of 160 µm. Arnesen described the species from a specimen in the collection of the Trondheim Museum but of which no further data were available.
Source: De Weerdt and Van Soest, 1987.

Kingdom Animalia
Phylum Porifera
Class Demospongiae
Order Haplosclerida
Suborder Haplosclerina
Family Niphatidae
Genus Hemigellius
Species Hemigellius arcofer

Status in World Register of Marine Species

Accepted name: Hemigellius arcofer (Vosmaer, 1885)

Scientific synonyms and common names

Gellius arcoferus n.sp. Vosmaer, 1885: 29, Pl.IV, Figs 18, 19, Pl.V, Figs 87-90; Fristedt, 1887: 438, Pl.24, Figs 29-31, Pl.28, Fig.16; Lambe, 1896: 184, Pl.I, Figs 3, 3 a-b; Lundbeck, 1902: 62, Pl. XII, Figs 11a-c; 1909: 433; Hentschel, 1929: 898; Burton, 1930a: 498.
Gelliodes plexa n.sp. Lundbeck, 1902: 75, Pl.V, Figs 3, 4, Pl. XIV, Figs 3-5;1909: 434.
Gelliodes consimilis n.sp. Lundbeck, 1902: 77, Pl. XIV, Figs 6a-c.
Gellius esperi n.sp. Arnesen, 1903: 7, Pl.I, Fig.2.
Orina consimilis: De Laubenfels, 1942: 263.
Haliclona arcofera: Burton (pars), 1948: 282; 1959: 18 (Not: Burton, 1957).
Gellius jugosus: Koltun, 1959: 211, Fig. 167
(Not: Isodictya jugosa Bowerbank, 1866 = Haliclona fibulata (Schmidt, 1862)).

Arnesen, E., 1903. Spongien von der norwegischen Küste, Monaxonida: Halichondrina. Bergens Mus. Årbok, 1903 (1): 1-30, pls. I-VII.

Burton, M., 1930a. Norwegian sponges from the Norman collection. Proc. zool. Soc. London, 2: 487-546.

Burton, M., 1948. The synonymies of Haliclona angulata (Bowerbank) and H. arcoferus (Vosmaer). Ann. Mag. nat. Hist., (12) 1: 273-284.

Burton, M., 1959a. Spongia. Zoology of Iceland, 2: 1-71.

Fristedt, K., 1887. Sponges from the Atlantic and Arctic Ocean and the Behring Sea. Vega Exped., vetensk. Arbeten, 4: 403-471, pls. 22-31.

Hentschel, E., 1929. Die Kiesel-und Hornschwämme des nördlichen Eismeers. Fauna Arctica, 5: 859-1042.

Koltun, V.M., 1959. [The Cornacuspongida of the northern and far-eastern seas of the USSR. Keys to the fauna of the USSR]. Akademia Nauk, Moscow, Leningrad, 236 pp., XLII pls.

Lambe, L.M., 1896. Sponges from the Atlantic coast of Canada. Trans. roy. Soc. Canada, (2)2: 181-211.

Laubenfels, M.W. de, 1942. Porifera from Greenland and Baffinland collected by Capt. Robert A. Bartlett. J. Washington Acad. Sci., 32 (9): 263-269.

Lundbeck, W., 1902. Porifera. Part I. Homorrhaphidae and Heterorrhaphidae. Danish Ingolf Exped., 6: 1-108.

Vosmaer, G.C.J., 1885. Sponges of the "Willem Barents" Expedition, 1880 and 1881. Bijdr. Dierk., 12: 1-47.

You can continue searching for Hemigellius arcofer on one of these Web sites:

Fauna Europaea (animals) | IOPI (plants) | NCBI (genetic)

Google | Yahoo | MSN | Wikipedia