Coelosphaera oglalai, Lehnert, Helmut, Stone, Robert & Heimler, Wolfgang, 2006

Lehnert, Helmut, Stone, Robert & Heimler, Wolfgang, 2006, New species of Poecilosclerida (Demospongiae, Porifera) from the Aleutian Islands, Alaska, USA, Zootaxa 1155, pp. 1-23 : 6-9

Coelosphaera oglalai sp. nov.

( Fig 3 a–f)

Material

Holotype: T­5E­34 (51°37’19.3’’N, 177°14’21.0’’W, approximately 6.5 km south of Cape Tusik, Kanaga Island, 155 m depth). Paratype: 6206­18­9B (51°51’58.2’’N, 176°15’7.8’’W, Little Tanaga Strait, 100 m depth). Both the holotype and the paratype are deposited at the National Museum of Natural History, Washington, D.C., U.S.A. under the registration numbers USNM 1082994 and USNM 1082995, respectively.

Description

The holotype is a subglobular sponge, about 5 cm in diameter ( Fig. 3 a). Alive it is orange colored and beige in ethanol. The smooth surface is covered irregularly with conical papillae of very different sizes, ranging from 2–20 mm in height and 1–18 mm in diameter. A considerable area of the surface is overgrown with bryozoans. The paratype is a massively encrusting sponge, growing under an Iophon piceus abipocillus .

Skeleton. The ectosome is in areas a tangential arrangement of bundles of tylotes, in other areas there is a tangential arrangement of all spicule types occuring in the sponge. In the choanosome strongyles are arranged halichondroid, relatively dense, in parts polyspicular tracts are vaguely recognizable.

Spicules. The choanosomal megascleres vary from blunt ended (anis­) oxeas to strongyles ( Fig. 3 b), always with finely acanthose ends ( Fig. 3 c), 570–634 x 27–32 µm. Ectosomal tylotes ( Fig. 3 d) with slightly acanthose ends ( Fig. 3 e), 325–364 x 7–10 µm. Microscleres are arcuate isochelae ( Fig. 3 f), 47–52 µm.

Distribution

Known from the type­localities only.

Discussion

The family Coelosphaeridae Dendy, 1922 was rearranged by Van Soest (2002a). Our new species fits into the definition given there of “ Myxillina with reticulate choanosomal skeleton and arcuate isochelae” and it also meets Van Soest´s (2002a) definition of the genus Coelosphaera Thomson, 1873 of “ Coelosphaeridae with hollow bodies provided with fistules; megascleres tylotes or strongyles, to which echinating acanthostyles may be added; microscleres arcuate isochelae, sigmas and rhaphides (may be absent)”. Following this, the new species has a reduced set of spicules where echinating acanthostyles, sigmas and rhaphides are lacking and, unlike any other species of Coelosphaera , in which the choanosomal strongyles have acanthose ends with conically shaped spines. As there are no acanthostyles it has to be assigned to the subgenus Coelosphaera Thomson, 1873 .

According to the “world list of extant sponges (Van Soest & Hooper, 2005) there are 37 species of Coelosphaera described worldwide. Here we compare the new species with the ten species known from the N­Pacific and N­Atlantic.

Twelve species of Coelosphaera are described from the area but, C. appendiculata Carter, 1874 and C. ascidioides Fristedt, 1887 are regarded synonyms of C. tubifex Thomson, 1873 and C. physa ( Schmidt, 1875) respectively (Van Soest & Hooper, 2005). For the remaining species spicule types and sizes are listed in table 2. C. calcifera Burton, 1934 is reported to occur in the Sea of Japan by Tanita & Hoshino, 1989. This species differs in lacking acanthostyles, in having smaller tylotes, smaller isochelae and in the occurrence of sigmas. C. crusta Tanita & Hoshino, 1989 from Japan is a thinly (<1 mm) encrusting sponge with small cylindrical (<1 mm in diameter, <10 mm high) fistules. In spiculation it differs in having only tylotes as megascleres, it has smaller isochelae and has sigmas. C. dividuum ( Topsent, 1927) is a fistulose sponge with larger tylotes, with acanthostyles, and isochelae of a wider size range. Coelosphaera hatchi (Bakus, 1966) was described as Coelosphaericon but is regarded as a member of Coelosphaera by Van Soest (2002 a). It deviates from other species of the genus in the possession of toxiform microxeas and differs further from C. oglalai in larger tylotes and in smaller arcuate isochelae. C. peltata ( Topsent, 1904) is known from a small (<1 cm) patch of an encrustation. It has only smooth strongyles as megascleres, isochelae are of a wider sizerange and it differs in abundant rhaphides in trichodragmata. C. physa ( Schmidt, 1875) is a white fistular sponge from the N­Atlantic and the Sea of Japan ( Koltun, 1959). It differs in having very large tylotes as the only type of megasclere and in the occurrence of rhapides. C. phlyctenodes ( Carter, 1876) is again a subglobular fistule bearing sponge of yellowish color. It has only oxeas as megascleres, and further differs from C. oglalai in having smaller isochelae and in the possession of sigmas.

C. picoensis Topsent, 1928 differs in the possession of only one category of megasclere and additional sigmas among the microscleres. C. tubifex Thomson, 1873 is a subglobular sponge with tubular fistules of varying lengths. It differs from C. oglalai in having larger tylotes, stylotes of larger size than the strongyles in C. oglalai and in smaller isochelae.

The genus Damiriopsis Burton, 1928 , (family: Myxillidae ) known only with the single species D. brondstedi has choanosomal strongyles with finely acanthose ends and also shares the ectosomal tylotes with acanthose ends. However, Damiriopsis has anchorate isochelae while C. oglalai possesses arcuate isochelae which separates the genera on the family level.

Figures

FIGURE 3. Coelosphaera oglalai sp. nov. a, holotype. b, choanosomal strongyle. c, close up of microacanthose end of choanosomal strongyle. d, ectosomal tylote (upper left to lower right). e, close up of acanthose end of tylote. f, isochelae, on the left acanthose end of strongyle.