(Figs 7 a–f)
Material
Holotype, deposited at the National Museum of Natural History, Washington, D.C., U.S.A. under the registration number USNM 1082470 (51 ° 40 ’ 42.2 ’’N, 176 ° 15 ’ 39.5 ’’W, 7.2 km south of Ragged Point on Kagalaska Island, 150 m depth). Two paratypes are deposited at the Auke Bay Laboratory Museum, Juneau, Alaska, U.S.A. under the registration numbers: AB05 82 (51 ° 55 ’ 5.5 ’’N, 175 ° 17 ’ 37.6 ’’W, approximately 12 km south of Cape Kigun, Atka Island, 112 m depth), and AB05 81 (51 ° 40 ’ 40 ’’N, 176 ° 16 ’ 15.5 ’’W, 7.3 km south of Ragged Point on Kagalaska Island, 156 m depth). Additional material: 6221 2 B 7 (51 ° 54 ’ 49.1 ’’N, 173 ° 53 ’ 8.3 ’’W, 25.7 km southeast of the west end of Amlia Island, 119 m depth).
Description
Light brown, cylindrical, stalked sponge (Figs. 7 a, b). Consistency very soft, except for the wiry stalk. Surface smooth. The holotype is attached to a cobble with a stalk, ca. 2 cm in diameter. Other specimens have been observed in situ attached to pebbles, boulders, and bedrock. The sponge widens from the stalk upwards into a cylindrical body with a diameter of 7 cm. The sponge reaches a maximum height of ca. 45 cm, a second stubby cylinder branches off the main cylinder (Figs. 7 a, b) at about two thirds the height of the main cylinder. We have observed specimens in situ with up to four additional cylinders or branches.
Skeleton. The stalk consists of longitudinally arranged masses of tylostyles, no individual tracts are recognizable. There is no special ectosome developed. The choanosome consists of irregularly arranged pauci and polyspicular tracts of tylostyles with masses of sigmas and very abundant anisochelae, single and in rosettes.
Spicules. Tylostyles (Fig. 7 c) measure 470–520 x 10–14 µm, anisochelae (Figs. 7 d, e), 55–75 µm, sigmas (Figs. 7 f), 65–80 µm.
Distribution
Known from the typelocalities and observed from the submersible Delta at several other locations in the Central Aleutian Islands at depths between 82 and 260 m. Judging from observations made from the submersible this sponge is locally abundant.
Etymology
Named after its collector Dave Carlile.
Discussion
This species is assigned to the genus Mycale as the megascleres consist exclusively of “mycalostyles”. As a coherent ectosomal skeleton is lacking and the choanosomal skeleton is consisting of wispy plumose bundles of megascleres it fits quite well into the subgenus Carmia. Koltun (1959) listed 17 species of Mycale, two were further divided into several subspecies. Table 4 shows spicule types and measurements of all species of Mycale reported from the area. Mycale loveni (Fristedt, 1887) is the only species of Mycale which is also stalked. The body is funnel shaped or auricular and so differs in growth form.
FIGURE 7. Mycale carlilei sp. nov. a, holotype in situ. Width of photo approx. 40 cm. b, holotype on deck shortly after collection. Small quadrats equal 1 cm 2. c, all spicule types; styles, anisochelae and sigmas. d, anisochela, front view. e, anisochela, side view. f, sigma.
Additionally, there are differences in spiculation; M. loveni has a small sizecategory of anisochelae and lacks sigmas. M. loveni shares the relatively short tylostyles with a swelling near the pointed end and both species are probably closely related. M. loveni is known from the Chukchi Sea, Bering Sea and Sea of Okhotsk and occurs sympatrically with M. carlilei and the two species are often observed in situ in close association with each other. However, both species are clearly separated by their habitus and types of microscleres. Specimen 6221 2 B 7 is probably a juvenile specimen. It differs from other samples in having a much softer body and in the the occurrence of moderate numbers of sigmas, in contrast to very abundant sigmas in the larger specimens.
Mycale lobata (Bowerbank, 1866) is a widely distributed species and is also reported from the Bering Sea. It differs from M. carlilei sp. nov. in lacking a stalk, posessing smaller styles, smaller anisochelae and in the lack of sigmas. Mycale papillosa Koltun, 1959 is a cushionshaped sponge with tubular papillae. It has smaller styles, smaller anisochelae and smaller sigmas. It also occurs sympatrically with the newly described species. Koltun divided M. papillosa into the two subspecies M. p. papillosa and M. p. dulkeiti. M. ochotenis Koltun, 1959 is probably an encrusting species, described as “flattened out, slightly lobate”. It differs in smaller styles, smaller anisochelae and smaller sigmas. It is described from the Sea of Okhotsk. M. thaumatochela Lundbeck, 1905 is also an encrusting to lumpy species with a rough surface and differs mainly in the presence of a second category of peculiar shaped anisochelae, the lack of sigmas and, only slightly in smaller styles and in a smaller large category of anisochelae. M. thaumatochela also has a wide arctic distribution which includes records from the Bering Sea. M. hispida (Lambe, 1893) is a subspherical species that typically does not exceed 3cm in diameter. It has smaller styles and smaller sigmas.
M. helios (Fristedt, 1887) is a spheroid species with a maximum size of 4 cm in height. Its styles and sigmas are smaller. M. helios is known from the East Siberian Sea, Bering Sea, Sea of Okhotsk and the Sea of Japan. M. retifera Topsent, 1924 is an encrusting or cushion shaped species. Its styles are shorter and thinner, it has two size categories of anisochelae, both smaller than the anisochelae of M. carlilei and it has toxas, lacking in M. carlilei. M. retifera is recorded from the Sea of Japan and from shallow water in the Mediterranean. M. lingua (Bowerbank, 1866) is irregularly shaped but not stalked, it has much larger styles, larger anisochelae, smaller sigmas and rhapids in trichodramata, the latter lacking in M. carlilei. M. lingua has a circumarcticboreal distribution. M. adhaerens (Lambe, 1893) is also a sympatric species with Mycale carlilei, encrusting to cushionshaped and up to 9 cm in height. It has two, possibly three size categories of anisochelae and rhaphides. It is known from the Bering Sea, Sea of Okhotsk and the Sea of Japan.
Mycale arctica (Fristedt, 1887) is considered a subspecies of M. adhaerens by Koltun, 1959. It is again lumpy to cushionshaped and up to 2.5 cm in height. It has a nodose, smooth surface. Its styles are shorter, it has a second category of anisochelae where the large anisochelae are larger, the small anisochelae smaller, and it has rhaphides. M. toporoki Koltun, 1958 is a lumpy, fragile sponge. Its styles attain a larger size, and it has a smaller category in the ectosome. Its large category of anisochelae is larger, the small category smaller. The sigmas attain a larger size and it has rhaphides in trichodragmata. M. toporoki has been reported from the Bering Sea, the Sea of Okhotsk, Sea of Japan and the Kuril Islands. M. tylota Koltun, 1958 is a lumpy sponge, up to 8.5 cm in height. It has larger choanosomal styles and a smaller category of ectosomal styles and tylostrongyles. It has two size categories of anisochelae where the large category is larger and the small category is smaller than in M. carlilei sp. nov. M. tylota is known from the Kuril Islands.
M.cucumis Koltun, 1958 is elongated, cylindrical, and up to 8 cm in height. It has larger styles and a special category of ectosomal styles. The anisochelae occur in three size categories; large anisochelae are larger, rare mediumsize anisochelae and the small categories smaller than the anisochelae of M. carlilei. Sigmas are smaller and it has rhaphides in contrast to M. carlilei. M. cucumis has also been reported from the Kuril Islands. M. lindbergi Koltun, 1958 is spherical and up to 7 cm in height. The styles are larger, it has a second category of ectosomal styles, and has anisochelae in three size categories. The large category is larger, and both, the medium and small categories are smaller than in M. carlilei. M. lindbergi has rhaphides in trichodragmata. M. lindbergi is known from the Eastern Tartar Strait and the Kuril Islands. M. longistyla Koltun, 1958 is another lumpy Mycale, up to 8 cm in height. It is unique in having styles in three size categories; additionally there are strongyles, lacking in M. carlilei. It has two size categories of anisochelae, sigmas are smaller and it has rhaphides. M. longistyla is known from the Kuril Islands. M. japonica Koltun, 1959 is a lumpy, dark grey sponge with a bristly surface, up to 4 cm in height. Its styles are two to three times longer than in M. carlilei. It has ectosomal styles and strongyles while M. carlilei has no special category of ectosomal spicules. Microscleres of M. japonica are considerably longer large anisochelae and shorter small anisochelae. Its sigmas are smaller, it has toxa, rhaphides and microxeas. Toxa, rhaphides and microxeas are lacking in M. carlilei. M. japonica has been reported from the Sea of Japan at depths between 120– 140 m.