Tedania (Tedania) kagalaskai Lehnert, Stone & Heimler, 2006, sp. nov.

Tedania (Tedania) kagalaskai sp. nov.

(Fig 6 a–f)

Material

The holotype is deposited at the National Museum of Natural History, Washington, D.C., U.S.A. under the registration number USNM 1082468 (51°52’15.1’’N, 176°15’57.5’’W, Little Tanaga Strait, 146 m depth). One paratype is deposited at the National Museum of Natural History, Washington, D.C., U.S.A. under the registration number USNM 1082469 (51°51’56.4’’N, 176°15’7.4’’W, Little Tanaga Strait, 105 m depth). A second paratype is deposited at the Auke Bay Laboratory Museum, Juneau, Alaska, U.S.A. under the registration number AB­05­82 (51°37’19.3’’N, 177°14’21.0’’W, approximately 6.5 km south of Cape Tusik, Kanaga Island, 155 m depth).

Description

Large orange brown sponge, attached to bedrock, boulders, and cobbles by a firm stalk (Figs. 6 a, b). The body is much softer, flabellate, growing up to a height of 35 cm, approximately 10 cm above the attachment the body expands in one plane with a thickness of approximately 5 cm to to a maximum width at the top of about 30 x 5 cm. Surface smooth, oscules in one row at the narrow top of the sponge (Fig. 6 a). The consistency of the body is soft, elastic and compressible whereas the stalk is wiry, firm and inelastic.

Skeleton. The ectosome is smooth, consisting of bundles of parallel oriented tracts of tylotes which ascend to the surface and then follow sinuous courses parallel to the surface. The choanosomal styles are in a loose plumose­reticulate arrangement with numerous onychaetes in between.

Spicules. The ectosomal tylotes (Fig. 6 c) have acanthose ends (Fig. 6 d), measuring 290–355 x 4–7 µm, choanosomal smooth styles (Fig. 6 c), 360–405 x 17–20 µm, and onychaetes in two size categories, 170–210 µm (Fig. 6 e) and 30–40 µm (Fig. 6 f).

FIGURE 6. Tedania kagalaskai sp. nov. a, in situ. Width of photo approx. 30 cm. b, holotype shortly after collection. Small quadrats equal 1 cm 2. c, Thick choanosomal styles and ectosomal tylotes. d, close up of acanthose end of tylote. e, large category of onychaete (lower left to upper right) among tylotes. f, small category of onychaete, note unequal ends.

Distribution

Known from the type­localities and observed from the submersible Delta at several other locations in the Central Aleutian Islands at depths between 80 and 170 m. Judging from observations made from the submersible this sponge is locally abundant.

Etymology

Named after Kagalaska Island near where the holotype was collected.

Discussion

Assignment of this new species to the genus Tedania is unquestionable, due to its spicule complement of ectosomal tylotes with acanthose ends, choanosomal styles and onychaetes as the only microscleres. The growth form of this species is unique for the genus. This is the only species of Tedania which is stalked. Bundles of tangential, ectosomal tylotes are usual for the genus but, the observation that these bundles ascend perpendicular to the surface from below the ectosome and then follow sinuous courses parallel to the surface is new. According to Van Soest (2002c), T. kagalaskai sp. nov. belongs to the subgenus Tedania, due to the microspined ectosomal tylotes, and the subgenus is predominantly distributed in tropical and warm­temperate waters. However, Koltun (1959) reports seven species of Tedania from boreal and arctic waters which will be compared with the present species. For spicule types and sizes of all discussed species of Tedania we refer to table 3.

T. suctoria (Schmidt, 1870) is an encrusting or cushion­shaped species which may be partly ramified but is not stalked. It has a papillate surface and with a height of 9 cm is much smaller than T. kagalaskai n. sp. All types of spicules in T. suctoria have a much broader size range and the styles are thinner. T. suctoria is known only from the N­ Atlantic. T. gurjanovae Koltun, 1958 is a lumpy, cushion­shaped sponge of only 2 cm height. It has smaller styles, smaller ectosomal spicules which are tornotes and is known from the Eastern Tartar Strait. T. microrhaphidiophora Burton, 1935 is a semispherical or discoidal sponge with a height up to 8cm and a papillate surface. Its styles are somewhat smaller and it has also tornotes as ectosomal spicules. Onychaetes of T. microrhaphidiophora are only in one size­category and do not match one of the categories of T. kagalaskai. T. flexistrongyla Koltun, 1959 is a lumpy sponge, all occuring types of spicules are considerably larger (maximum sizes about two times larger) than in T. kagalaskai. T. flexistrongyla is known from the Sea of Okhotsk. T. dirhaphis (Hentschel, 1912) is an irregularly lumpy sponge which can have dactylate processes and has a smooth surface. Its styles occur in a broader size­range and are considerably thinner than the styles in T. kagalaskai. Ectosomal spicules are strongyles and tylotes whereas T. kagalaskai has tylotes only which are smaller. T. dirhaphis occurs in the Sea of Okhotsk, near the Kuril Islands and in the S­China Sea. T. digitata (Schmidt, 1862) is up to 5cm high and is a massive sponge with dactylate or lobate processes. Styles and tylotes are much smaller and thinner, onychaetes are only in one size category. T. digitata is described from the Sea of Japan, E­China Sea, the Malayan Archipelago, the Indian Ocean, the Mediterranean and the N­Atlantic. T. fragilis Lambe, 1894 grows up to seven cm in height and is of irregularly tabular or lumpy shape. It is brittle and inelastic with an uneven surface. The choanosomal styles are thinner and the ectosomal tylotes are smaller than in T. kagalaskai. T. fragilis is known from the Kuril Islands and from near Vancouver Island in shallow water.