Stelodoryx jamesorri, Lehnert & Stone, 2020

Lehnert, Helmut & Stone, Robert P., 2020, Three new species of Poecilosclerida (Porifera, Demospongiae, Heteroscleromorpha) from the Aleutian Islands, Alaska, Zootaxa 4851 (1), pp. 137-150 : 142-146

Stelodoryx jamesorri n. sp.

( Fig. 4 , Table 2)

Material examined. Holotype ZSM20200327 , intact specimen, stored in ethanol then dried (sample retained in ethanol), collected by J. Orr with a research survey bottom trawl from the FV Dominator; 4 June 2000, 144 m depth, haul station 71, north of Seguam Island , eastern Aleutian Islands (52° 44.04’ N, 172° 34.07’ W). Water temperature = 4.3 °C . Paratype. ZSM20200328 , intact specimen, stored in ethanol then dried, collected by W. Palsson with a research survey bottom trawl from the FV Sea Storm; 24 July 2012, 94 m depth, haul station 174, Tahoma Reef , south of Buldir Island, western Aleutian Islands (51° 44.66’ N, 175° 51.24’ E. Water temperature = 4.9 °C.

Description. The holotype ( Figs. 4A & B ) is funnel shaped and brown in color. Both sides of the funnel have a villous appearance, due to numerous ascending spicule tracts reaching above the surface. Numerous apertures, circular, 1–2 mm in diameter are present on the surfaces of both sides of the funnel, in most cases hidden by the long spicule tracts reaching above the surface. The short stalk merges gradually into the fan so it is difficult to give an exact height but, at 19 mm height the smooth surface of the stalk ends and the villous surface of the funnel begins. The stalk is round, 15 mm in diameter, hard and incompressible in the dry state. The paratype ( Fig. 4C ) is also stalked and flabellate, brown in color. The outline of the fan is undulating, approximately 32 x 22 cm with a thickness of 4–12 mm. The fan has two distinct sides, the upper side is optically smooth, the bottom side bears ridges, both sides with numerous circular apertures, 1–3 mm in diameter and flush with the surface. The sponge is only slightly compressible before breaking in the dry state. The stalk is hard, 3.5 cm in height, 3.4–4.2 cm in diameter.

Skeletal architecture. The choanosome consists of a plumoreticulate skeleton with branching spicule tracts of styles to strongyloxeas, 90–280 µm in diameter, that are connected by single spicules ( Fig. 4D ). The spicule tracts can be several mm long and are visible to the unaided eye where the sponge is torn. The tracts are often running parallel to the surface and then make a turn towards the direction of the surface. In areas with villous surfaces spicule tracts end above the surface ( Fig. 4E ). The ectosome is very thin and not present everywhere. It consists of micro- spined tylotes either in bundles parallel to the surface but mostly singly without orientation and many isochelae of both size categories in between ( Fig. 4F ). The villous surfaces are dominated by ascending polyspicular tracts and an often missing ectosome or, where present the ectosome consists of sparsely distributed tylotes and more abundant microscleres and is often found between the spicule tracts. The smooth surfaces have a more developed ectosome with bundles of tylotes mostly oriented parallel to the surface.

Spicules. Choanosomal strongyloxeas to styles ( Fig. 5A ), smooth or with one or both ends microspined ( Fig. 5B ), 325–520–657 x 33–36– 45 µm, ectosomal (aniso-) tylotes with microspined ends ( Fig. 5C ), 212–243–315 x 8–10– 12 µm, large polydentate isochelae ( Fig. 5D ), 82–123– 135 µm and small polydentate isochelae ( Fig. 5E ), 27–30– 32 µm.

Discussion. The new species deviates with its plumoreticulate skeleton from other Stelodoryx that have reticulate arrangements in the choanosome. Genetic sequences obtained from new material in the future might support the erection of a new genus for species with plumoreticulate choanosomal skeletons. Also unusual is the tendency of the styles to become strongyloxeas. In other respects it conforms to Stelodoryx in the combination of spicules, especially the isochelae are quite characteristic.

Differences with other congeners are: Stelodoryx toporoki Koltun, 1958 : from the Arctic Ocean and Sea of Okhotsk, is similar in habitus, both are stalked and flabellate to funnel-shaped species. Koltun described two different sides, an even oscular surface and a ridged ostial surface. Stelodoryx jamesorri n. sp. also has an even and a ridged surface in the paratype but indistinguishable apertures are present in abundance on both sides. The smaller holotype does not have different surfaces as both sides are villous. Stelodoryx toporoki has much longer choanosomal styles (up to 1140 µm vs. up to 657 µm in S. jamesorri n. sp.) that are considerably thinner (21–31 µm, vs. 34–45 µm) and has no strongyloxeas. Both categories of isochelae are smaller in S. jamesorri n. sp., though there is some overlap in size range. Stelodoryx flabellata Koltun, 1959 : from the Arctic Ocean, North Atlantic Ocean, and Greenland and Barents Seas, has thinner ectosomal tornotes that are smooth, microspined styles and strongyles that are shorter and thinner, and only one category of isochelae that is intermediate to the size ranges of those in S. jamesorri . Stelodoryx lissostyla Koltun, 1959 : from the Sea of Japan and North Pacific Ocean, has smooth ectosomal tornotes, shorter and thinner choanosomal styles, and two categories of isochelae both of which are smaller. Stelodoryx oxeata Lehnert et al., 2006 : from the Aleutian Islands, has choanosomal oxeas, three categories of isochelae, and centrotylote sigmas. Stelodoryx pectinata Topsent, 1890 : from the North Atlantic Ocean, has smooth ectosomal tornotes, choanosomal acanthostyles, and two categories of isochelae both of which are smaller. Stelodoryx pluridentata ( Lundbeck, 1905) : from the North and South Atlantic Ocean and North Pacific Ocean, has thinner choanosomal styles, and only one category of isochelae. Stelodoryx procera Topsent, 1904 : from the North Atlantic Ocean, has thinner ectosomal tornotes, two categories of choanosomal spicules, shorter and thinner smooth styles and only one category of isochelae intermediate in size to the two categories of S. jamesorri n. sp. Stelodoryx vitiazi Koltun, 1955 : from the North Pacific Ocean and Sea of Okhotsk, has thinner ectosomal tornotes, choanosomal acanthostyles, and only one category of isochelae. Stelodoryx mucosa Lehnert & Stone, 2015 : from the Aleutian Islands, has choanosomal acanthostyles, only one category of isochelae, and additional sigmas. Stelodoryx siphofuscus Lehnert & Stone, 2015 : from the Aleutian Islands, has style-shaped ectosomal spicules, choanosomal styles that are shorter and thinner, and two categories of isochelae with different size-ranges. Stelodoryx strongyloxeata n. sp. (description below): from the Aleutian Islands, has style-shaped ectosomal spicules that are shorter, shorter and thinner choanosomal strongyloxeas, and two categories of isochelae of different size-ranges.

Etymology: We name the new species in honour of James “Jay” Orr who has spent decades of his career as a fisheries research biologist with the Alaska Fisheries Research Center carefully collecting and cataloging the marine life of the North Pacific Ocean.

Figures

FIGURE 4. Stelodoryx jamesorri n. sp. A, Side-view of funnel-shaped holotype on a short stalk with a villous surface. B, Funnel-shaped holotype viewed from the top showing inner sides of the funnel. C, Flabellate paratype with a smooth surface and circular apertures. D, Plumoreticulate choanosomal skeleton, branching spicule tracts are connected by single spicules. E, Ascending and branching spicule tracts, connected by single spicules fanning out at the surface and often ending well above the surface. F, Weakly developed ectosome with abundant isochelae of both size categories.

FIGURE 5. Stelodoryx jamesorri n. sp. A, Chanosomal thick strongyloxea (right), occasionally strongylote (left). B, Blunt ends of strongyloxeas sometimes microspined. C, Ectosomal tylote with microspined heads. D, Large isochelae. E, Small isochelae.