ASBESTOPLUMA TOPSENT, 1901

Hestetun, Jon Thomassen, Tompkins-Macdonald, Gabrielle & Rapp, Hans Tore, 2017, A review of carnivorous sponges (Porifera: Cladorhizidae) from the Boreal North Atlantic and Arctic, Zoological Journal of the Linnean Society 181, pp. 1-69 : 4-5

SUBGENUS ASBESTOPLUMA TOPSENT, 1901

Diagnosis: Asbestopluma without spear-shaped microtylostyles (from Lopes, Bravo & Hajdu, 2011).

Type species: Cladorhiza pennatula Schmidt, 1875 (by subsequent designation; Topsent, 1901).

Remarks: The typical spicule complement of Asbestopluma is one category of mycalostyle, one category of subtylostyle, acanthotylostyles in the basal sheath, one larger and one smaller category of palmate anisochela and finally sigmancistras. The North Atlantic species treated here do not deviate from this except for the slightly modified larger anisochelae of A. (A.) ruetzleri sp. nov. However, globally Asbestopluma species can be found where the large palmate anisochelae are missing or where either type of anisochela has been modified into different morphologies such as arcuate ( Kelly & Vacelet, 2011; Hestetun, Rapp & Xavier, 2017) or anchorate unguiferate ( Lopes & Hajdu, 2014). Monocrepid desmas have also been reported in some species. Subgenus Asbestopluma is defined as species within the genus that do not have spear-shaped microtylostyles and thus do not meet the definition of subgenus Helophloeina Topsent, 1929 . Subgenus Helophloeina contains only three species. The type species of the subgenus, A. (H.) stylivarians ( Topsent, 1929) , was collected at the Canary Islands, and the subgenus is not present in the area covered here.

ASBESTOPLUMA (ASBESTOPLUMA) BIHAMATIFERA ( CARTER, 1876)

( FIG. 3)

Original description: Esperia cupressiformis var. bihamatifera Carter, 1876: 318 .

Synonyms and citations: Asbestopluma bihamatifera ( Lundbeck, 1905: 51; Topsent, 1913: 50; Hentschel, 1929: 875, 933; Koltun, 1959: 74, 1964: 151, 164). Not: Cladorhiza bihamatifera ( Vosmaer, 1882: 47) ; Esperia bihamatifera ( Hansen, 1885: 15) .

Material examined: The Danish Ingolf Expedition, BIOFAR, LAR2012, IceAGE 2 (see Supporting Information).

Diagnosis: Erect, single-axis Asbestopluma with upper part of stem with four to six filament rows. Megascleres mycalostyles, subtylostyles and acanthotylostyles; microscleres one type of palmate to arcuate anisochela c. 41–61 µm, one type of palmate anisochela c. 9–11 µm and sigmancistras c. 17–22 µm.

Description: Erect sponge consisting of a single, hard but flexible stem bare in the lower part; upper part with four to six filament rows, equally distributed around the stem. Stem round in cross section. Most specimens 5–10 cm tall and 1–2 mm in diameter, with filament-bearing part 1–2 cm in length. Sponge attached with branching root-like processes. Lower stem light brown; upper part, including filament-bearing part, light grey to white. Processes up to 3 mm long, but often reduced to knobs, either because filaments are withdrawn or due to specimen damage ( Fig. 3A, B).

Skeleton : Skeleton composed of a main axis of tightly packed mycalostyles with points toward the apex. Lower stem with outer layer of acanthotylostyles; upper part with several rows of filaments. Filaments composed of a central stem made up of overlapping subtylostyles perpendicular to and anchored in the centre of the main axis.