Sympagella clippertonae, Herzog & Amon & Smith & Janussen, 2018

Herzog, Sascha, Amon, Diva J., Smith, Craig R. & Janussen, Dorte, 2018, Two new species of Sympagella (Porifera: Hexactinellida: Rossellidae) collected from the Clarion-Clipperton Zone, East Pacific, Zootaxa 4466 (1), pp. 152-163 : 158-160

Sympagella clippertonae sp. nov.

( Fig 3 , Tables 1.3, 1.4)

Material examined: Holotype (unicum), SMF 12105, CS_19, ABYSSLINE Project, RV Melville, cruise MV1313, UK-1 Stratum A, Clarion-Clipperton Zone, East Pacific , 23 October 2013, 13°40.786 N, 114°24.873 W, 4110 m, fixed in 96% ethanol.

Description. The second specimen collected by ROV Remora III was also in good condition ( Fig 3a ). The long, solid but broken stalk of the specimen is 150 mm long and 4 mm thick. The stalk merges to the upper body in a smooth transition. As an additional piece, the foot of the stalk was collected. It has a stamp-like shape and is very small in comparison to the upper body of the sponge. The white body measures 76 mm in diameter and is 4 mm thick. It resembles a leaf with an irregular edge and is slightly damaged. It is also easy to see the apertures of the canals, which penetrate the body of the sponge.

Megascleres of the dermal and gastral sides are choanosomal diactins and hexactins, hypodermal and hypoatrial pentactins, as well as dermal and atrial pinular hexactins, and pinular pentactins. There is no notable difference between the dermal and gastral side, except the size of the pinular spicules. Pentactins mainly have a long distal ray and shorter tangential rays. Larger hexactins and pentactins ( Figs 3b, f ) have prominent spines on the proximal half to third part of the ray. The remainder of the ray is smooth or sprinkled with small spines. The strong, stable rays get thinner to the distal end and taper to a sharp or parabolic tip. Smaller pentactins ( Fig 3c ) have comparatively small spines, but in larger numbers. Often the distal ray of pentactins is slightly curved. The pinular hexactins and pentactins ( Fig 3g ) are very abundant. The pinular rays have a tapered structure of distal pointed spines, but not as feathery and dense as the pinules of S. abysslineae sp. nov. ( Fig 2 ). They are more narrow and rough. The distal end is rounded or parabolic. All other rays of the pinular spicules are studded with small spines and have a sharp pointed tip. Measurements show that the pinular spicules of the gastral side are a little bigger than the ones on the dermal side (Tables 1.3, 1.4).

Microscleres are discohexasters and strobiloplumicomes. The abundant discohexasters ( Figs 3d, e ) have short smooth primary rays that split into four long-shafted secondary rays. They are significantly shorter than the ones of S. abysslineae sp. nov. ( Fig 2 ) and the numerous spines on the shaft appear to be more concentrated. The rays also terminate in flat curved star-shaped discs, but with 5–7 jags. Overall, they appear to be more compact. The strobiloplumicomes ( Fig 3h ) were difficult to locate and are quite rare. Similar to S. abysslineae sp. nov. ( Fig 2 ), they have six short smooth rays which terminate in a wreath with four rows of long, sigmoidal protruding hairs with tiny spines on the inner concave surface of their distal halves. Because of the small size of the spicules and due to their fragility, they are very difficult to isolate and document.

Remarks: This new species is very similar in spicular content to S. abysslineae sp. nov., but its pinules (of both hexactins and pentactins) are generally smaller. Furthermore, the large hexactins and pentactins have prominent spines on the proximal parts of the rays, whereas in S. abysslineae , these spicules are smooth to very slightly spined.

Derivatio nominis: The specimen is named after the Clarion-Clipperton Zone, the location where it was collected.

Figures

FIGURE 2. Sympagella abysslineae sp. nov. (SMF 12104) a. Shape of the body as observed in situ (13.5 cm). b. Large smooth hexactin (300 µm). c./d. Pinular hexactin (100 µm). e. Pinular pentactin (100 µm). f. Discohexaster (30 µm). g./h. Strobiloplumicome (10 µm). i. Specimen’s upper surface viewed from above (5 cm) (Photo provided by A. Glover, T. Dahlgren and H. Wiklund, Natural History Museum and Uni Research).

FIGURE 3. Sympagella clippertonae sp. nov. (SMF 12105) a. Shape of the body and stalk as observed in situ (20 cm). b. Large spiny pentactin (300 µm). c. Smaller pentactin with small spines (100 µm). d/e. Discohexaster (30 µm). f. Large spiny hexactin (center, surrounded by smaller spicules) (400 µm). g. Pinular pentactin (30 µm). h. Strobiloplumicome (10 µm).