Hyalonema

Tabachnick, Konstantin R. & Menschenina, Dorte Janussen And Larisa L., 2008, New Australian Hexactinellida (Porifera) with a revision of Euplectella aspergillum *, Zootaxa 1866 (1), pp. 7-68 : 28-33

Hyalonema . (Cyliconema) keiense Ijima, 1927 ( Fig. 11 ; Tab. 11).

Material. NTM Z 0002594 —sta. NWS­0052, off Rowley Shoals , Northwest Shelf , Scampi trawl Grounds, 17 o 28’S 118 o 53’E, depth 405 m. WAM 136­82 — RV Soela , sta. SO 4/82/8 C, N of Port Headland, 18 o 43’S 117 o 12’E, depth 368 m.

Description. Body: The specimen NTM Z 0002594 is a complete upper part of the body, cup­like, 70 mm high and oval in the upper part of the body 60x 100 mm; the atrial cavity is slightly depressed. The sieve­plate is similar to that of Hyalonema (Hyalonema) ; open meshes are assembled in groups separated by imperforate tracts). The other specimen is a fragment.

Spicules: The most important measurements are given in the Tab. 11. Choanosomal hexactins were found neither in our material nor in the holotype ( Ijima, 1927 wrote that their presence is uncertain). Unlike the holotype, many atrial pinular diactins were found in both new specimens; the pinular ray is conically pointed with few short spines. Some macramphidiscs in the specimen WAM 136­82 have sparsely spiny shafts. Unlike the holotype, small macramphidiscs were not observed in the investigated specimens.

Remarks. The primary description was made from a single representative, a poor fragment, likely from the dermal surface. Unlike the new Australian specimens, pinular diactins located among atrial spicules are entirely absent in the holotype. All the other spicules are very similar in size and shape, the only exception being the small macramphidiscs; amphidiscs of such size are entirely absent in both of the new specimens (see Tab. 11). Neither of these differences seems to be significant enough to consider the new specimens to be a new species nor to distinguish them as a new subspecies.

H. ( Oonema ) Lendenfeld, 1915

Hyalonema . ( Oonema ?) microstauractina Tabachnick and Levi, 2000 ( Fig. 12 , 13 ; Tab. 12)

Material. MNHN (p1088; fr865)—Cidaris I, RV Franklin, sta. 24­ 2, 17 o 19.58’ S 147 o 47.61’ E, depth 1187– 1200 m . MNHN (p8)—Cidaris I, RV Franklin, sta. 3­ 1, 18 o 8.22’ S 147 o 33.97’ E, depth 1044–1067 m .

Description. Body: The most complete specimen (p1088) has a conical body 45 mm high and oval in the upper part of the body 20x 40 mm, other specimen are fragments.

Spicules: The measurements of spicules are given in Tab. 12, their specific features are discussed below. Macramphidiscs are regular but abnormal forms with 4 teeth and with several umbels were found in MNHN (fr865).

Remarks. These specimens are very similar to H. ( Oonema ?) microstauractina described from relatively close to Australian regions, off New Caledonia, Wallis and Futuna Islands. The complete absence of spicules with spindle­like pinular ray and apical cone is not an outstanding feature because the construction of the pinular ray in dermal spicules varies in the type series: All pinular rays are conical without an apical cone as it is in the newly found Australian as well as in the type series: MNHN HCL 430; 434; 435. The abnormal amphidiscs in the form of staurodiscs and hexadiscs found sometimes in the ‘Australian’ specimens should be considered as an intraspecific variation, as known for other species of Hyalonema .

Chalaronema Ijima, 1927

Figures

FIGURE 11. Spicules of Hyalonema. (Cyliconema) keiense Ijima, 1927, WAM 136­82. A, dermal pinular pentactin. B, atrial pinular pentactin. C, atrial pinular diactin. D, hypodermal pentactin. E, choanosomal diactin. F, microhexactin. G, macramphidisc. H­J, mesamphidisc. K, micramphidisc.

FIGURE 12. Spicules of Hyalonema. (Oonema?) microstauractina Tabachnick & Lévi, 2000, MNHN(p1088). A, dermal pinular pentactin. B, atrial pinular pentactin. C, pinular diactin. D­E, abnormal macramphidiscs.

FIGURE 13. Hyalonema. (Oonema?) microstauractina Tabachnick & Lévi, 2000, A­D, MNHN(fr865). A, overview of spicules, scale 300 µm. B, macramphidisc, scale 30 µm. C, mesamphidisc, scale 30 µm. D, micramphidisc, scale 10 µm.