Hyalonema soelae, Tabachnick & Menschenina, 2008

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 : 14-18

Hyalonema ( Hyalonema ?) soelae sp. nov. ( Fig. 2 , Tab. 3)

Etymology. The species name refers to the RV Soela, from which the holotype was collected.

Material. Holotype: WAM 108­82 — RV Soela, SO 2/82/ 38, 18 o 22’–23’ S 117 o 56’ –54’E, depth 316– 309 m.

Description. Body: The holotype is conical without an atrial cavity, but with a well­recognizable sieveplate with meshes regularly distributed. Total length of the sponge body is 100 mm, the upper part is oval 40x 50 mm, basalia are broken. The sieve­plate net shows meshes of 1–2 mm diameter, the spaces between the meshes are very narrow, about 0.3 mm.

Spicules: Choanosomal spicules are diactins and ambuncinates. The diactins 0.4–10/ 0.01–0.25 mm have a widening in the middle, the biggest ones are stout. Ambuncinates measure 0.3–1.37/ 0.002–0.01 mm; they have a widening in the middle or four rudimental tubercles. Hypodermalia are pentactins with unpaired rays 0.3–0.7 mm long, tangential rays 0.24–0.62 mm long, their diameter is 0.019 –0.038 mm. Specific hypoatrialia as pentactins are mostly absent. Dermalia are pinular pentactins with pinular ray fine, gradually tapering towards the end. The pinular ray of dermal pentactins is 0.255 –0.581 mm long, tangential rays are 0.02–0.046 mm long, the rays are 0.005 –0.011 mm in diameter, the outer ends of tangential rays are rough and conically pointed. Atrialia are pinular pentactins with pinular rays similar to those of the dermal spicules. The pinular rays of atrial pentactins 0.099 –0.449 mm long, tangential rays 0.023 ­0.046 mm long, the rays are 0.005 –0.008 mm in diameter, the tangential rays are rough, conically pointed. Some probable canalaria are found: Pinular pentactins, rarely hexactins with pinular rays 0.061 –0.133 mm, rough tangential rays 0.02–0.082 mm, their diameter is about 0.005 mm.

Microscleres are two types of amphidiscs: Macramphidiscs and micramphidiscs. Total length of macramphidiscs is 0.357–0.52 mm, the umbel length 0.087 –0.148 mm, the umbel diameter 0.117 –0.158 mm; their shafts are densely tuberculated, sometimes it is possible to find a staurodisc of similar dimensions. The only mesamphidisc found in this specimen may be of allochthonic origin. Total length of mesamphidisc is 0.032

mm, the umbel length 0.016, the umbel diameter 0.012 mm. Total length of micramphidiscs is 0.011 –0.021 mm, the umbel length 0.003 –0.007 mm, the umbel diameter 0.003–0.06 mm; their shafts have a widening in the middle. Microhexactins or micropentactins seems to be absent in this species.

Remarks. The species is referred to as H. ( Hyalonema ) in spite of a different construction of the sieveplate. According to previous Hyalonema subgenera diagnoses in Ijima (1927) and Tabachnick and Menshenina (2002a), H. soelae should be referred to H. ( Coscinonema ), since when erected ( Ijima 1927) H. ( Coscinonema ) was considered to have ambuncinates (diagnosis and key to subgenera). As is clear now, no species in Ijima’s scope of the subgenus (including the type species) has ambuncinates. The only species with ambuncinates, H. (Coscinonema) polycoelum Levi and Levi, 1989 , was transferred to H. (Pteronema) due to its long spines in the pinular ray as well as some other characters ( Tabachnick and Menshenina 2002). Thus ‘ Coscinonema’ is a subgenus without ambuncinates. Species ‘soelae’ is referred to Hyalonema (Hyalonema) with some hesitations in order not to erect another new subgenus. The most notable difference of the new species from other representatives of the subgenus is the absence of a specific atrial sieve­plate, where areas with meshes are interrupted by imperforate tracts. The diagnosis of Hyalonema (Hyalonema) should be widened according to this specific feature of the new species.

Hyalonema . ( Corynonema ) Ijima, 1927

Hyalonema . ( Corynonema ?) intersubgenerica sp. nov. ( Fig. 3 , 4 ; Tab. 4)

Etymology. The name is given because of the diagnostic features of this species, which are in some respects intermediate between the subgenera Corynonema and Cyliconema .

Material. Holotype: MNHN (p1) Cidaris I, RV Franklin, sta. 27­ 2, 17 o 19.76’ S 147 o 28.05’ E, depth 1310–

1357 m.

Paratypes: MNHN (p2)—same as the holotype . MNHN (p27)— Cidaris I , RV Franklin, sta. 24­ 2, 17 o 19.58’ S 147 o 47.61’ E, depth 1187–1200 m . Other materials: MHNH (p541.1, p541.2)— Cidaris I, RV Franklin, sta. 31­ 1, 17 o 12.15’ S 147 o 10.80’ E, depth 1489–1491 m .

Description. Body: The holotype is conical with a slightly depressed atrial cavity and well­defined sieveplate. Total length of this sponge is 90 mm, the upper part is oval 30x 80 mm, basalia are remnants 150 mm long. Paratypes are similar to the holotype; they are 43–80 mm in length 25–60 mm in diameter. The sieveplates are nets with meshes 1–3 mm.

Spicules: Choanosomal spicules are diactins and hexactins. The diactins 0.5–1.5/ 0.006 –0.023 mm have a widening in the middle or occasionally 4 rudimental tubercles. Rays of hexactins are 0.18–0.65/ 0.015–0.03 mm. Hypodermalia are pentactins with tangential rays 0.14–0.6 mm long, proximal ray is 0.27–0.8 mm long, their diameters are 0.011–0.04 mm. Specific hypoatrial pentactins are likely to be absent. Dermalia are pinular pentactins with pinular ray spindle­like in overall shape, the rachis is stout. The pinular ray of dermal pentactins is 0.179–0.51 mm long, tangential rays are 0.02–0.082 mm long, the rays are about 0.01 mm in diameter, outer ends of tangential rays are rough or they have small spines and conically pointed outer ends. Atrialia are pinular pentactins and diactins. The pinular ray of atrial pentactins is 0.143 –0.357 mm long, tangential rays are 0.031 –0.071 mm long, all rays are about 0.01 mm in diameter but some spicules have pinular rays with a thickness up to 0.014 mm in the upper parts, the shape of such rays is clavate and they have a remarkable apical cone. The atrial pinular diactins have widenings or 4 rudimental tubercles in the middle. The pinular ray is spindle­like in shape or slightly clavate, length of the pinular ray is 0.153 –0.561 mm, the proximal ray is 0.219 –0.918 mm long, diameter of these rays is about 0.013 mm.

Microscleres are represented by three types of amphidiscs and a range of oxyoidal spicules. Total length of macramphidiscs is 0.174 –0.311 mm, the umbel length 0.036 –0.092 mm, the umbel diameter 0.041 –0.102 mm; their shafts are notably tuberculated. Total length of mesamphidiscs is 0.048 –0.151 mm, the umbel length 0.015 –0.074 mm, umbel diameter 0.015 –0.061 mm; their shafts are numerously spined or tuberculated, some mesamphidiscs are oval in shape – their umbels nearly meet at the equator. Abnormal macramphidiscs and mesamphidiscs with irregular umbels may be present. Total length of micramphidiscs is 0.015 –0.034 mm, the umbel length 0.004 –0.017 mm, the umbel diameter 0.005 –0.019 mm; their shafts have a widening or several spines in the middle. The oxyoidal microscleres are pentactins, stauractins, paratetractins and tauactins with rough rays 0.036 –0.092 mm long.

Remarks. The species ‘intersubgenerica’ is here attributed to the subgenus Corynonema with some hesitation. According to the construction of dermal pentactins it should be classified as Hyalonema (Cyliconema) , but representatives of the latter have no sieve­plates. Another feature peculiar to this species is the presence of atrial pentactins with clavate pinular ray and apical cone, which should be present as dermal spicules in Hyalonema (Corynonema) , while the atrial pentactins in this subgenus have previously been known to be similar in shape to the dermal pentactins in this new species. The diagnosis of the subgenus Corynonema should be accomplished by mentioning that its dermal and/or only atrial spicules may be the thickest at a distance from the base. One specific character unknown in formerly described representatives of both subgenera Corynonema and Cyliconema is the predominance of other than hexactin types of oxyoidal microscleres (from pentactins to tauactins).

H. ( Cyliconema ) Ijima, 1927

Figures

FIGURE 2. Hyalonema (Hyalonema?) soelae, sp. nov., spicules. A, dermal pinular pentactin. B, atrial pinular pentactin. C, canalar pinular pentactin. D, choanosomal diactin. E, ambuncinate. F, large choanosomal diactin. G, macramphidisc. H, micramphidisc. I, hypodermal pentacin. A­I, holotype.

FIGURE 3. Hyalonema (Corynonema) intermedia, sp. nov., spicules. A, dermal pinular pentactin. B, outer end of dermal pinular pentactin. C­D, atrial pinular pentactin. E, atrial pinular diactin. F, hypodermal pentactin. G, choanosomal hexactin. H, choanosomal diactin. I, micropentactin. J, microstauractin. K, microtauactin. L­M, macramphidiscs. N­P, mesamphidiscs. Q, micramphidisc. A­L; N­Q, holotype. M, MNHN(p2).

FIGURE 4. H. (Corynonema). intersubgenerica, sp. nov., holotype. A, body view from the side and from above, scale 20mm. B, dermal pinules, macramphidisc and mesamphidics, scale 100 µm.C, two mesamphidiscs, scale 30 µm.